MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Current Opinion in Plant Biology' source. Sun, 14 Mar 2010 16:02:55 +0100 http://www.medworm.com/index.php?rid=3336034&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20197238%26dopt%3DAbstract Authors: Møller BL Cyanogenic glucosides are present in many plants and their ability to liberate toxic HCN offers an immediate chemical defense response to herbivores and pathogens causing damage of the plant tissue. Countermeasures have evolved to overcome this type of defense and in some cases herbivores and pathogens are able to exploit the presence of cyanogenic glucosides to their own advantage. In plants, cyanogenic glucosides have gained additional functionalities as transporters of nitrogen and operation of an endogenous turnover pathway may enable plants to withdraw the nitrogen and glucose deposited in cyanogenic glucosides for use in primary metabolism. The aim of this review is to provide an overview of the new knowledge on these diverse functionalities of cyanogenic ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3336034 Sun, 28 Feb 2010 00:00:00 +0100 3336034 http://www.medworm.com/index.php?rid=3328040&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20188622%26dopt%3DAbstract Authors: Weber AP, von Caemmerer S Recent progress in genomics has provided complete or near complete genome sequences of several C(3) (e.g. Arabidopsis, rice, and poplar) and C(4) (e.g. sorghum and maize) plant species. These genome sequences enabled comparative quantitative proteomic and transcriptomic analyses of C(3) and C(4) plants, in particular of their chloroplasts. Such analyses have revealed a comprehensive picture of the distribution of C(4) pathway components between bundle sheath and mesophyll cell chloroplasts and they permitted the prediction of novel pathway components. A comprehensive understanding of the C(4) photosynthetic mechanism is required for the transfer of C(4)-like photosynthesis into C(3) crop plants, such as rice. PMID: 20188622 [PubMed - as supplied b... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3328040 Wed, 24 Feb 2010 00:00:00 +0100 3328040 http://www.medworm.com/index.php?rid=3315493&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20185358%26dopt%3DAbstract Authors: Maurino VG, Peterhansel C Photorespiration results from the oxygenase reaction catalysed by ribulose-1,5-bisphosphate carboxylase/oxygenase and serves as a carbon recovery system. It comprises enzymatic reactions distributed in chloroplasts, peroxisomes and mitochondria. The recent discovery of a cytosolic bypass and the requirement of complex formation between some photorespiratory proteins added additional levels of complexity to the known pathway. Photorespiration may have evolved in both, C(3) and C(4) plants, to prevent an accumulation of toxic levels of glycolate. Moreover, it is suggested that photorespiration evolved in cyanobacteria before the origin of chloroplasts. Synthetic detours, reminiscent of secondary photorespiratory pathways naturally occurring in cyanobact... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3315493 Tue, 23 Feb 2010 00:00:00 +0100 3315493 http://www.medworm.com/index.php?rid=3315492&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20185359%26dopt%3DAbstract Authors: Napier JA, Graham IA Plant neutral lipids such as seed oil triacylglycerols play a key role in many aspects of human life, ranging from providing essential nutrition to acting as biolubricants. There is also growing interest in using plant oils as a replacement for petrochemicals, either for fuel or as a chemical feedstock. Considerable effort has been focused on modifying the fatty acid composition of seed oils and/or increasing the levels of storage triacylglycerol. Certainly, it is now possible to successfully modify the profile of plant oils via transgenic metabolic engineering to generate something approaching a 'designer oil'. This is specifically true for the accumulation of omega-3 long chain polyunsaturated fatty acids that now stand at levels equivalent to those foun... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3315492 Tue, 23 Feb 2010 00:00:00 +0100 3315492 http://www.medworm.com/index.php?rid=3302858&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20171927%26dopt%3DAbstract Authors: Kötting O, Kossmann J, Zeeman SC, Lloyd JR Starch and sucrose are the primary products of photosynthesis in the leaves of most plants. Starch represents the major plant storage carbohydrate providing energy during the times of heterotrophic growth. Starch metabolism has been studied extensively, leading to a good knowledge of the numerous enzymes involved. In contrast, understanding of the regulation of starch metabolism is fragmentary. This review summarises briefly the known steps in starch metabolism, highlighting recent discoveries. We also focus on evidence for potential regulatory mechanisms of the enzymes involved. These mechanisms include allosteric regulation by metabolites, redox regulation, protein-protein interactions and reversible protein phosphorylation. Mo... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3302858 Thu, 18 Feb 2010 00:00:00 +0100 3302858 http://www.medworm.com/index.php?rid=3302859&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20171137%26dopt%3DAbstract Authors: Börnke F, Broer I Genetic engineering of plants for the production of novel polymers and platform chemicals can help to alleviate the demands for limited resources and potentially provide a platform to produce valuable compounds in bulk quantities. However, the success of transgenic plants as bioreactors depends on competitive high-yield production capacities. Recent advances in enhancing the production of novel compounds in transgenic plants include multigene transformation and the direction of biosynthetic pathways to specific intracellular compartments. It now appears feasible to produce interesting proteins such as spider silk or collagen, novel carbohydrates, and biopolymers that could replace petroleum-based plastics using transgenic plants. Direct production of nov... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3302859 Wed, 17 Feb 2010 00:00:00 +0100 3302859 http://www.medworm.com/index.php?rid=3291293&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20167531%26dopt%3DAbstract Authors: Glaszmann J, Kilian B, Upadhyaya H, Varshney R Vast germplasm collections are accessible but their use for crop improvement is limited-efficiently accessing genetic diversity is still a challenge. Molecular markers have clarified the structure of genetic diversity in a broad range of crops. Recent developments have made whole-genome surveys and gene-targeted surveys possible, shedding light on population dynamics and on the impact of selection during domestication. Thanks to this new precision, germplasm description has gained analytical power for resolving the genetic basis of trait variation and adaptation in crops such as major cereals, chickpea, grapevine, cacao, or banana. The challenge now is to finely characterize all the facets of plant behavior in carefully chosen mat... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3291293 Tue, 16 Feb 2010 00:00:00 +0100 3291293 http://www.medworm.com/index.php?rid=3276621&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20153244%26dopt%3DAbstract Authors: Ouyang Y, Liu YG, Zhang Q Hybrid sterility is the most common form of postzygotic reproductive isolation in plants. The best-known example is perhaps the hybrid sterility between indica and japonica subspecies of Asian cultivated rice (Oryza sativa L.). Major progress has been reported recently in rice in identifying and cloning hybrid sterility genes at two loci regulating female and male fertility, respectively. Genetic analyses and molecular characterization of these genes, together with the results from other model organisms especially Drosophila, have advanced the understanding of the processes underlying reproductive isolation and speciation. These findings also have significant implications for crop genetic improvement, by providing the feasibility and strategies for ov... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3276621 Wed, 10 Feb 2010 00:00:00 +0100 3276621 http://www.medworm.com/index.php?rid=3255000&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20137999%26dopt%3DAbstract Authors: van Eeuwijk FA, Bink MC, Chenu K, Chapman SC QTL mapping methods for complex traits are challenged by new developments in marker technology, phenotyping platforms, and breeding methods. In meeting these challenges, QTL mapping approaches will need to also acknowledge the central roles of QTL by environment interactions (QEI) and QTL by trait interactions in the expression of complex traits like yield. This paper presents an overview of mixed model QTL methodology that is suitable for many types of populations and that allows predictive modeling of QEI, both for environmental and developmental gradients. Attention is also given to multi-trait QTL models which are essential to interpret the genetic basis of trait correlations. Biophysical (crop growth) model simulations are prop... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3255000 Wed, 03 Feb 2010 00:00:00 +0100 3255000 http://www.medworm.com/index.php?rid=3219044&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20106715%26dopt%3DAbstract Authors: Ribaut JM, de Vicente M, Delannay X Molecular breeding (MB) holds great promise for developing countries. However, the developing countries are hardly homogeneous in its implementation. Whilst newly industrialised countries routinely use several MB applications and are exploring the latest approaches, developing countries with mid-level economies are testing marker applications and taking initial steps towards adopting MB in day-to-day breeding. Various bottlenecks still impede adoption in these countries. Limited human resources and inadequate field infrastructure remain major challenges, although through virtual platforms aided by the information and communication technology revolution, breeders now have better access to genomic resources, advanced laboratory services, and r... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3219044 Mon, 25 Jan 2010 00:00:00 +0100 3219044 http://www.medworm.com/index.php?rid=3212765&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20097596%26dopt%3DAbstract Authors: Tardieu F, Tuberosa R Plants have acquired a variety of whole-plant protection mechanisms in response to abiotic stresses, often at the expenses of performance. Hence, a given trait can have positive, negative or no effect depending on the stress scenario. A new approach has emerged that dissects yield and integrative traits that influence stress tolerance into heritable traits (e.g. sensitivity parameters or architectural traits) by using phenotyping platforms with model-assisted methods. The genetic and physiological mechanisms accounting for the variability of these traits and their effects on yield are considered in a second step. Effects of traits on yield are analysed via a combination of modelling and field experiments, which allows identification of the stress scenario... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3212765 Fri, 22 Jan 2010 00:00:00 +0100 3212765 http://www.medworm.com/index.php?rid=3212768&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20097118%26dopt%3DAbstract Authors: Kou Y, Wang S Although quantitative resistance loci provide partial and durable resistance to a range of pathogen species in different crops, the molecular mechanism of quantitative disease resistance has remained largely unknown. Recent advances in characterization of the genes contributing to quantitative disease resistance and plant-pathogen interactions at the molecular level provide clues to the molecular bases of broad-spectrum resistance and durable resistance. This emerging knowledge will help in identifying genes involved in quantitative broad-spectrum resistance and durable resistance leading to formulation of efficient ways for using these genetic resources for crop improvement. This knowledge is also turning quantitative resistance genes with minor effects into a p... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3212768 Thu, 21 Jan 2010 00:00:00 +0100 3212768 http://www.medworm.com/index.php?rid=3212767&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20097119%26dopt%3DAbstract Authors: Pauly M, Keegstra K The conversion of plant biomass into liquid transportation fuels is a complex process that could be simplified by altering the ratios of the cell wall polymers that constitute the main biomass components. The composition of biomass varies naturally depending upon plant species and cell type, including some highly specialized walls that consist mainly of a single component. Progress is being made in understanding the molecular basis of these natural variations in wall composition. This new knowledge will be a valuable resource that can be used during efforts to generate designer biofuel crops using either selected breeding methods or recombinant DNA techniques. PMID: 20097119 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3212767 Thu, 21 Jan 2010 00:00:00 +0100 3212767 http://www.medworm.com/index.php?rid=3212766&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20097120%26dopt%3DAbstract Authors: Schulze WX Signaling pathways in all organisms consist of series of phosphorylation and dephosphorylation events that define directionality and allow different levels of feedback-regulation. Mass spectrometry-based proteomic analyses in recent years have led to a proteome-wide identification of thousands of phosphorylation sites in various plant species. Given this magnitude of mostly qualitative information about protein phosphorylation, discovery of specific phosphoproteins with regulatory functions represents a major challenge. In future large-scale experiments, combinations of data-driven modeling strategies based on quantitative data, targeted kinase-substrate screens, and verification in biochemical and genetic experiments are required to specifically spot phosphorylatio... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3212766 Thu, 21 Jan 2010 00:00:00 +0100 3212766 http://www.medworm.com/index.php?rid=3200966&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20093067%26dopt%3DAbstract Authors: Krouk G, Crawford NM, Coruzzi GM, Tsay YF Nitrate (NO(3)(-)) is a key nutrient as well as a signaling molecule that impacts both metabolism and development of plants. Understanding the complexity of the regulatory networks that control nitrate uptake, metabolism, and associated responses has the potential to provide solutions that address the major issues of nitrate pollution and toxicity that threaten agricultural and ecological sustainability and human health. Recently, major advances have been made in cataloguing the nitrate transcriptome and in identifying key components that mediate nitrate signaling. In this perspective, we describe the genes involved in nitrate regulation and how they influence nitrate transport and assimilation, and we discuss the role of systems biolo... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3200966 Tue, 19 Jan 2010 00:00:00 +0100 3200966 http://www.medworm.com/index.php?rid=3200967&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20089441%26dopt%3DAbstract Authors: Rafalski JA Increased availability of high throughput genotyping technology together with advances in DNA sequencing and in the development of statistical methodology appropriate for genome-wide association scan mapping in presence of considerable population structure contributed to the increased interest association mapping in plants. While most published studies in crop species are candidate gene-based, genome-wide studies are on the increase. New types of populations providing for increased resolution and power of detection of modest-size effects and for the analysis of epistatic interactions have been developed. Classical biparental mapping remains the method of choice for mapping the effects of alleles rare in germplasm collections, such as some disease resistance genes o... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3200967 Mon, 18 Jan 2010 00:00:00 +0100 3200967 http://www.medworm.com/index.php?rid=3186238&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20080055%26dopt%3DAbstract Authors: Urano K, Kurihara Y, Seki M, Shinozaki K Plants must respond and adapt to abiotic stresses to survive in various environmental conditions. Plants have acquired various stress tolerance mechanisms, which are different processes involving physiological and biochemical changes that result in adaptive or morphological changes. Recent advances in genome-wide analyses have revealed complex regulatory networks that control global gene expression, protein modification, and metabolite composition. Genetic regulation and epigenetic regulation, including changes in nucleosome distribution, histone modification, DNA methylation, and npcRNAs (non-protein-coding RNA) play important roles in abiotic stress gene networks. Transcriptomics, metabolomics, bioinformatics, and high-through-put DNA... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3186238 Thu, 14 Jan 2010 00:00:00 +0100 3186238 http://www.medworm.com/index.php?rid=3177469&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20071214%26dopt%3DAbstract Authors: Sato S, Isobe S, Tabata S The genome sequencing of two model legumes and soybean (Glycine max) is near completion. In addition, genomic information, such as ESTs, genomic sequences, and DNA markers has been intensively collected from a variety of crop legumes using new genomic technologies. The accumulating information provides an opportunity to perform comparative analyses to decipher the evolutionary process of genomic structures and functions in leguminous plants. Furthermore, it can serve as a basis to exchange knowledge among the model and crop legumes, which, when combined with the new experimental techniques developed in the model legumes, will not only facilitate an understanding of the basic genetic systems in crop legumes, but also accelerate the breeding process. ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3177469 Mon, 11 Jan 2010 00:00:00 +0100 3177469 http://www.medworm.com/index.php?rid=3172276&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20064738%26dopt%3DAbstract Authors: Devos KM The genomes of five species belonging to the grass family have been fully sequenced and provide insight into the structural organization and evolution of grass genomes. Comparative analyses have shown that genes and repeats are organized differently in small genomes compared to large genomes. Small genomes show a clear partitioning between gene-rich euchromatic and gene-poor pericentromeric regions. This is far less the case in larger genomes because many repeats are also interspersed between single genes or small gene islands. This organizational pattern may enhance erosion of colinearity because of the inherent mutagenic effects of transposable elements. Factors contributing to genome diversification, which is not constant in either space or time, are rapid turnover... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3172276 Sat, 09 Jan 2010 00:00:00 +0100 3172276 http://www.medworm.com/index.php?rid=3146736&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20047852%26dopt%3DAbstract Authors: Bergmann DC, Fleming AJ PMID: 20047852 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3146736 Sat, 02 Jan 2010 00:00:00 +0100 3146736 http://www.medworm.com/index.php?rid=3129979&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20036612%26dopt%3DAbstract Authors: Moreno-Risueno MA, Busch W, Benfey PN Many genomic-scale datasets in plants have been generated over the last few years. This substantial achievement has led to impressive progress, including some of the most detailed molecular maps in any multicellular organism. Networks and pathways have been reconstructed using transcriptome, genome-wide transcription factor binding, proteome and metabolome data, and subsequently used to infer functional interactions among genes, proteins, and metabolites. However, more sophisticated systems biology approaches are needed to integrate different omics datasets. Ultimately, the integration of diverse and massive datasets into coherent models will improve our understanding of the molecular networks that underlie biological processes. PMID: ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3129979 Thu, 24 Dec 2009 00:00:00 +0100 3129979 http://www.medworm.com/index.php?rid=3122552&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20031477%26dopt%3DAbstract Authors: Jackson S, Chen ZJ Polyploidy or whole genome duplication (WGD) occurs throughout the evolutionary history of many plants and some animals, including crops such as wheat, cotton, and sugarcane. Recent studies have documented rapid and dynamic changes in genomic structure and gene expression in plant polyploids, which reflects genomic and functional plasticity of duplicate genes and genomes in plants. Common features of uniparental gene regulation and nonadditive gene expression in regulatory pathways responsive to growth, development, and stresses in many polyploids have led to the conclusion that epigenetic mechanisms including chromatin modifications and small RNAs play central roles in shaping molecular and phenotypic novelty that may be selected and domesticated in many po... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3122552 Mon, 21 Dec 2009 00:00:00 +0100 3122552 http://www.medworm.com/index.php?rid=3105452&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20004136%26dopt%3DAbstract Authors: Tang W, Deng Z, Wang ZY Large numbers of receptor-like kinases (RLKs) play key roles in plant development and defense by perceiving extracellular signals. The mechanisms of ligand-induced kinase activation and downstream signal transduction have been studied for only a few RLK pathways, among which the brassinosteroid (BR) pathway is the best characterized. Recently, proteomics studies identified new components that bridge the last gap in the genetically defined BR-signaling pathway, establishing the first complete pathway from an RLK to transcription factors in plants. Furthermore, analyses of phosphorylation events, mostly by mass spectrometry, provided insights into the mechanistic details of receptor kinase activation and regulation of downstream components by phosphorylat... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3105452 Mon, 07 Dec 2009 00:00:00 +0100 3105452 http://www.medworm.com/index.php?rid=3065998&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19963429%26dopt%3DAbstract Authors: Harashima H, Schnittger A The development of a multicellular organism such as a flowering plant relies on the patterned control of cell proliferation, differentiation, and growth. Research in the recent years has revealed that the control of cell-cycle progression and growth in plants is distinct from the regulation found in yeast or metazoans. Understanding these plant-specific regulators and networks, in which they act, is key for the understanding of plant development and is of current global importance as a basis for breeding of energy crops as well as the breeding of plants adapted for changing environmental conditions. However, the production of cells and their specification and differentiation overlap in time and space and build an intricate interrelationship of depende... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3065998 Fri, 04 Dec 2009 00:00:00 +0100 3065998 http://www.medworm.com/index.php?rid=3048992&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944637%26dopt%3DAbstract Authors: Tang H, Sezen U, Paterson AH The techniques of plant improvement have been evolving with the advancement of technology, progressing from crop domestication by Neolithic humans to scientific plant breeding, and now including DNA-based genotyping and genetic engineering. Archeological findings have shown that early human ancestors often unintentionally selected for and finally fixed a few major domestication traits over time. Recent advancement of molecular and genomic tools has enabled scientists to pinpoint changes to specific chromosomal regions and genetic loci that are responsible for dramatic morphological and other transitions that distinguish crops from their wild progenitors. Extensive studies in a multitude of additional crop species, facilitated by rapid progress in s... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3048992 Wed, 25 Nov 2009 00:00:00 +0100 3048992 http://www.medworm.com/index.php?rid=3036433&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19942473%26dopt%3DAbstract Authors: Kieffer M, Neve J, Kepinski S The apparent domination of so much of plant development by the hormone auxin raises important questions about how this simple, generic signalling molecule can give rise to such an enormous range of very specific developmental outputs. What is becoming increasingly clear is that alongside the tight control of auxin distribution within the plant, the cellular and developmental context in which the auxin signal is received is of utmost importance. Recent work has highlighted that these distinct auxin response contexts are defined by complex and inter-dependent relationships between auxin metabolism, transport and response that can be modulated at many levels by inputs from both endogenous and environmental signals. PMID: 19942473 [PubMed - as sup... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3036433 Tue, 24 Nov 2009 00:00:00 +0100 3036433 http://www.medworm.com/index.php?rid=3019378&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19926333%26dopt%3DAbstract Authors: Schumacher K, Friml J PMID: 19926333 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3019378 Tue, 17 Nov 2009 00:00:00 +0100 3019378 http://www.medworm.com/index.php?rid=3000597&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19914858%26dopt%3DAbstract Authors: Szymanski DB The slow and irreversible changes in plant cell shape include the cytoplasmic control of cell wall yielding in response to turgor pressure and the genesis of intracellular trafficking routes to the cell cortex. However, we lack a clear understanding of how interactions between cytoskeletal arrays and endomembrane compartments influence the physical properties of the cell wall. Recent forward and chemical genetic screens and sophisticated imaging analyses are revealing novel intracellular compartments and cytoskeleton interactions that impact the patterns of cellulose synthesis at the plasma membrane. These baseline data on the growth behavior of cylindrical cells provide a useful framework to better understand cell type specific strategies to generate complex shap... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3000597 Fri, 13 Nov 2009 00:00:00 +0100 3000597 http://www.medworm.com/index.php?rid=3000598&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19914123%26dopt%3DAbstract Authors: Uyttewaal M, Traas J, Hamant O Linking the gene regulatory network to morphogenesis is a central question in developmental biology. Shape relies on the combined actions of biochemistry and biophysics, two parameters that are under local genetic control. The blooming of molecular biology since the 1970s has promoted a biochemical view of development, leaving behind the contribution of physical forces. Recently, the development of new techniques, such as live imaging, micromechanical approaches, and computer modeling, has revitalized the biomechanics field. In this review, we use shoot apical meristem development to illustrate how biochemistry and biomechanics cooperate to integrate the local cellular gene input into global growth patterns. PMID: 19914123 [PubMed - as suppli... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3000598 Thu, 12 Nov 2009 00:00:00 +0100 3000598 http://www.medworm.com/index.php?rid=3000599&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19913454%26dopt%3DAbstract Authors: Beveridge CA, Kyozuka J Shoot branching is controlled by the formation and subsequent outgrowth of axillary buds in the axils of leaves. Axillary buds are indeterminate structures that can be arrested and await endogenous or environmental cues for outgrowth. A major breakthrough in this area of plant development has been the discovery that a specific group of terpenoid lactones, named strigolactones, can directly or indirectly, inhibit axillary bud outgrowth. Since that discovery, new branching mutants have been identified with reduced strigolactone levels or which are defective in strigolactone regulation or response. DWARF27 and DWARF14 probably act on strigolactone biosynthesis and strigolactone metabolism or signal transduction, respectively. Auxin signaling mutants have a... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3000599 Wed, 11 Nov 2009 00:00:00 +0100 3000599 http://www.medworm.com/index.php?rid=3000600&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19910239%26dopt%3DAbstract Authors: Jönsson H, Krupinski P Plants continue to grow and generate new organs in symmetric patterns throughout their lives. This development requires an interconnected regulation of genes, hormones, and anisotropic growth, which in part is guided by environmental cues. Recently, several studies have used a combination of experiments and mathematical modeling to elucidate the mechanisms behind different growth and molecular patterns in plants. The computational models were used to investigate the often non-intuitive consequences of different hypotheses, and the in silico simulations of the models inspired further experimentation. PMID: 19910239 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3000600 Tue, 10 Nov 2009 00:00:00 +0100 3000600 http://www.medworm.com/index.php?rid=2985178&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19897405%26dopt%3DAbstract Authors: Boyce CK Contrary to what might be expected from the observation of extant plants alone, the fossil record indicates that most aspects of vascular plant form evolved multiple times during their Paleozoic radiation. Opportunity is increasing to unite information from fossil and living plants to understand the evolution of developmental mechanisms and each field can provide tests for hypotheses derived from the other. The paleontological context to recent advances in developmental genetics is reviewed for the evolution of a functionally independent sporophyte generation, of leaves, and of roots-all of which are integral to understanding the explosive radiation of vascular plants during the Devonian, 400 million years ago. PMID: 19897405 [PubMed - as supplied by publisher] (S... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2985178 Fri, 06 Nov 2009 00:00:00 +0100 2985178 http://www.medworm.com/index.php?rid=2985179&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19896414%26dopt%3DAbstract Authors: Dresselhaus T, Márton ML After the first description of fertilization in flowering plants some 125 years ago (Strasburger E: Neue-Untersuchungen über den Befruchtungsvorgang bei den Phanerogamen als Grundlage für eine Theorie der Zeugung. Gustav Fischer; 1884), we are finally beginning to understand the various molecular mechanisms leading to sperm delivery and discharge inside the hidden micropylar region of the female gametophyte (embryo sac). The last phase of pollen tube guidance culminating in tube burst and explosive release of tube contents requires extensive crosstalk between both male and female gametophytes. The first molecules identified that play key roles in these processes represent highly polymorphic proteins, similar to major components of the pl... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2985179 Wed, 04 Nov 2009 00:00:00 +0100 2985179 http://www.medworm.com/index.php?rid=2951358&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19875325%26dopt%3DAbstract Authors: Meier I, Brkljacic J The nuclear envelope (NE) and the nuclear pores are important structures that both separate and selectively connect the nucleoplasm and the cytoplasm. NE and nuclear pore research in plants have recently seen an elevated level of interest. This is based both on new findings demonstrating the importance of nucleocytoplasmic trafficking for several signal transduction events, and on increasing evidence that NE and nuclear pore components play important roles during plant cell division. Here, we review the most recent reports in the field and compare them to the more advanced knowledge about yeast and animal model systems. They deal with the refined ultrastructure of the NE and NPC, with the discovery of novel NE components, and, importantly, with novel roles... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2951358 Tue, 27 Oct 2009 00:00:00 +0100 2951358 http://www.medworm.com/index.php?rid=2951359&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19864175%26dopt%3DAbstract Authors: Kunst L, Samuels L The plant cuticle is an extracellular lipid structure deposited over the aerial surfaces of land plants, which seals the shoot and protects it from biotic and abiotic stresses. It is composed of cutin polymer matrix and waxes, produced and secreted by epidermal cells. The use of forward and reverse genetic approaches in Arabidopsis has led to the identification of enzymes involved in fatty acid elongation and biosynthesis of wax components, as well as transporters required for lipid delivery to the cuticle. However, major questions concerning alkane formation, intracellular and extracellular wax transport, regulation of wax deposition, and assembly of cuticular components into a functional cuticle remain to be resolved. PMID: 19864175 [PubMed - as suppli... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2951359 Mon, 26 Oct 2009 00:00:00 +0100 2951359 http://www.medworm.com/index.php?rid=2935298&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19857986%26dopt%3DAbstract Authors: Mikosch M, Homann U The function of cells is strongly affected by the type and number of ion channels in the plasma membrane. Recent investigations have highlighted the complexity of the regulation of ion channel trafficking and uncovered several trafficking determinants including diacidic ER export motifs that influence surface expression of ion channels. The large number of ion channels for which functional diacidic motifs have already been identified underlines their general importance and has led to increasing research into the molecular function of these motifs. This review will summarize recent progress in identifying the molecular basis for recognition of ER export signals and the physiological relevance of regulated ER export of ion channels and its role in targeting o... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2935298 Sat, 24 Oct 2009 00:00:00 +0100 2935298 http://www.medworm.com/index.php?rid=2935297&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19857987%26dopt%3DAbstract Authors: Sultan SE Evolutionary ecology and developmental biology have converged on the key insight that phenotypic expression is powerfully conditioned by environmental information. Plant ecological development (eco-devo) aims to firstly, determine precisely how plants perceive and respond to the varying environmental conditions they encounter in the real world and secondly, understand the ecological and evolutionary consequences of environmentally mediated phenotypic outcomes. This full explanatory scope, from molecular interactions to natural populations and communities, is just now being realized for two adaptively important aspects of developmental response: shade avoidance and flood tolerance. These and other new findings point to the complex, interactive nature of both environme... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2935297 Sat, 24 Oct 2009 00:00:00 +0100 2935297 http://www.medworm.com/index.php?rid=2935302&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19853496%26dopt%3DAbstract Authors: Blein T, Hasson A, Laufs P Formation of dissected compound leaves involves the transient maintenance of an indeterminate environment and the generation of new growth axes that will generate leaflets. Recent work has revealed additional multi-layered mechanisms controlling the activities of the KNOXI homeodomains factors that play a prominent role in the control of indeterminacy associated with compound leaf development. Patterning and individualisation of the leaflets has been shown to involve gradients of the phytohormone auxin and the contribution of the NAM/CUC3 boundary genes. Identification of these novel actors governing compound leaf development opens the opportunity for further comparative studies aimed at understanding the molecular basis of leaf shape evolution. ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2935302 Thu, 22 Oct 2009 00:00:00 +0100 2935302 http://www.medworm.com/index.php?rid=2935300&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19854097%26dopt%3DAbstract Authors: Petrášek J, Schwarzerová K Plant cytoskeleton consists of two major networks of protein polymers, actin microfilaments (AFs) and microtubules (MTs). These networks perform numerous functions that are essential for cell division and for maintaining the integrity of cytoplasm required for intracellular transport and cell shape. Besides the more or less indirect cooperation between AFs and MTs, their direct interactions through specific physically interacting proteins has been well described in yeast, nematodes, insect and animal cells. Recently, promising candidates for corresponding homologous proteins have been identified in plants, although there is still lack of functional evidence for these interactions. Here we summarize recent advances in our knowledge abo... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2935300 Thu, 22 Oct 2009 00:00:00 +0100 2935300 http://www.medworm.com/index.php?rid=2935299&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19854098%26dopt%3DAbstract Authors: Hwang I, Robinson DG In protein trafficking, transport vesicles bud from donor compartments and carry cargo proteins to target compartments with which they fuse. Thus, vesicle formation is an essential step in protein trafficking. As for mammals, plant cells contain the three major types of vesicles: COPI, COPII, and CCV and the major molecular players in vesicle-mediated protein transport are also present. However, plant cells generally contain more isoforms of the coat proteins, ARF GTPases and their regulatory proteins, as well as SNAREs. In addition, plants have established some unique subfamilies, which may reflect plant cell-specific conditions such as the absence of an ER-Golgi intermediate compartment and the combined activities of the TGN and early endosome. Thus, eve... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2935299 Thu, 22 Oct 2009 00:00:00 +0100 2935299 http://www.medworm.com/index.php?rid=2935301&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19853497%26dopt%3DAbstract Authors: Rudall PJ Understanding floral patterning is a primary goal in plant biology, yet the temporal sequence of organ development is rarely factored into developmental models. In flowers, occasional examples of centrifugal or basipetal organ initiation, both within organ zones (intrazonal) and between them (interzonal), present a paradox with respect to developmental models. A centripetal/acropetal sequence of floral organ initiation is ancestral in angiosperms, but centrifugal/basipetal development has evolved many times, indicating that these apparently major developmental shifts have relatively simple genetic triggers. Review of the sequence of organ initiation in angiosperms supports evidence that the four floral organ types develop independently of each other, in response to g... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2935301 Wed, 21 Oct 2009 00:00:00 +0100 2935301 http://www.medworm.com/index.php?rid=2923993&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19850508%26dopt%3DAbstract Authors: Van Damme D Division plane determination in plant cells involves the transformation of the cortical microtubular array into a preprophase band (PPB) with the nucleus anchored at the center. This likely occurs through polarity cues controlling proteins affecting cytoskeletal dynamics. Crosstalk with cell cycle machinery should assure that this happens in concert with cell cycle progression. Before PPB breakdown, targeted deposition of factors at the position of the PPB translates this position into a signal which remains present throughout cytokinesis and directs the centrifugal growing cell plate to the correct cortical position. Anchoring and maturation of the cell plate ultimately divides the two daughter cells. This review aims to provide an up-to-date overview of the mecha... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2923993 Tue, 20 Oct 2009 00:00:00 +0100 2923993 http://www.medworm.com/index.php?rid=2923992&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19850509%26dopt%3DAbstract Authors: Irani NG, Russinova E The emerging complexity of plant endocytic systems puts it on a par with their animal counterparts, reflecting an essential role in signal transduction. The endocytic machinery regulates the space and the time of signal transduction and processing in the cell. Plants possess numerous cell surface receptor-like kinases (RLKs) (more than 600 members in Arabidopsis thaliana and 1100 in rice), a trend attributed to their indeterminate mode of growth, the absence of cell migration, and the need for adaptation towards the environment. Thus, plants would require a robust and highly plastic endocytic system in order to integrate multiple signaling cues from neighboring cells as well as the environment. Although a comprehensive understanding of how plant endocytos... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2923992 Tue, 20 Oct 2009 00:00:00 +0100 2923992 http://www.medworm.com/index.php?rid=2923991&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19850510%26dopt%3DAbstract Authors: Perilli S, Moubayidin L, Sabatini S Cytokinins are a class of phytohormones that regulate a wide variety of physiological and developmental processes such as shoot and root growth. Cytokinin signaling relies on a phosphorelay mechanism similar to the prokaryotic two-component system. Although the principal components mediating this cascade have been identified, only recently have we begun to understand the molecular basis of cytokinin action. For example cytokinins control cell differentiation rate during root meristem development by suppressing both auxin signaling and transport, whereas at early stages of embryo development auxin counteracts cytokinin signaling to establish the embryonic root stem-cell niche. The antagonistic interaction between cytokinins and auxin seems to... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2923991 Tue, 20 Oct 2009 00:00:00 +0100 2923991 http://www.medworm.com/index.php?rid=2923994&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19846334%26dopt%3DAbstract Authors: Boutté Y, Grebe M Sterols are lipophilic membrane components essential for diverse cellular functions. The plant sterol biosynthesis pathway has largely been defined by biochemical approaches. Sterol function has been investigated by the pharmacological and genetic manipulation of sterol biosynthesis. However, mechanisms by which sterols influence cellular processes and targets of sterol function remain largely unknown. During the last two years, new Arabidopsis sterol biosynthesis mutants have been characterized. Their analysis has revealed the contributions of known and alternative routes of sterol biosynthesis to various cellular processes. Subcellular localization and trafficking of a sterol-binding protein have been investigated and first steps towards in vivo charac... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2923994 Mon, 19 Oct 2009 00:00:00 +0100 2923994 http://www.medworm.com/index.php?rid=2909754&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19836992%26dopt%3DAbstract Authors: Schellmann S, Pimpl P Endosomes are hubs of endomembrane trafficking. They integrate vesicular traffic from different sources such as the plasma membrane or the Golgi apparatus and sort cargo to different destinations such as the vacuole, the plasma membrane or back to the Golgi apparatus. As endomembrane trafficking is largely via transport vesicles, endosomes employ different adaptor proteins and coats to accommodate their multiple functions. Retromer and ESCRT are coat/adapter combinations that are crucial for endosomal trafficking pathways. Retromer mediates recycling of sorting receptors back to the Golgi apparatus, ESCRT is needed for sorting of transmembrane cargo to the vacuole. While both are well-studied in yeast and animals, knowledge about their plant counterparts ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2909754 Wed, 14 Oct 2009 23:00:00 +0100 2909754 http://www.medworm.com/index.php?rid=2909753&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19836993%26dopt%3DAbstract Authors: Stahl Y, Simon R Primary plant meristems are the shoot and root meristems that are initiated at opposite poles of the plant embryo. They contain stem cells, which remain undifferentiated, and supply new cells for growth and the formation of tissues. The maintenance of a long-lasting stem cell population in meristems is achieved by signal exchange between organizing regions and the stem cells, and also by feedback signals emanating from differentiating cells. Related peptide signals that make use of different receptor classes were found to control the stem cell populations in both meristem types by regulating evolutionarily conserved homeodomain transcription factors. The precise interplay of auxin and cytokinin signaling pathways is central to keep cells in the meristem, or di... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2909753 Wed, 14 Oct 2009 23:00:00 +0100 2909753 http://www.medworm.com/index.php?rid=2909756&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19836293%26dopt%3DAbstract Authors: Fuji K, Miwa K, Fujiwara T For mineral nutrients to be used by plants, they must be taken up from soil solutions into root cells and then transported to shoots. Mineral nutrient transporters play a central role in this process, and their expression and accumulation are known to be strictly regulated in response to change in nutrient conditions. Roots are cylindrically shaped organs with various types of cells. For the nutrients to move from soil solution toward the xylem they have to be transported across various types of cells. Nutrient condition-dependent accumulation and polar distributions of transporters in plant cells are established by membrane trafficking systems. The present article provides an overview of current findings regarding the membrane trafficking of mineral... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2909756 Tue, 13 Oct 2009 23:00:00 +0100 2909756 http://www.medworm.com/index.php?rid=2909755&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19836294%26dopt%3DAbstract Authors: Imaizumi T Plants possess a circadian clock that enables them to coordinate internal biological events with external daily changes. Recent studies in Arabidopsis revealed that tissue-specific clock components exist and that the clock network architecture also varies within different organs. These findings indicate that the makeup of circadian clock(s) within a plant is quite variable. Plants utilize the circadian clock to measure day-length changes for regulating seasonal responses, such as flowering. To ensure that flowering occurs under optimum conditions, the clock regulates diurnal CONSTANS (CO) expression. Subsequently, CO protein induces FLOWERING LOCUS T (FT) expression which leads to flowering. It is emerging that both CO and FT expression are intricately controlled by... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2909755 Tue, 13 Oct 2009 23:00:00 +0100 2909755 http://www.medworm.com/index.php?rid=2858306&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19796984%26dopt%3DAbstract Authors: Sorek N, Bloch D, Yalovsky S Classically perceived as means for recruiting proteins to the membranes, protein lipid modifications are known today to play diverse roles in subcellular targeting, protein-protein interactions and signaling. This review focuses on three protein lipid modifications: prenylation, S-acylation and N-myristoylation and attempts to provide an up-to-date view of their function by focusing on several model proteins. PMID: 19796984 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2858306 Mon, 28 Sep 2009 23:00:00 +0100 2858306 http://www.medworm.com/index.php?rid=2858305&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19796985%26dopt%3DAbstract Authors: Chuck G, O'Connor D Small RNAs are 19-27 nucleotide long RNAs that negatively regulate gene expression and function as important regulators of diverse aspects of plant development. Current models for how they function continue to be modified as new research uncovers additional aspects of their biology. Unexpectedly, several previously characterized small RNAs appear to function non-cell autonomously, some moving a few cells away, others moving throughout the plant. This fact may reflect that small RNAs are an essential component of a larger signaling network that orchestrates plant development. PMID: 19796985 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2858305 Mon, 28 Sep 2009 23:00:00 +0100 2858305 http://www.medworm.com/index.php?rid=2847131&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19783198%26dopt%3DAbstract Authors: Monshausen GB, Gilroy S Because of their sessile lifestyle, the areas which plants can access to forage for resources are confined to those which can be explored by growth. High sensitivity to environmental conditions coupled to the appropriate readjustment of growth and developmental responses are thus critical to plant survival. In this review, we focus on how roots perceive physical cues such as soil water status and mechanical properties and translate them into physiological signals to redirect organ growth and modulate root system architecture. Because the precise molecular identity of most of the sensors used by the root to sample the soil environment remain to be determined, the mechanisms underlying similar processes in microbes are providing important models for how t... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2847131 Thu, 24 Sep 2009 23:00:00 +0100 2847131 http://www.medworm.com/index.php?rid=2847130&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19783199%26dopt%3DAbstract Authors: Lehesranta SJ, Lichtenberger R, Helariutta Y The plant vascular system consists of two conductive cell types, xylem and phloem, which are both produced by procambial cells. Recently, several novel regulatory mechanisms that control the specification of vascular patterning and differentiation have been uncovered. The non-cell-autonomous TDIF/CLE signalling mediates phloem-xylem cross-talk and cambial maintenance; a flowering-related long-distance signal governs secondary development; and novel genetic players such as LHW regulate vascular morphogenesis. A future challenge is to conflate data on the various genetic, hormonal and other factors to understand the networks underlying vascular tissue formation. PMID: 19783199 [PubMed - as supplied by publisher] (Source: Current O... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2847130 Thu, 24 Sep 2009 23:00:00 +0100 2847130 http://www.medworm.com/index.php?rid=2847129&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19783200%26dopt%3DAbstract Authors: Maurel C, Santoni V, Luu DT, Wudick MM, Verdoucq L Aquaporins are channel proteins that facilitate the transport of water and small neutral molecules, including gases, across cell membranes of most of the living organisms. Integrative studies have stressed the role of aquaporins in maintaining the whole plant water and nutrient status. Cellular aspects of plant aquaporin functions and regulations are also extensively investigated. The present review provides a glance at recent progresses in this area. One first direction concerns the mechanisms that determine aquaporin targeting to specific subcellular membranes and a dynamic and stimulus-dependent control of their density in these membranes. The regulation of aquaporin opening and closing and its links to cell signalling casc... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2847129 Thu, 24 Sep 2009 23:00:00 +0100 2847129 http://www.medworm.com/index.php?rid=2847132&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19781980%26dopt%3DAbstract Authors: Casson SA, Hetherington AM Stomata are microscopic structures in the epidermis of the aerial parts of flowering plants formed by two specialized guard cells flanking a central pore. The role of stomata is to optimize gas exchange (the uptake of carbon dioxide and the loss of water vapor) to suit the prevailing environmental conditions. To do this plants open and close the stomatal pores and regulates the number of stomata that develop on the epidermes. Both these responses are controlled by integrating information from environmental cues and hormonal signals. Recent work has resulted in significant advances in our understanding of the underlying pathway controlling stomatal development. Here we shall discuss how environmental cues might modulate this pathway such that gas exch... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2847132 Tue, 22 Sep 2009 23:00:00 +0100 2847132 http://www.medworm.com/index.php?rid=2847128&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19783467%26dopt%3DAbstract Authors: Lohmann JU, Nemhauser JL PMID: 19783467 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2847128 Mon, 21 Sep 2009 23:00:00 +0100 2847128 http://www.medworm.com/index.php?rid=2847127&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19783468%26dopt%3DAbstract Authors: Zouhar J, Rojo E Genetic and technical advances of the past few years have allowed us to test some of the vacuolar trafficking and vacuole biogenesis models that had been previously proposed mainly on the basis of morphological and immunolocalization studies. We have now tools to start answering some fundamental questions such as: How are vacuoles formed? Are all vacuoles formed similarly? Do different types of vacuoles coexist in a cell? How are proteins sorted to the vacuole? How many trafficking pathways to vacuoles exist? Can there be trafficking to two types of vacuoles simultaneously? Last but not least, how do vacuoles balance the continuous flow of new materials, cargo and membrane, and maintain their volume? We will review recent data trying to answer these questions ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2847127 Mon, 21 Sep 2009 23:00:00 +0100 2847127 http://www.medworm.com/index.php?rid=2847126&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19783469%26dopt%3DAbstract Authors: Pesch M, Hülskamp M Trichome patterning in Arabidopsis rosette leaves serves as a model system to study how individual cells are determined in a regular spacing pattern from initially equivalent cells. A conserved gene cassette regulates this spacing pattern. bHLH, MYB, and WD40 factors are positive regulators of trichome development that are inhibited by R3 single-repeat MYB proteins. One positive regulator, the WD40-protein, and the negative regulators are mobile and are transported in opposite directions: the WD40 factor moves to the negative regulators away from trichome initials. This movement behavior and the genetic and molecular interactions between the contributing genes and proteins make it very difficult to derive the mechanistic core behind pattern formation. ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2847126 Mon, 21 Sep 2009 23:00:00 +0100 2847126 http://www.medworm.com/index.php?rid=2797297&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19748819%26dopt%3DAbstract Authors: Oecking C, Jaspert N Members of the eukaryotic 14-3-3 family are highly conserved proteins that have been implicated in the modulation of distinct biological processes by phosphorylation-dependent protein-protein interactions. In plants, 14-3-3 mediated regulation of house-keeping proteins such as nitrate reductase and the plasma membrane localized H(+)-ATPase has been intensely studied. Recent proteome-wide approaches have indicated that the plant 14-3-3 interactome is comparable in size and functional complexity to its animal counterpart and, furthermore, shifted the focus of attention to signal mediators. In this regard, in vivo analyses of certain signaling proteins, such as BRASSINAZOLE-RESISTANT 1, a transcription factor controlling brassinosteroid responsive gene expres... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2797297 Thu, 10 Sep 2009 23:00:00 +0100 2797297 http://www.medworm.com/index.php?rid=2786951&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19740698%26dopt%3DAbstract Authors: Werner T, Schmülling T Cytokinin regulates many important aspects of plant development in aerial and subterranean organs. The hormone is part of an intrinsic genetic network controlling organ development and growth in these two distinct environments that plants have to cope with. Cytokinin also mediates the responses to variable extrinsic factors, such as light conditions in the shoot and availability of nutrients and water in the root, and has a role in the response to biotic and abiotic stress. Together, these activities contribute to the fine-tuning of quantitative growth regulation in plants. We review recent progress in understanding the cytokinin system and its links to the regulatory pathways that respond to internal and external signals. PMID: 19740698 [PubMed... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2786951 Sun, 06 Sep 2009 23:00:00 +0100 2786951 http://www.medworm.com/index.php?rid=2775126&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19734083%26dopt%3DAbstract Authors: Kaur N, Hu J Peroxisomes are highly dynamic subcellular organelles that undergo proliferation in response to a variety of environmental stimuli. The past few years have witnessed the identification and characterization of several key classes of proteins required for peroxisome division and proliferation in Arabidopsis. These include the PEROXIN11 (PEX11) family, the dynamin-related proteins (DRPs), and the FISSION1 (FIS1) proteins, some of which are shared by the division machineries of peroxisomes and other organelles. Recent studies have also uncovered a role for the photoreceptor phyA and the bZIP transcription factor HY5 homolog (HYH) in regulating light-induced peroxisome proliferation in Arabidopsis. In this review we attempt to summarize the current state of our knowled... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2775126 Thu, 03 Sep 2009 23:00:00 +0100 2775126 http://www.medworm.com/index.php?rid=2766840&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19726222%26dopt%3DAbstract Authors: Tsuchiya Y, McCourt P The recent discovery of an endogenous hormonal activity for strigolactones in shoot branching was surprising since these molecules were thought to mostly play roles as signaling molecules between organisms. Even in the context of plant hormones, strigolactones appear to be different in that their role in plant development is quite restricted. This most probably reflects early days and new hormonal functions will most probably be found for these compounds in the future. In this respect, the exogenous role of strigolactones in parasitic plant seed germination may hint to functions of this compound in seed development. However, showing new roles for strigolactones in the seed or any other aspect of plant development for that matter will require developing as... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2766840 Sun, 30 Aug 2009 23:00:00 +0100 2766840 http://www.medworm.com/index.php?rid=2752266&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19717332%26dopt%3DAbstract Authors: Priest HD, Filichkin SA, Mockler TC Plant cell signaling pathways are in part dependent on transcriptional regulatory networks comprising circuits of transcription factors (TFs) and regulatory DNA elements that control the expression of target genes. Here, we describe experimental and bioinformatic approaches for identifying potential cis-regulatory elements. We also discuss recent integrative genomics studies aimed at elucidating the functions of cis-regulatory elements in aspects of plant biology, including the circadian clock, interactions with the environment, stress responses, and regulation of growth and development by phytohormones. Finally, we discuss emerging technologies and approaches that offer great potential for accelerating the discovery and functional character... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2752266 Thu, 27 Aug 2009 23:00:00 +0100 2752266 http://www.medworm.com/index.php?rid=2752269&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19716757%26dopt%3DAbstract Authors: Fonseca S, Chico JM, Solano R Jasmonates regulate specific developmental processes and plant adaptation to environment by controlling responses to external biotic or abiotic stimuli. The core events of jasmonate signalling are now defined. After hormone perception by SCF(COI1), JAZ (JAsmonate ZIM domain) repressors are targeted for proteasome degradation, releasing MYC2 and de-repressing transcriptional activation. JAZs are homomeric and heteromeric proteins and have been instrumental in recent advances in the field, such as the identification of COI1 as a critical component of the jasmonate receptor and the discovery of the bioactive jasmonate in Arabidopsis, (+)-7-iso-JA-Ile. Small changes in jasmonate structure result in hormone inactivation and might be the key to switchin... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2752269 Wed, 26 Aug 2009 23:00:00 +0100 2752269 http://www.medworm.com/index.php?rid=2752268&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19716758%26dopt%3DAbstract Authors: Fiil BK, Petersen K, Petersen M, Mundy J Mitogen-activated protein kinase (MAPK) cascades are signaling modules that transduce extracellular stimuli to a range of cellular responses. Research in yeast and metazoans has shown that MAPK-mediated phosphorylation directly or indirectly regulates the activity of transcription factors. Plant MAPK cascades have been implicated in development and stress responses, but little is known about the specific downstream targets they control. Recent studies have begun to identify direct MAPK transcriptional targets, and provide insights into the mechanisms by which MAPK signaling networks regulate gene expression. PMID: 19716758 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2752268 Wed, 26 Aug 2009 23:00:00 +0100 2752268 http://www.medworm.com/index.php?rid=2752267&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19716759%26dopt%3DAbstract Authors: Hanson J, Smeekens S Sugars act as potent signaling molecules in plants. Several sugar sensors, including the highly studied glucose sensor HEXOKINASE1 (HXK1), have been identified or proposed. Many additional sensors likely exist, as plants respond to other sugars and sugar metabolites, such as sucrose and trehalose 6-phosphate. Sugar sensing and signaling is a highly complex process resulting in many changes in physiology and development and is integrated with other signaling pathways in plants such as those for inorganic nutrients, hormones, and different stress factors. Importantly, KIN10 and KIN11 protein kinases are central in coordinating several of the responses to sugars and stress. bZIP transcription factors were found to mediate effects of sugar signaling on gene ex... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2752267 Wed, 26 Aug 2009 23:00:00 +0100 2752267 http://www.medworm.com/index.php?rid=2752270&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19716335%26dopt%3DAbstract Authors: Hua J Plants are capable of adapting to a wide range of temperatures by reprogramming their transcriptome, proteome, and metabolome. Early investigations uncovered a regulatory network containing the CBF-COR pathway in freezing tolerance and the HSF-HSP pathway in thermotolerance. Recent studies have identified additional signaling components for extreme temperature tolerance and new regulators of plant form in response to temperature variation within the nonextreme range. Some common regulators are shared between temperature responses and other environmental and developmental responses. These discoveries further reveal the complexity and sophistication of molecular mechanisms underlying plants' adaptation to their environment. PMID: 19716335 [PubMed - as supplied by publi... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2752270 Tue, 25 Aug 2009 23:00:00 +0100 2752270 http://www.medworm.com/index.php?rid=2741986&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19709921%26dopt%3DAbstract Authors: Más P, Yanovsky MJ Most organisms adjust their physiology and metabolism in synchronization with the diurnal and seasonal time by using an endogenous mechanism known as circadian clock. In plants, light and temperature signals interact with the circadian system to regulate the circadian rhythmicity of physiological and developmental processes including flowering time. Recent studies in Arabidopsis thaliana now reveal that the circadian clock orchestrates not only the expression of protein coding genes but also the rhythmic oscillation of introns, intergenic regions, and noncoding RNAs. Furthermore, recent evidence showing the existence of different oscillators at separate parts of the plant has placed the spotlight on the diverse mechanisms and communicating channels that... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2741986 Sun, 23 Aug 2009 23:00:00 +0100 2741986 http://www.medworm.com/index.php?rid=2741985&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19709922%26dopt%3DAbstract Authors: Grieneisen VA, Scheres B There has been a recent surge of studies in plant biology that combine experimental data with computational modeling. Here, we categorize a diversity of theoretical models and emphasize the need to tailor modeling approaches to the questions at hand. Models can start from biophysical or purely heuristic basic principles, and can focus at several levels of biological organization. Recent examples illustrate that this entire spectrum can be useful to understand plant development, and point to a future direction where more approaches are combined in fruitful ways-either by proving the same result with different basic principles or by exploring interactions across levels, in the so-called multilevel models. PMID: 19709922 [PubMed - as supplied by publi... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2741985 Sun, 23 Aug 2009 23:00:00 +0100 2741985 http://www.medworm.com/index.php?rid=2741984&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19709923%26dopt%3DAbstract Authors: Jullien PE, Berger F Although most genes are expressed equally from both parental alleles, imprinted genes are differentially expressed depending on their parental origin. In flowering plants, imprinting depends on DNA methylation. Conversely, activation of the expressed allele requires DNA demethylation. This is achieved during female gametogenesis by the synergy between the DNA glycosylase DEMETER and the repression of DNA methylation by the Retinoblastoma pathway. DEMETER is only expressed in the central cell and the resulting DNA demethylation is propagated in the fertilized central cell developing into the endosperm, which nurtures embryo growth. In addition other imprinted genes are regulated by histone methylation by Polycomb Group activity. The identification of new im... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2741984 Sun, 23 Aug 2009 23:00:00 +0100 2741984 http://www.medworm.com/index.php?rid=2741983&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19709924%26dopt%3DAbstract Authors: Stepanova AN, Alonso JM The structural simplicity of the gaseous hormone ethylene stands in contrast with the complexity of the physiological processes ethylene regulates. Initial studies suggested a simple linear arrangement of signaling molecules leading from the ethylene receptors to the EIN3 family of transcription factors. Recent discoveries have substantially changed this view. Current models suggest existence of a complex signaling pathway composed of several phosphorylation cascades, feedback-regulated transcriptional networks, and protein and mRNA turnover regulatory modules. Interactions between ethylene and other signals determine which of the ethylene-mediated responses get activated in a particular cell at a particular time. Tissue-specific regulation of auxin bio... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2741983 Sun, 23 Aug 2009 23:00:00 +0100 2741983 http://www.medworm.com/index.php?rid=2735034&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19700365%26dopt%3DAbstract Authors: Krogan NT, Long JA To ensure correct patterns of gene expression, eukaryotes use a variety of strategies to repress transcription. The transcriptional regulators mediating this repression can be broadly categorized as either passive or active repressors. While passive repressors rely on mechanisms such as steric hindrance of transcriptional activators to repress gene expression, active repressors display inherent repressive abilities commonly conferred by discrete repression domains. Recent studies have indicated that both categories of regulators function in a variety of plant processes, including hormone signal transduction, developmental pathways, and response to biotic and abiotic stresses. PMID: 19700365 [PubMed - as supplied by publisher] (Source: Current Opinion in ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2735034 Thu, 20 Aug 2009 23:00:00 +0100 2735034 http://www.medworm.com/index.php?rid=2735033&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19700366%26dopt%3DAbstract Authors: Berckmans B, De Veylder L Cell division is a highly coordinated process. In the last decades, many plant cell cycle regulators have been identified. Strikingly, only a few transcriptional regulators are known, although a significant amount of the genome is transcribed in a cell cycle phase-dependent manner. E2F-DP transcription factors and three repeat MYB proteins are responsible for the expression of genes at the G1-to-S and G2-to-M transition, respectively. However, these two mechanisms cannot explain completely the transcriptional regulation seen during the cell cycle. Correspondingly, several new transcriptional regulators have been characterized, stressing the importance of transcriptional control during the cell cycle. PMID: 19700366 [PubMed - as supplied by publish... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2735033 Thu, 20 Aug 2009 23:00:00 +0100 2735033 http://www.medworm.com/index.php?rid=2735035&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19699140%26dopt%3DAbstract Authors: Rubio-Somoza I, Cuperus JT, Weigel D, Carrington JC The expansion of gene families for miRNA and tasiRNA, small RNA effector proteins (ARGONAUTEs or AGOs), and miRNA/tasiRNA targets has contributed to regulatory diversity in plants. Loss or acquisition of small RNA-generating loci and target site sequences in multigene families represent striking examples of subfunctionalization or neo-functionalization, where regulatory diversity is achieved at the post-transcriptional level. Differential regulation of small RNA and target gene family members, and evolution of unique functionality of distinct small RNA-AGO complexes, provide further regulatory diversity. Here, we focus on the idea of distinct small RNA-target transcript pairs as nodes within biological networks, and review pr... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2735035 Tue, 18 Aug 2009 23:00:00 +0100 2735035 http://www.medworm.com/index.php?rid=2723590&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19695945%26dopt%3DAbstract Authors: Lokerse AS, Weijers D The basic mechanism of auxin as a modulator of gene expression is now well understood. Interactions among three components are required for this process. Auxin is first perceived by its receptor, which then promotes degradation of inhibitors of auxin response transcription factors. These in turn are released from inhibition and modify expression of target genes. How this simple signaling pathway is able to regulate a diverse range of auxin responses is not as well understood, however a clue lies in the existence of large gene families for all components. Recent data indicates that diversification of gene expression patterns, protein activity, and protein-protein interactions among components establishes a matrix of response machineries that generates spec... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2723590 Mon, 17 Aug 2009 23:00:00 +0100 2723590 http://www.medworm.com/index.php?rid=2723589&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19695946%26dopt%3DAbstract Authors: Yant L, Mathieu J, Schmid M Floral repressors ensure correct reproductive timing by safeguarding against premature flowering. In the past decade, several mechanisms of floral repression have come to light. Discrimination between direct and indirect repressors has been facilitated by increasing the use of chromatin immunoprecipitation assays. Certain MADS-domain transcription factors such as SHORT VEGETATIVE PHASE and FLOWERING LOCUS C bind directly to target euchromatin to repress specific loci including FLOWERING LOCUS T (FT) and FD. The AP2-domain transcription factor TEMPRANILLO 1 has also been shown to directly repress FT by binding its 5' UTR. We highlight emerging systems level approaches, including genome-scale direct binding studies (ChIP-chip and ChIP-Seq), which stan... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2723589 Mon, 17 Aug 2009 23:00:00 +0100 2723589 http://www.medworm.com/index.php?rid=2668358&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19647476%26dopt%3DAbstract Authors: Dong X, Kahmann R PMID: 19647476 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2668358 Wed, 29 Jul 2009 23:00:00 +0100 2668358 http://www.medworm.com/index.php?rid=2645814&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19632141%26dopt%3DAbstract Authors: Den Herder G, Parniske M The mechanisms by which legumes choose their rhizobial partners operate independently from their ability to fix nitrogen. As a result of this naivety, symbiotic nitrogen fixation is often suboptimal. The initial recognition of the bacterial partner and the subsequent signal transduction in the host root utilises components that are functionally conserved between legumes and probably actinorhiza host plants. However, the later steps, which largely determine symbiotic performance, are subject to ongoing evolutionary diversification of molecular mechanisms. For example, the impact of bacterial effector proteins, the occurrence of terminal bacteroid differentiation and the expression of bacterial hydrogenase, all depend on the plant genotype. Strategies to... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2645814 Wed, 22 Jul 2009 23:00:00 +0100 2645814 http://www.medworm.com/index.php?rid=2645813&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19632142%26dopt%3DAbstract Authors: Hay A, Tsiantis M Knotted1 defined the first homeobox gene family to be isolated in plants and was identified from dominant maize mutants that produced 'knots' of mis-specified tissue on the leaf. The Knotted1-like homeobox (KNOX) gene family expanded last year to include members lacking the defining homeobox with exciting implications for KNOX gene regulation and function. Recent evidence for direct KNOX regulation by myb-related ARP proteins and epigenetic silencing by polycomb repressive complexes have also shed light on the mechanisms defining KNOX gene expression. PMID: 19632142 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2645813 Wed, 22 Jul 2009 23:00:00 +0100 2645813 http://www.medworm.com/index.php?rid=2640087&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19625208%26dopt%3DAbstract Authors: Talbot NJ, Kershaw MJ Autophagy is emerging as an important process in plant infection by pathogenic fungi, which develop differentiated infection cells to breach the plant cuticle. Conversely, autophagic processes are also important in the defence responses of plants that are able to perceive and react to invading pathogens. The pivotal role of autophagy in both fungal pathogenesis and disease resistance is linked to its function in the regulation of programmed cell death which is a key component of plant immunity responses and fungal infection-related development. PMID: 19625208 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2640087 Sun, 19 Jul 2009 23:00:00 +0100 2640087 http://www.medworm.com/index.php?rid=2627215&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19616468%26dopt%3DAbstract Authors: Hématy K, Cherk C, Somerville S Plants have evolved sensory mechanisms to detect pathogen attack and trigger signalling pathways that induce rapid defence responses. These mechanisms include not only direct detection of pathogen-derived elicitors (e.g. pathogen-associated molecular patterns (PAMPs) and avirulence factors or effectors) but also indirect sensing of pathogens' impact on the host plant. Among the first plant barriers to pathogen ingress are the cell wall and the cuticle. For those pathogens that penetrate the plant cell wall to gain access to water and nutrients of the plant protoplast, small wounds at penetration sites are created by enzymatic or physical disruption of the plant cell wall. Thus, cell wall integrity sensing is one mechanism by which plants ma... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2627215 Wed, 15 Jul 2009 23:00:00 +0100 2627215 http://www.medworm.com/index.php?rid=2614657&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19608448%26dopt%3DAbstract Authors: Leitner M, Vandelle E, Gaupels F, Bellin D, Delledonne M Nitric oxide (NO) is gaining increasing attention as a regulator of diverse (patho-)physiological processes in plants. Although this molecule has been described as playing a role in numerous conditions, its production, turnover and mode of action are poorly understood. Recent studies on NO production have tended to highlight the questions that still remain unanswered rather than telling us more about NO metabolism. But regarding NO signalling and functions, new findings have given an impression of the intricacy of NO-related signalling networks. Different targets of protein S-nitrosylation have been characterised and enzymatic routes controlling this posttranslational modification are emerging, along with their physiolog... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2614657 Mon, 13 Jul 2009 23:00:00 +0100 2614657 http://www.medworm.com/index.php?rid=2614656&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19608449%26dopt%3DAbstract Authors: Pitzschke A, Schikora A, Hirt H The sensing of stress signals and their transduction into appropriate responses is crucial for the adaptation and survival of plants. Kinase cascades of the mitogen-activated protein kinase (MAPK) class play a remarkably important role in plant signalling of a variety of abiotic and biotic stresses. MAPK cascade-mediated signalling is an essential step in the establishment of resistance to pathogens. Here, we describe the most recent insights into MAPK-mediated pathogen defence response regulation with a particular focus on the cascades involving MPK3, MPK4 and MPK6. We also discuss the strategies developed by plant pathogens to circumvent, inactivate or even 'hijack' MAPK-mediated defence responses. PMID: 19608449 [PubMed - as supplied by p... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2614656 Mon, 13 Jul 2009 23:00:00 +0100 2614656 http://www.medworm.com/index.php?rid=2614655&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19608450%26dopt%3DAbstract Authors: Zipfel C In plant innate immunity, the first line of microbial recognition leading to active defence responses relies on the perception of pathogen-associated molecular patterns (PAMPs) by pattern-recognition receptors (PRRs). This recognition leads to PAMP-triggered immunity (PTI). Despite the numerous PAMPs recognised by plants, only a handful of PRRs are characterised. For most, they correspond to transmembrane proteins with a ligand-binding ectodomain. PRRs interact with additional transmembrane proteins that act as signalling adapters or amplifiers to achieve full functionality. The crucial role of PRRs in anti-microbial immunity is demonstrated by the direct targeting of PRRs and their associated proteins by pathogenic virulence effectors. PMID: 19608450 [PubMed - as... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2614655 Mon, 13 Jul 2009 23:00:00 +0100 2614655 http://www.medworm.com/index.php?rid=2614654&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19608451%26dopt%3DAbstract Authors: Shah J Efficient communication between the pest-colonised and non-colonised organs is vital for the timely manifestation of defences that restrict systemic spread of pests. The vasculature provides an important conduit for translocation of signals that contribute to long-distance communication within a plant. Airborne signals also contribute to this process. In recent years, major advances have been made in identifying metabolites that are candidate systemic signals in plant defence against pathogens. Methyl salicylate, jasmonates, azealic acid and a diterpenoid have been implicated as mobile signals associated with the activation of systemic acquired resistance (SAR), which confers enhanced resistance against a broad spectrum of pathogens. By contrast, auxins probably contrib... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2614654 Mon, 13 Jul 2009 23:00:00 +0100 2614654 http://www.medworm.com/index.php?rid=2614653&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19608452%26dopt%3DAbstract Authors: Frey NF, Robatzek S Membrane compartmentalization and trafficking are pivotal for eukaryotic life and demand a higher order of coordination. Even in their resting state, most plant cells exhibit a polarized localization of membrane compartments, which is redirected when plant cells are attacked by microbes. Repositioning of organelles at pathogen penetration sites has been reported since more than a decade; however, only recently has targeted vesicle trafficking upon biotic stress emerged. It has become evident that vesicle secretion and endocytic pathways are engaged in the plant's immune system to actively defend against potential pathogens. By contrast, invasive pathogens have evolved means to utilize these trafficking pathways for the suppression of plant defenses and to t... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2614653 Mon, 13 Jul 2009 23:00:00 +0100 2614653 http://www.medworm.com/index.php?rid=2614652&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19608453%26dopt%3DAbstract Authors: Möbius N, Hertweck C Many phytopathogenic fungi exert their destructive effects by producing and secreting toxic low molecular weight compounds. In the past years a large number of novel fungal virulence factors and their modes of action have been identified. This review highlights effective phytotoxin-mediated strategies to distress, weaken or kill the plant host. PMID: 19608453 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2614652 Mon, 13 Jul 2009 23:00:00 +0100 2614652 http://www.medworm.com/index.php?rid=2614651&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19608454%26dopt%3DAbstract Authors: Padmanabhan C, Zhang X, Jin H Small RNAs regulate gene expression in many cellular processes. Emerging evidence suggests that host endogenous small RNAs and host RNA-silencing machinery represent a fundamental layer of control in plant immune responses. Pathogen-responsive endogenous small RNAs regulate gene expression reprogramming and fine-tuning in plant immune responses. Here we discuss the function of endogenous small RNAs, including microRNAs (miRNAs), small interfering RNAs (siRNAs), and long siRNAs (lsiRNAs), in plant immune responses and the strategies that pathogens have acquired to suppress host small-RNA pathways. Host endogenous small RNAs and small-RNA pathways play an important role in the plant immune responses to pathogen challenges. PMID: 19608454 [PubMed... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2614651 Mon, 13 Jul 2009 23:00:00 +0100 2614651 http://www.medworm.com/index.php?rid=2577744&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19576840%26dopt%3DAbstract Authors: Bucher M, Wegmüller S, Drissner D The arbuscular mycorrhiza (AM) is a symbiosis between most terrestrial plants and fungi of the ancient phylum Glomeromycota. AM improves the uptake of water and mineral nutrients, such as phosphorus (P) and nitrogen (N), of the host plant in exchange for photosynthetically fixed carbon. Successful colonization and a functional interaction between host plant and mycobiont are based upon exchange of signaling molecules at different stages of symbiosis development. Strigolactones, a novel class of plant hormones, are secreted by plant roots stimulating presymbiotic growth of AM fungi. Fungi release soluble signaling molecules, the enigmatic 'Myc factors', that activate early symbiotic root responses. Lysophosphatidylcholine is a lipophilic i... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2577744 Tue, 30 Jun 2009 23:00:00 +0100 2577744 http://www.medworm.com/index.php?rid=2547268&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19540152%26dopt%3DAbstract Authors: Ellis JG, Rafiqi M, Gan P, Chakrabarti A, Dodds PN Plant-pathogen interactions involve processes of pathogen offence, host defence and pathogen counter-attack that are commonly played out using molecules secreted by hosts and pathogens. Secreted pathogen molecules involved in these events, referred to as 'effectors', function either in the plant extracellular space (apoplast) or inside of plant cells after translocation from the pathogen. These molecules have evolved as virulence factors that can be detected by polymorphic host resistance proteins. Advances are being made in the identification and in understanding the evolution of effectors and of host uptake signals used by eukaryotic effectors to enter host cells. PMID: 19540152 [PubMed - as supplied by publisher] (Sourc... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547268 Tue, 16 Jun 2009 23:00:00 +0100 2547268 http://www.medworm.com/index.php?rid=2547267&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19540153%26dopt%3DAbstract Authors: Rasmann S, Agrawal AA Plants respond to herbivore attack through a complex and variable system of defense, involving different physical barriers, toxic chemicals, and recruitment of natural enemies. To fully understand the relative role of each type of defense, their synergisms, redundancies, or antagonisms between traits, a variety of methods of enquiry, commonly used in plant physiology and ecology, have been employed. By overexpressing or silencing genes of interest, it is possible to understand the specific role of a particular defensive molecule or mode of action. We argue, however, that these types of experiments alone are not enough to holistically understand the physiological as well as ecological role of plant defenses. We thus advocate for the use of a combination of... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547267 Tue, 16 Jun 2009 23:00:00 +0100 2547267 http://www.medworm.com/index.php?rid=2547266&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19540154%26dopt%3DAbstract Authors: Martin F, Nehls U The ectomycorrhizal (ECM) symbiosis is increasingly seen as a crucial component for nutrient cycling in sustainable forest ecosystems. To date, the complete genome sequence of only a single symbiotic fungus, the ECM basidiomycete Laccaria bicolor, has been released. Its analysis revealed unexpected features, including numerous transposons, secreted effector-like proteins and a lack of carbohydrate-hydrolysing enzymes acting on plant cell walls. Genome-wide transcript profilings showed that most symbiosis-induced transcripts code for proteins with unknown function and identifying their role will be challenging. However, these studies confirmed the key role of membrane transporters in the symbiosis. The analysis of additional genomes from ECM fungi will provide... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547266 Tue, 16 Jun 2009 23:00:00 +0100 2547266 http://www.medworm.com/index.php?rid=2547286&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19473870%26dopt%3DAbstract Authors: Maathuis FJ Plants require calcium, magnesium, nitrogen, phosphorous, potassium and sulfur in relatively large amounts (>0.1% of dry mass) and each of these so-called macronutrients is essential for a plant to complete its life cycle. Normally, these minerals are taken up by plant roots from the soil solution in ionic form with the metals Ca(2+), Mg(2+) and K(+) present as free cations, P and S as their oxyanions phosphate (PO(4)(3-)) and sulfate (SO(4)(2-)) and N as anionic nitrate (NO(3)(-)) or cation ammonium (NH(4)(+)). Recently, important progress has been made in identifying transport and regulatory mechanisms for macronutrients and the mechanisms of uptake and distribution. These and the main physiological roles of each nutrient will be discussed. PMID: 19473870 ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547286 Sun, 31 May 2009 23:00:00 +0100 2547286 http://www.medworm.com/index.php?rid=2547285&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19473871%26dopt%3DAbstract Authors: Zhao FJ, McGrath SP Producing nutritious and safe foods sufficiently and sustainably is the ultimate goal of modern agriculture. Past efforts have focused on increasing crop yields, but enhancing the concentrations of mineral micronutrients has become an urgent task because about half of the world population suffers from the malnutrition of iron, zinc, and selenium. Biofortification of these trace elements can be achieved through fertilization, crop breeding or biotechnology. On the other hand, soils contaminated with metals or metalloids may be cleaned up by phytoextraction that combines hyperaccumulation with high biomass production. Progress has been made in identifying inter-species and intra-species variation in trace element accumulation, and mechanistic understanding of... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547285 Sun, 31 May 2009 23:00:00 +0100 2547285 http://www.medworm.com/index.php?rid=2547284&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19477676%26dopt%3DAbstract Authors: Pilon-Smits EA, Quinn CF, Tapken W, Malagoli M, Schiavon M Aluminum (Al), cobalt (Co), sodium (Na), selenium (Se), and silicon (Si) are considered beneficial elements for plants: they are not required by all plants but can promote plant growth and may be essential for particular taxa. These beneficial elements have been reported to enhance resistance to biotic stresses such as pathogens and herbivory, and to abiotic stresses such as drought, salinity, and nutrient toxicity or deficiency. The beneficial effects of low doses of Al, Co, Na and Se have received little attention compared to toxic effects that typically occur at higher concentrations. Better understanding of the effects of beneficial elements is important to improve crop productivity and enhance plant nutritional va... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547284 Sun, 31 May 2009 23:00:00 +0100 2547284 http://www.medworm.com/index.php?rid=2547283&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19481493%26dopt%3DAbstract Authors: Liu TY, Chang CY, Chiou TJ In response to varying nutrient availability in soil, plants display a high degree of physiological and developmental plasticity that relies on both local and systemic signaling pathways to coordinate the expression of genes involved in adaptive responses. The integration of these responses at the whole-plant level requires long-distance signaling mechanisms communicating the information between the two indispensable organs, the shoot and the root, which respectively provide photosynthates and mineral nutrients. Although such long-distance signaling is not well understood at the molecular level, several molecules, including hormones, sugars, and nutrients themselves or their metabolites, have been suggested to function as the systemic signals. Moreov... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547283 Sun, 31 May 2009 23:00:00 +0100 2547283 http://www.medworm.com/index.php?rid=2547282&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19481494%26dopt%3DAbstract Authors: Karley AJ, White PJ The principal dietary source to humans of the essential cationic mineral elements potassium, magnesium and calcium is through edible plants. The accumulation of these elements in edible portions is the product of selective transport processes catalysing their short-distance and long-distance movement within a plant. In this article we review recent work describing the identification and characterisation of the molecular mechanisms catalysing the uptake and distribution of potassium, magnesium and calcium between organs, cell types and subcellular compartments. Although potassium and magnesium are redistributed effectively within the plant, calcium concentrations in phloem-fed tissues, such as fruits, seeds and tubers, are generally low. However, limitations... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547282 Sun, 31 May 2009 23:00:00 +0100 2547282 http://www.medworm.com/index.php?rid=2547281&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19481495%26dopt%3DAbstract Authors: Miwa K, Kamiya T, Fujiwara T This review focuses on recent advances in understanding the transport mechanisms of two elements, B and Si in plants. Both are present as noncharged molecules in soil solution as boric acid and silicic acid. Both function in apoplast: pectic polysaccharides crosslinked with borate and polymers of hydrated silica are important for the physical strength of plant cells. In recent years, molecular genetics revealed analogous transport systems of B and Si. Combinations of NIP channels and exporters localized to distal and proximal sides, allow efficient trans-cellular transport of the nutrients. Polar localization, observed in these transport molecules, is likely to be a key to regulate directional transport of nutrients. PMID: 19481495 [PubMed - in... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547281 Sun, 31 May 2009 23:00:00 +0100 2547281 http://www.medworm.com/index.php?rid=2547280&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19481496%26dopt%3DAbstract Authors: Giehl RF, Meda AR, von Wirén N To cope with the variable availability of micronutrients, plants have evolved a complex set of physiological and developmental processes, which are under tight control of short-range and long-range signaling pathways. These signals act at the cellular and whole-plant scale to coordinate micronutrient homeostasis at the systemic and local level. Recently, several molecular components of the local and long-distance regulatory circuits as well as their putative positions in the signaling cascade have been identified. Since among the micronutrients comparatively most is known on the signaling of Fe, this review sets a focus on Fe, for which the regulatory pathway most likely involves signaling compounds such as nitric oxide and hormones (e.g. et... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547280 Sun, 31 May 2009 23:00:00 +0100 2547280 http://www.medworm.com/index.php?rid=2547279&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19481497%26dopt%3DAbstract Authors: Pilon M, Cohu CM, Ravet K, Abdel-Ghany SE, Gaymard F The homeostasis of the essential transition metals copper, iron, manganese and zinc requires balanced activities of transporters that mediate import into the cell, distribution to organelles and export from the cell. Transcriptional control is important for the regulation of cellular homeostasis. In the case of Fe and Cu much progress has been made in uncovering the regulatory networks that mediate homeostasis, and key transcription factors have now been described. A master regulator of Cu homeostasis in Arabidopsis thaliana, AtSPL7, is related to the Chlamydomonas master regulator CCR1, suggesting that the key switch is conserved between the two systems even though different sets of targets are regulated in the two systems.... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547279 Sun, 31 May 2009 23:00:00 +0100 2547279 http://www.medworm.com/index.php?rid=2547278&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19481498%26dopt%3DAbstract Authors: Puig S, Peñarrubia L Plants have developed finely tuned mechanisms to efficiently acquire and balance the concentrations of essential metal micronutrients including iron, zinc, copper, and manganese, both at the cellular and systemic levels. The application of new emerging technologies to the study of Arabidopsis thaliana is providing a novel spatiotemporal view of plant metal homeostasis. These advances are uncovering unexpected links of metal homeostasis to central cellular processes, such as compartmentalization, daily redox oscillations, or transcriptional regulation. The intracellular compartmentalization of metals seems essential for optimizing the use of micronutrients during development and in response to deficiencies. Furthermore, recent discoveries indicate that... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547278 Sun, 31 May 2009 23:00:00 +0100 2547278 http://www.medworm.com/index.php?rid=2547277&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19481499%26dopt%3DAbstract Authors: Miller AJ, Shen Q, Xu G This review focuses on plant acquisition and transport of the inorganic forms of nitrogen, phosphorus and sulfur. Families of membrane transporters have been identified and several members are well characterised. Although some families are large, specific members may be expressed in a particular membrane or cell type, or at certain times during development. Therefore, each transporter can have specific activities and the concept of functional redundancy is questionable. Structurally related proteins can mediate all transport steps within the plant, including uptake from the soil. Although transport mechanisms and membrane locations may be different, a picture is emerging that suggests sequence homology can be a reasonable indicator of the nutrient that ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547277 Sun, 31 May 2009 23:00:00 +0100 2547277 http://www.medworm.com/index.php?rid=2547276&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19481970%26dopt%3DAbstract Authors: Baxter I The accumulation of a given element is a complex process controlled by a network of gene products critical for uptake, binding, transportation, and sequestration. Many of these genes and physiological processes affect more than one element. Therefore, to understand how elements are regulated, it is necessary to measure as many of the elements contained in a cell, tissue, or organism (the ionome) as possible. The elements that share components of their network vary depending on the species and genotype of the plants that are studied and environment they are grown in. Several recent papers describe high-throughput elemental profiling studies of how the ionome responds to the environment or explores the genetics that control the ionome. When combined with new genotyping ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547276 Sun, 31 May 2009 23:00:00 +0100 2547276 http://www.medworm.com/index.php?rid=2547275&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19487155%26dopt%3DAbstract Authors: Tejada-Jiménez M, Galván A, Fernández E, Llamas A Homeostasis of three elements nickel, molybdenum and chloride is analysed. These micronutrients, at amounts varying in orders of magnitude, fulfil important cell functions. In general terms, cells use similar strategies to ensure that the elements are within physiological ranges avoiding high toxic concentrations. These strategies correspond to specific carriers, channels and pumps, intermediate steps (chelating/sequestration/binding/metabolic conversion/storage), final steps related to specific enzyme functionality and putative sensing proteins. Single cell homeostasis, coordinated with an efficient redistribution by xylem loading, ensures in turn homeostasis at the whole plant level. Recent advances are based o... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547275 Sun, 31 May 2009 23:00:00 +0100 2547275 http://www.medworm.com/index.php?rid=2547274&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19493694%26dopt%3DAbstract Authors: Amtmann A, Armengaud P Deficiency of mineral nutrients such as nitrate, phosphate, potassium and sulphate strongly affects the type and amount of metabolites produced by crops with knock-on effects on nutritional quality of the crop, its processing properties and disease resistance. Owing to the multitude of biochemical reactions underlying metabolism and the high degree of connectivity between biochemical pathways, predicting the output of the metabolic network in response to a change in nutrient input is an enormous challenge. Recently several studies have taken a systemic approach monitoring the response of plants to withdrawal and/or re-supply of mineral nutrients at the level of transcripts, metabolites and enzyme activities. These multi-level studies have provided import... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547274 Sun, 31 May 2009 23:00:00 +0100 2547274 http://www.medworm.com/index.php?rid=2547273&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19501014%26dopt%3DAbstract Authors: Luan S, Lan W, Chul Lee S Plant roots take up numerous minerals from the soil. Some minerals (e.g., K(+)) are essential nutrients and others (e.g., Na(+)) are toxic for plant growth and development. In addition to the absolute level, the balance among the minerals is critical for their physiological functions. For instance, [K(+)]/[Na(+)] ratio and homeostasis often determine plant growth rate. Either low-K or high-Na in the soil represents a stress condition that severely affects plant life and agricultural production. Earlier observations indicated that higher soil Ca2(+) improve plants growth under low-K or high-Na condition, implying functional interaction among the three cations. Recent studies have begun to delineate the signaling mechanisms underlying such interactions.... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547273 Sun, 31 May 2009 23:00:00 +0100 2547273 http://www.medworm.com/index.php?rid=2547272&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19501015%26dopt%3DAbstract Authors: Gojon A, Nacry P, Davidian JC Homeostasis of nitrogen, phosphorus and sulfur in growing plants requires a sustained intake of these elements into root cells. Under most situations, the adjustment of root N, P or S acquisition to the nutrient demand of the plant is hampered by the limiting and fluctuating availability of these elements in the soil. To cope with this constraint, higher plants modulate their root uptake capacity to compensate for the changes in external concentrations of the N, P or S sources. This adaptive response relies on both physiological and morphological changes in the root system, triggered by nutrient-specific sensing and signalling pathways. The underlying molecular mechanisms now begin to be elucidated. Key root membrane transport proteins have been i... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547272 Sun, 31 May 2009 23:00:00 +0100 2547272 http://www.medworm.com/index.php?rid=2547271&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19501016%26dopt%3DAbstract Authors: Verbruggen N, Hermans C, Schat H The metalloid arsenic and the heavy metal cadmium have no demonstrated biological function in plants. Both elements are highly toxic and of major concern with respect to their accumulation in soils, in the food-chain or in drinking water. Arsenate is taken up by phosphate transporters and rapidly reduced to arsenite, As(III). In reducing environments, As(III) is taken up by aquaporin nodulin 26-like intrinsic proteins. Cd(2+) enters the root via essential metal uptake systems. As(III) and Cd(2+) share some similarity between their toxicology and sequestration machineries. Recent progress in understanding the mechanisms of As and Cd uptake and detoxification is presented, including the elucidation of why rice takes up so much arsenic from soil a... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547271 Sun, 31 May 2009 23:00:00 +0100 2547271 http://www.medworm.com/index.php?rid=2547270&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19524481%26dopt%3DAbstract Authors: Williams L, Salt DE PMID: 19524481 [PubMed - in process] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547270 Sun, 31 May 2009 23:00:00 +0100 2547270 http://www.medworm.com/index.php?rid=2547269&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19524482%26dopt%3DAbstract Authors: Hänsch R, Mendel RR Micronutrients are involved in all metabolic and cellular functions. Plants differ in their need for micronutrients, and we will focus here only on those elements that are generally accepted as essential for all higher plants: boron (B), chloride (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn). Several of these elements are redox-active that makes them essential as catalytically active cofactors in enzymes, others have enzyme-activating functions, and yet others fulfill a structural role in stabilizing proteins. In this review, we focus on the major functions of mineral micronutrients, mostly in cases where they were shown as constituents of proteins, making a selection and highlighting some functions in more d... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547269 Sun, 31 May 2009 23:00:00 +0100 2547269 http://www.medworm.com/index.php?rid=2547287&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19467919%26dopt%3DAbstract Authors: Unsicker SB, Kunert G, Gershenzon J Herbivore damage to leaves and other vegetative tissues often stimulates the emission of volatile compounds, suggesting that these substances have a role in plant defense. In fact, ample evidence has accumulated in the last few years indicating that volatiles from vegetative plant parts can directly repel herbivores, such as ovipositing butterflies and host-seeking aphids. Volatiles have also been demonstrated to protect plants by attracting herbivore enemies, such as parasitic wasps, predatory arthropods and possibly even insectivorous birds. Even below ground herbivory results in the release of volatiles that attract herbivore enemies. However, plant volatiles are also known to attract enemies of plants. Hence, to determine the true value ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547287 Mon, 18 May 2009 23:00:00 +0100 2547287 http://www.medworm.com/index.php?rid=2547288&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19447671%26dopt%3DAbstract Authors: Brandenburg A, Dell'olivo A, Bshary R, Kuhlemeier C We all appreciate the beauty of flowers, but we seldom consider their function in the life cycle of the plant. The function of beautiful flowers is to advertise the presence of nectar. Floral nectar is the key component in the mutualism between flowering plants and their pollinators. Plants offer nectar as a reward for the transport of pollen by animal vectors. Studying nectar is challenging because of its complex physiology, complex polygenetic structure, and strong environmental variability. Recent advances set the stage for exciting future research that combines genetics and physiology to study ecological and evolutionary questions. PMID: 19447671 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Bi... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547288 Fri, 15 May 2009 23:00:00 +0100 2547288 http://www.medworm.com/index.php?rid=2547289&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19394891%26dopt%3DAbstract Authors: Lukasik E, Takken FL Resistance (R) proteins are involved in specific pathogen recognition and subsequent initiation of host defence. Most R proteins are nucleotide binding - leucine rich repeat (NB-LRR) proteins, which form a subgroup within the STAND (signal transduction ATPases with numerous domains) family. Activity of these multi-domain proteins depends on their ability to bind and hydrolyse nucleotides. Since R protein activation often triggers cell-death tight regulation of activation is essential. Autoinhibition, which seems to be accomplished by intramolecular interactions between the various domains, is important to retain R proteins inactive. This review summarizes recent data on intra- and intermolecular interactions that support a model in which pathogen perceptio... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2547289 Thu, 23 Apr 2009 23:00:00 +0100 2547289 http://www.medworm.com/index.php?rid=2273106&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19282235%26dopt%3DAbstract Authors: Cooper M, van Eeuwijk FA, Hammer GL, Podlich DW, Messina C The genetic architecture of a trait is defined by the set of genes contributing to genetic variation within a reference population together with information on their location in the genome and the effects of their alleles on traits, including intra-locus and inter-locus interactions, environmental dependencies, and pleiotropy. Accumulated evidence from trait mapping studies emphasizes that plant breeders work within a trait genetic complexity continuum. Some traits show a relatively simple genetic architecture while others, such as grain yield, have a complex architecture. An important advance is that we now have empirical genetic models of trait genetic architecture obtained from mapping studies (multi-QTL models incl... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2273106 Tue, 10 Mar 2009 04:00:00 +0100 2273106 http://www.medworm.com/index.php?rid=2232492&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19249238%26dopt%3DAbstract Authors: Freeling M, Subramaniam S Plant conserved noncoding sequences (CNSs)-a specific category of phylogenetic footprint-have been shown experimentally to function. No plant CNS is conserved to the extent that ultraconserved noncoding sequences are conserved in vertebrates. Plant CNSs are enriched in known transcription factor or other cis-acting binding sites, and are usually clustered around genes. Genes that encode transcription factors and/or those that respond to stimuli are particularly CNS-rich. Only rarely could this function involve small RNA binding. Some transcribed CNSs encode short translation products as a form of negative control. Approximately 4% of Arabidopsis gene content is estimated to be both CNS-rich and occupies a relatively long stretch of chromosome: Bigfoot... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2232492 Wed, 25 Feb 2009 05:00:00 +0100 2232492 http://www.medworm.com/index.php?rid=2182453&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19211299%26dopt%3DAbstract Authors: Yano M, Tuberosa R PMID: 19211299 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2182453 Mon, 09 Feb 2009 05:00:00 +0100 2182453 http://www.medworm.com/index.php?rid=2167517&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19195924%26dopt%3DAbstract Authors: Distelfeld A, Li C, Dubcovsky J Long exposure to cold (vernalization) accelerates flowering in winter cereals, a process regulated by the VRN1 ( approximately AP1), VRN2, and VRN3 ( approximately FT) vernalization genes. Flowering during the fall is prevented by the VRN2 downregulation of VRN3 and low VRN1 transcription. Vernalization induces VRN1, which is followed by the downregulation of VRN2, thereby releasing VRN3. In the longer days of spring, photoperiod genes PPD1 and CO upregulate VRN3, which induces VRN1 above the threshold levels required for flowering initiation. VRN3 transcription is modulated through interactions involving CCT-domain proteins and HAP2/HAP3/HAP5 complexes coded by multiple genes. The vast number of HAP-CCT combinations can provide the flexibility ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2167517 Tue, 03 Feb 2009 05:00:00 +0100 2167517 http://www.medworm.com/index.php?rid=2167516&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19196544%26dopt%3DAbstract Authors: Jansen RC, Tesson BM, Fu J, Yang Y, McIntyre LM Current technologies for high-throughput molecular profiling of large numbers of genetically different individuals offer great potential for elucidating the genotype-to-phenotype relationship. Variation in molecular and phenotypic traits can be correlated to DNA sequence variation using the methods of quantitative trait locus (QTL) mapping. In addition, the correlation structure in the molecular and phenotypic traits can be informative for inferring the underlying molecular networks. For this, new methods are emerging to distinguish among causality, reactivity, or independence of traits based upon logic involving underlying QTL. These methods are becoming increasingly popular in plant genetic studies as well as in studies on many... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2167516 Mon, 02 Feb 2009 05:00:00 +0100 2167516 http://www.medworm.com/index.php?rid=2156392&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19186095%26dopt%3DAbstract Authors: Ganal MW, Altmann T, Röder MS In many plants, single nucleotide polymorphism (SNP) markers are increasingly becoming the marker system of choice. However, for many crop plants there are surprisingly low numbers of validated SNP markers available although they are needed in large numbers for studies regarding genetic variation, linkage mapping, population structure analysis, association genetics, map-based gene isolation, and plant breeding. This review summarizes the current status of SNP marker development technologies for major crop plants. It will also provide an outlook into the future regarding possible SNP identification approaches in crop plants on the basis of current development in model systems such as Arabidopsis which will become available with the full sequen... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2156392 Thu, 29 Jan 2009 05:00:00 +0100 2156392 http://www.medworm.com/index.php?rid=2156391&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19186096%26dopt%3DAbstract Authors: Grattapaglia D, Plomion C, Kirst M, Sederoff RR Growth traits in trees are fundamental components of adaptation in a forest ecosystem and of productivity in planted forests. A number of processes determine tree growth, which are controlled by genetic and epigenetic factors that respond dynamically to environmental signals throughout centuries. Advances in genomics have allowed an increased comprehension of the complex mechanisms of tree growth and adaptation. Yet, the application of genomics to improving forest productivity and sustainability still entails capturing a large proportion of the total genetic variation controlling the component traits. Nonetheless, genetics and genomics are unifying disciplines that will serve well to dissect the variables and mechanisms of tree g... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2156391 Thu, 29 Jan 2009 05:00:00 +0100 2156391 http://www.medworm.com/index.php?rid=2156394&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19185529%26dopt%3DAbstract Authors: Izawa T, Konishi S, Shomura A, Yano M Crop domestication can be considered a model system of plant evolution. Genome analyses of rice have revealed the fine population structure of this major crop associated with local origins of landraces. Recent cloning of rice domestication-related genes and identification of the responsible functional nucleotide polymorphisms in landraces, while taking into account their population structures, have revealed the existence of historical signatures of the DNA involved in the domestication process. These signatures imply the importance of multiple selection steps wherein natural variants were combined to improve crop performance during domestication. These analyses will provide new insights into the relationship between Darwinian selection for... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2156394 Wed, 28 Jan 2009 05:00:00 +0100 2156394 http://www.medworm.com/index.php?rid=2156393&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19185530%26dopt%3DAbstract Authors: Waugh R, Jannink JL, Muehlbauer GJ, Ramsay L Barley geneticists are currently using association genetics to identify and fine map traits directly in elite plant breeding material. This has been made possible by the development of a highly parallel SNP assay platform that provides sufficient marker density for genome-wide scans and linkage disequilibrium-led gene identification. By leveraging the combined resources of the barley research and breeding sectors, marker-trait associations are being identified and a renewed interest has emerged in novel strategies for barley improvement. New database and visualization tools have been developed and statistical methods adapted from human genetics to account for complexities in the datasets. Exciting early results suggest that associat... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2156393 Wed, 28 Jan 2009 05:00:00 +0100 2156393 http://www.medworm.com/index.php?rid=2149603&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19179104%26dopt%3DAbstract Authors: Chinnusamy V, Zhu JK Gene expression driven by developmental and stress cues often depends on nucleosome histone post-translational modifications and sometimes on DNA methylation. A number of studies have shown that these DNA and histone modifications play a key role in gene expression and plant development under stress. Most of these stress-induced modifications are reset to the basal level once the stress is relieved, while some of the modifications may be stable, that is, may be carried forward as 'stress memory' and may be inherited across mitotic or even meiotic cell divisions. Epigenetic stress memory may help plants more effectively cope with subsequent stresses. Comparative studies on stress-responsive epigenomes and transcriptomes will enhance our understanding of str... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2149603 Tue, 27 Jan 2009 05:00:00 +0100 2149603 http://www.medworm.com/index.php?rid=2137513&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19168383%26dopt%3DAbstract Authors: Fincher GB A key distinguishing feature of the grasses is that their cell walls contain (1,3;1,4)-beta-d-glucans, which are distributed almost exclusively within the Poaceae. The identification of genes that mediate in (1,3;1,4)-beta-d-glucan biosynthesis has been possible through relatively recent genome sequencing programmes and comparative genomics techniques. The evolution of a single new gene appears to have been sufficient for the first synthesis of (1,3;1,4)-beta-d-glucans and there is compelling evidence that existing hydrolytic enzymes were adapted for the specific hydrolysis of the polysaccharide during wall turnover or degradation. Manipulation of the expression levels of genes involved in (1,3;1,4)-beta-d-glucan synthesis is likely to provide opportunities to enhan... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2137513 Fri, 23 Jan 2009 05:00:00 +0100 2137513 http://www.medworm.com/index.php?rid=2131295&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19162531%26dopt%3DAbstract Authors: Keurentjes JJ One of the long-standing goals in plant biology has been to link genotypic variation to natural variation in plant development and adaptive traits. From recent studies it has become clear that a complex interacting network is underlying phenotypic diversity. A major role in this regulatory mechanism is assigned to the metabolism since plants are extremely rich and variable in metabolic content profiles. Technological advances in detecting and quantifying biochemical content as well as novel experimental approaches have accelerated data generation and increased our understanding of regulatory mechanisms in plant biology. It is now clear that modern plant sciences can benefit enormously from integrated multidisciplinary approaches. PMID: 19162531 [PubMed - as s... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2131295 Tue, 20 Jan 2009 05:00:00 +0100 2131295 http://www.medworm.com/index.php?rid=2131294&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19162532%26dopt%3DAbstract Authors: Young ND, Udvardi M Genomic resources developed in the model legume, Medicago truncatula, have the potential to accelerate practical advances in crop legumes. M. truncatula is closely related to many economically important legumes, frequently displaying genome-scale synteny. Translating genome data from M. truncatula should be highly effective in marker development, gene discovery, and positional cloning in crop legumes. The M. truncatula genome sequence also provides valuable insights about gene families of practical importance, especially those that are legume-specific. The M. truncatula genome sequence should also simplify the assembly of next-generation sequence data in closely related taxa, especially alfalfa. Genomic resources, such as whole-genome arrays, make it possib... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2131294 Tue, 20 Jan 2009 05:00:00 +0100 2131294 http://www.medworm.com/index.php?rid=2128845&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19157956%26dopt%3DAbstract Authors: Hochholdinger F, Tuberosa R The complex architecture and plasticity of the maize root system is controlled by a plethora of genes. Mutant analyses have identified genes regulating shoot-borne root initiation (RTCS) and root hair elongation (RTH1 and RTH3). Quantitative trait locus (QTL) studies have highlighted the importance of seminal roots, lateral roots, and root hairs in phosphorus acquisition. Additionally, QTLs that influence root features were shown to affect yield under different water regimes and under flooding conditions. Finally, proteome and transcriptome analyses provided insights into maize root development and identified candidate genes associated with cell specification, and lateral root initiation in pericycle cells. The targeted application of forward-geneti... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2128845 Mon, 19 Jan 2009 05:00:00 +0100 2128845 http://www.medworm.com/index.php?rid=2128844&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19157957%26dopt%3DAbstract Authors: Lister R, Gregory BD, Ecker JR The sudden availability of DNA sequencing technologies that rapidly produce vast amounts of sequence information has triggered a paradigm shift in genomics, enabling massively parallel surveying of complex nucleic acid populations. The diversity of applications to which these technologies have already been applied demonstrates the immense range of cellular processes and properties that can now be studied at the single-base resolution. These include genome resequencing and polymorphism discovery, mutation mapping, DNA methylation, histone modifications, transcriptome sequencing, gene discovery, alternative splicing identification, small RNA profiling, DNA-protein, and possibly even protein-protein interactions. Thus, these deep sequencing technolo... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2128844 Mon, 19 Jan 2009 05:00:00 +0100 2128844 http://www.medworm.com/index.php?rid=2128843&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19157958%26dopt%3DAbstract Authors: Varshney RK, Close TJ, Singh NK, Hoisington DA, Cook DR Many of the world's most important food legumes are grown in arid and semi-arid regions of Africa and Asia, where crop productivity is hampered by biotic and abiotic stresses. Until recently, these crops have also suffered from a dearth of genomic and molecular-genetic resources and thus were 'orphans' of the genome revolution. However, the community of legume researchers has begun a concerted effort to change this situation. The driving force is a series of international collaborations that benefit from recent advances in genome sequencing and genotyping technologies. The focus of these activities is the development of genome-scale data sets that can be used in high-throughput approaches to facilitate genomics-assisted b... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2128843 Mon, 19 Jan 2009 05:00:00 +0100 2128843 http://www.medworm.com/index.php?rid=2077731&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19119056%26dopt%3DAbstract Authors: Gonzalez N, Beemster GT, Inzé D In the next decades, the world market for plant-derived products is expected to expand exponentially. Not only do we rely on plants to feed the growing world population, but plants will also play a pivotal role in providing a significant part of our increasing energy demands. Whereas in the 1960s the green revolution contributed to increase plant productivity, it is expected that biotechnological advances will further boost biomass production and plant yield. To do this effectively, it will be necessary to understand how the molecular machinery that determines yield parameters operates. Although of no direct economic significance, the model plant Arabidopsis can be used to find genes and regulatory networks controlling biomass production, w... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2077731 Tue, 30 Dec 2008 05:00:00 +0100 2077731 http://www.medworm.com/index.php?rid=2073926&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19117793%26dopt%3DAbstract Authors: Iyer-Pascuzzi A, Simpson J, Herrera-Estrella L, Benfey PN Roots are vital for the uptake of water and nutrients, and for anchorage in the soil. They are highly plastic, able to adapt developmentally and physiologically to changing environmental conditions. Understanding the molecular mechanisms behind this growth and development requires knowledge of root transcriptomics, proteomics, and metabolomics. Genomics approaches, including the recent publication of a root expression map, root proteome, and environment-specific root expression studies, are uncovering complex transcriptional and post-transcriptional networks underlying root development. The challenge is in further capitalizing on the information in these datasets to understand the fundamental principles of root growth a... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2073926 Mon, 29 Dec 2008 05:00:00 +0100 2073926 http://www.medworm.com/index.php?rid=2073928&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19112042%26dopt%3DAbstract Authors: Dolan L Land plants are derived from green algal ancestors and made their first appearance on land 460 million years ago. The life cycle of the land plant body comprises two multicellular stages-one haploid (gametophyte) and the other diploid (sporophyte). Recent discoveries suggest that the genes controlling diploid development in ancestral green algal zygotes diversified in the land plant lineage where they control the development of the diploid body plan. There are also numerous examples of the independent recruitment of sets of genes to control the development of structures that are morphologically and functionally similar. These discoveries are giving insights into the mechanism by which land plant morphologies changed over the past 460 million years. PMID: 19112042 [... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2073928 Fri, 26 Dec 2008 05:00:00 +0100 2073928 http://www.medworm.com/index.php?rid=2073927&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19112043%26dopt%3DAbstract Authors: Gasser CS, Dean C PMID: 19112043 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2073927 Fri, 26 Dec 2008 05:00:00 +0100 2073927 http://www.medworm.com/index.php?rid=2067368&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19109050%26dopt%3DAbstract Authors: Micol JL Molecular cloning of mutations affecting the morphology of plant leaves has proven to be useful for the causal analysis of leaf development. Studies of leaf mutants have produced a wealth of biologically meaningful information on the genes that participate in leaf initiation, leaf polarity specification and maintenance, and leaf expansion and maturation. The availability of collections of gene-indexed insertional mutants, automated platforms for high-throughput imaging, and new morphometry software is making genome-wide leaf phenomics possible and complements classical forward genetics approaches. Large-scale phenomic studies will further our understanding, among others, of two intriguing phenomena that recently reentered the leaf scenario. One is the unexpected relat... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2067368 Mon, 22 Dec 2008 05:00:00 +0100 2067368 http://www.medworm.com/index.php?rid=2055802&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19095493%26dopt%3DAbstract Authors: Bolot S, Abrouk M, Masood-Quraishi U, Stein N, Messing J, Feuillet C, Salse J Early marker-based macrocolinearity studies between the grass genomes led to arranging their chromosomes into concentric 'crop circles' of synteny blocks that initially consisted of 30 rice-independent linkage groups representing the ancestral cereal genome structure. Recently, increased marker density and genome sequencing of several cereal genomes allowed the characterization of intragenomic duplications and their integration with intergenomic colinearity data to identify paleo-duplications and propose a model for the evolution of the grass genomes from a common ancestor. On the basis of these data an 'inner circle' comprising five ancestral chromosomes was defined providing a new reference for the... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2055802 Tue, 16 Dec 2008 05:00:00 +0100 2055802 http://www.medworm.com/index.php?rid=2046727&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19084466%26dopt%3DAbstract This article focuses on recent advances made on the study of ubiquitin-mediated proteolysis of several light-related signaling pathways, such as photomorphogenesis, circadian clock function, and photoperiodic flowering. PMID: 19084466 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=2046727 Wed, 10 Dec 2008 05:00:00 +0100 2046727 http://www.medworm.com/index.php?rid=1990662&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19028348%26dopt%3DAbstract Authors: PMID: 19028348 [PubMed - in process] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1990662 Thu, 27 Nov 2008 10:36:19 +0100 1990662 http://www.medworm.com/index.php?rid=1990661&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19028349%26dopt%3DAbstract Authors: Thole JM, Nielsen E Tight regulation of membrane trafficking is crucial to the proper maintenance of the endomembrane trafficking system of eukaryotic cells. Distinct organelles must maintain their identities while at the same time continuously accepting, sorting, and exchanging membrane and luminal cargo constituents. Additionally, many of these organelles differentiate specialized subdomains containing distinct sets of lipids and proteins and restrict certain aspects of membrane trafficking to these regions of the organelle. Phosphoinositides (PIs) are a class of membrane lipids that have emerged as key components in some of these membrane trafficking events. The ability of these lipids to be rapidly produced, modified, and hydrolyzed by distinct classes of phosphatidylinosi... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1990661 Thu, 27 Nov 2008 10:36:15 +0100 1990661 http://www.medworm.com/index.php?rid=1980594&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19019722%26dopt%3DAbstract Authors: Chen YN, Slabaugh E, Brandizzi F Membrane-tethered transcription factors (MTTFs) differ from cytosolic transcription factors (TF) in that they are innately membrane-bound. To attain TF activity, MTTFs are released from the membrane anchor as a result of proteolytic cleavage. This enables MTTFs to travel to the nucleus and modulate gene expression. Arabidopsis MTTFs characterized to date belong to either the bZIP or the NAC family. In this review, we highlight the most recent findings on Arabidopsis MTTFs that ascribe different yet important roles to these proteins: the MTTFs in the bZIP family appear to regulate stress signaling pathways, whereas members of the NAC family are involved in both development and stress response. PMID: 19019722 [PubMed - as supplied by publishe... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1980594 Mon, 17 Nov 2008 05:00:00 +0100 1980594 http://www.medworm.com/index.php?rid=1968732&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19010080%26dopt%3DAbstract Authors: Cools T, De Veylder L Plants are sedentary, and so have unavoidably close contact with agents that target their genome integrity. To sense and react to these threats, plants have evolved DNA stress checkpoint mechanisms that arrest the cell cycle and activate the DNA repair machinery to preserve the genome content. Although the pathways that maintain DNA integrity are largely conserved among eukaryotic organisms, plants put different accents on cell cycle control under DNA stress and might have their own way to cope with it. PMID: 19010080 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1968732 Thu, 13 Nov 2008 05:00:00 +0100 1968732 http://www.medworm.com/index.php?rid=1968731&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19013099%26dopt%3DAbstract Authors: Ostergaard L The fruit of Arabidopsis thaliana is derived from two fused carpels in the centre of the developing flower. Significant progress has been made in the study of Arabidopsis gynoecium and fruit development during the past few years with the identification of key regulators and analysis of the interactions between them. Many of these factors also have roles in leaf development, thereby emphasising the evolutionary origin of carpels as modified leaves. Although work on fruit development has largely been focused on the analysis of individual genes and mutants, the data clearly indicate that in order to get an integrated view of fruit patterning it is necessary to understand the role of the plant hormone auxin in the process and how it becomes distributed. PMID: 1901... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1968731 Wed, 12 Nov 2008 05:00:00 +0100 1968731 http://www.medworm.com/index.php?rid=1951800&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18993110%26dopt%3DAbstract Authors: Geldner N Plants have acquired the ability for organized multicellular development independent from animals. Because of this, they represent an independent example in nature for the development of coordinated, complex cell polarity from the simple polarity found in unicellular eukaryotes. Plants display a striking array of polarized cell types, with different axes of polarity being defined in one cell. The most investigated and best understood aspect of plant polarity is the apical-basal polarity of the PIN family of auxin efflux facilitators, which are of crucial importance for the organization of the entire plant body. Striking differences exist between the PAR-polarity modules known in animals and the ways PINs polarize plant cells. Nonetheless, a common regulatory logic pr... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1951800 Wed, 05 Nov 2008 05:00:00 +0100 1951800 http://www.medworm.com/index.php?rid=1945177&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18990607%26dopt%3DAbstract Authors: Belostotsky DA, Sieburth LE A pervasive theme in development is that dynamic changes in gene expression drive developmental progression; yet in studies of gene expression, the general RNA decay pathways have historically played second fiddle to transcription. However, recent advances in this field have revealed a surprising degree of mRNA specificity for particular branches of these RNA decay pathways. General cytoplasmic mRNA decay typically initiates with deadenylation, following which the deadenylated mRNA can continue decay from the 3'-end through the action of the exosome, or it can undergo 5'-to-3' decay. Functional characterization of exosome subunits using inducible knock-outs uncovered a surprising complexity of molecular phenotypes and RNA substrates. Decay in the 5'... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1945177 Tue, 04 Nov 2008 05:00:00 +0100 1945177 http://www.medworm.com/index.php?rid=1945176&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18990608%26dopt%3DAbstract Authors: Yang Y, Glynn JM, Olson BJ, Schmitz AJ, Osteryoung KW Plastid division is executed by the coordinated action of at least two molecular machineries-an internal machinery situated on the stromal side of the inner envelope membrane that was contributed by the cyanobacterial endosymbiont from which plastids evolved, and an external machinery situated on the cytosolic side of the outer envelope membrane that was contributed by the host. Here we review progress in defining the components of the plastid division complex and understanding the mechanisms of envelope constriction and division-site placement in plants. We also highlight recent work identifying the first molecular linkage between the internal and external division machineries, shedding light on how their mid-plastid posit... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1945176 Tue, 04 Nov 2008 05:00:00 +0100 1945176 http://www.medworm.com/index.php?rid=1945175&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18990609%26dopt%3DAbstract Authors: Cline K, Dabney-Smith C Chloroplasts contain several thousand different proteins, of which more than 95% are encoded on nuclear genes, synthesized in the cytosol as precursor proteins, and imported into the organelle. The major pathways for import and routing have been described; a general import apparatus in the chloroplast envelope and several ancestral translocases in the thylakoid membranes. In this update we focus on some interesting and emerging areas: the Tat translocase, which operates in parallel with the Sec system but transports folded proteins; different routes to the envelope membranes, which promises an understanding of the ways the Tic apparatus sorts transmembrane domains (TMDs) and may also uncover developmental relationships between envelope and thylakoids; a... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1945175 Tue, 04 Nov 2008 05:00:00 +0100 1945175 http://www.medworm.com/index.php?rid=1933990&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18980858%26dopt%3DAbstract Authors: Chuck G, Candela H, Hake S The identification and study of small RNAs, including microRNAs and trans-acting small interfering RNAs, have added a layer of complexity to the many pathways that regulate plant development. These molecules, which function as negative regulators of gene expression, are now known to have greatly expanded roles in a variety of developmental processes affecting all major plant structures, including meristems, leaves, roots, and inflorescences. Mutants with specific developmental phenotypes have also advanced our knowledge of the biogenesis and mode of action of these diverse small RNAs. In addition, previous models on the cell autonomy of microRNAs may have to be revised as more data accumulate supporting their long distance transport. As many of these... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1933990 Sat, 01 Nov 2008 04:00:00 +0100 1933990 http://www.medworm.com/index.php?rid=1933992&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18977684%26dopt%3DAbstract Authors: Lloyd C, Chan J A major breakthrough was the recent discovery that cellulose synthases really do move along the plasma membrane upon tracks provided by the underlying cortical microtubules. It emphasized the cytoplasmic contribution to cell wall organization. A growing number of microtubule-associated proteins has been identified and shown to affect the way that microtubules are ordered, with downstream effects on the pattern of growth. The dynamic properties of microtubules turn out to be key in understanding the behaviour of the global array and good progress has been made in deciphering the rules by which the array is self-organized. PMID: 18977684 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1933992 Fri, 31 Oct 2008 04:00:00 +0100 1933992 http://www.medworm.com/index.php?rid=1933991&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18977685%26dopt%3DAbstract Authors: Giakountis A, Coupland G Seasonal variability in environmental parameters such as day length regulates many aspects of plant development. The transition from vegetative growth to flowering in Arabidopsis is regulated by seasonal changes in day length through a genetically defined molecular cascade known as the photoperiod pathway. Recent advances were made in understanding the tissues in which different components of the photoperiod pathway act to regulate floral induction. These studies highlighted the key role of the FT protein, which is produced in the leaves in response to inductive day lengths and traffics through the phloem to initiate flowering at the shoot apex. Unveiling the cellular and molecular details of this systemic signaling process will be required for a compl... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1933991 Fri, 31 Oct 2008 04:00:00 +0100 1933991 http://www.medworm.com/index.php?rid=1933993&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18977167%26dopt%3DAbstract Authors: Lee YJ, Yang Z Signaling molecules, such as ROP/RAC GTPases and their regulators, reactive oxygen species (ROS) and phospholipids, play pivotal roles in the control of tip growth in pollen tubes and root hairs. They are often localized to the apical growing region of these cells, where their functions are tightly interconnected with cytoskeletal rearrangement and polar vesicle trafficking, which participate in tip growth as well as affect the generation and maintenance of the apical growing region. Recent advances in our understanding of the interface between these cellular activities and signaling in tip growth will be discussed. PMID: 18977167 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1933993 Thu, 30 Oct 2008 04:00:00 +0100 1933993 http://www.medworm.com/index.php?rid=1914565&cid=s_35497_62_f&fid=35497&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18952493%26dopt%3DAbstract Authors: Woollard AA, Moore I Rab GTPases are important determinants of membrane identity and membrane targeting. Higher plants have evolved a unique set of Rab GTPases that presumably reflects the specific demands of plant cell trafficking. In recent years, significant progress has been made in identifying Rab GTPases involved in endosome organisation, cytokinesis and in post-Golgi traffic to the plasma membrane and vacuoles. These include members of the Rab-F1, Rab-F2, Rab-A1, Rab-A2 and Rab-A4 subclasses. Some important regulators or effectors have also been identified for Rab-F, Rab-A1 and Rab-A4 proteins. However, uncertainties remain about the trafficking pathways that connect the compartments in the trans-Golgi/prevacuolar/endosomal system and there is still little or no insight... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=1914565 Fri, 24 Oct 2008 04:00:00 +0100 1914565