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. Thu, 09 Feb 2012 14:32:04 +0100 http://www.medworm.com/index.php?rid=5621185&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%3D22244679%26dopt%3DAbstract Authors: Schilmiller AL, Pichersky E, Last RL Abstract Specialized (traditionally called 'secondary') metabolism can be thought of as a hydra with hundreds of thousands of compounds produced by thousands of enzymes across the entire plant kingdom. Until recently, plants that produce the most interesting and valuable metabolites were recalcitrant to modern molecular biology approaches for gene and pathway discovery. Recent advances in technologies for genomic, transcriptomic, proteomic, and metabolomic methods now allow for deployment of 'systems biology' approaches to help elucidate unknown steps in specialized metabolite pathways, for example through co-expression analyses. Inexpensive transcriptome and whole genome sequencing (WGS) promises to provide direct access to metabolic p... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5621185 Thu, 12 Jan 2012 05:00:00 +0100 5621185 http://www.medworm.com/index.php?rid=5621187&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%3D22244081%26dopt%3DAbstract Authors: Tcherkez G, Boex-Fontvieille E, Mahé A, Hodges M Abstract Leaf respiration is a major metabolic process that drives energy production and growth. Earlier works in this field were focused on the measurement of respiration rates in relation to carbohydrate content, photosynthesis, enzymatic activities or nitrogen content. Recently, several studies have shed light on the mechanisms describing the regulation of respiration in the light and in the dark and on associated metabolic flux patterns. This review will highlight advances made into characterizing respiratory fluxes and provide a discussion of metabolic respiration dynamics in relation to important biological functions. PMID: 22244081 [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=5621187 Wed, 11 Jan 2012 05:00:00 +0100 5621187 http://www.medworm.com/index.php?rid=5621186&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%3D22244082%26dopt%3DAbstract Authors: Durbak A, Yao H, McSteen P Abstract Hormone signaling plays diverse and critical roles during plant development. In particular, hormone interactions regulate meristem function and therefore control formation of all organs in the plant. Recent advances have dissected commonalities and differences in the interaction of auxin and cytokinin in the regulation of shoot and root apical meristem function. In addition, brassinosteroid hormones have recently been discovered to regulate root apical meristem size. Further insights have also been made into our understanding of the mechanism of crosstalk among auxin, cytokinin, and strigolactone in axillary meristems. PMID: 22244082 [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=5621186 Wed, 11 Jan 2012 05:00:00 +0100 5621186 http://www.medworm.com/index.php?rid=5578079&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%3D22226570%26dopt%3DAbstract Authors: König J, Muthuramalingam M, Dietz KJ Abstract Plant cells sense, weigh and integrate various endogenous and exogenous cues in order to optimize acclimation and resource allocation. The thiol/disulfide redox network appears to be in the core of this versatile integration process. In plant cells its complexity exceeds by far that of other organisms. Recent research has elucidated the multiplicity of the diversified input elements, transmitters (thioredoxin, glutaredoxins), targets and sensors (peroxiredoxins and other peroxidases), controlled processes and final acceptors (reactive oxygen species). An additional level of thiol/disulfide regulation is achieved by introducing dynamics in time and subcompartment and complex association. PMID: 22226570 [PubMed - as supplied... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5578079 Wed, 04 Jan 2012 05:00:00 +0100 5578079 http://www.medworm.com/index.php?rid=5578080&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%3D22217656%26dopt%3DAbstract Authors: Chen X, Laux T PMID: 22217656 [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=5578080 Mon, 02 Jan 2012 05:00:00 +0100 5578080 http://www.medworm.com/index.php?rid=5533880&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%3D22153653%26dopt%3DAbstract Authors: Hamamura Y, Nagahara S, Higashiyama T Abstract Double fertilization is a flowering plant mechanism whereby two immotile sperm cells fertilize two different female gametes. One of the two sperm cells fertilizes the egg cell to produce the embryo and the other fertilizes the central cell to produce the endosperm. Despite the biological and agricultural significance of double fertilization, the mechanism remains largely unknown owing to difficulties associated with the embedded structure of female gametes in the maternal tissue. However, molecular genetic approaches combined with novel live-cell imaging techniques have begun to clarify the actual behavior of the sperm cells, which is different from that described by previous hypotheses. In this review article, we discuss the ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5533880 Mon, 05 Dec 2011 05:00:00 +0100 5533880 http://www.medworm.com/index.php?rid=5419448&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%3D22079783%26dopt%3DAbstract Authors: Perilli S, Di Mambro R, Sabatini S Abstract A key question in plant developmental biology is how cell division and cell differentiation are balanced to modulate organ growth and shape organ size. In recent years, several advances have been made in understanding how this balance is achieved during root development. In the Arabidopsis root meristem, stem cells in the apical region of the meristem self-renew and produce daughter cells that differentiate in the distal meristem transition zone. Several factors have been implicated in controlling the different functional zones of the root meristem to modulate root growth; among these, plant hormones have been shown to play a main role. In this review, we summarize recent findings regarding the role of hormone signaling and trans... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5419448 Fri, 11 Nov 2011 05:00:00 +0100 5419448 http://www.medworm.com/index.php?rid=5419447&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%3D22079784%26dopt%3DAbstract Authors: Byrne ME Abstract Leaves are determinate organs that develop from the flanks of the shoot apical meristem through founder cell recruitment, establishment of proximodistal, dorsoventral and mediolateral axes, and subsequent growth, expansion and differentiation along these axes. Maintenance of the shoot apical meristem and production of leaves requires balanced partitioning of cells between pluripotent and differentiation fates. Hormones have a significant role in this balance but it is becoming apparent that additional intrinsic and extrinsic inputs influence hormone signalling to control meristem function and leaf initiation. As leaves develop, temporal and spatial regulation of growth and maturation determines leaf shape and complexity. Remarkably genes involved in leaf ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5419447 Fri, 11 Nov 2011 05:00:00 +0100 5419447 http://www.medworm.com/index.php?rid=5419446&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%3D22079785%26dopt%3DAbstract Authors: Jeong S, Volny M, Lukowitz W Abstract Apical-to-basal auxin flux is a defining feature of land plants and determines their main body axis. How is the axis first set up in the embryo? Recent studies reveal that the establishment of embryonic polarity with the asymmetric first division as well as the separation of shoot and root fates within the proembryo depend on transcriptional regulation in the zygote and early embryo. Although the functional connections need to be better defined, this transcriptional network likely provides the positional information required for initiating the machinery capable of processing the systemic signal auxin in a context-dependent manner. PMID: 22079785 [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=5419446 Fri, 11 Nov 2011 05:00:00 +0100 5419446 http://www.medworm.com/index.php?rid=5419445&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%3D22079786%26dopt%3DAbstract Authors: Grebe M Abstract Epidermal hairs of Arabidopsis thaliana emerge in regular spacing patterns providing excellent model systems for studies of biological pattern formation. A number of root-hair and leaf-trichome patterning mutants and tools for cell-specific and tissue-specific manipulation of patterning protein activities have been combined in cycles of experimentation and mathematical modelling. These approaches have provided insight into molecular mechanisms of epidermal patterning. During the last two years, endoreplication has, unexpectedly, been found to control cell-fate maintenance during trichome patterning. New genetic interactions between a downstream, positive transcriptional regulator and lateral inhibitors of trichome or non-root-hair fate specification have b... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5419445 Fri, 11 Nov 2011 05:00:00 +0100 5419445 http://www.medworm.com/index.php?rid=5419444&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%3D22079787%26dopt%3DAbstract Authors: Perales M, Reddy GV Abstract Stem cell homeostasis in shoot apical meristems of higher plants is regulated through a dynamic balance between spatial regulation of gene expression, cell growth patterns and patterns of differentiation. Cell-cell communication mediated by both the local factors and long-range signals have been implicated in stem cell homeostasis. Here we have reviewed recent developments on spatio-temporal regulation of cell-cell communication processes with an emphasis on how ubiquitously utilized signals such as plant hormones function with local factors in mediating stem cell homeostasis. We also provide a brief overview of how the activity of ubiquitously utilized epigenetic regulators are modulated locally to orchestrate gene expression. PMID: 220797... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5419444 Fri, 11 Nov 2011 05:00:00 +0100 5419444 http://www.medworm.com/index.php?rid=5419450&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%3D22078062%26dopt%3DAbstract Authors: Kim DH, Sung S Abstract In Arabidopsis, the role of the vernalization pathway is to repress expression of a potent floral repressor, FLOWERING LOCUS C (FLC), after a sufficient period of winter cold has been perceived. Following winter, the lack of FLC expression allows unimpeded operation of the photoperiod pathway and hence rapid flowering of vernalized plants in spring via the activation of floral integrator genes. Molecular studies revealed that regulation of the key floral repressor, FLC, is under the control of the interplay between Trithorax group (TrxG)-mediated activation and Polycomb group (PcG)-mediated repression. On-off switch of genes by TrxG and PcG is an evolutionarily conserved mechanism to coordinate cellular identity in eukaryotes. Regulation of FLC by e... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5419450 Wed, 09 Nov 2011 05:00:00 +0100 5419450 http://www.medworm.com/index.php?rid=5419449&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%3D22078063%26dopt%3DAbstract Authors: Oda Y, Fukuda H Abstract Xylem cell differentiation involves temporal and spatial regulation of secondary cell wall deposition. The cortical microtubules are known to regulate the spatial pattern of the secondary cell wall by orientating cellulose deposition. However, it is largely unknown how the microtubule arrangement is regulated during secondary wall formation. Recent findings of novel plant microtubule-associated proteins in developing xylem vessels shed new light on the regulation mechanism of the microtubule arrangement leading to secondary wall patterning. In addition, in vitro culture systems allow the dynamics of microtubules and microtubule-associated proteins during secondary cell wall formation to be followed. Therefore, this review focuses on novel aspects o... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5419449 Wed, 09 Nov 2011 05:00:00 +0100 5419449 http://www.medworm.com/index.php?rid=5379566&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%3D22037465%26dopt%3DAbstract Authors: Grimanelli D Abstract Apomictic plants reproduce asexually through seeds by avoiding both meiosis and fertilization. While apomixis is genetically controlled, individual loci contributing to its expression have yet to be identified. Here, we review recent results indicating that RNA-dependent DNA methylation pathways acting during female reproduction are essential for proper reproductive development in plants, and may represent key regulators of the differentiation between apomictic and sexual reproduction. PMID: 22037465 [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=5379566 Fri, 28 Oct 2011 04:00:00 +0100 5379566 http://www.medworm.com/index.php?rid=5379565&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%3D22037466%26dopt%3DAbstract Authors: Jones B, Ljung K Abstract The colonisation of terrestrial environments offered plants a host of advantages. It also presented them with major challenges. The foremost amongst these, the dichotomous nature of terrestrial environments, was clearly successfully met by the development of an integrated but divergent root-shoot structure. Whereas they share many similarities, roots and shoots evolved specialist functions in line with their principle roles and their growth environment. In this review, we discuss a number of areas where recent discoveries, principally in Arabidopsis, are shedding light on the mechanisms that enable the successful colonisation of the soil environment. PMID: 22037466 [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=5379565 Fri, 28 Oct 2011 04:00:00 +0100 5379565 http://www.medworm.com/index.php?rid=5379567&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%3D22035873%26dopt%3DAbstract Authors: Wollmann H, Berger F Abstract Epigenetic processes such as DNA methylation are crucial for the development of flowering plants, and for protection of genome integrity via silencing of transposable elements (TEs). Recent advances in genome-wide profiling suggest that during reproduction DNA methylation patterns are at least partially transmitted or even enhanced in the next generation to ensure stable silencing of TEs. At the same time, parent-of-origin specific removal of DNA methylation in the accompanying tissue allows imprinted expression of genes. Here we summarize the dynamics of DNA methylation as a major epigenetic regulatory pathway during reproduction and seed development. PMID: 22035873 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Bio... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5379567 Thu, 27 Oct 2011 04:00:00 +0100 5379567 http://www.medworm.com/index.php?rid=5379568&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%3D22001935%26dopt%3DAbstract Authors: Shan X, Yan J, Xie D Abstract Plant hormones are crucial signaling molecules that coordinate all aspects of plant growth, development and defense. A great deal of attention has been attracted from biologists to study the molecular mechanisms for perception and signal transduction of plant hormones during the last two decades. Tremendous progress has been made in identifying receptors and key signaling components of plant hormones. The holistic picture of hormone signaling pathways is extremely complicated, this review will give a general overview of perception and signal transduction mechanisms of auxin, gibberellin, cytokinin, abscisic acid, ethylene, brassinosteroid, and jasmonate. PMID: 22001935 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant B... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5379568 Fri, 14 Oct 2011 04:00:00 +0100 5379568 http://www.medworm.com/index.php?rid=5379570&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%3D22000039%26dopt%3DAbstract Authors: Jönsson H, Gruel J, Krupinski P, Troein C Abstract Recent advances in experimental plant biology have led to an increased potential to investigate plant development at a systems level. The emerging research field of Computational Morphodynamics has the aim to lead this development by combining dynamic spatial experimental data with computational models of molecular networks, growth, and mechanics in a multicellular context. The increased number of published models may lead to a diversification of our understanding of the systems, and methods for evaluating, comparing, and sharing models are main challenges for the future. We will discuss this problem using ideas originating from physics and use recent computational models of plant development as examples. PMID: 220000... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5379570 Thu, 13 Oct 2011 04:00:00 +0100 5379570 http://www.medworm.com/index.php?rid=5379569&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%3D22000040%26dopt%3DAbstract Authors: Konrad KR, Wudick MM, Feijó JA Abstract We review the recent advances on Ca(2+) in tip-growing cells, with a special focus on pollen tubes. New genes for Ca(2+) pumps, channels and sensing proteins have been recently described, with special emphasis on cyclic nucleotide gated channels (CNGCs) and glutamate receptor-like channels (GLRs). We also review the current state of knowledge in what concerns Ca(2+) sensor and relay proteins, where the knowledge of the cell models is less advanced. While these newly described genes offer promise to a better understanding of the spatial and temporal patterns of Ca(2+) signalling that may be relevant for the formation of the phenotype, we discuss the necessity to investigate further links in the network downstream of the Ca(2+) signat... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5379569 Thu, 13 Oct 2011 04:00:00 +0100 5379569 http://www.medworm.com/index.php?rid=5379571&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%3D21996565%26dopt%3DAbstract Authors: Gilroy S, Davies J PMID: 21996565 [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=5379571 Tue, 11 Oct 2011 04:00:00 +0100 5379571 http://www.medworm.com/index.php?rid=5296670&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%3D21974961%26dopt%3DAbstract Authors: Posé D, Yant L, Schmid M Abstract Substantial recent advances in genome-scale transcription factor target mapping have provided a fresh view of the gene networks governing developmental transitions. In particular, our understanding of the fine-scale spatial and temporal dynamics underlying the floral transition at the shoot apex has seen great advances in the past two years. Single transcription factors are regularly observed to act in complex manners, directly promoting the expression of particular targets while directly repressing the expression of others, based at least partly on defined heterodimerization patterns. For single regulators this behavior reaches into distinct physiological processes, providing compelling evidence that particular transcription factors act ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5296670 Mon, 03 Oct 2011 04:00:00 +0100 5296670 http://www.medworm.com/index.php?rid=5296671&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%3D21968124%26dopt%3DAbstract Authors: Iwano M, Takayama S Abstract Self-incompatibility (SI) in angiosperms prevents inbreeding and promotes outcrossing to generate genetic diversity. In many angiosperms, self/non-self recognition in SI is accomplished by male-specificity and female-specificity determinants (S-determinants), encoded at the S-locus. Recent studies using genetic, molecular biological and biochemical approaches have revealed that angiosperms utilize diverse self/non-self discrimination systems, which can be classified into two fundamentally different systems, self-recognition and non-self recognition systems. The self-recognition system, adopted by Brassicaceae and Papaveraceae, depends on a specific interaction between male and female S-determinants derived from the same S-haplotype. The non-sel... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5296671 Sat, 01 Oct 2011 04:00:00 +0100 5296671 http://www.medworm.com/index.php?rid=5296672&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%3D21963060%26dopt%3DAbstract Authors: Cheung AY, Wu HM Abstract The plant cell wall provides form and integrity to the cell as well as a dynamic interface between a cell and its environment. Therefore mechanisms capable of policing changes in the cell wall, signaling cellular responses including those that would feedback regulate cell wall properties are expected to play important roles in facilitating growth and ensuring survival. Discoveries in the last few years that the Arabidopsis THESEUS 1 receptor-like kinase (RLK) may function as a sensor for cell wall defects to regulate growth and that its relatives FERONIA and ANXURs regulate pollen tube integrity imply strongly that they play key roles in cell wall-related processes. Furthermore, FERONIA acts as a cell surface regulator for RAC/ROP GTPases and acti... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5296672 Thu, 29 Sep 2011 04:00:00 +0100 5296672 http://www.medworm.com/index.php?rid=5279055&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%3D21945181%26dopt%3DAbstract Authors: Chen X, Irani NG, Friml J Abstract Endocytosis in plants has an essential role not only for basic cellular functions but also for growth and development, hormonal signaling and communication with the environment including nutrient delivery, toxin avoidance, and pathogen defense. The major endocytic mechanism in plants depends on the coat protein clathrin. It starts by clathrin-coated vesicle formation at the plasma membrane, where specific cargoes are recognized and packaged for internalization. Recently, genetic, biochemical and advanced microscopy studies provided initial insights into mechanisms and roles of clathrin-mediated endocytosis in plants. Here we summarize the present state of knowledge and compare mechanisms of clathrin-mediated endocytosis in plants with ani... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5279055 Thu, 22 Sep 2011 04:00:00 +0100 5279055 http://www.medworm.com/index.php?rid=5246529&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%3D21924669%26dopt%3DAbstract Authors: Hückelhoven R, Panstruga R Abstract Powdery mildew fungi represent a paradigm for obligate biotrophic parasites, which only propagate in long-lasting intimate interactions with living host cells. These highly specialized phytopathogens induce re-organization of host cell architecture and physiology for their own demands. This probably includes the corruption of basal host cellular functions for successful fungal pathogenesis. Recent studies revealed secretory processes by both interaction partners as key incidents of the combat at the plant-fungus interface. The analysis of cellular events during plant-powdery mildew interactions may not only lead to a better understanding of plant pathological features, but may also foster novel discoveries in the area of plant cell biol... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5246529 Wed, 14 Sep 2011 04:00:00 +0100 5246529 http://www.medworm.com/index.php?rid=5218783&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%3D21906991%26dopt%3DAbstract Authors: Cutler S, Testerink C PMID: 21906991 [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=5218783 Wed, 07 Sep 2011 04:00:00 +0100 5218783 http://www.medworm.com/index.php?rid=5218784&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%3D21903451%26dopt%3DAbstract Authors: Simon-Plas F, Perraki A, Bayer E, Gerbeau-Pissot P, Mongrand S Abstract The dynamic segregation of membrane components within microdomains, such as the sterol-enriched and sphingolipid-enriched membrane rafts, emerges as a central regulatory mechanism governing physiological responses in various organisms. Over the past five years, plasma membrane located raft-like domains have been described in several plant species. The protein and lipid compositions of detergent-insoluble membranes, supposed to contain these domains, have been extensively characterised. Imaging methods have shown that lateral segregation of lipids and proteins exists at the nanoscale level at the plant plasma membrane, correlating detergent insolubility and membrane-domain localisation of presumptive ra... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5218784 Tue, 06 Sep 2011 04:00:00 +0100 5218784 http://www.medworm.com/index.php?rid=5175231&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%3D21865080%26dopt%3DAbstract Authors: Spalding EP, Harper JF Abstract The cytoplasmic Ca(2+) signals that participate in nearly all aspects of plant growth and development encode information as binary switches or information-rich signatures. They are the result of influx (thermodynamically passive) and efflux (thermodynamically active) activities mediated by membrane transport proteins. On the influx side, confirming the molecular identities of Ca(2+)-permeable channels is still a major research topic. Cyclic nucleotide-gated channels and glutamate receptor-like channels are candidates well supported by evidence. On the efflux side, CAX antiporters and P-type ATPase pumps are the principal molecular entities. Both of these active transporters load Ca(2+) into specific compartments and have the potential to red... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5175231 Sun, 21 Aug 2011 23:00:00 +0100 5175231 http://www.medworm.com/index.php?rid=5157205&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%3D21862389%26dopt%3DAbstract Authors: Brosnan CA, Voinnet O Abstract In plants, once triggered within a single-cell type, transgene-mediated RNA-silencing can move from cell-to-cell and over long distances through the vasculature to alter gene expression in tissues remote form the primary sites of its initiation. Although, transgenic approaches have been instrumental to genetically decipher the components and channels required for mobile silencing, the possible existence and biological significance of comparable endogenous mobile silencing pathways has remained an open question. Here, we summarize the results from recent studies that shed light on the molecular nature of the nucleic acids involved and on existing endogenous mechanisms that allow long-distance gene regulation and epigenetic modifications. We fu... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5157205 Thu, 18 Aug 2011 23:00:00 +0100 5157205 http://www.medworm.com/index.php?rid=5157204&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%3D21862390%26dopt%3DAbstract Authors: Suzuki N, Miller G, Morales J, Shulaev V, Torres MA, Mittler R Abstract Reactive oxygen species (ROS) play a key signal transduction role in cells. They are involved in the regulation of growth, development, responses to environmental stimuli and cell death. The level of ROS in cells is determined by interplay between ROS producing pathways and ROS scavenging mechanisms, part of the ROS gene network of plants. Recent studies identified respiratory burst oxidase homologues (RBOHs) as key signaling nodes in the ROS gene network of plants integrating a multitude of signal transduction pathways with ROS signaling. The ability of RBOHs to integrate calcium signaling and protein phosphorylation with ROS production, coupled with genetic studies demonstrating their involvement in ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5157204 Thu, 18 Aug 2011 23:00:00 +0100 5157204 http://www.medworm.com/index.php?rid=5157208&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%3D21855396%26dopt%3DAbstract Authors: Takeuchi H, Higashiyama T Abstract Pollen tube guidance is the mechanism whereby the direction of pollen tube growth is controlled by female cells of the pistil. Some key genes and molecules have recently been identified as being involved in pollen tube guidance. In this review article, we discuss the molecular basis of pollen tube guidance, especially in Arabidopsis thaliana, by summarizing recent progress in various plant species. Attractant molecules and receptors for gametophytic pollen tube guidance are the focus of this article. PMID: 21855396 [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=5157208 Wed, 17 Aug 2011 23:00:00 +0100 5157208 http://www.medworm.com/index.php?rid=5157207&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%3D21855397%26dopt%3DAbstract Authors: Clark G, Roux SJ Abstract Although no definitive receptor for extracellular ATP (eATP) has been identified in plants, there is now stronger physiological evidence that the effects of eATP on plant growth are mediated by a receptor, or, as in animals, by multiple receptors. Recent papers clarify how extracellular nucleotides induce changes in [Ca(2+)](cyt), and the production of nitric oxide (NO) and reactive oxygen species. They document links between eATP signaling and the synthesis or transport of hormones, and they reveal that applied nucleotides can regulate the aperture of stomates, which release ATP when stimulated by light and hormones. Ectoapyrases (ecto-nucleoside triphosphate-diphosphohydrolase) help control both the diverse signaling changes and downstream growt... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5157207 Wed, 17 Aug 2011 23:00:00 +0100 5157207 http://www.medworm.com/index.php?rid=5157206&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%3D21855398%26dopt%3DAbstract Authors: Kessler SA, Grossniklaus U Abstract In angiosperms, the sperm cells are carried within the pollen tubes (male gametophytes) to the female gametophyte so that double fertilization can occur. The female gametophyte exerts control over the male, with specialized cells known as synergids guiding the pollen tubes and controlling their behavior when they enter the female gametophyte so that the sperm cells can be delivered to the egg and central cell. Upon pollen tube arrival at the ovule, signal transduction cascades mediated by receptor-like kinases are initiated in both the synergid and the tip of the pollen tube, leading to synergid cell death and pollen tube rupture. In this review, we discuss the role of these receptors and of newly discovered members of the pollen tube re... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5157206 Wed, 17 Aug 2011 23:00:00 +0100 5157206 http://www.medworm.com/index.php?rid=5098822&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%3D21816662%26dopt%3DAbstract Authors: Gaupels F, Kuruthukulangarakoola GT, Durner J Nitric oxide (NO) is now recognised as a crucial player in plant defence against pathogens. Considerable progress has been made in defining upstream and downstream signals of NO. Recently, MAP kinases, cyclic nucleotide phosphates, calcium and phosphatidic acid were demonstrated to be involved in pathogen-induced NO-production. However, the search for inducers of NO synthesis is difficult because of the still ambiguous enzymatic source of NO. Accumulation of NO triggers signal transduction by other second messengers. Here we depict NON-EXPRESSOR OF PATHOGENESIS-RELATED 1 and glyceraldehyde-3-phosphate dehydrogenase as central redox switches translating NO redox signalling into cellular responses. Although the exact position of NO i... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5098822 Mon, 01 Aug 2011 23:00:00 +0100 5098822 http://www.medworm.com/index.php?rid=5098825&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%3D21807551%26dopt%3DAbstract Authors: Azevedo J, Cooke R, Lagrange T Argonautes are central and common components of crucial effectors of RNA silencing pathways. Although earlier steps in these pathways, such as small RNA biogenesis and their loading into AGO, have been quite well described, our knowledge on regulation of the action of AGO and their partners is still poor. Recent breakthroughs have highlighted the existence in many eukaryotes of an evolutionarily conserved motif, the Ago-hook, in factors implicated in AGO action. Furthermore, it has been shown that certain plant pathogen proteins have co-opted the Ago-hook as a means of evasion of plant defense systems. Here we discuss the roles and properties of Ago-hook proteins in divergent RNAi-related pathways. PMID: 21807551 [PubMed - as supplied by publ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5098825 Fri, 29 Jul 2011 23:00:00 +0100 5098825 http://www.medworm.com/index.php?rid=5098824&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%3D21807552%26dopt%3DAbstract Authors: Van Ex F, Jacob Y, Martienssen RA Germline development and early embryogenesis in eukaryotes are characterized by large-scale genome reprogramming events. In companion cells of the Arabidopsis male gametophyte, epigenome reorganization leads to loss of heterochromatin and production of a distinct small RNA (sRNA) population. A specific class of sRNA derived from transposons appears to be mobile and can accumulate in germ cells. In the germline of maize, rice, and Arabidopsis, specific ARGONAUTE-sRNA silencing complexes appear to play key roles in reproductive development, including meiosis and regulation of germ cell fate. These results reveal new roles for sRNAs during plant reproduction and suggest that mobility of sRNAs could be critical for some of these functions. PMI... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5098824 Fri, 29 Jul 2011 23:00:00 +0100 5098824 http://www.medworm.com/index.php?rid=5098823&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%3D21807553%26dopt%3DAbstract Authors: Tarutani Y, Takayama S Although the majority of genes are expressed equally from both alleles, some genes are differentially expressed. Monoallelic gene expression, the differential gene expression of the alleles such as genomic imprinting, is reported in several organisms and plays significant roles in proper development and diversity in gene expression and phenotypic variation. Recent studies in flowering plants have greatly increased our understanding of the underlying mechanisms of monoallelic gene expression. They indicate that machineries of gene silencing such as DNA methylation, histone modifications, and noncoding RNAs function in monoallelic gene expression. A combination of genetics and high-throughput technologies expands the scope of study on monoallelic gene expr... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5098823 Fri, 29 Jul 2011 23:00:00 +0100 5098823 http://www.medworm.com/index.php?rid=5098826&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%3D21803639%26dopt%3DAbstract Authors: Kumari S, van der Hoorn RA Structural biology efforts in recent years have generated numerous co-crystal structures of bioactive small molecules interacting with their plant targets. These studies include the targets of various phytohormones, pathogen-derived effectors, herbicides and other bioactive compounds. Here we discuss that this collection of structures contains excellent examples of nine collective observations: molecular glues, allostery, inhibitors, molecular mimicry, promiscuous binding sites, unexpected electron densities, natural selection at atomic resolution, and applications in structure-guided mutagenesis and small molecule design. PMID: 21803639 [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=5098826 Thu, 28 Jul 2011 23:00:00 +0100 5098826 http://www.medworm.com/index.php?rid=5098827&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%3D21802346%26dopt%3DAbstract Authors: Gudesblat GE, Russinova E Brassinosteroids (BRs) are plant steroid hormones known mainly for promoting organ growth through their combined effect on cell expansion and division. In addition, BRs regulate a broad spectrum of plant developmental and physiological responses, including plant architecture, vascular differentiation, male fertility, flowering, senescence, photomorphogenesis and tolerance to biotic and abiotic stresses. Recently, a complete core BR signaling pathway was defined in which BR signals are conveyed from the cell surface to the nucleus through sequential signaling modules. A major challenge now is to understand precisely how this signaling pathway controls the different BR-regulated actions. The current identification of direct targets of BRASSINAZOLE-RESIS... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5098827 Tue, 26 Jul 2011 23:00:00 +0100 5098827 http://www.medworm.com/index.php?rid=5051871&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%3D21775194%26dopt%3DAbstract Authors: Munnik T, Nielsen E Plant genomes lack homologues of the inositol 1,4,5-trisphosphate receptor and protein kinase C, which are important components of the canonical phospholipase C signalling system in animals. Instead, plants seem to utilize alternative downstream signalling molecules, that is, InsP(6) and phosphatidic acid. Inositol lipids may also function as second messengers themselves. By reversible phosphorylation of the inositol headgroup, five biologically active plant polyphosphoinositides can be detected. Protein targets interact with specific polyphosphoinositide isomers via selective lipid-binding domains, thereby altering their intracellular localization and/or enzymatic activity. Such lipid-binding domains have also been used to create GFP based-lipid biosensors... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5051871 Sun, 17 Jul 2011 23:00:00 +0100 5051871 http://www.medworm.com/index.php?rid=5051874&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%3D21764358%26dopt%3DAbstract Authors: Yao HY, Xue HW Vesicular trafficking is mediated by distinct exocytic and endocytic routes in eukaryotic cells. These pathways involve RAB family proteins, ADP-ribosylation factor, RHO proteins of the Ras superfamily, and SNAREs (soluble N-ethylmaleimide-sensitive factor adaptors). Studies have shown that vesicular trafficking plays a crucial role in protein localization and movement, signal transduction, and multiple developmental processes. Here we summarize the role of vesicular trafficking in root and root hair growth and in auxin-mediated root development, focusing on the regulation of the polarized subcellular distribution of the PIN proteins (auxin efflux carriers). PMID: 21764358 [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=5051874 Thu, 14 Jul 2011 23:00:00 +0100 5051874 http://www.medworm.com/index.php?rid=5051873&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%3D21764628%26dopt%3DAbstract Authors: Meier I, Somers DE The timing and position of molecular components within the cell are clearly important in the context of signal transduction. One challenge in attaining correct cellular positioning is the nuclear envelope, which separates the cell into two fundamentally different compartments. Molecular passaging from one to the other is highly selective due to the required recognition by the nucleocytoplasmic transport machinery. It is becoming increasingly clear that a highly diverse set of mechanisms have developed to allow environmental (biotic and abiotic) and endogenous signals to alter the nucleocytoplasmic partitioning of key molecules. In many cases this occurs by adjusting the access of the regulated species to the canonical import/export machinery. Recent studies ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5051873 Wed, 13 Jul 2011 23:00:00 +0100 5051873 http://www.medworm.com/index.php?rid=5051872&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%3D21764629%26dopt%3DAbstract Authors: Kline-Jonakin KG, Barrett-Wilt GA, Sussman MR Protein phosphorylation is a major post-translational modification in plants crucial for the regulation of diverse cellular functions. In the early stages of this field, efforts were focused on the qualitative detection, identification, and cataloging of in vivo protein phosphorylation sites. Recently these studies have advanced into utilizing quantitative mass spectrometric measurements, capable of dynamically monitoring changes in phosphorylation levels in response to genetic and environmental alterations. This review will highlight current untargeted and targeted mass spectral technologies used for quantitative phosphoproteome measurements in plants, and provide a discussion of these phosphorylation changes in relation to import... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5051872 Wed, 13 Jul 2011 23:00:00 +0100 5051872 http://www.medworm.com/index.php?rid=5051875&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%3D21763178%26dopt%3DAbstract Authors: Wu S, Gallagher KL Cell-to-cell signaling is essential for normal development and physiology. In both plants and animals, cells secrete proteins or peptides that influence the behavior or fate of neighboring cells. However in plants, signaling is also possible through direct transport of transcription factors between cells. Here we discuss some of the signaling pathways mediated by mobile transcription factors and their implications for plant growth and development. PMID: 21763178 [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=5051875 Tue, 12 Jul 2011 23:00:00 +0100 5051875 http://www.medworm.com/index.php?rid=5051876&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%3D21742545%26dopt%3DAbstract Authors: Antoni R, Rodriguez L, Gonzalez-Guzman M, Pizzio GA, Rodriguez PL The recent identification of abscisic acid (ABA) transporters provides an important insight into the delivery of ABA from the vascular system and its uptake by target cells. A putative connection with PYR/PYL receptors is envisaged, linking ABA uptake and intracellular perception by a fast and efficient mechanism. Downstream signaling of the core pathway involves regulation of ABA-responsive element binding factors (ABFs/AREBs) through phosphorylation, ubiquitination, and sumoylation in the case of ABI5. Several E3 ligases appear to regulate ABA signaling either positively or negatively, although relatively few targets are known yet. ABFs/AREBs are themselves subjected to transcriptional regulation, and some tra... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5051876 Thu, 07 Jul 2011 23:00:00 +0100 5051876 http://www.medworm.com/index.php?rid=5051877&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%3D21741297%26dopt%3DAbstract Authors: Oldroyd GE, Robatzek S PMID: 21741297 [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=5051877 Tue, 05 Jul 2011 23:00:00 +0100 5051877 http://www.medworm.com/index.php?rid=5051878&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%3D21733743%26dopt%3DAbstract Authors: Ulijasz AT, Vierstra RD Phytochromes are nature's primary photoreceptors dedicated to detecting the red and far-red regions of the visible light spectrum, a region also essential for photosynthesis and thus crucial to the survival of plants and other photosynthetic organisms. Given their roles in measuring competition and diurnal/seasonal light fluctuations, understanding how phytochromes work at the molecular level would greatly aid in engineering crop plants better suited to specific agricultural settings. Recently, scientists have determined the three-dimensional structures of prokaryotic phytochromes, which now provide clues as to how these modular photoreceptors might work at the atomic level. The models point toward a largely unifying mechanism whereby novel knot, hairpi... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5051878 Sun, 03 Jul 2011 23:00:00 +0100 5051878 http://www.medworm.com/index.php?rid=5006585&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%3D21723182%26dopt%3DAbstract Authors: Bernoux M, Ellis JG, Dodds PN Plant disease resistance can be triggered by specific recognition of microbial effectors by plant nucleotide binding-leucine rich repeat (NB-LRR) receptors. Over the last few years, many efforts have greatly improved the understanding of effector and NB-LRR function, but have left a lot of questions as to how effector perception activates NB-LRR induction of defense signaling. This review describes exciting new findings showing similarities and differences in function of diverse plant NB-LRR proteins in terms of pathogen recognition and where and how resistance proteins are activated. Localization studies have shown that some NB-LRRs can activate signaling from the cytosol while others act in the nucleus. Also, the structural determination of two ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=5006585 Tue, 28 Jun 2011 23:00:00 +0100 5006585 http://www.medworm.com/index.php?rid=4959694&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%3D21684190%26dopt%3DAbstract Authors: Hogenhout SA, Bos JI Insect herbivores have highly diverse life cycles and feeding behaviors. They establish close interactions with their plant hosts and suppress plant defenses. Chewing herbivores evoke characteristic defense responses distinguishable from general mechanical damage. In addition, piercing-sucking hemipteran insects display typical feeding behavior that suggests active suppression of plant defense responses. Effectors that modulate plant defenses have been identified in the saliva of these insects. Tools for high-throughput effector identification and functional characterization have been developed. In addition, in some insect species it is possible to silence gene expression by RNAi. Together, this technological progress has enabled the identification of inse... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4959694 Wed, 15 Jun 2011 23:00:00 +0100 4959694 http://www.medworm.com/index.php?rid=4911944&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%3D21641854%26dopt%3DAbstract Authors: Stassen JH, Van den Ackerveken G Oomycete genomes have yielded a large number of predicted effector proteins that collectively interfere with plant life in order to create a favourable environment for pathogen infection. Oomycetes secrete effectors that can be active in the host's extracellular environment, for example inhibiting host defence enzymes, or inside host cells where they can interfere with plant processes, in particular suppression of defence. Two classes of effectors are known to be host-translocated: the RXLRs and Crinklers. Many effectors show defence-suppressive activity that is important for pathogen virulence. A striking example is AVR3a of Phytophthora infestans that targets an ubiquitin ligase, the stabilisation of which may prevent host cell death. The que... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4911944 Thu, 02 Jun 2011 23:00:00 +0100 4911944 http://www.medworm.com/index.php?rid=4911945&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%3D21636314%26dopt%3DAbstract Authors: Yamaguchi Y, Huffaker A Plant defense responses against invading organisms are initiated through the perception of molecules associated with attacking microbes and herbivores by pattern recognition receptors. In addition to elicitor molecules derived from attacking organisms, plants recognize host-derived molecules. These endogenous elicitors induce and amplify the defense responses against invading organisms both locally and systemically. Several classes of plant-derived molecules elicit defense, including cell wall fragments and peptides. Endogenous peptide elicitors have been discovered in species across the plant kingdom, and their role regulating immunity to both herbivores and pathogens is becoming increasingly appreciated. In this review, we will focus on the five known... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4911945 Mon, 30 May 2011 23:00:00 +0100 4911945 http://www.medworm.com/index.php?rid=4862152&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%3D21600838%26dopt%3DAbstract Authors: Krämer U, Amtmann A PMID: 21600838 [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=4862152 Tue, 17 May 2011 23:00:00 +0100 4862152 http://www.medworm.com/index.php?rid=4862153&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%3D21571579%26dopt%3DAbstract Authors: Abel S Phosphate (Pi) and its anhydrides constitute major nodes in metabolism. Thus, plant performance depends directly on Pi nutrition. Inadequate Pi availability in the rhizosphere is a common challenge to plants, which activate metabolic and developmental responses to maximize Pi usage and acquisition. The sensory mechanisms that monitor environmental Pi and transmit the nutritional signal to adjust root development have increasingly come into focus. Recent transcriptomic analyses and genetic approaches have highlighted complex antagonistic interactions between external Pi and Fe bioavailability and have implicated the stem cell niche as a target of Pi sensing to regulate root meristem activity. PMID: 21571579 [PubMed - as supplied by publisher] (Source: Current Opinion... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4862153 Thu, 12 May 2011 23:00:00 +0100 4862153 http://www.medworm.com/index.php?rid=4862155&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%3D21561797%26dopt%3DAbstract Authors: Alcázar R, Reymond M, Schmitz G, de Meaux J There is now ample evidence that plant development, responses to abiotic environments, and immune responses are tightly intertwined in their physiology. Thus optimization of the immune system during evolution will occur in coordination with that of plant development. Two alternative and possibly complementary forces are at play: genetic constraints due to the pleiotropic action of players in both systems, and coevolution, if developmental changes modulate the cost-benefit balance of immunity. A current challenge is to elucidate the ecological forces driving evolution of quantitative variation for defense at molecular level. The analysis of natural co-variation for developmental and immunity traits in Arabidopsis thaliana promises to... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4862155 Sun, 08 May 2011 23:00:00 +0100 4862155 http://www.medworm.com/index.php?rid=4862154&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%3D21561798%26dopt%3DAbstract Authors: Verslues PE, Juenger TE Drought elicits substantial changes in plant metabolism and it remains a challenge to determine which of these changes represent adaptive responses and which of them are merely neutral effects or even symptoms of damage. Arabidopsis primarily uses low water potential/dehydration avoidance strategies to respond to water limitation. The large variation in evolved stress responses among accessions can be a powerful tool to identify ecologically important and adaptive traits; however, collection of relevant phenotype data under controlled water stress is often a limiting factor. Quantitative genetics of Arabidopsis has great potential to find the genes underlying variation in drought-affected metabolic traits, for example proline metabolism, as well as over... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4862154 Sun, 08 May 2011 23:00:00 +0100 4862154 http://www.medworm.com/index.php?rid=4804892&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%3D21550295%26dopt%3DAbstract Authors: Long TA Plants react to abiotic stress with a number of physiological, biochemical, and developmental alterations. These responses include changes in signaling components, gene transcription, non-coding RNAs, proteins, and metabolites that occur in a cell-type and tissue-specific manner. Recent advances in cell-type specifically isolating protoplasts and nuclei from plants, extracting mRNA from targeted cells, and whole-genome transcriptional profiling have enabled scientists to gain insight into how cells and tissues respond transcriptionally to abiotic stress. Continued technological advances in profiling the proteomes, metabolomes, and other biological components of specific cells will continue to broaden our understanding of plant stress responses. PMID: 21550295 [PubM... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804892 Wed, 04 May 2011 23:00:00 +0100 4804892 http://www.medworm.com/index.php?rid=4804894&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%3D21536479%26dopt%3DAbstract Authors: Trontin C, Tisné S, Bach L, Loudet O Sessile organisms such as plants have to develop adaptive responses to face environmental change. In Arabidopsis thaliana populations, natural variation for stress responses have been observed at different levels of integration and the genetic bases of those variations have been analysed using two strategies: classical linkage and association (LD) mapping. The strength of Arabidopsis resides in the huge amount of genomic data and molecular tools available leading to the identification of many polymorphisms responsible for phenotypic variation. Remaining limitations to clearly understand how Arabidopsis adapts to its environment, that is the complexity of the genetic architecture and the lack of ecological data, should be partially solved t... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804894 Fri, 29 Apr 2011 23:00:00 +0100 4804894 http://www.medworm.com/index.php?rid=4804893&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%3D21536480%26dopt%3DAbstract Authors: Reinhold-Hurek B, Hurek T As current research activities have focused on symbiotic or parasitic plant-microbe interactions, other types of associations between plants and microorganisms are often overlooked. Endophytic bacteria colonize inner host tissues, sometimes in high numbers, without damaging the host or eliciting strong defense responses. Unlike endosymbionts they are not residing in living plant cells or surrounded by a membrane compartment. The molecular basis of endophytic interactions is still not well understood. Several traits involved in the establishment of endophytes have been elucidated. Culture-independent methods for community analysis and functional genomic as well as comparative genomic analyses will provide a better understanding of community dynamics, s... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804893 Fri, 29 Apr 2011 23:00:00 +0100 4804893 http://www.medworm.com/index.php?rid=4804896&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%3D21531166%26dopt%3DAbstract Authors: Hanikenne M, Nouet C In the course of evolution, plants adapted to widely differing metal availabilities in soils and therefore represent an important source of natural variation of metal homeostasis networks. Research on plant metal homeostasis can thus provide insights into the functioning, regulation and adaptation of biological networks. Here, we describe major recent breakthroughs in the understanding of the genetic and molecular basis of metal hyperaccumulation and associated hypertolerance, a naturally selected complex trait which represents an extreme adaptation of the metal homeostasis network. Investigations in this field reveal further the molecular alterations underlying the evolution of natural phenotypic diversity and provide a highly relevant framework for compa... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804896 Wed, 27 Apr 2011 23:00:00 +0100 4804896 http://www.medworm.com/index.php?rid=4804895&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%3D21531167%26dopt%3DAbstract Authors: Wulff BB, Horvath DM, Ward ER Crop disease remains a major cause of yield loss and emerging diseases pose new threats to global food security. Despite the dearth of commercial development to date, progress in using our rapidly expanding knowledge of plant-pathogen interactions to invent new ways of controlling diseases in crops has been good. Many major resistance genes have now been shown to retain function when transferred between species, and evidence indicates that resistance genes are more effective when deployed in a background containing quantitative resistance traits. The EFR pattern-recognition receptor, present in only the Brassicaceae, functions to provide bacterial disease control in the Solanaceae. Knowledge of how transcription activator-like effectors bind DNA i... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804895 Wed, 27 Apr 2011 23:00:00 +0100 4804895 http://www.medworm.com/index.php?rid=4804900&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%3D21530365%26dopt%3DAbstract Authors: Kessler D, Baldwin IT Manipulations of the interactions between plants and their floral visitors remain the most successful path to an understanding of floral traits, which may have been shaped by both herbivores and pollinators. By using genetic tools in combination with old-fashioned field work the dual protective/advertisement functions of floral traits are being realized. The distinction between wanted and unwanted floral visitors is blurring, and plants with specialized pollination systems are being found capable of using alternative pollinators if the specialized pollinators fail to perform. PMID: 21530365 [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=4804900 Tue, 26 Apr 2011 23:00:00 +0100 4804900 http://www.medworm.com/index.php?rid=4804899&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%3D21530366%26dopt%3DAbstract Authors: Veneault-Fourrey C, Martin F Saprophytic, ectomycorrhizal (ECM) and pathogenic fungi play a key role in carbon and nutrient cycling in forest ecosystems. Whereas more than 50 genomes of saprotrophic and pathogenic fungi have been published, only two genomes of ECM fungi, Laccaria bicolor and Tuber melanosporum, have been released. Comparative analysis of the genomes of biotrophic species highlighted convergent evolution. Mutualistic and pathogenic biotrophic fungi share expansion of genome size through transposon proliferation and common strategies to avoid plant detection. Differences mainly rely on nutritional strategies. Such analyses also pinpointed how blurred the molecular boundaries are between saprotrophism, symbiosis and pathogenesis. Sequencing of additional ECM spec... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804899 Tue, 26 Apr 2011 23:00:00 +0100 4804899 http://www.medworm.com/index.php?rid=4804898&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%3D21530367%26dopt%3DAbstract Authors: Zhu J, Ingram PA, Benfey PN, Elich T Plant root system architecture (RSA) is plastic and dynamic, allowing plants to respond to their environment in order to optimize acquisition of important soil resources. A number of RSA traits are known to be correlated with improved crop performance. There is increasing recognition that future gains in productivity, especially under low input conditions, can be achieved through optimization of RSA. However, realization of this goal has been hampered by low resolution and low throughput approaches for characterizing RSA. To overcome these limitations, new methods are being developed to facilitate high throughput and high content RSA phenotyping. Here we summarize laboratory and field approaches for phenotyping RSA, drawing particular atten... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804898 Tue, 26 Apr 2011 23:00:00 +0100 4804898 http://www.medworm.com/index.php?rid=4804897&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%3D21530368%26dopt%3DAbstract Authors: Walker EL, Waters BM For human health, transition metal accumulation in edible seeds like cereal grains is of worldwide importance, since Fe and Zn deficiencies are among the most prevalent human nutritional disorders in the world. There have been many recent developments in our understanding of the patterns in which transition metals accumulate in the seeds, the identity of some specific transporters that are required for efficient seed metal accumulation, and the central role played by the ubiquitous plant metal chelator nicotianamine (NA). These and other recent discoveries will be reviewed here. PMID: 21530368 [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=4804897 Tue, 26 Apr 2011 23:00:00 +0100 4804897 http://www.medworm.com/index.php?rid=4804901&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%3D21514879%26dopt%3DAbstract Authors: Kroymann J Technological advances in metabolomics, transcriptomics and genomics have facilitated the detection of genes that contribute to diversification in plant secondary metabolism. Statistical tools from molecular population genetics may help in evaluating whether the corresponding genes or genomic regions carry a signature of selection and answering the question of whether novel compounds are 'adaptive'. Gene duplication fuels diversification in plant secondary metabolism and the evolutionary mechanism for adaptation may follow a path of neofunctionalization subsequent to gene duplication, or gene duplication may occur subsequent to - and resolve - an adaptive conflict present in a single ancestral gene sequence. PMID: 21514879 [PubMed - as supplied by publisher] (So... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804901 Thu, 21 Apr 2011 23:00:00 +0100 4804901 http://www.medworm.com/index.php?rid=4804903&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%3D21511515%26dopt%3DAbstract Authors: Galvan-Ampudia CS, Testerink C Plants use different strategies to deal with high soil salinity. One strategy is activation of pathways that allow the plant to export or compartmentalise salt. Relying on their phenotypic plasticity, plants can also adjust their root system architecture (RSA) and the direction of root growth to avoid locally high salt concentrations. Here, we highlight RSA responses to salt and osmotic stress and the underlying mechanisms. A model is presented that describes how salinity affects auxin distribution in the root. Possible intracellular signalling pathways linking salinity to root development and direction of root growth are discussed. These involve perception of high cytosolic Na(+) concentrations in the root, activation of lipid signalling and pro... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804903 Mon, 18 Apr 2011 23:00:00 +0100 4804903 http://www.medworm.com/index.php?rid=4804902&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%3D21511516%26dopt%3DAbstract Authors: Farrant JM, Moore JP Desiccation-tolerance (DT) evolved as the key solution to survival on land by the early algal ancestors of terrestrial plants. This 'first' DT involved utilizing rapidly mobilisable repair mechanisms and is still found today in mosses, such as Tortula ruralis, and ferns, such as Mohria caffrorum. The first seed plants lost vegetative DT while investing their seeds with tolerance mechanisms improving their survival in unfavourable environments. The mechanisms of DT in seeds are strongly connected to their developmentally regulated maturation programs. We propose that angiosperm resurrection plants acquired tolerance by re-activating their innate DT mechanisms in their vegetative tissues. Here we review the current hypotheses regarding the genetic evidence f... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804902 Mon, 18 Apr 2011 23:00:00 +0100 4804902 http://www.medworm.com/index.php?rid=4804904&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%3D21507708%26dopt%3DAbstract Authors: Grefen C, Honsbein A, Blatt MR Throughout their development, plants balance cell surface area and volume with ion transport and turgor. This balance lies at the core of cellular homeostatic networks and is central to the capacity to withstand abiotic as well as biotic stress. Remarkably, very little is known of its mechanics, notably how membrane traffic is coupled with osmotic solute transport and its control. Here we outline recent developments in the understanding of so-called SNARE proteins that form part of the machinery for membrane vesicle traffic in all eukaryotes. We focus on SNAREs active at the plasma membrane and the evidence for specialisation in enhanced, homeostatic and stress-related traffic. Recent studies have placed a canonical SNARE complex associated with ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804904 Sun, 17 Apr 2011 23:00:00 +0100 4804904 http://www.medworm.com/index.php?rid=4804906&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%3D21489860%26dopt%3DAbstract Authors: Popp C, Ott T Among plant-microbe interactions, root nodule symbiosis is one of the most important beneficial interactions providing legume plants with nitrogenous compounds. Over the past years a number of genes required for root nodule symbiosis has been identified but most recently great advances have been made to dissect signalling pathways and molecular interactions triggered by a set of receptor-like kinases. Genetic and biochemical approaches have not only provided evidence for the cross talk between bacterial infection of the host plant and organogenesis of a root nodule but also gained insights into dynamic regulation processes underlying successful infection events. Here, we summarise recent progress in the understanding of molecular mechanisms that regulate and trig... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804906 Mon, 11 Apr 2011 23:00:00 +0100 4804906 http://www.medworm.com/index.php?rid=4804905&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%3D21489861%26dopt%3DAbstract Authors: Bonfante P, Requena N The arbuscular mycorrhizal symbiosis that involves most plants and Glomeromycota fungi is the result of a complex exchange of molecular information, which commences before the partners are in physical contact. On the one hand, plants release soluble factors, including strigolactones that activate both the metabolism and branching of the fungal partners. On the other hand, fungi use compounds that trigger the signaling transduction pathways that are required for the symbiotic modus of plant cells. Here we describe some of the recent discoveries regarding the fungal molecules involved in rhizospheric conversation, and the way in which they are perceived by their hosts. We conclude that similar signaling molecules may have different meanings, depending on th... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4804905 Mon, 11 Apr 2011 23:00:00 +0100 4804905 http://www.medworm.com/index.php?rid=4699188&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%3D21478048%26dopt%3DAbstract Authors: Richards EJ Researchers are beginning to use wild plant populations to survey and assess cytosine methylation polymorphisms in a population and ecological genetic framework. These studies support the plausibility of adaptive epigenetic alleles, but uncertainty remains due to the difficulty in untangling genetic and epigenetic variation in wild populations. The increasing emphasis on stress-induced epigenetic alterations and transgenerational phenomena among researchers focused on epigenetic mechanisms should push practitioners of this subfield to consider the questions and tools of colleagues grappling with epigenetics from ecological and evolutionary perspectives. PMID: 21478048 [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=4699188 Tue, 05 Apr 2011 23:00:00 +0100 4699188 http://www.medworm.com/index.php?rid=4699186&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%3D21478049%26dopt%3DAbstract Authors: Roy SJ, Tucker EJ, Tester M Abiotic stress tolerance is complex, but as phenotyping technologies improve, components that contribute to abiotic stress tolerance can be quantified with increasing ease. In parallel with these phenomics advances, genetic approaches with more complex genomes are becoming increasingly tractable as genomic information in non-model crops increases and even whole crop genomes can be re-sequenced. Thus, genetic approaches to elucidating the molecular basis to abiotic stress tolerance in crops are becoming more easily achievable. PMID: 21478049 [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=4699186 Tue, 05 Apr 2011 23:00:00 +0100 4699186 http://www.medworm.com/index.php?rid=4699205&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%3D21444239%26dopt%3DAbstract Authors: Lisch D, Bennetzen JL Transposable elements (TEs) are massively abundant and unstable in all plant genomes, but are mostly silent because of epigenetic suppression. Because all known epigenetic pathways act on all TEs, it is likely that the specialized epigenetic regulation of regular host genes (RHGs) was co-opted from this ubiquitous need for the silencing of TEs and viruses. With their internally repetitive and rearranging structures, and the acquisition of fragments of RHGs, the expression of TEs commonly makes antisense RNAs for both TE genes and RHGs. These antisense RNAs, particularly from heterochromatic reservoirs of 'zombie' TEs that are rearranged to form variously internally repetitive structures, may be advantageous because their induction will help rapidly suppre... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699205 Sun, 03 Apr 2011 23:00:00 +0100 4699205 http://www.medworm.com/index.php?rid=4699191&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%3D21470900%26dopt%3DAbstract Authors: Mayfield D, Chen ZJ, Pires JC Polyploidy plays a significant role in the evolution of flowering plants. Understanding the effects of polyploidy on the epigenetic regulation of adaptive traits may resolve questions about the success of polyploids. One such trait, flowering time, has been the subject of several gene expression studies because it has one of the best characterized genetic networks and because polyploidy has a significant impact on generating variation in flowering time. Future research on the epigenetic consequences of polyploidy on flowering time should begin to examine natural variation in an ecological context, while continuing to make use of resynthesized polyploids. PMID: 21470900 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biolo... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699191 Sun, 03 Apr 2011 23:00:00 +0100 4699191 http://www.medworm.com/index.php?rid=4699190&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%3D21470901%26dopt%3DAbstract Authors: Schmitz RJ, Zhang X In plant cells, DNA is packaged into chromatin by wrapping around histone octamers. Pathways that lead to cytosine DNA methylation, posttranslational histone modifications and certain components of the RNA interfering (RNAi) pathway are critically important in modulating chromatin structure, thereby affecting many molecular processes that take place in a cell. Recent advances in microarray and high-throughput sequencing technologies have made it possible to study these pathways on a genome-wide scale. Results from such epigenomic studies are broadening our understanding of plant genomes and are also providing important clues regarding the mechanisms and functions of these pathways that can be further tested using genetic and biochemical approaches. This rev... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699190 Sun, 03 Apr 2011 23:00:00 +0100 4699190 http://www.medworm.com/index.php?rid=4699192&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%3D21459033%26dopt%3DAbstract Authors: Elmore JM, Lin ZJ, Coaker G Plant disease resistance proteins commonly belong to the nucleotide binding-leucine rich repeat (NB-LRR) protein family. These specialized immune proteins mediate recognition of diverse pathogen-derived effector proteins and initiate potent defense responses. NB-LRRs exhibit a multidomain architecture and each domain appears to have discrete functions depending on the stage of NB-LRR signaling. Novel proteins that were found to interact with the core HSP90 chaperone complex regulate accumulation and activation of NB-LRR immune receptors. Recent studies have also advanced our understanding of how accessory proteins contribute to NB-LRR activation. The dynamic nature of NB-LRR localization to different subcellular compartments before and after activat... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699192 Wed, 30 Mar 2011 23:00:00 +0100 4699192 http://www.medworm.com/index.php?rid=4699195&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%3D21458359%26dopt%3DAbstract Authors: Schmidt SM, Panstruga R Members of the kingdom fungi comprise numerous plant pathogens, including the causal agents of many agriculturally relevant plant diseases such as rust, powdery mildew, rice blast and cereal head blight. Data from recent sequencing projects provide deep insight into the genomes of a range of fungi that infect different organs of monocotyledonous or dicotyledonous hosts and that have diverse pathogenic lifestyles. These studies have revealed that, similar to sequenced phytopathogenic oomycetes, these plant parasites possess very plastic and dynamic genomes, which typically encode several hundred candidate secreted effector proteins that can be highly divergent even among related species. A new insight is the presence of lineage-specific genes on mobile a... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699195 Tue, 29 Mar 2011 23:00:00 +0100 4699195 http://www.medworm.com/index.php?rid=4699194&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%3D21458360%26dopt%3DAbstract Authors: Elena SF, Carrera J, Rodrigo G Omic approaches to the analysis of plant-virus interactions are becoming increasingly popular. These types of data, in combination with models of interaction networks, will aid in revealing not only host components that are important for the virus life cycle, but also general patterns about the way in which different viruses manipulate host regulation of gene expression for their own benefit and possible mechanisms by which viruses evade host defenses. Here, we review studies identifying host genes regulated by viruses and discuss how these genes integrate in host regulatory and interaction networks, with a particular focus on the physical properties of these networks. PMID: 21458360 [PubMed - as supplied by publisher] (Source: Current Opinio... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699194 Tue, 29 Mar 2011 23:00:00 +0100 4699194 http://www.medworm.com/index.php?rid=4699193&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%3D21458361%26dopt%3DAbstract Authors: Gheysen G, Mitchum MG Sedentary plant-parasitic nematodes establish long term relationships with their hosts. Root vascular cells are transformed into large multinucleate feeding cells from which the nematodes feed for more than one month. Recent transcriptome analyses suggest that feeding cells are different from other plant cell types. Their development, however, remains poorly understood, despite new evidence that appears to confirm previously proposed models, such as the important role of auxin. From the analysis of nematode effector proteins that interact with plant proteins, it has become clear that nematodes manipulate many aspects of plant development, including auxin transport and plant cell differentiation pathways. These studies are also revealing roles for effector... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699193 Tue, 29 Mar 2011 23:00:00 +0100 4699193 http://www.medworm.com/index.php?rid=4699202&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%3D21454120%26dopt%3DAbstract Authors: de Jonge R, Bolton MD, Thomma BP Research on effectors secreted by pathogens during host attack has dominated the field of molecular plant-microbe interactions over recent years. Functional analysis of type III secreted effectors injected by pathogenic bacteria into host cells has significantly advanced the field and demonstrated that many function to suppress host defense. Fungal and oomycete effectors are delivered outside the host plasma membrane, and although research has lagged behind on bacterial effectors, we are gradually learning more and more about the functions of these effectors. While some function outside the host cell to disarm defense, others exploit host cellular uptake mechanisms to suppress defense or liberate nutrients intracellularly. Comparative genomics ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699202 Mon, 28 Mar 2011 23:00:00 +0100 4699202 http://www.medworm.com/index.php?rid=4699196&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%3D21454121%26dopt%3DAbstract Authors: Spoel SH, Loake GJ Activation of plant immunity is associated with dramatic changes in the cellular redox status. Both oxidative and reductive bursts have been described that trigger a set of down stream responses resulting in reprogramming of the transcriptome and establishment of disease resistance. Nonetheless, how these redox changes are sensed and signal to downstream regulators remained a missing link in studies of plant immunity. Emerging evidence now indicates that pathogen-induced changes in the cellular redox environment are sensed by reactive cysteine residues of key regulatory proteins. Varying degrees of reversible, oxidative cysteine modifications control the activity, localization, protein-interaction and stability of regulatory proteins. These diverse effects o... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699196 Mon, 28 Mar 2011 23:00:00 +0100 4699196 http://www.medworm.com/index.php?rid=4699203&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%3D21450514%26dopt%3DAbstract Authors: Mirouze M, Paszkowski J Plant epigenetics has recently gained unprecedented interest, not only as a subject of basic research but also as a possible new source of beneficial traits for plant breeding. We discuss here mechanisms of epigenetic regulation that should be considered when undertaking the latter. Since these mechanisms are responsible for the formation of heritable epigenetic gene variants (epialleles) and also regulate transposons mobility, both aspects could be exploited to broaden plant phenotypic and genetic variation, which could improve long-term plant adaptation to environmental challenges and, thus, increase productivity. PMID: 21450514 [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=4699203 Sun, 27 Mar 2011 23:00:00 +0100 4699203 http://www.medworm.com/index.php?rid=4699204&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%3D21444240%26dopt%3DAbstract Authors: Arnold DL, Jackson RW Bacterial pathogens continue to pose a major threat to economically important plant resources. Disease outbreaks can occur through rapid evolution of a pathogen to overcome host defences. The advent of genome sequencing, especially next-generation technologies, has seen a revolution in the study of plant pathogen evolution over the past five years. This review highlights recent developments in understanding bacterial plant pathogen evolution, enabled by genomics and specifically focusing on type III protein effectors. The genotypic changes and mechanisms involved in pathogen evolution are now much better understood. However, there is still much to be learned about the drivers of pathogen evolution, both in terms of plant resistance and bacterial lifestyle... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699204 Sat, 26 Mar 2011 00:00:00 +0100 4699204 http://www.medworm.com/index.php?rid=4699206&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%3D21440490%26dopt%3DAbstract Authors: Boyko A, Kovalchuk I As sessile organisms, plants need to continuously adjust their responses to external stimuli to cope with changing growth conditions. Since the seed dispersal range is often rather limited, exposure of progeny to the growth conditions of parents is very probable. The plasticity of plant phenotypes cannot be simply explained by genetic changes such as point mutations, deletions, insertions and gross chromosomal rearrangements. Since many environmental stresses persist for only one or several plant generations, other mechanisms of adaptation must exist. The heritability of reversible epigenetic modifications that regulate gene expression without changing DNA sequence makes them an attractive alternative mechanism. In this review, we discuss recent advances i... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4699206 Thu, 24 Mar 2011 00:00:00 +0100 4699206 http://www.medworm.com/index.php?rid=4643105&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%3D21435940%26dopt%3DAbstract Authors: Bauer MJ, Fischer RL Imprinting occurs in the endosperm of flowering plants. The endosperm, a product of central cell fertilization, is critical for embryo and seed development. Imprinting in the endosperm is mainly due to the inherited differences in gamete epigenetic composition. Studies have also shown that there are differences in genomic DNA methylation patterns between embryo and endosperm. Examining those differences, along with mutations in the DNA demethylase gene DEMETER, gives insight into the number of imprinted genes and how an antagonistic relationship between TE defense and gene regulation could evolutionarily affect imprinting establishment. Finally, studies demonstrate that DEMETER demethylase activity influences endosperm chromatin composition, and could poss... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4643105 Tue, 22 Mar 2011 00:00:00 +0100 4643105 http://www.medworm.com/index.php?rid=4643107&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%3D21420347%26dopt%3DAbstract Authors: Erhard KF, Hollick JB Basic tenets of Mendelian inheritance are violated by paramutations in which trans-homolog interactions lead to heritable changes in gene regulation and phenotype. First described in plants, similar behaviors have now been noted in diverse eukaryotes. Genetic and molecular studies of paramutations occurring in maize indicate that components of a small interfering RNA (siRNA) biogenesis pathway are required for the maintenance of meiotically heritable regulatory states. Although these findings lead to a hypothesis that siRNAs themselves mediate paramutation interactions, an assessment of existing data supports the opinion that siRNAs alone are insufficient. Recent evidence implies that transcription of paramutation-associated repeats and siRNA-facilitated ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4643107 Thu, 17 Mar 2011 00:00:00 +0100 4643107 http://www.medworm.com/index.php?rid=4643106&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%3D21420348%26dopt%3DAbstract Authors: Zhang H, Zhu JK DNA methylation is an important epigenetic mechanism for silencing transposons and other repetitive elements, and for stable repression of specific transgenes and endogenous genes. Plants can utilize small interfering RNAs (siRNAs) to guide de novo DNA methyltransferases for the establishment of sequence-specific DNA methylation. Genetic and biochemical approaches have identified many components involved in RNA-directed DNA methylation (RdDM). These components function in one or more of the following three aspects: biogenesis of siRNAs, production of scaffold RNAs, and the assembly of an effector complex that involves the complementary pairing between the guide siRNAs and nascent scaffold RNAs and that recruits the DNA methyltransferases. Recent studies not onl... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4643106 Thu, 17 Mar 2011 00:00:00 +0100 4643106 http://www.medworm.com/index.php?rid=4643109&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%3D21411363%26dopt%3DAbstract Authors: De Block M, Van Lijsebettens M The importance of energy metabolism in plant performance and plant productivity is conceptually well recognized. In the eighties, several independent studies in Lolium perenne (ryegrass), Zea mays (maize), and Festuca arundinacea (tall fescue) correlated low respiration rates with high yields. Similar reports in the nineties largely confirmed this correlation in Solanum lycopersicum (tomato) and Cucumis sativus (cucumber). However, selection for reduced respiration does not always result in high-yielding cultivars. Indeed, the ratio between energy content and respiration, defined here as energy efficiency, rather than respiration on its own, has a major impact on the yield potential of a crop. Besides energy efficiency, energy homeostasis, repres... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4643109 Mon, 14 Mar 2011 00:00:00 +0100 4643109 http://www.medworm.com/index.php?rid=4643108&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%3D21411364%26dopt%3DAbstract Authors: Birchler JA, Gao Z, Sharma A, Presting GG, Han F Centromeres were once thought to be boring structures on the chromosome involved with transmission through mitosis and meiosis. Recent data from a wide spectrum of organisms reveal an epigenetic component to centromere specification in that they can become inactive easily or form over unique DNA as neocentromeres. However, the constancy of centromere repeats at primary constrictions in most species, the fact that these repeats are transcribed and incorporated into the kinetochore, and the phenomenon of reactivation of formerly inactive centromeres at the same chromosomal sites suggests some type of role of DNA sequence or configuration in establishing the site of kinetochores. Here we present evidence for epigenetic and structur... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4643108 Mon, 14 Mar 2011 00:00:00 +0100 4643108 http://www.medworm.com/index.php?rid=4580846&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%3D21388861%26dopt%3DAbstract Authors: Tardieu F, Granier C, Muller B Water deficit affects plant growth via reduced carbon accumulation, cell number and tissue expansion. We review the ways in which these processes are co-ordinated. Tissue expansion and its sensitivity to water deficit may be the most crucial process, involving tight co-ordination between the mechanisms which govern cell wall mechanical properties and plant hydraulics. The analyses of sensitivities, time constants and genetic correlations suggest that tissue expansion is loosely co-ordinated with cell division and carbon accumulation which may have limited direct effects on growth under water deficit. We therefore argue for essentially uncoupled mechanisms with feedbacks between them, rather than for a co-ordinated re-programming of all processes.... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4580846 Mon, 07 Mar 2011 00:00:00 +0100 4580846 http://www.medworm.com/index.php?rid=4580847&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%3D21377404%26dopt%3DAbstract Authors: Peleg Z, Blumwald E Plant hormones play central roles in the ability of plants to adapt to changing environments, by mediating growth, development, nutrient allocation, and source/sink transitions. Although ABA is the most studied stress-responsive hormone, the role of cytokinins, brassinosteroids, and auxins during environmental stress is emerging. Recent evidence indicated that plant hormones are involved in multiple processes. Cross-talk between the different plant hormones results in synergetic or antagonic interactions that play crucial roles in response of plants to abiotic stress. The characterization of the molecular mechanisms regulating hormone synthesis, signaling, and action are facilitating the modification of hormone biosynthetic pathways for the generation of tr... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4580847 Thu, 03 Mar 2011 00:00:00 +0100 4580847 http://www.medworm.com/index.php?rid=4527188&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%3D21333585%26dopt%3DAbstract Authors: Paszkowski J, Grossniklaus U Transgenerational epigenetic inheritance (TEI), which is the inheritance of expression states and thus traits that are not determined by the DNA sequence, is often postulated but the molecular mechanisms involved are only rarely verified. This especially applies to the heritability of environmentally induced traits, which have gained interest over the last years. Here we will discuss selected examples of epigenetic inheritance in plants and artificially divide them according to the occurrence of inter-generational resetting. The decision which epigenetic marks are reset and which ones are not is crucial for the understanding of TEI. We will consider examples of epialleles found in natural populations and epialleles induced by genetic and/or environ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4527188 Wed, 16 Feb 2011 00:00:00 +0100 4527188 http://www.medworm.com/index.php?rid=4527189&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%3D21330185%26dopt%3DAbstract Authors: Zheng B, Chen X The development of multicellular organisms is governed partly by temporally and spatially controlled gene expression. DNA methylation, covalent modifications of histones, and the use of histone variants are the major epigenetic mechanisms governing gene expression in plant development. In this review, we zoom in onto histone H3 lysine 27 trimethylation (H3K27me3), a repressive mark that plays a crucial role in the dynamic regulation of gene expression in plant development, to discuss recent advances as well as outstanding questions in the deposition, recognition, and removal of the mark and the impacts of these molecular processes on plant development. PMID: 21330185 [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=4527189 Tue, 15 Feb 2011 00:00:00 +0100 4527189 http://www.medworm.com/index.php?rid=4405781&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%3D21233005%26dopt%3DAbstract Authors: Feng S, Jacobsen SE Plant genomes are modified by an array of epigenetic marks that help regulate plant growth and reproduction. Although plants share many epigenetic features with animals and fungi, some epigenetic marks are unique to plants. In different organisms, the same epigenetic mark can play different roles and/or similar functions can be carried out by different epigenetic marks. Furthermore, while the enzymatic systems responsible for generating or eliminating epigenetic marks are often conserved, there are also cases where they are quite divergent between plants and other organisms. DNA methylation and methylation of histone tails on the lysine 4, 9, and 27 positions are among the best characterized epigenetic marks in both plants and animals. Recent studies have g... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4405781 Tue, 11 Jan 2011 00:00:00 +0100 4405781 http://www.medworm.com/index.php?rid=4405780&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%3D21233006%26dopt%3DAbstract Authors: Liu Q, Gong Z In multicellular organisms, each cell contains the same DNA sequence, but with different epigenetic information that determines the cell specificity. Semi-conservative DNA replication faithfully copies the parental nucleotide sequence into two DNA daughter strands during each cell cycle. At the same time, epigenetic marks such as DNA methylation and histone modifications are either precisely transmitted to the daughter cells or dynamically changed during S-phase. Recent studies indicate that in each cell cycle, many DNA replication related proteins are involved in not only genomic but also epigenomic replication. Histone modification proteins, chromatin remodeling proteins, histone variants, and RNAs participate in the epigenomic replication during S-phase. As a ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4405780 Tue, 11 Jan 2011 00:00:00 +0100 4405780 http://www.medworm.com/index.php?rid=4277382&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%3D21168359%26dopt%3DAbstract Authors: De Lucia F, Dean C Microarray analysis and new sequencing technologies have revealed that the majority of the genome is transcribed in many eukaryotes. Much of the RNA appears to be non-coding and an ongoing debate is how much of a functional role it has. Different mechanisms by which ncRNA can be regulatory have been described: direct ncRNA effects on transcription; recruitment of chromatin modifiers; formation of silent nuclear compartments. These have been documented chiefly in yeasts and mammals but examples are now appearing in plants. To date RNA-mediated transcriptional silencing studies in plants have focused on siRNAs, but data now show longer ncRNAs are also involved in this silencing. Roles for long ncRNAs in the phenotypic plasticity of plants are also suggested by... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4277382 Thu, 16 Dec 2010 00:00:00 +0100 4277382 http://www.medworm.com/index.php?rid=4277385&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%3D21159545%26dopt%3DAbstract Authors: Simon SA, Meyers BC Epigenetic modifications in plants can be directed and mediated by small RNAs (sRNAs). This regulation is composed of a highly interactive network of sRNA-directed DNA methylation, histone, and chromatin modifications, all of which control transcription. Identification and functional characterization of components of the siRNA-directed DNA methylation pathway have provided insights into epigenetic pathways that form heterochromatin and into chromatin-based pathways for gene silencing, paramutation, genetic imprinting, and epigenetic reprogramming. Next-generation sequencing technologies have facilitated new discoveries and have helped create a basic blueprint of the plant epigenome. As the multiple layers of epigenetic regulation in plants are dissected, a ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4277385 Mon, 13 Dec 2010 00:00:00 +0100 4277385 http://www.medworm.com/index.php?rid=4277384&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%3D21159546%26dopt%3DAbstract Authors: Furner IJ, Matzke M The primary sequence of the genome is broadly constant and superimposed upon that constancy is the postreplicative modification of a small number of cytosine residues to 5-methylcytosine. The pattern of methylation is non-random; some sequence contexts are frequently methylated and some rarely methylated and some regions of the genome are highly methylated and some rarely methylated. Once established, methylation is not static: it can potentially change in response to developmental or environmental cues and this may result in correlated changes in gene expression. Changes can occur passively owing to a failure to maintain DNA methylation through rounds of DNA replication, or actively, through the action of enzymes with DNA glycosylase activity. Recent advan... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4277384 Mon, 13 Dec 2010 00:00:00 +0100 4277384 http://www.medworm.com/index.php?rid=4277383&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%3D21159547%26dopt%3DAbstract Authors: Deal RB, Henikoff S Genomes are packaged by complexing DNA with histone proteins, which provides an opportunity to regulate gene expression by dynamically impeding access of transcriptional regulatory proteins and RNA polymerases to DNA. The incorporation of histone variants into nucleosomes and addition of post-translational modifications to histones can alter the physical properties of nucleosomes and thereby serve as a mechanism for regulating DNA exposure. Chromatin-based gene regulation has profound effects on developmental processes including regulation of the vegetative to reproductive transition, as well as responses to pathogens and abiotic factors. Incorporation of the histone variant H2A.Z and methylation of histone H3 lysine residues 4 and 27 have emerged as key el... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4277383 Mon, 13 Dec 2010 00:00:00 +0100 4277383 http://www.medworm.com/index.php?rid=4277386&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%3D21145279%26dopt%3DAbstract Authors: Chang F, Wang Y, Wang S, Ma H Microsporogenesis is essential for male fertility and requires both the formation of somatic and reproductive cells in the anther and meiotic segregation of homologous chromosomes. Molecular genetic studies have uncovered signaling molecules and transcription factors that play crucial roles in determining the anther cell types and in controlling gene expression for microsporogenesis. At the same time, key components of in meiotic recombination pathways have been discovered, enriching our knowledge about plant reproductive development. PMID: 21145279 [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=4277386 Tue, 07 Dec 2010 00:00:00 +0100 4277386 http://www.medworm.com/index.php?rid=4277388&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%3D21144795%26dopt%3DAbstract Authors: Li J, Chua NH PMID: 21144795 [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=4277388 Mon, 06 Dec 2010 00:00:00 +0100 4277388 http://www.medworm.com/index.php?rid=4277387&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%3D21144796%26dopt%3DAbstract Authors: Wang Y, Li J Rice branching, including the formation of tillers and panicle branches, has been well investigated over the past several years because of its agronomic importance. A major breakthrough in elucidating rice tillering in the recent years was the discovery of strigolactones, a specific group of terpenoid lactones that can inhibit axillary bud outgrowth. Since that discovery, new tillering mutants, that is, dwarf 27 (d27) or dwarf14 (d14, also reported as d88 or htd2), have been identified with reduced strigolactone levels or strigolactone response. DWARF27 (D27) and DWARF14 (D14) probably act on strigolactone biosynthesis and signal transduction, respectively. Additionally, several genes controlling panicle branches have been identified recently. DEP1 and IPA1/WFP ar... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4277387 Mon, 06 Dec 2010 00:00:00 +0100 4277387 http://www.medworm.com/index.php?rid=4219125&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%3D21093352%26dopt%3DAbstract Authors: Hawes C, Osterrieder A, Sparkes IA, Ketelaar T Laser trapping of micron-sized particles can be achieved utilizing the radiation pressure generated by a focused infrared laser beam. Thus, it is theoretically possible to trap and manipulate organelles within the cytoplasm and remodel the architecture of the cytoplasm and membrane systems. Here we describe recent progress, using this under utilized technology, in the manipulation of cytoplasmic strands and organelles in plant cells. PMID: 21093352 [PubMed - in process] (Source: Current Opinion in Plant Biology) Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4219125 Wed, 01 Dec 2010 00:00:00 +0100 4219125 http://www.medworm.com/index.php?rid=4219124&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%3D21094078%26dopt%3DAbstract Authors: Breuer C, Ishida T, Sugimoto K Timely progression of the mitotic cell cycle is central for growth and development of plant organs. Many cell types in plants also enter an alternative cell cycle called the endoreduplication cycle or endocycle in which cells increase their ploidy through repeated rounds of chromosomal replication without cell divisions. The transition from the mitotic cycle into the endocycle often coincides with the initiation of cell expansion and cell differentiation, and strong correlations between final ploidy level and cell size have been reported in many plant species. Recent studies have begun to unveil how developmental signals modulate entry and exit of the endocycle through both transcriptional and post-transcriptional mechanisms. An increase in ploid... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4219124 Wed, 01 Dec 2010 00:00:00 +0100 4219124 http://www.medworm.com/index.php?rid=4185849&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%3D21075046%26dopt%3DAbstract Authors: Xu J, Chua NH Processing bodies (P-bodies) contain RNA-protein complexes linked to cytoplasmic RNA decay pathways including mRNA decapping, nonsense-mediated decay (NMD) and small RNA-mediated decay. Plants deficient in P-body components display severe developmental perturbations, suggesting that these cytoplasmic bodies play important roles in regulating gene expression during plant development. Here, we summarize recent progress in the genetic dissection of P-body components and their roles in translational repression and mRNA decapping. PMID: 21075046 [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=4185849 Thu, 11 Nov 2010 00:00:00 +0100 4185849 http://www.medworm.com/index.php?rid=4185848&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%3D21075047%26dopt%3DAbstract Authors: Nishii I, Miller SM Volvox, Chlamydomonas, and their close relatives - collectively the volvocine green algae - comprise an excellent system for investigating the origins of developmental complexity. Over a relatively short period of time Volvox evolved an impressive suite of developmental traits, including asymmetric cell division, multicellularity with germ-soma division of labor, embryonic morphogenesis, and oogamy. Recent molecular genetic analyses of important developmental genes and comparative analyses of the fully sequenced Volvox and Chlamydomonas genomes have provided important insights into how these and other traits came to be. Surprisingly, the acquisition of much of the developmental innovation in this family seems to have involved relatively minor tinkering with... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4185848 Thu, 11 Nov 2010 00:00:00 +0100 4185848 http://www.medworm.com/index.php?rid=4167160&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%3D21071264%26dopt%3DAbstract Authors: Liu J, Grieson CS, Webb AA, Hussey PJ A major challenge in plant biology is to understand how functions in plant cells emerge from interactions between molecular components. Computational and mathematical modelling can encapsulate the relationships between molecular components and reveal how biological functions emerge. We review recent progress in modelling in metabolism, growth, signalling and circadian rhythms in plant cells. We discuss challenges and opportunities for future directions. PMID: 21071264 [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=4167160 Tue, 09 Nov 2010 00:00:00 +0100 4167160 http://www.medworm.com/index.php?rid=4139708&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%3D21051277%26dopt%3DAbstract Authors: Luschnig C, Grierson C PMID: 21051277 [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=4139708 Tue, 02 Nov 2010 00:00:00 +0100 4139708 http://www.medworm.com/index.php?rid=4107994&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%3D20971032%26dopt%3DAbstract Authors: Geitmann A Plant cell growth is a fundamental process during plant development whose spatial and temporal dynamics are controlled by the cell wall. Modeling mechanical aspects of cell growth therefore requires the integration of structural cell wall details with quantitative biophysical parameters. Recent advances in microscopic techniques and mechanical modeling have made significant contributions to the field of cell wall biomechanics. Live observation of cellulose microfibrils at high z-resolution now enables determining the dynamic orientation of these polymers in the different wall layers of growing cells. Mechanical modeling approaches have been developed to operate at the scale of individual molecules and will thus be able to exploit the availability of the high-resolut... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4107994 Wed, 20 Oct 2010 23:00:00 +0100 4107994 http://www.medworm.com/index.php?rid=4107993&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%3D20971033%26dopt%3DAbstract Authors: Wang Z, Choi G PMID: 20971033 [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=4107993 Wed, 20 Oct 2010 23:00:00 +0100 4107993 http://www.medworm.com/index.php?rid=4107998&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%3D20970369%26dopt%3DAbstract Authors: Pawlowski WP The past few years have brought renewed interest in understanding the dynamics of chromosomes in interphase cells as well as during cell division, particularly meiosis. This research has been fueled by new imaging methods, particularly three-dimensional, high-resolution, and live microscopy. Major contributors are also new genetic tools that allow elucidation of mechanisms controlling chromosome behavior. Recent studies in plants have explored chromatin arrangement in interphase nuclei, chromosome interactions and movement during meiotic prophase I, and mechanisms that ensure correct segregation of chromosomes during anaphase. These studies shed light on chromosome dynamics in a small-genome plant Arabidopsis thaliana, as well as in plants with large and complex g... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4107998 Tue, 19 Oct 2010 23:00:00 +0100 4107998 http://www.medworm.com/index.php?rid=4107997&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%3D20970370%26dopt%3DAbstract Authors: Paciorek T, Bergmann DC Asymmetric cell divisions (ACDs) are used to create organismal form and cellular diversity during plant development. In several embryonic and postembryonic contexts, genes that specify cell fates and networks that provide positional information have been identified. The cellular mechanisms that translate this information into a physically ACD, however, are still obscure. In this review we examine the cell polarization events that precede asymmetric divisions in plants. Using principles derived from studies of other organisms and from postmitotic polarity generation in plants, we endeavor to provide a framework of what is known, what is on the horizon and what is critically needed to develop a rigorous mechanistic understanding of ACDs in plants. PMI... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4107997 Tue, 19 Oct 2010 23:00:00 +0100 4107997 http://www.medworm.com/index.php?rid=4107996&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%3D20970371%26dopt%3DAbstract Authors: Bowler C, De Martino A, Falciatore A Studies of cell division in organisms derived from secondary endosymbiosis such as diatoms have revealed that the mechanisms are far from those found in more conventional model eukaryotes. An atypical acentriolar microtuble-organizing centre, centripetal cytokinesis combined with centrifugal cell wall neosynthesis, and the role of sex in relation to cell size restoration make diatoms an exciting system to re-investigate the evolution, differentiation and regulation of cell division. Such studies are further justified considering the ecological relevance of these microalgae in contemporary oceans and the need to understand the mechanisms controlling their growth and distribution in an environmental context. Recent work derived from genome-wi... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4107996 Tue, 19 Oct 2010 23:00:00 +0100 4107996 http://www.medworm.com/index.php?rid=4107995&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%3D20970372%26dopt%3DAbstract Authors: Blanchoin L, Boujemaa-Paterski R, Henty JL, Khurana P, Staiger CJ Gazing at a giant redwood tree in the Pacific Northwest, that has grown to enormous heights over centuries, does little to convince one that plants are built for speed and versatility. Even at the cellular level, a system of polymers-the cell skeleton or cytoskeleton-integrates signals and generates subcellular structures spanning scales of a few nanometers to hundreds of micrometers that coordinate cell growth. The term cytoskeleton itself connotes a stable structure. Clearly, this is not the case. Recent studies using advanced imaging modalities reveal the plant actin cytoskeleton to be a highly dynamic, ever changing assemblage of polymers. These insights along with growing evidence about the biochemical/biop... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4107995 Tue, 19 Oct 2010 23:00:00 +0100 4107995 http://www.medworm.com/index.php?rid=4077740&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%3D20943427%26dopt%3DAbstract Authors: Liu B, Liu H, Zhong D, Lin C The initial photochemistry of plant cryptochromes has been extensively investigated in recent years. It is hypothesized that cryptochrome photoexcitation involves a Trp-triad-dependent photoreduction. According to this hypothesis, cryptochromes in the resting state contain oxidized FAD; light triggers a sequential electron transfer from three tryptophan residues to reduce FAD to a neutral semiquinone (FADH); FADH is the presumed signaling state and it is re-oxidized to complete the photocycle. However, this photoreduction hypothesis is currently under debate. An alternative model argues that the initial photochemistry of cryptochromes involves a photolyase-like cyclic electron shuttle without a bona fide redox reaction mediated by the Trp-triad res... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4077740 Sun, 10 Oct 2010 23:00:00 +0100 4077740 http://www.medworm.com/index.php?rid=4077739&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%3D20943428%26dopt%3DAbstract Authors: Qin YM, Zhu YX Cotton fibers (cotton lint) are single-celled trichomes that differentiate from the ovule epidermis. Unidirectional and fast-growing cells generally expand at the dome-shaped apical zone (tip-growth mode); however, previous studies suggest that elongating fiber cells expand via a diffuse-growth mode. Tip-localized Ca(2+) gradient and active secretary vesicle trafficking are two important phenomena of tip-growth. Recently, a high Ca(2+) gradient is found in the cytoplasm of fast-elongating cotton fiber cells near the growing tip. Several protein coding genes participating in vesicle coating and transport are highly expressed in elongating fiber cells. Taken together with the observation that ethylene acts as a positive regulator for cotton fiber and several Arabi... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4077739 Sun, 10 Oct 2010 23:00:00 +0100 4077739 http://www.medworm.com/index.php?rid=4077738&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%3D20943429%26dopt%3DAbstract Authors: Thines B, Harmon FG The circadian clock confers rhythms of approximately 24hours to biological events. It elevates plant fitness by allowing plants to anticipate predictable environmental changes and organize life process to coincide with the most favorable environmental conditions. Many developmental events are circadian regulated to ensure that growth occurs at the ideal time or season relative to available resources. Circadian clock control over growth and development is often achieved through regulation of key phytohormone action. Circadian influence over the genome is widespread and the clock modulates genes involved in phytohormone synthesis and signaling, in addition to other pathways shaping growth and development. This review presents four nonmutually exclusive mechan... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4077738 Sun, 10 Oct 2010 23:00:00 +0100 4077738 http://www.medworm.com/index.php?rid=4063130&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%3D20934900%26dopt%3DAbstract Authors: Weiner JJ, Peterson FC, Volkman BF, Cutler SR A series of papers in the last year reported major advances in our understanding of abscisic acid (ABA) signaling: the identification of soluble ABA receptors, the elucidation of a core ABA signaling pathway and structural insights into the mechanism of ABA perception and signaling. Here we summarize these advances, which have shown in atomic resolution that the ABA receptors PYR1, PYL1 and PYL2 function as allosteric switches that inhibit type 2C protein phosphatases (PP2Cs) in response to ABA. These receptors function at the apex of a core signaling pathway that regulates ABA responses by controlling SnRK2 kinase activity and the phosphorylation of downstream target proteins such as ABFs, which control nuclear responses, and the ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4063130 Thu, 07 Oct 2010 23:00:00 +0100 4063130 http://www.medworm.com/index.php?rid=4063129&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%3D20934901%26dopt%3DAbstract Authors: Xu XM, Jackson D Plasmodesmata (PDs), tiny channels connecting neighboring plant cells, play big roles in the transport of metabolites, viral movement, cell fate specification and development. Many recent studies are opening our eyes to the composition and formation of PDs, as well as the function and regulation of trafficking through them. Both proteomic and genetic approaches have revealed the central importance of callose in modulating PD connectivity. Moreover, many new developmental regulators, including transcription factors as well as small RNAs (sRNAs), have been found to be mobile and essential for specifying cell fate and tissue patterning. PMID: 20934901 [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=4063129 Thu, 07 Oct 2010 23:00:00 +0100 4063129 http://www.medworm.com/index.php?rid=4063134&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%3D20934368%26dopt%3DAbstract Authors: Benková E, Bielach A Unlike locomotive organisms capable of actively approaching essential resources, sessile plants must efficiently exploit their habitat for water and nutrients. This involves root-mediated underground interactions allowing plants to adapt to soils of diverse qualities. The root system of plants is a dynamic structure that modulates primary root growth and root branching by continuous integration of environmental inputs, such as nutrition availability, soil aeration, humidity, or salinity. Root branching is an extremely flexible means to rapidly adjust the overall surface of the root system and plants have evolved efficient control mechanisms, including, firstly initiation, when and where to start lateral root formation; secondly lateral root primordia orga... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4063134 Wed, 06 Oct 2010 23:00:00 +0100 4063134 http://www.medworm.com/index.php?rid=4063133&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%3D20934369%26dopt%3DAbstract Authors: Hermann K, Kuhlemeier C A pollination syndrome is defined as a suite of floral traits that are associated with the attraction of a specific group of animals as pollinators. Traits such as flower morphology, color, scent, and rewards contribute to the plant's reproductive success by attracting pollinators. Here we focus on the genetics of natural variation in flower morphology and how the adaptation between plants and their cognate pollinator class contributes to plant's reproductive success. We review recent work on the genetic basis of interspecific differences in reproductive organ morphology and discuss possible genetic mechanisms for coordinated changes in complex syndromes. PMID: 20934369 [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=4063133 Wed, 06 Oct 2010 23:00:00 +0100 4063133 http://www.medworm.com/index.php?rid=4063132&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%3D20934370%26dopt%3DAbstract Authors: Hattori Y, Nagai K, Ashikari M Flooding is one of the most hazardous natural disasters, and there are several levels of flooding. Recently, research on flood-tolerant rice plants revealed that some rice varieties have evolved to overcome two different flood types, 'flash flood' and 'deepwater flood', using two different mechanisms, and their molecular mechanisms were determined. During flash flooding, the tolerant plants that are fully submerged for a few weeks stop elongating and thus avoid energy consumption that will be needed to restart growth when the water recedes. On the contrary, during deepwater flooding, with water depth up to several meters for several months, the deepwater-flood-tolerant rice plants promote elongation of internodes to keep the foliage above the wat... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4063132 Wed, 06 Oct 2010 23:00:00 +0100 4063132 http://www.medworm.com/index.php?rid=4063131&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%3D20934371%26dopt%3DAbstract Authors: Hirakawa Y, Kondo Y, Fukuda H During plant development, cell fates are often determined by cell-to-cell communication. The vascular system, in which procambial/cambial cells continue to provide cells to two conductive tissues, xylem and phloem, is an excellent model for understanding cell-to-cell communication as a developmental cue. Recent studies on vascular development have revealed several novel intercellular signaling molecules that regulate vascular cell fates by unique mechanisms. This review focuses on emerging novel concepts such that reciprocal signaling by a transcription factor and microRNAs between the stele and the endodermis determines xylem cell patterns, and that a small peptide secreted from phloem governs vascular stem-cell maintenance. PMID: 20934371 [P... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4063131 Wed, 06 Oct 2010 23:00:00 +0100 4063131 http://www.medworm.com/index.php?rid=4063136&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%3D20926334%26dopt%3DAbstract Authors: Li J Receptor-like protein kinases (RLKs) are transmembrane proteins crucial for cell-to-cell and cell-to-environment communications. The extracellular domain of a RLK is responsible for perception of a specific extracellular ligand to trigger a unique intercellular signaling cascade, often via phosphorylation of cellular proteins. The signal is then transduced to the nucleus of a cell where it alters gene expression. There are more than 610 RLKs in Arabidopsis thaliana, only a handful of them have been functionally characterized. This review focuses on recent advances in our understanding of a small group of RLKs named somatic embryogenesis receptor-like protein kinases (SERKs). SERKs act as coreceptors in multiple signaling pathways via their physical interactions with disti... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4063136 Sun, 03 Oct 2010 23:00:00 +0100 4063136 http://www.medworm.com/index.php?rid=4063135&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%3D20926335%26dopt%3DAbstract Authors: Bishopp A, Benková E, Helariutta Y Despite their relatively simple appearance, roots are incredibly complex organs that are highly adapted to differing environments. Many aspects of root development are co-ordinated by subtle spatial differences in the concentrations of the phytohormones auxin and cytokinin. Events from the formation of a root during embryogenesis to the determination of the network of lateral roots are controlled by interactions between these hormones. Recently, interactions have been defined where auxin signaling promotes the expression of cytokinin signaling inhibitors, cytokinin signaling promotes the expression of auxin signaling inhibitors and finally where cytokinin signaling regulates the complex network of auxin transport proteins to position zones o... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4063135 Sun, 03 Oct 2010 23:00:00 +0100 4063135 http://www.medworm.com/index.php?rid=4044230&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%3D20920881%26dopt%3DAbstract In this report, we will review the common steps of phototropin signaling and the numerous interactive proteins of phototropins, which may act as signal transducers for the diverse responses. We also describe the phototropin-mediated signaling process of stomatal guard cells and its crosstalk with abscisic acid signaling. PMID: 20920881 [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=4044230 Wed, 29 Sep 2010 23:00:00 +0100 4044230 http://www.medworm.com/index.php?rid=4044232&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%3D20884277%26dopt%3DAbstract Authors: Crevillén P, Dean C The genetic pathways regulating the floral transition in Arabidopsis are becoming increasingly well understood. The ease with which mutant phenotypes can be quantified has led to many suppressor screens and the molecular identification of the underlying genes. One focus has been on the pathways that regulate the gene encoding the floral repressor FLC. This has revealed a set of antagonistic pathways comprising evolutionary conserved activities that link chromatin regulation, transcription level and co-transcriptional RNA metabolism. Here we discuss our current understanding of the transcriptional activation of FLC, how different activities are integrated at this one locus and why FLC regulation seems so sensitive to mutation in these conserved gene regulat... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4044232 Mon, 27 Sep 2010 23:00:00 +0100 4044232 http://www.medworm.com/index.php?rid=4044231&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%3D20884278%26dopt%3DAbstract Authors: Shi DQ, Yang WC Female gametophyte, the central core of the ovule, is a simple seven-celled reproductive structure. Its stereotyped ontogeny provides a traceable model system to study mechanisms controlling cell growth, cell division, cell fate, pattern formation, and perhaps the function of essential genes in plants. An auxin concentration gradient was demonstrated for the first time in the embryo sac to control gametic cell fate. Mutant analysis also indicates a role of RNA processing in the mitotic progression of the gametophytic generation and cell fate determination in the embryo sac. Combined studies of genetics and transcriptome analysis revealed recently that epigenetic pathways play a critical role in female gametophyte development. In addition, the discovery that a l... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4044231 Mon, 27 Sep 2010 23:00:00 +0100 4044231 http://www.medworm.com/index.php?rid=4026609&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%3D20875768%26dopt%3DAbstract Authors: Sun X, Shantharaj D, Kang X, Ni M In angiosperms, a double-fertilization event leads to the formation of a diploid embryo and a triploid endosperm. In Arabidopsis and many dicots, seed development undergoes an initial phase of active endosperm proliferation followed by a second phase in which embryo grows to full size and replaces most of the endosperm volume at its maturity. Since the seed coat and endosperm growth in Arabidopsis precedes embryo growth, the major volume of the mature seed is largely attained before the enlargement of the embryo. Therefore, the seed size is coordinately regulated by the growth of the triploid endosperm, the diploid maternal ovule, and the diploid embryo. Recent studies have identified many new pathway components and revealed possible mechanism... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4026609 Fri, 24 Sep 2010 23:00:00 +0100 4026609 http://www.medworm.com/index.php?rid=4003502&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%3D20870452%26dopt%3DAbstract Authors: Moon J, Hake S Leaves are formed from a group of initial cells within the meristem. One of the earliest markers of leaf initiation is the down-regulation of KNOX genes in initial cells. Polar auxin activity, MYB and LOB domain transcription factors function to keep KNOX out of the initiating leaf. If KNOX genes are expressed in initial cells, leaves fail to form. As the leaf grows away from the meristem, its shape is determined by growth in three axes, proximal-distal, abaxial-adaxial and medial-lateral. HD-ZIPIII, KANADI and the small RNA pathway play a significant role in the latter two axes. KNOX proteins play a role in the proximal-distal axis. Although genetic networks are conserved between monocots and dicots, the outcome in leaf shape often differs. PMID: 20870452 [... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4003502 Fri, 24 Sep 2010 23:00:00 +0100 4003502 http://www.medworm.com/index.php?rid=4003569&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%3D20870451%26dopt%3DAbstract Authors: Sadanandom A, Napier RM Biosensors come in an increasing array of forms and their development is defining the rate of advance for our understanding of many natural processes. Developmental biology is increasingly using mathematical models and yet few of these models are based on quantitative recordings. In particular, we know comparatively little about the endogenous concentrations or fluxes of signalling molecules such as the phytohormones, an area of great potential for new biosensors. There are extremely useful biosensors for some signals, but most remain qualitative. Other qualities sought in biosensors are temporal and spatial resolution and, usually, an ability to use them without significantly perturbing the system. Currently, the biosensors with the best properties are... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4003569 Thu, 23 Sep 2010 23:00:00 +0100 4003569 http://www.medworm.com/index.php?rid=4003773&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%3D20869907%26dopt%3DAbstract Authors: Ito T Floral homeotic genes encode transcription factors and act as master regulators of flower development. The homeotic protein complex is expressed in a specific whorl of the floral primordium and determines floral organ identity by the combinatorial action. Homeotic proteins continue to be expressed until late in flower development to coordinate growth and organogenesis. Recent genomic studies have shown that homeotic proteins bind thousands of target sites in the genome and regulate the expression of transcription factors, chromatin components and various proteins involved in hormone biosynthesis and signaling and other physiological activities. Further, homeotic proteins program chromatin to direct the developmental coordination of stem cell maintenance and differentiati... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4003773 Wed, 22 Sep 2010 23:00:00 +0100 4003773 http://www.medworm.com/index.php?rid=4003922&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%3D20869293%26dopt%3DAbstract Authors: Ohashi-Ito K, Fukuda H In vascular development, uncommitted cells differentiate into different xylem cells through vascular stem cells, such as procambial cells, during vein formation as well as embryogenesis. Cascades of transcriptional regulation of genes play crucial roles in the progress of vascular development. Auxin, cytokinin, and brassinosteroids also function in procambial cell determination, procambial maintenance, and xylem cell differentiation from procambial cells, respectively, through transcriptional regulation. The positive feedback loop typically shown in auxin-flow-MONOPTEROS-(HD-ZIP IIIs)-PIN1-auxin-flow in procambial precursor cell determination and VND7-ASL/LBD-VND7 in xylem vessel cell determination, may be a crucial mechanism that determines vascular cel... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4003922 Tue, 21 Sep 2010 23:00:00 +0100 4003922 http://www.medworm.com/index.php?rid=4003850&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%3D20869294%26dopt%3DAbstract Authors: Saze H, Kakutani T Transposable elements (TEs) and repeats are methylated and silenced epigenetically in a variety of organisms including plants. Recent results in Arabidopsis suggest that the TE silencing can be reprogrammed by small RNA during gametogenesis. On the other hand, TE-specific DNA methylation independent of small RNA can be induced by H3K9 methylation through mechanisms conserved between plants and fungi. Methylation of CG sites is found not only in TEs but also in the body of constitutively transcribed genes. Although the function of gene-body methylation is still elusive, the distribution and control of this type of DNA methylation are very similar between plants and animals. Possible interactions of these multiple layers of epigenetic marks and their evolution... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4003850 Tue, 21 Sep 2010 23:00:00 +0100 4003850 http://www.medworm.com/index.php?rid=4003980&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%3D20864385%26dopt%3DAbstract Authors: Tsuji H, Taoka KI, Shimamoto K Photoperiodic control of flowering time consists of a complicated network that converges into the generation of a mobile flowering signal called florigen. Recent advances identifying the protein FT/Hd3a as the molecular nature responsible for florigen activity have focused current research on florigen genes as the important output of this complex signaling network. Rice is a model system for short-day plants and recent progress in elucidating the flowering network from rice and Arabidopsis, a long-day plant, provides an evolutionarily comparative view of the photoperiodic flowering pathway. This review summarizes photoperiodic flowering control in rice, including the interaction of complex layers of gene networks contributed from evolutionarily u... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4003980 Mon, 20 Sep 2010 23:00:00 +0100 4003980 http://www.medworm.com/index.php?rid=4004036&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%3D20851666%26dopt%3DAbstract Authors: Hicks GR, Raikhel NV Chemical genomics is relatively new to plant biology in academia; however, the ability of this approach to present novel discoveries is being demonstrated clearly. One particularly suitable application of this approach is plant endomembrane trafficking. The rapid and dynamic nature of vesicular trafficking plus genetic redundancy has hampered effective study of this complex network. The ability of small molecules to act quickly to inhibit or arrest vesicular trafficking should permit the association of specific vesicles, especially endosome compartments, with their cargoes, particularly those destined for the plasma membrane. This approach and the large target space presented by the endomembrane trafficking network require the discovery of many new bioacti... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4004036 Thu, 16 Sep 2010 23:00:00 +0100 4004036 http://www.medworm.com/index.php?rid=4004171&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%3D20851038%26dopt%3DAbstract Authors: Argueso CT, Raines T, Kieber JJ The cytokinin signaling pathway consists of a phosphorelay mechanism that is initiated by binding of cytokinin to histidine kinase receptors and culminates with the transcription of cytokinin-responsive genes in the nucleus. Type-B response regulators (ARR) encode transcription factors that act as major players in the transcriptional activation of cytokinin-responsive genes, among which are many transcription factors. In this review, we highlight the transcriptional networks regulated by cytokinin that have been identified and their roles in the regulation of a subset of the many developmental and physiological processes regulated by this plant hormone. PMID: 20851038 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biol... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4004171 Wed, 15 Sep 2010 23:00:00 +0100 4004171 http://www.medworm.com/index.php?rid=4004130&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%3D20851039%26dopt%3DAbstract Authors: Li J Brassinosteroids (BRs) are important plant growth hormones that largely rely on transcription factors (TFs) to regulate a variety of plant physiological/developmental processes. Past genetic and biochemical studies have identified two key TFs and interacting partners that play major roles in regulating many BR-responsive genes, while genome-wide microarray experiments have discovered at least 50 BR-regulated TFs. However, little is known how these TFs function or whether additional TFs are involved in BR signaling. In the past few years, genetic studies and yeast one/two-hybrid screens coupled with microarray and chromatin immunoprecipitation experiments not only revealed new roles of the key regulatory TFs but also implicated additional TFs and other nuclear proteins in ... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4004130 Wed, 15 Sep 2010 23:00:00 +0100 4004130 http://www.medworm.com/index.php?rid=4004088&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%3D20851040%26dopt%3DAbstract Authors: Ueguchi-Tanaka M, Matsuoka M The discovery of GID1, a soluble receptor for gibberellins (GAs), has revealed new insights into how GA is perceived. X-ray analysis has demonstrated similarities in the tertiary structure of GID1 to hormone sensitive lipase (HSL), and the GA-binding pocket of GID1 corresponds to the active site of HSL. X-ray analysis has also revealed the structural basis of the GA-GID1 interaction, and evolutionary aspects of GID1 have been discovered by comparison to GID1 from non-flowering plants. Recent studies have also demonstrated the complexity of GA signaling in Arabidopsis, which is mediated by three GID1 and five DELLA proteins. Finally, mechanistic and structural similarities for hormone signaling are compared for GA, auxin and abscisic acid, three hor... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=4004088 Wed, 15 Sep 2010 23:00:00 +0100 4004088 http://www.medworm.com/index.php?rid=3971130&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%3D20833581%26dopt%3DAbstract Authors: Ho CH, Tsay YF Plants acquire numerous nutrients from the soil. In addition, nutrients elicit many physiological and morphological responses especially in roots. Recently, there has been significant progress in identifying the sensing and regulatory mechanisms of several essential nutrients. In this review, we describe the newly identified signaling components of nitrate, ammonium, and potassium, focusing specifically on the initial sensing steps. PMID: 20833581 [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=3971130 Thu, 09 Sep 2010 23:00:00 +0100 3971130 http://www.medworm.com/index.php?rid=3954598&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%3D20822948%26dopt%3DAbstract Authors: Crowell E, Gonneau M, Stierhof Y, Höfte H, Vernhettes S New findings reveal that proteins involved in cellulose biosynthesis undergo regulated trafficking between intracellular compartments and the plasma membrane. The coordinated secretion and internalization of these proteins involve both the actin and cortical microtubule cytoskeletons. This regulated trafficking allows the dynamic remodeling of cellulose synthase complex (CSC) secretion during cell expansion and differentiation. Several new actors of the cellulose synthesis machinery have been recently identified. PMID: 20822948 [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=3954598 Thu, 02 Sep 2010 23:00:00 +0100 3954598 http://www.medworm.com/index.php?rid=3954599&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%3D20817544%26dopt%3DAbstract Authors: Charpentier M, Oldroyd G Engineering nitrogen-fixing cereals is essential for sustainable food production for the projected global population of 9 billion people in 2050. This process will require engineering cereals for nodule organogenesis and infection by nitrogen-fixing bacteria. The symbiosis signalling pathway is essential to establish both bacterial infection and nodule organogenesis in legumes and is also necessary for the establishment of mycorrhizal colonisation. Hence this signalling pathway is also present in cereals and it should be feasible to engineer this signalling pathway for cereal recognition of nitrogen-fixing bacteria. However, establishing a fully function nitrogen-fixing symbiosis in cereals will probably require additional genetic engineering for bacte... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3954599 Wed, 01 Sep 2010 23:00:00 +0100 3954599 http://www.medworm.com/index.php?rid=3954600&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%3D20813578%26dopt%3DAbstract Authors: Bailey-Serres J, Voesenek LA Recent reports on responses to flooding, submergence, and low-oxygen stress have connected components in an essential regulatory network that underlies plasticity in growth and metabolism essential for the survival of distinct flooding regimes. Here, we discuss growth under severe oxygen-limited conditions (anaerobic growth) and less oxygen-deficient underwater conditions (ethylene-driven underwater growth). Low-oxygen stress causes an energy and carbohydrate crisis that must be controlled through regulated consumption of carbohydrates and energy reserves. In rice (Oryza sativa L.), low-oxygen stress, energy homeostasis and growth are connected by a calcineurin B-like interacting binding kinase (CIPK) in seeds germinated under water. In shoots, two... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3954600 Mon, 30 Aug 2010 23:00:00 +0100 3954600 http://www.medworm.com/index.php?rid=3954601&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%3D20810305%26dopt%3DAbstract Authors: Marrocco K, Bergdoll M, Achard P, Criqui MC, Genschik P Ubiquitin-mediated proteolysis is one of the key mechanisms underlying cell cycle control in all eukaryotes. This is achieved by the action of ubiquitin ligases (E3s), which remove both negative and positive regulators of the cell cycle. Though our current understanding of the plant cell cycle has improved a lot these recent years, the identity of the E3s regulating it and their mode of action is still in its infancy. Nevertheless, recent research in Arabidopsis revealed some novel findings in this area. Thus the anaphase promoting complex/cyclosome (APC/C) not only controls mitotic events, but is also important in post-mitotic cells for normal plant development and cell differentiation. Moreover conserved and novel E3s w... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3954601 Sun, 29 Aug 2010 23:00:00 +0100 3954601 http://www.medworm.com/index.php?rid=3954602&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%3D20801708%26dopt%3DAbstract Authors: Nagatani A Phytochrome mediates various physiological as well as developmental responses to light stimuli in plants. Phytochrome is a soluble chromoprotein consisting of the N-terminal photosensory and C-terminal dimerization moieties. Close homologues of plant phytochromes are widely found in prokaryotes. Recently, the crystal structures of the core photosensory module of bacterial phytochromes are resolved. Intriguingly, three sub-domains (PAS, GAF and PHY) in the module are connected by unusual structures named 'light-sensing knot' and 'tongue', which are in tight contact with the chromophore. These findings enable us to review previous data on the structure-function relationships in phytochrome. Consequently, functional importance of these peculiar structures is further hi... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3954602 Thu, 26 Aug 2010 23:00:00 +0100 3954602 http://www.medworm.com/index.php?rid=3954603&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%3D20801076%26dopt%3DAbstract Authors: Schumacher K, Krebs M About 30 years ago seminal reports of anion-sensitive proton-pumping activity associated with microsomal membranes initiated research on the plant vacuolar-type H(+)-ATPase (V-ATPase, VHA). Since, it has been firmly established that these complex molecular machines are essential for what can be defined as cellular logistics. In a eukaryotic cell, the flow of goods between compartments is achieved either by protein-mediated membrane transport or via vesicular trafficking. Over the past years, it has become increasingly clear that V-ATPases do not only energize secondary active transport but are also important regulators of membrane trafficking. PMID: 20801076 [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=3954603 Wed, 25 Aug 2010 23:00:00 +0100 3954603 http://www.medworm.com/index.php?rid=3911902&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%3D20739214%26dopt%3DAbstract Authors: Sablowski R The shoot and root meristems contain small populations of stem cells that constantly renew themselves while providing precursor cells to build all other plant tissues and organs. Cell renewal, growth and differentiation in the meristems are co-ordinated by networks of transcription factors and intercellular signals. The past two years have revealed how auxin and cytokinin signals are integrated with each other and with regulatory genes in the shoot and root meristems. Small RNAs have also emerged as novel intercellular signals. Downstream of meristem regulatory genes, links have been made to cell division control and chromatin function. Protection of genome integrity, partly through programmed cell death after DNA damage, has recently been revealed as a specialised... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3911902 Sun, 22 Aug 2010 23:00:00 +0100 3911902 http://www.medworm.com/index.php?rid=3911901&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%3D20739215%26dopt%3DAbstract Authors: Lau OS, Deng XW Light is an important environmental signal that regulates diverse growth and developmental processes in plants. In these light-regulated processes, multiple hormonal pathways are often modulated by light to mediate the developmental changes. Conversely, hormone levels in plants also serve as endogenous cues in influencing light responsiveness. Although interactions between light and hormone signaling pathways have long been observed, recent studies have advanced our understanding by identifying signaling integrators that connect the pathways. These integrators, namely PHYTOCHROME-INTERACTING FACTOR 3 (PIF3), PIF4, PIF3-LIKE 5 (PIL5)/PIF1 and LONG HYPOCOTYL 5 (HY5), are key light signaling components and they link light signals to the signaling of phytohormones,... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3911901 Sun, 22 Aug 2010 23:00:00 +0100 3911901 http://www.medworm.com/index.php?rid=3823526&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%3D20684067%26dopt%3DAbstract Authors: Oliver RP, Solomon PS It was generally considered that necrotrophic plant pathogenic fungi possessed simplistic pathogenic mechanisms being typically reliant on 'blasting their way through host tissue with a battery of lytic and degradative enzymes. However recent studies have suggested that this is not true and that necrotrophic fungal pathogens can subtly manipulate the host during infection in a manner similar to biotrophic pathogens. For example, it has been demonstrated that the wheat pathogens Stagonospora nodorum and Pyrenophora triticirepentis secrete small unique proteins (effectors) that are internalised by host cells and interact with the host in a gene-for-gene relationship to initiate disease, albeit in an inverse manner compared to biotrophs. This paper reviews r... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3823526 Sat, 31 Jul 2010 23:00:00 +0100 3823526 http://www.medworm.com/index.php?rid=3823527&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%3D20667764%26dopt%3DAbstract Authors: Tantikanjana T, Nasrallah ME, Nasrallah JB The self-pollination barrier of self-incompatibility in the Brassicaceae is based on the activity of a polymorphic stigma receptor and its pollen ligand, whose allele-specific interaction triggers a signaling cascade within the stigma epidermal cell that culminates in the inhibition of pollen tube development. Recent analyses have identified signaling intermediates and revealed unexpected cross-talk between self-incompatibility signaling and pistil development. The self-incompatibility response is now thought to be based on a phosphorylation and ubiquitin-mediated degradation pathway that inhibits the secretion of factors required for successful pollination. Because manipulation of the identified signaling intermediates results in onl... Current Opinion in Plant Biology journals http://www.medworm.com/rss/comments.php?id=3823527 Sun, 25 Jul 2010 23:00:00 +0100 3823527