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375 records returned

Plant cells taking shape: new insights into cytoplasmic control.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The slow and irreversible changes in plant cell shape include the cytoplasmic control of cell wall yielding in response to turgor pressure and the genesis of intracellular trafficking routes to the cell cortex. However, we lack a clear understanding of how interactions between cytoskeletal arrays and endomembrane compartments influence the physical properties of the cell wall. Recent forward and chemical genetic screens and sophisticated imaging analyses are revealing novel intracellular compartments and cytoskeleton interactions that impact the patterns of cellulose synthesis at the plasma membrane. These baseline dat...
Source: Current Opinion in Plant Biology - November 13, 2009 Category: Biology Authors: Szymanski DB Tags: Curr Opin Plant Biol Source Type: journals

Integrating physical stress, growth, and development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Linking the gene regulatory network to morphogenesis is a central question in developmental biology. Shape relies on the combined actions of biochemistry and biophysics, two parameters that are under local genetic control. The blooming of molecular biology since the 1970s has promoted a biochemical view of development, leaving behind the contribution of physical forces. Recently, the development of new techniques, such as live imaging, micromechanical approaches, and computer modeling, has revitalized the biomechanics field. In this review, we use shoot apical meristem development to illustrate how biochemistry and bio...
Source: Current Opinion in Plant Biology - November 12, 2009 Category: Biology Authors: Uyttewaal M, Traas J, Hamant O Tags: Curr Opin Plant Biol Source Type: journals

New genes in the strigolactone-related shoot branching pathway.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Shoot branching is controlled by the formation and subsequent outgrowth of axillary buds in the axils of leaves. Axillary buds are indeterminate structures that can be arrested and await endogenous or environmental cues for outgrowth. A major breakthrough in this area of plant development has been the discovery that a specific group of terpenoid lactones, named strigolactones, can directly or indirectly, inhibit axillary bud outgrowth. Since that discovery, new branching mutants have been identified with reduced strigolactone levels or which are defective in strigolactone regulation or response. DWARF27 and DWARF14 pro...
Source: Current Opinion in Plant Biology - November 11, 2009 Category: Biology Authors: Beveridge CA, Kyozuka J Tags: Curr Opin Plant Biol Source Type: journals

Modeling plant growth and pattern formation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Plants continue to grow and generate new organs in symmetric patterns throughout their lives. This development requires an interconnected regulation of genes, hormones, and anisotropic growth, which in part is guided by environmental cues. Recently, several studies have used a combination of experiments and mathematical modeling to elucidate the mechanisms behind different growth and molecular patterns in plants. The computational models were used to investigate the often non-intuitive consequences of different hypotheses, and the in silico simulations of the models inspired further experimentation. PMID: 19910239 ...
Source: Current Opinion in Plant Biology - November 10, 2009 Category: Biology Authors: Jönsson H, Krupinski P Tags: Curr Opin Plant Biol Source Type: journals

The evolution of plant development in a paleontological context.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Contrary to what might be expected from the observation of extant plants alone, the fossil record indicates that most aspects of vascular plant form evolved multiple times during their Paleozoic radiation. Opportunity is increasing to unite information from fossil and living plants to understand the evolution of developmental mechanisms and each field can provide tests for hypotheses derived from the other. The paleontological context to recent advances in developmental genetics is reviewed for the evolution of a functionally independent sporophyte generation, of leaves, and of roots-all of which are integral to unders...
Source: Current Opinion in Plant Biology - November 6, 2009 Category: Biology Authors: Boyce CK Tags: Curr Opin Plant Biol Source Type: journals

Micropylar pollen tube guidance and burst: adapted from defense mechanisms?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
After the first description of fertilization in flowering plants some 125 years ago (Strasburger E: Neue-Untersuchungen über den Befruchtungsvorgang bei den Phanerogamen als Grundlage für eine Theorie der Zeugung. Gustav Fischer; 1884), we are finally beginning to understand the various molecular mechanisms leading to sperm delivery and discharge inside the hidden micropylar region of the female gametophyte (embryo sac). The last phase of pollen tube guidance culminating in tube burst and explosive release of tube contents requires extensive crosstalk between both male and female gametophytes. The first molec...
Source: Current Opinion in Plant Biology - November 4, 2009 Category: Biology Authors: Dresselhaus T, Márton ML Tags: Curr Opin Plant Biol Source Type: journals

Adding pieces to the puzzling plant nuclear envelope.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The nuclear envelope (NE) and the nuclear pores are important structures that both separate and selectively connect the nucleoplasm and the cytoplasm. NE and nuclear pore research in plants have recently seen an elevated level of interest. This is based both on new findings demonstrating the importance of nucleocytoplasmic trafficking for several signal transduction events, and on increasing evidence that NE and nuclear pore components play important roles during plant cell division. Here, we review the most recent reports in the field and compare them to the more advanced knowledge about yeast and animal model systems...
Source: Current Opinion in Plant Biology - October 27, 2009 Category: Biology Authors: Meier I, Brkljacic J Tags: Curr Opin Plant Biol Source Type: journals

Plant cuticles shine: advances in wax biosynthesis and export.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The plant cuticle is an extracellular lipid structure deposited over the aerial surfaces of land plants, which seals the shoot and protects it from biotic and abiotic stresses. It is composed of cutin polymer matrix and waxes, produced and secreted by epidermal cells. The use of forward and reverse genetic approaches in Arabidopsis has led to the identification of enzymes involved in fatty acid elongation and biosynthesis of wax components, as well as transporters required for lipid delivery to the cuticle. However, major questions concerning alkane formation, intracellular and extracellular wax transport, regulation o...
Source: Current Opinion in Plant Biology - October 26, 2009 Category: Biology Authors: Kunst L, Samuels L Tags: Curr Opin Plant Biol Source Type: journals

How do ER export motifs work on ion channel trafficking?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The function of cells is strongly affected by the type and number of ion channels in the plasma membrane. Recent investigations have highlighted the complexity of the regulation of ion channel trafficking and uncovered several trafficking determinants including diacidic ER export motifs that influence surface expression of ion channels. The large number of ion channels for which functional diacidic motifs have already been identified underlines their general importance and has led to increasing research into the molecular function of these motifs. This review will summarize recent progress in identifying the molecular ...
Source: Current Opinion in Plant Biology - October 24, 2009 Category: Biology Authors: Mikosch M, Homann U Tags: Curr Opin Plant Biol Source Type: journals

Plant developmental responses to the environment: eco-devo insights.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Evolutionary ecology and developmental biology have converged on the key insight that phenotypic expression is powerfully conditioned by environmental information. Plant ecological development (eco-devo) aims to firstly, determine precisely how plants perceive and respond to the varying environmental conditions they encounter in the real world and secondly, understand the ecological and evolutionary consequences of environmentally mediated phenotypic outcomes. This full explanatory scope, from molecular interactions to natural populations and communities, is just now being realized for two adaptively important aspects ...
Source: Current Opinion in Plant Biology - October 24, 2009 Category: Biology Authors: Sultan SE Tags: Curr Opin Plant Biol Source Type: journals

Leaf development: what it needs to be complex.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Formation of dissected compound leaves involves the transient maintenance of an indeterminate environment and the generation of new growth axes that will generate leaflets. Recent work has revealed additional multi-layered mechanisms controlling the activities of the KNOXI homeodomains factors that play a prominent role in the control of indeterminacy associated with compound leaf development. Patterning and individualisation of the leaflets has been shown to involve gradients of the phytohormone auxin and the contribution of the NAM/CUC3 boundary genes. Identification of these novel actors governing compound leaf deve...
Source: Current Opinion in Plant Biology - October 22, 2009 Category: Biology Authors: Blein T, Hasson A, Laufs P Tags: Curr Opin Plant Biol Source Type: journals

Actin and microtubule cytoskeleton interactions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Plant cytoskeleton consists of two major networks of protein polymers, actin microfilaments (AFs) and microtubules (MTs). These networks perform numerous functions that are essential for cell division and for maintaining the integrity of cytoplasm required for intracellular transport and cell shape. Besides the more or less indirect cooperation between AFs and MTs, their direct interactions through specific physically interacting proteins has been well described in yeast, nematodes, insect and animal cells. Recently, promising candidates for corresponding homologous proteins have been identified in plants, although the...
Source: Current Opinion in Plant Biology - October 22, 2009 Category: Biology Authors: Petrášek J, Schwarzerová K Tags: Curr Opin Plant Biol Source Type: journals

Transport vesicle formation in plant cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In protein trafficking, transport vesicles bud from donor compartments and carry cargo proteins to target compartments with which they fuse. Thus, vesicle formation is an essential step in protein trafficking. As for mammals, plant cells contain the three major types of vesicles: COPI, COPII, and CCV and the major molecular players in vesicle-mediated protein transport are also present. However, plant cells generally contain more isoforms of the coat proteins, ARF GTPases and their regulatory proteins, as well as SNAREs. In addition, plants have established some unique subfamilies, which may reflect plant cell-specific...
Source: Current Opinion in Plant Biology - October 22, 2009 Category: Biology Authors: Hwang I, Robinson DG Tags: Curr Opin Plant Biol Source Type: journals

All in a spin: centrifugal organ formation and floral patterning.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Understanding floral patterning is a primary goal in plant biology, yet the temporal sequence of organ development is rarely factored into developmental models. In flowers, occasional examples of centrifugal or basipetal organ initiation, both within organ zones (intrazonal) and between them (interzonal), present a paradox with respect to developmental models. A centripetal/acropetal sequence of floral organ initiation is ancestral in angiosperms, but centrifugal/basipetal development has evolved many times, indicating that these apparently major developmental shifts have relatively simple genetic triggers. Review of t...
Source: Current Opinion in Plant Biology - October 21, 2009 Category: Biology Authors: Rudall PJ Tags: Curr Opin Plant Biol Source Type: journals

Division plane determination during plant somatic cytokinesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Division plane determination in plant cells involves the transformation of the cortical microtubular array into a preprophase band (PPB) with the nucleus anchored at the center. This likely occurs through polarity cues controlling proteins affecting cytoskeletal dynamics. Crosstalk with cell cycle machinery should assure that this happens in concert with cell cycle progression. Before PPB breakdown, targeted deposition of factors at the position of the PPB translates this position into a signal which remains present throughout cytokinesis and directs the centrifugal growing cell plate to the correct cortical position. ...
Source: Current Opinion in Plant Biology - October 20, 2009 Category: Biology Authors: Van Damme D Tags: Curr Opin Plant Biol Source Type: journals

Receptor endocytosis and signaling in plants.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The emerging complexity of plant endocytic systems puts it on a par with their animal counterparts, reflecting an essential role in signal transduction. The endocytic machinery regulates the space and the time of signal transduction and processing in the cell. Plants possess numerous cell surface receptor-like kinases (RLKs) (more than 600 members in Arabidopsis thaliana and 1100 in rice), a trend attributed to their indeterminate mode of growth, the absence of cell migration, and the need for adaptation towards the environment. Thus, plants would require a robust and highly plastic endocytic system in order to integra...
Source: Current Opinion in Plant Biology - October 20, 2009 Category: Biology Authors: Irani NG, Russinova E Tags: Curr Opin Plant Biol Source Type: journals

The molecular basis of cytokinin function.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cytokinins are a class of phytohormones that regulate a wide variety of physiological and developmental processes such as shoot and root growth. Cytokinin signaling relies on a phosphorelay mechanism similar to the prokaryotic two-component system. Although the principal components mediating this cascade have been identified, only recently have we begun to understand the molecular basis of cytokinin action. For example cytokinins control cell differentiation rate during root meristem development by suppressing both auxin signaling and transport, whereas at early stages of embryo development auxin counteracts cytokinin ...
Source: Current Opinion in Plant Biology - October 20, 2009 Category: Biology Authors: Perilli S, Moubayidin L, Sabatini S Tags: Curr Opin Plant Biol Source Type: journals

Cellular processes relying on sterol function in plants.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Sterols are lipophilic membrane components essential for diverse cellular functions. The plant sterol biosynthesis pathway has largely been defined by biochemical approaches. Sterol function has been investigated by the pharmacological and genetic manipulation of sterol biosynthesis. However, mechanisms by which sterols influence cellular processes and targets of sterol function remain largely unknown. During the last two years, new Arabidopsis sterol biosynthesis mutants have been characterized. Their analysis has revealed the contributions of known and alternative routes of sterol biosynthesis to various cellular pro...
Source: Current Opinion in Plant Biology - October 19, 2009 Category: Biology Authors: Boutté Y, Grebe M Tags: Curr Opin Plant Biol Source Type: journals

Coats of endosomal protein sorting: retromer and ESCRT.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Endosomes are hubs of endomembrane trafficking. They integrate vesicular traffic from different sources such as the plasma membrane or the Golgi apparatus and sort cargo to different destinations such as the vacuole, the plasma membrane or back to the Golgi apparatus. As endomembrane trafficking is largely via transport vesicles, endosomes employ different adaptor proteins and coats to accommodate their multiple functions. Retromer and ESCRT are coat/adapter combinations that are crucial for endosomal trafficking pathways. Retromer mediates recycling of sorting receptors back to the Golgi apparatus, ESCRT is needed for...
Source: Current Opinion in Plant Biology - October 14, 2009 Category: Biology Authors: Schellmann S, Pimpl P Tags: Curr Opin Plant Biol Source Type: journals

Plant primary meristems: shared functions and regulatory mechanisms.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Primary plant meristems are the shoot and root meristems that are initiated at opposite poles of the plant embryo. They contain stem cells, which remain undifferentiated, and supply new cells for growth and the formation of tissues. The maintenance of a long-lasting stem cell population in meristems is achieved by signal exchange between organizing regions and the stem cells, and also by feedback signals emanating from differentiating cells. Related peptide signals that make use of different receptor classes were found to control the stem cell populations in both meristem types by regulating evolutionarily conserved ho...
Source: Current Opinion in Plant Biology - October 14, 2009 Category: Biology Authors: Stahl Y, Simon R Tags: Curr Opin Plant Biol Source Type: journals

The intracellular transport of transporters: membrane trafficking of mineral transporters.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
For mineral nutrients to be used by plants, they must be taken up from soil solutions into root cells and then transported to shoots. Mineral nutrient transporters play a central role in this process, and their expression and accumulation are known to be strictly regulated in response to change in nutrient conditions. Roots are cylindrically shaped organs with various types of cells. For the nutrients to move from soil solution toward the xylem they have to be transported across various types of cells. Nutrient condition-dependent accumulation and polar distributions of transporters in plant cells are established by me...
Source: Current Opinion in Plant Biology - October 13, 2009 Category: Biology Authors: Fuji K, Miwa K, Fujiwara T Tags: Curr Opin Plant Biol Source Type: journals

Arabidopsis circadian clock and photoperiodism: time to think about location.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Plants possess a circadian clock that enables them to coordinate internal biological events with external daily changes. Recent studies in Arabidopsis revealed that tissue-specific clock components exist and that the clock network architecture also varies within different organs. These findings indicate that the makeup of circadian clock(s) within a plant is quite variable. Plants utilize the circadian clock to measure day-length changes for regulating seasonal responses, such as flowering. To ensure that flowering occurs under optimum conditions, the clock regulates diurnal CONSTANS (CO) expression. Subsequently, CO p...
Source: Current Opinion in Plant Biology - October 13, 2009 Category: Biology Authors: Imaizumi T Tags: Curr Opin Plant Biol Source Type: journals

Protein lipid modifications in signaling and subcellular targeting.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Classically perceived as means for recruiting proteins to the membranes, protein lipid modifications are known today to play diverse roles in subcellular targeting, protein-protein interactions and signaling. This review focuses on three protein lipid modifications: prenylation, S-acylation and N-myristoylation and attempts to provide an up-to-date view of their function by focusing on several model proteins. PMID: 19796984 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology)
Source: Current Opinion in Plant Biology - September 28, 2009 Category: Biology Authors: Sorek N, Bloch D, Yalovsky S Tags: Curr Opin Plant Biol Source Type: journals

Small RNAs going the distance during plant development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Small RNAs are 19-27 nucleotide long RNAs that negatively regulate gene expression and function as important regulators of diverse aspects of plant development. Current models for how they function continue to be modified as new research uncovers additional aspects of their biology. Unexpectedly, several previously characterized small RNAs appear to function non-cell autonomously, some moving a few cells away, others moving throughout the plant. This fact may reflect that small RNAs are an essential component of a larger signaling network that orchestrates plant development. PMID: 19796985 [PubMed - as supplied by ...
Source: Current Opinion in Plant Biology - September 28, 2009 Category: Biology Authors: Chuck G, O'Connor D Tags: Curr Opin Plant Biol Source Type: journals

The exploring root-root growth responses to local environmental conditions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Because of their sessile lifestyle, the areas which plants can access to forage for resources are confined to those which can be explored by growth. High sensitivity to environmental conditions coupled to the appropriate readjustment of growth and developmental responses are thus critical to plant survival. In this review, we focus on how roots perceive physical cues such as soil water status and mechanical properties and translate them into physiological signals to redirect organ growth and modulate root system architecture. Because the precise molecular identity of most of the sensors used by the root to sample the s...
Source: Current Opinion in Plant Biology - September 24, 2009 Category: Biology Authors: Monshausen GB, Gilroy S Tags: Curr Opin Plant Biol Source Type: journals

Cell-to-cell communication in vascular morphogenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The plant vascular system consists of two conductive cell types, xylem and phloem, which are both produced by procambial cells. Recently, several novel regulatory mechanisms that control the specification of vascular patterning and differentiation have been uncovered. The non-cell-autonomous TDIF/CLE signalling mediates phloem-xylem cross-talk and cambial maintenance; a flowering-related long-distance signal governs secondary development; and novel genetic players such as LHW regulate vascular morphogenesis. A future challenge is to conflate data on the various genetic, hormonal and other factors to understand the netw...
Source: Current Opinion in Plant Biology - September 24, 2009 Category: Biology Authors: Lehesranta SJ, Lichtenberger R, Helariutta Y Tags: Curr Opin Plant Biol Source Type: journals

The cellular dynamics of plant aquaporin expression and functions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Aquaporins are channel proteins that facilitate the transport of water and small neutral molecules, including gases, across cell membranes of most of the living organisms. Integrative studies have stressed the role of aquaporins in maintaining the whole plant water and nutrient status. Cellular aspects of plant aquaporin functions and regulations are also extensively investigated. The present review provides a glance at recent progresses in this area. One first direction concerns the mechanisms that determine aquaporin targeting to specific subcellular membranes and a dynamic and stimulus-dependent control of their den...
Source: Current Opinion in Plant Biology - September 24, 2009 Category: Biology Authors: Maurel C, Santoni V, Luu DT, Wudick MM, Verdoucq L Tags: Curr Opin Plant Biol Source Type: journals

Environmental regulation of stomatal development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Stomata are microscopic structures in the epidermis of the aerial parts of flowering plants formed by two specialized guard cells flanking a central pore. The role of stomata is to optimize gas exchange (the uptake of carbon dioxide and the loss of water vapor) to suit the prevailing environmental conditions. To do this plants open and close the stomatal pores and regulates the number of stomata that develop on the epidermes. Both these responses are controlled by integrating information from environmental cues and hormonal signals. Recent work has resulted in significant advances in our understanding of the underlying...
Source: Current Opinion in Plant Biology - September 22, 2009 Category: Biology Authors: Casson SA, Hetherington AM Tags: Curr Opin Plant Biol Source Type: journals

Cell signaling and gene regulation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19783467 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology)
Source: Current Opinion in Plant Biology - September 21, 2009 Category: Biology Authors: Lohmann JU, Nemhauser JL Tags: Curr Opin Plant Biol Source Type: journals

Plant vacuoles: where did they come from and where are they heading?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Genetic and technical advances of the past few years have allowed us to test some of the vacuolar trafficking and vacuole biogenesis models that had been previously proposed mainly on the basis of morphological and immunolocalization studies. We have now tools to start answering some fundamental questions such as: How are vacuoles formed? Are all vacuoles formed similarly? Do different types of vacuoles coexist in a cell? How are proteins sorted to the vacuole? How many trafficking pathways to vacuoles exist? Can there be trafficking to two types of vacuoles simultaneously? Last but not least, how do vacuoles balance t...
Source: Current Opinion in Plant Biology - September 21, 2009 Category: Biology Authors: Zouhar J, Rojo E Tags: Curr Opin Plant Biol Source Type: journals

One, two, three...models for trichome patterning in Arabidopsis?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Trichome patterning in Arabidopsis rosette leaves serves as a model system to study how individual cells are determined in a regular spacing pattern from initially equivalent cells. A conserved gene cassette regulates this spacing pattern. bHLH, MYB, and WD40 factors are positive regulators of trichome development that are inhibited by R3 single-repeat MYB proteins. One positive regulator, the WD40-protein, and the negative regulators are mobile and are transported in opposite directions: the WD40 factor moves to the negative regulators away from trichome initials. This movement behavior and the genetic and molecular i...
Source: Current Opinion in Plant Biology - September 21, 2009 Category: Biology Authors: Pesch M, Hülskamp M Tags: Curr Opin Plant Biol Source Type: journals

Plant 14-3-3 proteins catch up with their mammalian orthologs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Members of the eukaryotic 14-3-3 family are highly conserved proteins that have been implicated in the modulation of distinct biological processes by phosphorylation-dependent protein-protein interactions. In plants, 14-3-3 mediated regulation of house-keeping proteins such as nitrate reductase and the plasma membrane localized H(+)-ATPase has been intensely studied. Recent proteome-wide approaches have indicated that the plant 14-3-3 interactome is comparable in size and functional complexity to its animal counterpart and, furthermore, shifted the focus of attention to signal mediators. In this regard, in vivo analyse...
Source: Current Opinion in Plant Biology - September 10, 2009 Category: Biology Authors: Oecking C, Jaspert N Tags: Curr Opin Plant Biol Source Type: journals

Cytokinin action in plant development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cytokinin regulates many important aspects of plant development in aerial and subterranean organs. The hormone is part of an intrinsic genetic network controlling organ development and growth in these two distinct environments that plants have to cope with. Cytokinin also mediates the responses to variable extrinsic factors, such as light conditions in the shoot and availability of nutrients and water in the root, and has a role in the response to biotic and abiotic stress. Together, these activities contribute to the fine-tuning of quantitative growth regulation in plants. We review recent progress in understanding th...
Source: Current Opinion in Plant Biology - September 6, 2009 Category: Biology Authors: Werner T, Schmülling T Tags: Curr Opin Plant Biol Source Type: journals

Dynamics of peroxisome abundance: a tale of division and proliferation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Peroxisomes are highly dynamic subcellular organelles that undergo proliferation in response to a variety of environmental stimuli. The past few years have witnessed the identification and characterization of several key classes of proteins required for peroxisome division and proliferation in Arabidopsis. These include the PEROXIN11 (PEX11) family, the dynamin-related proteins (DRPs), and the FISSION1 (FIS1) proteins, some of which are shared by the division machineries of peroxisomes and other organelles. Recent studies have also uncovered a role for the photoreceptor phyA and the bZIP transcription factor HY5 homolo...
Source: Current Opinion in Plant Biology - September 3, 2009 Category: Biology Authors: Kaur N, Hu J Tags: Curr Opin Plant Biol Source Type: journals

Stigolactones: a new hormone with a past.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The recent discovery of an endogenous hormonal activity for strigolactones in shoot branching was surprising since these molecules were thought to mostly play roles as signaling molecules between organisms. Even in the context of plant hormones, strigolactones appear to be different in that their role in plant development is quite restricted. This most probably reflects early days and new hormonal functions will most probably be found for these compounds in the future. In this respect, the exogenous role of strigolactones in parasitic plant seed germination may hint to functions of this compound in seed development. Ho...
Source: Current Opinion in Plant Biology - August 30, 2009 Category: Biology Authors: Tsuchiya Y, McCourt P Tags: Curr Opin Plant Biol Source Type: journals

cis-Regulatory elements in plant cell signaling.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Plant cell signaling pathways are in part dependent on transcriptional regulatory networks comprising circuits of transcription factors (TFs) and regulatory DNA elements that control the expression of target genes. Here, we describe experimental and bioinformatic approaches for identifying potential cis-regulatory elements. We also discuss recent integrative genomics studies aimed at elucidating the functions of cis-regulatory elements in aspects of plant biology, including the circadian clock, interactions with the environment, stress responses, and regulation of growth and development by phytohormones. Finally, we di...
Source: Current Opinion in Plant Biology - August 27, 2009 Category: Biology Authors: Priest HD, Filichkin SA, Mockler TC Tags: Curr Opin Plant Biol Source Type: journals

The jasmonate pathway: the ligand, the receptor and the core signalling module.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Jasmonates regulate specific developmental processes and plant adaptation to environment by controlling responses to external biotic or abiotic stimuli. The core events of jasmonate signalling are now defined. After hormone perception by SCF(COI1), JAZ (JAsmonate ZIM domain) repressors are targeted for proteasome degradation, releasing MYC2 and de-repressing transcriptional activation. JAZs are homomeric and heteromeric proteins and have been instrumental in recent advances in the field, such as the identification of COI1 as a critical component of the jasmonate receptor and the discovery of the bioactive jasmonate in ...
Source: Current Opinion in Plant Biology - August 26, 2009 Category: Biology Authors: Fonseca S, Chico JM, Solano R Tags: Curr Opin Plant Biol Source Type: journals

Gene regulation by MAP kinase cascades.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mitogen-activated protein kinase (MAPK) cascades are signaling modules that transduce extracellular stimuli to a range of cellular responses. Research in yeast and metazoans has shown that MAPK-mediated phosphorylation directly or indirectly regulates the activity of transcription factors. Plant MAPK cascades have been implicated in development and stress responses, but little is known about the specific downstream targets they control. Recent studies have begun to identify direct MAPK transcriptional targets, and provide insights into the mechanisms by which MAPK signaling networks regulate gene expression. PMID: ...
Source: Current Opinion in Plant Biology - August 26, 2009 Category: Biology Authors: Fiil BK, Petersen K, Petersen M, Mundy J Tags: Curr Opin Plant Biol Source Type: journals

Sugar perception and signaling-an update.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Sugars act as potent signaling molecules in plants. Several sugar sensors, including the highly studied glucose sensor HEXOKINASE1 (HXK1), have been identified or proposed. Many additional sensors likely exist, as plants respond to other sugars and sugar metabolites, such as sucrose and trehalose 6-phosphate. Sugar sensing and signaling is a highly complex process resulting in many changes in physiology and development and is integrated with other signaling pathways in plants such as those for inorganic nutrients, hormones, and different stress factors. Importantly, KIN10 and KIN11 protein kinases are central in coordi...
Source: Current Opinion in Plant Biology - August 26, 2009 Category: Biology Authors: Hanson J, Smeekens S Tags: Curr Opin Plant Biol Source Type: journals

From freezing to scorching, transcriptional responses to temperature variations in plants.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Plants are capable of adapting to a wide range of temperatures by reprogramming their transcriptome, proteome, and metabolome. Early investigations uncovered a regulatory network containing the CBF-COR pathway in freezing tolerance and the HSF-HSP pathway in thermotolerance. Recent studies have identified additional signaling components for extreme temperature tolerance and new regulators of plant form in response to temperature variation within the nonextreme range. Some common regulators are shared between temperature responses and other environmental and developmental responses. These discoveries further reveal the ...
Source: Current Opinion in Plant Biology - August 25, 2009 Category: Biology Authors: Hua J Tags: Curr Opin Plant Biol Source Type: journals

Time for circadian rhythms: plants get synchronized.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Most organisms adjust their physiology and metabolism in synchronization with the diurnal and seasonal time by using an endogenous mechanism known as circadian clock. In plants, light and temperature signals interact with the circadian system to regulate the circadian rhythmicity of physiological and developmental processes including flowering time. Recent studies in Arabidopsis thaliana now reveal that the circadian clock orchestrates not only the expression of protein coding genes but also the rhythmic oscillation of introns, intergenic regions, and noncoding RNAs. Furthermore, recent evidence showing the existence o...
Source: Current Opinion in Plant Biology - August 23, 2009 Category: Biology Authors: Más P, Yanovsky MJ Tags: Curr Opin Plant Biol Source Type: journals

Back to the future: evolution of computational models in plant morphogenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
There has been a recent surge of studies in plant biology that combine experimental data with computational modeling. Here, we categorize a diversity of theoretical models and emphasize the need to tailor modeling approaches to the questions at hand. Models can start from biophysical or purely heuristic basic principles, and can focus at several levels of biological organization. Recent examples illustrate that this entire spectrum can be useful to understand plant development, and point to a future direction where more approaches are combined in fruitful ways-either by proving the same result with different basic prin...
Source: Current Opinion in Plant Biology - August 23, 2009 Category: Biology Authors: Grieneisen VA, Scheres B Tags: Curr Opin Plant Biol Source Type: journals

Gamete-specific epigenetic mechanisms shape genomic imprinting.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Although most genes are expressed equally from both parental alleles, imprinted genes are differentially expressed depending on their parental origin. In flowering plants, imprinting depends on DNA methylation. Conversely, activation of the expressed allele requires DNA demethylation. This is achieved during female gametogenesis by the synergy between the DNA glycosylase DEMETER and the repression of DNA methylation by the Retinoblastoma pathway. DEMETER is only expressed in the central cell and the resulting DNA demethylation is propagated in the fertilized central cell developing into the endosperm, which nurtures em...
Source: Current Opinion in Plant Biology - August 23, 2009 Category: Biology Authors: Jullien PE, Berger F Tags: Curr Opin Plant Biol Source Type: journals

Ethylene signaling and response: where different regulatory modules meet.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The structural simplicity of the gaseous hormone ethylene stands in contrast with the complexity of the physiological processes ethylene regulates. Initial studies suggested a simple linear arrangement of signaling molecules leading from the ethylene receptors to the EIN3 family of transcription factors. Recent discoveries have substantially changed this view. Current models suggest existence of a complex signaling pathway composed of several phosphorylation cascades, feedback-regulated transcriptional networks, and protein and mRNA turnover regulatory modules. Interactions between ethylene and other signals determine ...
Source: Current Opinion in Plant Biology - August 23, 2009 Category: Biology Authors: Stepanova AN, Alonso JM Tags: Curr Opin Plant Biol Source Type: journals

Why so repressed? Turning off transcription during plant growth and development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
To ensure correct patterns of gene expression, eukaryotes use a variety of strategies to repress transcription. The transcriptional regulators mediating this repression can be broadly categorized as either passive or active repressors. While passive repressors rely on mechanisms such as steric hindrance of transcriptional activators to repress gene expression, active repressors display inherent repressive abilities commonly conferred by discrete repression domains. Recent studies have indicated that both categories of regulators function in a variety of plant processes, including hormone signal transduction, developmen...
Source: Current Opinion in Plant Biology - August 20, 2009 Category: Biology Authors: Krogan NT, Long JA Tags: Curr Opin Plant Biol Source Type: journals

Transcriptional control of the cell cycle.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cell division is a highly coordinated process. In the last decades, many plant cell cycle regulators have been identified. Strikingly, only a few transcriptional regulators are known, although a significant amount of the genome is transcribed in a cell cycle phase-dependent manner. E2F-DP transcription factors and three repeat MYB proteins are responsible for the expression of genes at the G1-to-S and G2-to-M transition, respectively. However, these two mechanisms cannot explain completely the transcriptional regulation seen during the cell cycle. Correspondingly, several new transcriptional regulators have been charac...
Source: Current Opinion in Plant Biology - August 20, 2009 Category: Biology Authors: Berckmans B, De Veylder L Tags: Curr Opin Plant Biol Source Type: journals

Regulation and functional specialization of small RNA-target nodes during plant development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The expansion of gene families for miRNA and tasiRNA, small RNA effector proteins (ARGONAUTEs or AGOs), and miRNA/tasiRNA targets has contributed to regulatory diversity in plants. Loss or acquisition of small RNA-generating loci and target site sequences in multigene families represent striking examples of subfunctionalization or neo-functionalization, where regulatory diversity is achieved at the post-transcriptional level. Differential regulation of small RNA and target gene family members, and evolution of unique functionality of distinct small RNA-AGO complexes, provide further regulatory diversity. Here, we focus...
Source: Current Opinion in Plant Biology - August 18, 2009 Category: Biology Authors: Rubio-Somoza I, Cuperus JT, Weigel D, Carrington JC Tags: Curr Opin Plant Biol Source Type: journals

Auxin enters the matrix-assembly of response machineries for specific outputs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The basic mechanism of auxin as a modulator of gene expression is now well understood. Interactions among three components are required for this process. Auxin is first perceived by its receptor, which then promotes degradation of inhibitors of auxin response transcription factors. These in turn are released from inhibition and modify expression of target genes. How this simple signaling pathway is able to regulate a diverse range of auxin responses is not as well understood, however a clue lies in the existence of large gene families for all components. Recent data indicates that diversification of gene expression pat...
Source: Current Opinion in Plant Biology - August 17, 2009 Category: Biology Authors: Lokerse AS, Weijers D Tags: Curr Opin Plant Biol Source Type: journals

Just say no: floral repressors help Arabidopsis bide the time.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Floral repressors ensure correct reproductive timing by safeguarding against premature flowering. In the past decade, several mechanisms of floral repression have come to light. Discrimination between direct and indirect repressors has been facilitated by increasing the use of chromatin immunoprecipitation assays. Certain MADS-domain transcription factors such as SHORT VEGETATIVE PHASE and FLOWERING LOCUS C bind directly to target euchromatin to repress specific loci including FLOWERING LOCUS T (FT) and FD. The AP2-domain transcription factor TEMPRANILLO 1 has also been shown to directly repress FT by binding its 5' UT...
Source: Current Opinion in Plant Biology - August 17, 2009 Category: Biology Authors: Yant L, Mathieu J, Schmid M Tags: Curr Opin Plant Biol Source Type: journals

Battle for survival: plants and their allies and enemies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19647476 [PubMed - as supplied by publisher] (Source: Current Opinion in Plant Biology)
Source: Current Opinion in Plant Biology - July 29, 2009 Category: Biology Authors: Dong X, Kahmann R Tags: Curr Opin Plant Biol Source Type: journals