| structure-based design of a periplasmic binding protein antagonist that prevents domain closure. | many receptors undergo ligand-induced conformational changes to initiate signal transduction. periplasmic binding proteins (pbps) are bacterial receptors that exhibit dramatic conformational changes upon ligand binding. these proteins mediate a wide variety of fundamental processes including transport, chemotaxis, and quorum sensing. despite the importance of these receptors, no pbp antagonists have been identified and characterized. in this study, we identify 3-o-methyl-d-glucose as an antagoni ... | 2009 | 19348466 |
| a metastable dwarf1 epigenetic mutant affecting plant stature in rice. | epigenetic mutations confer heritable changes in gene expression that are not due to changes in the underlying sequence of the dna. we identified a spontaneous rice mutant, epi-d1, that shows a metastable dwarf phenotype. the phenotype is mitotically and meiotically inheritable and corresponds to the metastable epigenetic silencing of the dwarf1 (d1) gene. the silenced state is correlated with repressive histone and dna methylation marks in the d1 promoter region but is not associated with dna s ... | 2009 | 19541604 |
| actin turnover is required for myosin-dependent mitochondrial movements in arabidopsis root hairs. | previous studies have shown that plant mitochondrial movements are myosin-based along actin filaments, which undergo continuous turnover by the exchange of actin subunits from existing filaments. although earlier studies revealed that actin filament dynamics are essential for many functions of the actin cytoskeleton, there are little data connecting actin dynamics and mitochondrial movements. | 2009 | 19536333 |
| genetically engineered plants: greener than you think. | | 2009 | 21255271 |
| expression of unprocessed glutelin precursor alters polymerization without affecting trafficking and accumulation. | rice glutelin is synthesized as a precursor in the endosperm endoplasmic reticulum and then deposited within the protein storage vacuole protein body-ii (pb-ii) as an aggregate, with a high degree of polymerized higher-order structure comprising mature acidic and basic subunits after post-translation processing cleavage. in order to investigate the functional role of this processing and its effect on folding assembly, wild-type glua2 and its mutant cdna (mglua2), in which the conserved processin ... | 2009 | 19528530 |
| two terpene synthases are responsible for the major sesquiterpenes emitted from the flowers of kiwifruit (actinidia deliciosa). | kiwifruit vines rely on bees for pollen transfer between spatially separated male and female individuals and require synchronized flowering to ensure pollination. volatile terpene compounds, which are important cues for insect pollinator attraction, were studied by dynamic headspace sampling in the major green-fleshed kiwifruit (actinidia deliciosa) cultivar 'hayward' and its male pollinator 'chieftain'. terpene volatile levels showed a profile dominated by the sesquiterpenes alpha-farnesene and ... | 2009 | 19516075 |
| conserved threonine residues within the a-loop of the receptor nik differentially regulate the kinase function required for antiviral signaling. | nsp-interacting kinase (nik1) is a receptor-like kinase identified as a virulence target of the begomovirus nuclear shuttle protein (nsp). we found that nik1 undergoes a stepwise pattern of phosphorylation within its activation-loop domain (a-loop) with distinct roles for different threonine residues. mutations at thr-474 or thr-468 impaired autophosphorylation and were defective for kinase activation. in contrast, a mutation at thr-469 did not impact autophosphorylation and increased substrate ... | 2009 | 19492062 |
| autoinducer-2-based chemical communication in bacteria: complexities of interspecies signaling. | cell-cell communication in bacteria, called quorum sensing, relies on production, release, and detection of signaling molecules, termed autoinducers. communication enables populations of cells to synchronize gene expression and therefore behave as a group in a manner akin to cells in multicellular organisms. most quorum-sensing systems allow communication within an individual species of bacteria. however, one autoinducer, called ai-2, is produced and recognized by many different bacterial specie ... | 2009 | 19494577 |
| subunits of the plastid clppr protease complex have differential contributions to embryogenesis, plastid biogenesis, and plant development in arabidopsis. | the plastid clppr protease complex in arabidopsis thaliana consists of five catalytic clpp and four noncatalytic clpr subunits. an extensive analysis of the clpr family and clpp5 is presented to address this complexity. null alleles for clpr2 and clpr4 showed delayed embryogenesis and albino embryos, with seedling development blocked in the cotyledon stage; this developmental block was overcome under heterotrophic conditions, and seedlings developed into small albino to virescent seedlings. by c ... | 2009 | 19525416 |
| the plastidic bile acid transporter 5 is required for the biosynthesis of methionine-derived glucosinolates in arabidopsis thaliana. | aliphatic glucosinolate biosynthesis is highly compartmentalized, requiring import of 2-keto acids or amino acids into chloroplasts for side chain elongation and export of the resulting compounds into the cytosol for conversion into glucosinolate. aliphatic glucosinolate biosynthesis in arabidopsis thaliana is regulated by three r2r3-myb transcription factors, the major player being high aliphatic glucosinolate 1 (hag1/myb28). here, we show that bat5, which belongs to the putative bile acid tran ... | 2009 | 19542295 |
| the maize transcription factor knotted1 directly regulates the gibberellin catabolism gene ga2ox1. | knotted1 (kn1)-like homeobox (knox) transcription factors are involved in the establishment and maintenance of plant meristems; however, few direct targets of knox proteins have been recognized. using a combination of double mutant analysis and biochemistry, we found that in maize (zea mays), kn1 negatively modulates the accumulation of gibberellin (ga) through the control of ga2ox1, which codes for an enzyme that inactivates ga. the ga2ox1 mrna level is elevated in immature leaves of dominant k ... | 2009 | 19567707 |
| the plastid division1 and 2 components of the chloroplast division machinery determine the rate of chloroplast division in land plant cell differentiation. | in most algae, the chloroplast division rate is held constant to maintain the proper number of chloroplasts per cell. by contrast, land plants evolved cell and chloroplast differentiation systems in which the size and number of chloroplasts change along with their respective cellular function by regulation of the division rate. here, we show that plastid division (pdv) proteins, land plant-specific components of the division apparatus, determine the rate of chloroplast division. overexpression o ... | 2009 | 19567705 |
| a pivotal role of the basic leucine zipper transcription factor bzip53 in the regulation of arabidopsis seed maturation gene expression based on heterodimerization and protein complex formation. | transcription of arabidopsis thaliana seed maturation (mat) genes is controlled by members of several transcription factor families, such as basic leucine zippers (bzips), b3s, mybs, and dofs. in this work, we identify arabidopsis bzip53 as a novel transcriptional regulator of mat genes. bzip53 expression in developing seeds precedes and overlaps that of its target genes. gain- and loss-of-function approaches indicate a correlation between the amount of bzip53 protein and mat gene expression. sp ... | 2009 | 19531597 |
| arabidopsis chli2 can substitute for chli1. | the i subunit of magnesium-chelatase (chli) is encoded by two genes in arabidopsis (arabidopsis thaliana), chli1 and chli2. conflicting results have been reported concerning the functions of the two proteins. we show here that the chli1/chli1 chli2/chli2 double knockout mutant was albino. comparison with the pale-green phenotype of a chli1/chli1 single knockout mutant indicates that chli2 could support some chlorophyll biosynthesis in the complete absence of chli1. real-time quantitative reverse ... | 2009 | 19363094 |
| arabidopsis iar4 modulates auxin response by regulating auxin homeostasis. | in a screen for enhancers of tir1-1 auxin resistance, we identified two novel alleles of the putative mitochondrial pyruvate dehydrogenase e1alpha-subunit, iaa-alanine resistant4 (iar4). in addition to enhancing the auxin response defects of tir1-1, iar4 single mutants exhibit numerous auxin-related phenotypes including auxin-resistant root growth and reduced lateral root development, as well as defects in primary root growth, root hair initiation, and root hair elongation. remarkably, all of th ... | 2009 | 19395411 |
| antisense down-regulation of the fapg1 gene reveals an unexpected central role for polygalacturonase in strawberry fruit softening. | the strawberry (fragaria x ananassa 'chandler') fruit undergoes a fast softening during ripening. polygalacturonase (pg) activity is low during this process, but two ripening-related pg genes, fapg1 and fapg2, have been cloned. both genes were up-regulated during fruit ripening and were also negatively regulated by auxin. to further assess the role of fapg1 on strawberry softening, transgenic plants containing an antisense sequence of this gene under the control of the 35s promoter (apg lines) w ... | 2009 | 19395408 |
| circadian clock associated1 and late elongated hypocotyl function synergistically in the circadian clock of arabidopsis. | the circadian clock is an endogenous mechanism that coordinates biological processes with daily and seasonal changes in the environment. heterodimerization of central clock components is an important way of controlling clock function in several different circadian systems. circadian clock associated1 (cca1) and late elongated hypocotyl (lhy) are myb-related proteins that function in or close to the central oscillator in arabidopsis (arabidopsis thaliana). single mutants of cca1 and lhy have a ph ... | 2009 | 19218364 |
| bin2 functions redundantly with other arabidopsis gsk3-like kinases to regulate brassinosteroid signaling. | glycogen synthase kinase3 (gsk3) is a highly conserved serine/threonine kinase involved in a variety of developmental signaling processes. the arabidopsis (arabidopsis thaliana) genome encodes 10 gsk3-like kinases that are clustered into four groups. forward genetic screens have so far uncovered eight mutants, all of which carry gain-of-function mutations in brassinosteroid-insensitive2 (bin2), one of the three members in group ii. genetic and biochemical studies have implicated a negative regul ... | 2009 | 19395409 |
| cia2 coordinately up-regulates protein import and synthesis in leaf chloroplasts. | plastid biogenesis and maintenance depend on the coordinated assembly of proteins imported from the cytosol with proteins translated within plastids. chloroplasts in leaf cells have a greater need for protein import and protein synthesis than plastids in other organs due to the large amount of proteins required for photosynthesis. we previously reported that the arabidopsis (arabidopsis thaliana) transcription factor cia2 specifically up-regulates leaf expression of genes encoding protein transl ... | 2009 | 19386807 |
| a comparative genomics approach identifies a ppr-dyw protein that is essential for c-to-u editing of the arabidopsis chloroplast accd transcript. | several nuclear-encoded proteins containing pentatricopeptide repeat (ppr) motifs have previously been identified to be trans-factors essential for particular chloroplast rna editing events through analysis of mutants affected in chloroplast biogenesis or function. other ppr genes are known to encode proteins involved in other aspects of organelle rna metabolism. a function has not been assigned to most members of the large plant ppr gene family. arabidopsis and rice each contain over 400 ppr ge ... | 2009 | 19395655 |
| a primer for using transgenic insecticidal cotton in developing countries. | many developing countries face the decision of whether to approve the testing and commercial use of insecticidal transgenic cotton and the task of developing adequate regulations for its use. in this review, we outline concepts and provide information to assist farmers, regulators and scientists in making decisions concerning this technology. we address seven critical topics: 1) molecular and breeding techniques used for the development of transgenic cotton cultivars, 2) properties of transgenic ... | 2009 | 19613464 |
| replication and conjugative mobilization of broad host-range incq plasmids. | the incq plasmids have a broader host-range than any other known replicating element in bacteria. studies on the replication and conjugative mobilization of these plasmids, which have mostly been focused on the nearly identical rsf1010 and r1162, are summarized with a view to understanding how this broad host-range is achieved. several significant features of incq plasmids emerge from these studies: (1) initiation of replication, involving dnaa-independent activation of the origin and a dedicate ... | 2009 | 19465049 |
| inefficient double-strand dna break repair is associated with increased fasciation in arabidopsis brca2 mutants. | brca2 is a breast tumour susceptibility factor with functions in maintaining genome stability through ensuring efficient double-strand dna break (dsb) repair via homologous recombination. although best known in vertebrates, fungi, and higher plants also possess brca2-like genes. to investigate the role of arabidopsis brca2 genes in dna repair in somatic cells, transposon insertion mutants of the atbrca2a and atbrca2b genes were identified and characterized. atbrca2a-1 and atbrca2b-1 mutant plant ... | 2009 | 19457980 |
| a reliable protocol for transformation of catharanthus roseus through agrobacterium tumefaciens. | proliferation of axillary shoot buds and multiple shoot formation in catharanthus roseus was obtained in 96 % explants on ms medium (3 % sucrose) containing naa + ba. 2,4-d induced callusing in both, the nodal as well as in leaf segments. leaf-derived callus was used for transformation with agrobacterium tumefaciens lba4404/pbi-s1. bacterial cell concentration, duration of co-cultivation and acetosyringone concentration influenced transformation efficiency. under optimal co-cultivation condition ... | 2009 | 23572917 |
| pollen grain development is compromised in arabidopsis agp6 agp11 null mutants. | arabinogalactan proteins (agps) are structurally complex plasma membrane and cell wall proteoglycans that are implicated in diverse developmental processes, including plant sexual reproduction. male gametogenesis (pollen grain development) is fundamental to plant sexual reproduction. the role of two abundant, pollen-specific agps, agp6, and agp11, have been investigated here. the pollen specificity of these proteoglycans suggested that they are integral to pollen biogenesis and their strong sequ ... | 2009 | 19433479 |
| isolation and identification of ubiquitin-related proteins from arabidopsis seedlings. | the majority of proteins in eukaryotic cells are modified according to highly regulated mechanisms to fulfill specific functions and to achieve localization, stability, and transport. protein ubiquitination is one of the major post-translational modifications occurring in eukaryotic cells. to obtain the proteomic dataset related to the ubiquitin (ub)-dependent regulatory system in arabidopsis, affinity purification with an anti-ub antibody under native condition was performed. using ms/ms analys ... | 2009 | 19429840 |
| review of fructosyl amino acid oxidase engineering research: a glimpse into the future of hemoglobin a1c biosensing. | glycated proteins, particularly glycated hemoglobin a1c, are important markers for assessing the effectiveness of diabetes treatment. convenient and reproducible assay systems based on the enzyme fructosyl amino acid oxidase (faod) have become attractive alternatives to conventional detection methods. we review the available faod-based assays for measurement of glycated proteins as well as the recent advances and future direction of faod research. future research is expected to lead to the next ... | 2009 | 20144298 |
| dwarf27, an iron-containing protein required for the biosynthesis of strigolactones, regulates rice tiller bud outgrowth. | tillering in rice (oryza sativa) is one of the most important agronomic traits that determine grain yields. previous studies on rice tillering mutants have shown that the outgrowth of tiller buds in rice is regulated by a carotenoid-derived max/rms/d (more axillary branching) pathway, which may be conserved in higher plants. strigolactones, a group of terpenoid lactones, have been recently identified as products of the max/rms/d pathway that inhibits axillary bud outgrowth. we report here the mo ... | 2009 | 19470589 |
| association genetics reveals three novel avirulence genes from the rice blast fungal pathogen magnaporthe oryzae. | to subvert rice (oryza sativa) host defenses, the devastating ascomycete fungus pathogen magnaporthe oryzae produces a battery of effector molecules, including some with avirulence (avr) activity, which are recognized by host resistance (r) proteins resulting in rapid and effective activation of innate immunity. to isolate novel avirulence genes from m. oryzae, we examined dna polymorphisms of secreted protein genes predicted from the genome sequence of isolate 70-15 and looked for an associatio ... | 2009 | 19454732 |
| dynamic behavior of arabidopsis eif4a-iii, putative core protein of exon junction complex: fast relocation to nucleolus and splicing speckles under hypoxia. | here, we identify the arabidopsis thaliana ortholog of the mammalian dead box helicase, eif4a-iii, the putative anchor protein of exon junction complex (ejc) on mrna. arabidopsis eif4a-iii interacts with an ortholog of the core ejc component, aly/ref, and colocalizes with other ejc components, such as mago, y14, and rnps1, suggesting a similar function in ejc assembly to animal eif4a-iii. a green fluorescent protein (gfp)-eif4a-iii fusion protein showed localization to several subnuclear domains ... | 2009 | 19435936 |
| the ethylene receptor etr2 delays floral transition and affects starch accumulation in rice. | ethylene regulates multiple aspects of plant growth and development in dicotyledonous plants; however, its roles in monocotyledonous plants are poorly known. here, we characterized a subfamily ii ethylene receptor, ethylene response2 (etr2), in rice (oryza sativa). the etr2 receptor with a diverged his kinase domain is a ser/thr kinase, but not a his kinase, and can phosphorylate its receiver domain. mutation of the n box of the kinase domain abolished the kinase activity of etr2. overexpression ... | 2009 | 19417056 |
| gibberellin modulates anther development in rice via the transcriptional regulation of gamyb. | gibberellins (gas) play important roles in regulating reproductive development, especially anther development. our previous studies revealed that the myb transcriptional factor gamyb, an important component of ga signaling in cereal aleurone cells, is also important for anther development. here, we examined the physiological functions of ga during anther development through phenotypic analyses of rice (oryza sativa) ga-deficient, ga-insensitive, and gamyb mutants. the mutants exhibited common de ... | 2009 | 19454733 |
| the ngatha distal organ development genes are essential for style specification in arabidopsis. | floral organ identities are specified by a few transcription factors that act as master regulators. subsequently, specification of organ axes programs the distribution of distinct tissue types within the organs that themselves develop unique identities. the c-class, agamous-clade mads box genes are primary promoters of the gynoecium, which is divided into a distal style and a subtending ovary along the apical-basal axis. we show that members of a clade of b3 domain transcription factors, ngatha1 ... | 2009 | 19435933 |
| arabidopsis asa1 is important for jasmonate-mediated regulation of auxin biosynthesis and transport during lateral root formation. | plant roots show an impressive degree of plasticity in adapting their branching patterns to ever-changing growth conditions. an important mechanism underlying this adaptation ability is the interaction between hormonal and developmental signals. here, we analyze the interaction of jasmonate with auxin to regulate lateral root (lr) formation through characterization of an arabidopsis thaliana mutant, jasmonate-induced defective lateral root1 (jdl1/asa1-1). we demonstrate that, whereas exogenous j ... | 2009 | 19435934 |
| phosphorylation of sos3-like calcium binding protein8 by sos2 protein kinase stabilizes their protein complex and regulates salt tolerance in arabidopsis. | the salt overly sensitive (sos) pathway plays an important role in the regulation of na+/k+ ion homeostasis and salt tolerance in arabidopsis thaliana. previously, we reported that the calcium binding proteins sos3 and sos3-like calcium binding protein8 (scabp8) nonredundantly activate the protein kinase sos2. here, we show that sos2 phosphorylates scabp8 at its c terminus but does not phosphorylate sos3. in vitro, sos2 phosphorylation of scabp8 was enhanced by the bimolecular interaction of sos ... | 2009 | 19448033 |
| alternative splicing of anciently exonized 5s rrna regulates plant transcription factor tfiiia. | identifying conserved alternative splicing (as) events among evolutionarily distant species can prioritize as events for functional characterization and help uncover relevant cis- and trans-regulatory factors. a genome-wide search for conserved cassette exon as events in higher plants revealed the exonization of 5s ribosomal rna (5s rrna) within the gene of its own transcription regulator, tfiiia (transcription factor for polymerase iii a). the 5s rrna-derived exon in tfiiia gene exists in all r ... | 2009 | 19211543 |
| enhanced tolerance to chilling stress in osmyb3r-2 transgenic rice is mediated by alteration in cell cycle and ectopic expression of stress genes. | myb transcription factors play central roles in plant responses to abiotic stresses. how stress affects development is poorly understood. here, we show that osmyb3r-2 functions in both stress and developmental processes in rice (oryza sativa). transgenic plants overexpressing osmyb3r-2 exhibited enhanced cold tolerance. cold treatment greatly induced the expression of osmyb3r-2, which encodes an active transcription factor. we show that osmyb3r-2 specifically bound to a mitosis-specific activato ... | 2009 | 19279197 |
| the arabidopsis ring finger e3 ligase rha2a is a novel positive regulator of abscisic acid signaling during seed germination and early seedling development. | the phytohormone abscisic acid (aba) is well known for its regulatory roles in integrating environmental constraints with the developmental programs of plants. here, we characterize the biological function of the arabidopsis (arabidopsis thaliana) ring-h2 protein rha2a in aba signaling. the rha2a mutant is less sensitive to aba than the wild type during seed germination and early seedling development, whereas transgenic plants overexpressing rha2a are hypersensitive, indicating that rha2a positi ... | 2009 | 19286935 |
| a nuclear gene encoding the iron-sulfur subunit of mitochondrial complex ii is regulated by b3 domain transcription factors during seed development in arabidopsis. | mitochondrial complex ii (succinate dehydrogenase) is part of the tricarboxylic acid cycle and the respiratory chain. three nuclear genes encode its essential iron-sulfur subunit in arabidopsis (arabidopsis thaliana). one of them, succinate dehydrogenase2-3 (sdh2-3), is specifically expressed in the embryo during seed maturation, suggesting that sdh2-3 may have a role as the complex ii iron-sulfur subunit during embryo maturation and/or germination. here, we present data demonstrating that three ... | 2009 | 19261733 |
| the arabidopsis callose synthase gene gsl8 is required for cytokinesis and cell patterning. | cytokinesis is the division of the cytoplasm and its separation into two daughter cells. cell plate growth and cytokinesis appear to require callose, but direct functional evidence is still lacking. to determine the role of callose and its synthesis during cytokinesis, we identified and characterized mutants in many members of the glucan synthase-like (gsl; or callose synthase) gene family in arabidopsis (arabidopsis thaliana). most gsl mutants (gsl1-gsl7, gsl9, gsl11, and gsl12) exhibited rough ... | 2009 | 19286936 |
| an arabidopsis mitogen-activated protein kinase cascade, mkk9-mpk6, plays a role in leaf senescence. | leaf senescence is a developmentally programmed cell death process that constitutes the final step of leaf development, and it can be regulated by multiple environmental cues and endogenous signals. the mitogen-activated protein kinase (mapk) cascades play diverse roles in intracellular and extracellular signaling in plants. roles of the mapk signaling module in leaf senescence are unknown. here, a mapk cascade involving mkk9-mpk6 is shown to play an important role in regulating leaf senescence ... | 2009 | 19251906 |
| in-depth proteome analysis of arabidopsis leaf peroxisomes combined with in vivo subcellular targeting verification indicates novel metabolic and regulatory functions of peroxisomes. | peroxisomes are metabolically diverse organelles with essential roles in plant development. the major protein constituents of plant peroxisomes are well characterized, whereas only a few low-abundance and regulatory proteins have been reported to date. we performed an in-depth proteome analysis of arabidopsis (arabidopsis thaliana) leaf peroxisomes using one-dimensional gel electrophoresis followed by liquid chromatography and tandem mass spectrometry. we detected 65 established plant peroxisoma ... | 2009 | 19329564 |
| the chromodomain of like heterochromatin protein 1 is essential for h3k27me3 binding and function during arabidopsis development. | polycomb group (pcg) proteins are essential to maintain gene expression patterns during development. transcriptional repression by pcg proteins involves trimethylation of h3k27 (h3k27me3) by polycomb repressive complex 2 (prc2) in animals and plants. prc1 binds to h3k27me3 and is required for transcriptional repression in animals, but in plants prc1-like activities have remained elusive. one candidate protein that could be involved in prc1-like functions in plants is like heterochromatin protein ... | 2009 | 19399177 |
| proteomics identification of azaspiracid toxin biomarkers in blue mussels, mytilus edulis. | azaspiracids are a class of recently discovered algae-derived shellfish toxins. their distribution globally is on the increase with mussels being most widely implicated in azaspiracid-related food poisoning events. evidence that these toxins were bound to proteins in contaminated mussels has been shown recently. in the present study characterization of these proteins in blue mussels, mytilus edulis, was achieved using a range of advanced proteomics tools. four proteins present only in the hepato ... | 2009 | 19390117 |
| cassava brown streak virus (potyviridae) encodes a putative maf/ham1 pyrophosphatase implicated in reduction of mutations and a p1 proteinase that suppresses rna silencing but contains no hc-pro. | the complete positive-sense single-stranded rna genome of cassava brown streak virus (cbsv; genus ipomovirus; potyviridae) was found to consist of 9,069 nucleotides and predicted to produce a polyprotein of 2,902 amino acids. it was lacking helper-component proteinase but contained a single p1 serine proteinase that strongly suppressed rna silencing. besides the exceptional structure of the 5'-proximal part of the genome, cbsv also contained a maf/ham1-like sequence (678 nucleotides, 226 amino a ... | 2009 | 19386713 |
| transgenerational stress memory is not a general response in arabidopsis. | adverse conditions can trigger dna damage as well as dna repair responses in plants. a variety of stress factors are known to stimulate homologous recombination, the most accurate repair pathway, by increasing the concentration of necessary enzymatic components and the frequency of events. this effect has been reported to last into subsequent generations not exposed to the stress. to establish a basis for a genetic analysis of this transgenerational stress memory, a broad range of treatments was ... | 2009 | 19381297 |
| light-induced vegetative anthocyanin pigmentation in petunia. | the lc petunia system, which displays enhanced, light-induced vegetative pigmentation, was used to investigate how high light affects anthocyanin biosynthesis, and to assess the effects of anthocyanin pigmentation upon photosynthesis. lc petunia plants displayed intense purple anthocyanin pigmentation throughout the leaves and stems when grown under high-light conditions, yet remain acyanic when grown under shade conditions. the coloured phenotypes matched with an accumulation of anthocyanins an ... | 2009 | 19380423 |
| proliferation and cell fate establishment during arabidopsis male gametogenesis depends on the retinoblastoma protein. | the retinoblastoma (rb) protein is a conserved repressor of cell proliferation. in animals and plants, deregulation of rb protein causes hyperproliferation and perturbs cell differentiation to various degrees. however, the primary developmental impact of the loss of rb protein has remained unclear. in this study we investigated the direct consequences of rb protein knockout in the arabidopsis male germline using cytological and molecular markers. the arabidopsis germ line derives from the unequa ... | 2009 | 19359496 |
| phylogenetic and molecular analysis of hydrogen-producing green algae. | a select set of microalgae are reported to be able to catalyse photobiological h(2) production from water. based on the model organism chlamydomonas reinhardtii, a method was developed for the screening of naturally occurring h(2)-producing microalgae. by purging algal cultures with n(2) in the dark and subsequent illumination, it is possible to rapidly induce photobiological h(2) evolution. using nmr spectroscopy for metabolic profiling in c. reinhardtii, acetate, formate, and ethanol were foun ... | 2009 | 19342428 |
| arabidopsis ltpg is a glycosylphosphatidylinositol-anchored lipid transfer protein required for export of lipids to the plant surface. | plant epidermal cells dedicate more than half of their lipid metabolism to the synthesis of cuticular lipids, which seal and protect the plant shoot. the cuticle is made up of a cutin polymer and waxes, diverse hydrophobic compounds including very-long-chain fatty acids and their derivatives. how such hydrophobic compounds are exported to the cuticle, especially through the hydrophilic plant cell wall, is not known. by performing a reverse genetic screen, we have identified ltpg, a glycosylphosp ... | 2009 | 19366900 |
| interaction transcriptome analysis identifies magnaporthe oryzae bas1-4 as biotrophy-associated secreted proteins in rice blast disease. | biotrophic invasive hyphae (ih) of the blast fungus magnaporthe oryzae secrete effectors to alter host defenses and cellular processes as they successively invade living rice (oryza sativa) cells. however, few blast effectors have been identified. indeed, understanding fungal and rice genes contributing to biotrophic invasion has been difficult because so few plant cells have encountered ih at the earliest infection stages. we developed a robust procedure for isolating infected-rice sheath rnas ... | 2009 | 19357089 |
| the wd40 repeat protein nedd1 functions in microtubule organization during cell division in arabidopsis thaliana. | although cells of flowering plants lack a structurally defined microtubule-organizing center like the centrosome, organization of the spindles and phragmoplasts in mitosis is known to involve the evolutionarily conserved gamma-tubulin complex. we have investigated the function of arabidopsis thaliana nedd1, a wd40 repeat protein related to the animal nedd1/gcp-wd protein, which interacts with the gamma-tubulin complex. the nedd1 protein decorates spindle microtubules (mts) preferentially toward ... | 2009 | 19383896 |
| the myb23 gene provides a positive feedback loop for cell fate specification in the arabidopsis root epidermis. | the specification of cell fates during development requires precise regulatory mechanisms to ensure robust cell type patterns. theoretical models of pattern formation suggest that a combination of negative and positive feedback mechanisms are necessary for efficient specification of distinct fates in a field of differentiating cells. here, we examine the role of the r2r3-myb transcription factor gene, atmyb23 (myb23), in the establishment of the root epidermal cell type pattern in arabidopsis th ... | 2009 | 19395683 |
| pausing of golgi bodies on microtubules regulates secretion of cellulose synthase complexes in arabidopsis. | plant growth and organ formation depend on the oriented deposition of load-bearing cellulose microfibrils in the cell wall. cellulose is synthesized by plasma membrane-bound complexes containing cellulose synthase proteins (cesas). here, we establish a role for the cytoskeleton in intracellular trafficking of cellulose synthase complexes (cscs) through the in vivo study of the green fluorescent protein (gfp)-cesa3 fusion protein in arabidopsis thaliana hypocotyls. gfp-cesa3 localizes to the plas ... | 2009 | 19376932 |
| the rna binding protein elf9 directly reduces suppressor of overexpression of co1 transcript levels in arabidopsis, possibly via nonsense-mediated mrna decay. | suppressor of overexpression of co1 (soc1) is regulated by a complex transcriptional regulatory network that allows for the integration of multiple floral regulatory inputs from photoperiods, gibberellin, and flowering locus c. however, the posttranscriptional regulation of soc1 has not been explored. here, we report that early flowering9 (elf9), an arabidopsis thaliana rna binding protein, directly targets the soc1 transcript and reduces soc1 mrna levels, possibly through a nonsense-mediated mr ... | 2009 | 19376936 |
| methyl jasmonate reduces grain yield by mediating stress signals to alter spikelet development in rice. | jasmonic acid (ja) is involved in plant development and the defense response. transgenic overexpression of the arabidopsis (arabidopsis thaliana) jasmonic acid carboxyl methyltransferase gene (atjmt) linked to the ubi1 promoter increased levels of methyl jasmonate (meja) by 6-fold in young panicles. grain yield was greatly reduced in ubi1:atjmt plants due to a lower numbers of spikelets and lower filling rates than were observed for nontransgenic (nt) controls. ubi1:atjmt plants had altered numb ... | 2009 | 19211695 |
| a role for the toc complex in arabidopsis root gravitropism. | arabidopsis (arabidopsis thaliana) roots perceive gravity and reorient their growth accordingly. starch-dense amyloplasts within the columella cells of the root cap are important for gravitropism, and starchless mutants such as pgm1 display an attenuated response to gravistimulation. the altered response to gravity1 (arg1) mutant is known to be involved with the early phases of gravity signal transduction. arg1 responds slowly to gravistimulation and is in a genetically distinct pathway from pgm ... | 2009 | 19211693 |
| molecular and genetic evidence for the key role of atcam3 in heat-shock signal transduction in arabidopsis. | heat shock (hs) is a common form of stress suffered by plants. it has been proposed that calmodulin (cam) is involved in hs signal transduction, but direct evidence has been lacking. to investigate the potential regulatory function of cam in the hs signal transduction pathway, t-dna knockout mutants for atcam2, atcam3, and atcam4 were obtained and their thermotolerance tested. of the three knockout mutant plants, there were no differences compared with wild-type plants under normal conditions. h ... | 2009 | 19211698 |
| snrk1 isoforms akin10 and akin11 are differentially regulated in arabidopsis plants under phosphate starvation. | during phosphate starvation, snf1-related kinase 1 (snrk1) activity significantly decreases compared with plants growing under normal nutritional conditions. an analysis of the expression of the genes encoding for the catalytic subunits of snrk1 showed that these subunits were not affected by phosphate starvation. transgenic arabidopsis (arabidopsis thaliana) plants overexpressing the akin10 and akin11 catalytic subunits fused with green fluorescent protein (gfp) were produced, and their localiz ... | 2009 | 19211700 |
| the short-rooted phenotype of the brevis radix mutant partly reflects root abscisic acid hypersensitivity. | to gain further insight into abscisic acid (aba) signaling and its role in growth regulation, we have screened for arabidopsis (arabidopsis thaliana) mutants hypersensitive to aba-mediated root growth inhibition. as a result, we have identified a loss-of-function allele of brevis radix (brx) in the columbia background, named brx-2, which shows enhanced response to aba-mediated inhibition of root growth. brx encodes a key regulator of cell proliferation and elongation in the root, which has been ... | 2009 | 19201913 |
| atvps45 is a positive regulator of the syp41/syp61/vti12 snare complex involved in trafficking of vacuolar cargo. | we report a functional characterization of atvps45 (for vacuolar protein sorting 45), a protein from the sec1/munc18 family in arabidopsis (arabidopsis thaliana) that interacts at the trans-golgi network (tgn) with the syp41/syp61/vti12 snare complex. a null allele of atvps45 was male gametophytic lethal, whereas stable rna interference lines with reduced atvps45 protein levels had stunted growth but were viable and fertile. in the silenced lines, we observed defects in vacuole formation that co ... | 2009 | 19251905 |
| drought and abscisic acid effects on aquaporin content translate into changes in hydraulic conductivity and leaf growth rate: a trans-scale approach. | the effects of abscisic acid (aba) on aquaporin content, root hydraulic conductivity (lpr), whole plant hydraulic conductance, and leaf growth are controversial. we addressed these effects via a combination of experiments at different scales of plant organization and tested their consistency via a model. we analyzed under moderate water deficit a series of transformed maize (zea mays) lines, one sense and three antisense, affected in nced (for 9-cis-epoxycarotenoid dioxygenase) gene expression a ... | 2009 | 19211703 |
| gibberellins regulate lateral root formation in populus through interactions with auxin and other hormones. | the role of gibberellins (gas) in regulation of lateral root development is poorly understood. we show that ga-deficient (35s:pcga2ox1) and ga-insensitive (35s:rgl1) transgenic populus exhibited increased lateral root proliferation and elongation under in vitro and greenhouse conditions, and these effects were reversed by exogenous ga treatment. in addition, rna interference suppression of two poplar ga 2-oxidases predominantly expressed in roots also decreased lateral root formation. gas negati ... | 2009 | 20354195 |
| gibberellin acts through jasmonate to control the expression of myb21, myb24, and myb57 to promote stamen filament growth in arabidopsis. | precise coordination between stamen and pistil development is essential to make a fertile flower. mutations impairing stamen filament elongation, pollen maturation, or anther dehiscence will cause male sterility. deficiency in plant hormone gibberellin (ga) causes male sterility due to accumulation of della proteins, and ga triggers della degradation to promote stamen development. deficiency in plant hormone jasmonate (ja) also causes male sterility. however, little is known about the relationsh ... | 2009 | 19325888 |
| a barley cellulose synthase-like cslh gene mediates (1,3;1,4)-beta-d-glucan synthesis in transgenic arabidopsis. | the walls of grasses and related members of the poales are characterized by the presence of the polysaccharide (1,3, 1,4)-beta-d-glucan (beta-glucan). to date, only members of the grass-specific cellulose synthase-like f (cslf) gene family have been implicated in its synthesis. assuming that other grass-specific csl genes also might encode synthases for this polysaccharide, we cloned hvcslh1, a cslh gene from barley (hordeum vulgare l.), and expressed an epitope-tagged version of the cdna in ara ... | 2009 | 19321749 |
| a plant germline-specific integrator of sperm specification and cell cycle progression. | the unique double fertilisation mechanism in flowering plants depends upon a pair of functional sperm cells. during male gametogenesis, each haploid microspore undergoes an asymmetric division to produce a large, non-germline vegetative cell and a single germ cell that divides once to produce the sperm cell pair. despite the importance of sperm cells in plant reproduction, relatively little is known about the molecular mechanisms controlling germ cell proliferation and specification. here, we in ... | 2009 | 19300502 |
| expression of the somatic embryogenesis receptor-like kinase1 (serk1) gene is associated with developmental change in the life cycle of the model legume medicago truncatula. | somatic embryogenesis receptor-like kinase (serk) genes have been demonstrated to play a role in somatic embryogenesis in several plant species. as more is learnt about these genes, the view of their role in plant development has broadened. the medicago truncatula mtserk1 gene has been associated with somatic embryogenesis and in vitro root formation. in order to study the role of mtserk1 in development further, the mtserk1 promoter sequence has been isolated and cloned into a promoter-gus analy ... | 2009 | 19305022 |
| analytical approaches to photobiological hydrogen production in unicellular green algae. | several species of unicellular green algae, such as the model green microalga chlamydomonas reinhardtii, can operate under either aerobic photosynthesis or anaerobic metabolism conditions. a particularly interesting metabolic condition is that of "anaerobic oxygenic photosynthesis", whereby photosynthetically generated oxygen is consumed by the cell's own respiration, causing anaerobiosis in the culture in the light, and induction of the cellular "hydrogen metabolism" process. the latter entails ... | 2009 | 19291418 |
| heat-shock dependent oligomeric status alters the function of a plant-specific thioredoxin-like protein, attdx. | we found that arabidopsis attdx, a heat-stable and plant-specific thioredoxin (trx)-like protein, exhibits multiple functions, acting as a disulfide reductase, foldase chaperone, and holdase chaperone. the activity of attdx, which contains 3 tetratricopeptide repeat (tpr) domains and a trx motif, depends on its oligomeric status. the disulfide reductase and foldase chaperone functions predominate when attdx occurs in the low molecular weight (lmw) form, whereas the holdase chaperone function pre ... | 2009 | 19293385 |
| phosphorylation modification of wheat lectin ver2 is associated with vernalization-induced o-glcnac signaling and intracellular motility. | o-linked beta-n-acetylglucosamine (o-glcnac) modification of proteins mediates stress response and cellular motility in animal cells. the plant lectin concanavalin a can increase nuclear o-glcnac levels and decrease cytoplasmic o-glcnac levels in t lymphocytes. however, the functions of o-glcnac signaling in plants, as well as the relation between plant lectins and o-glcnac in response to environmental stimuli are largely undefined. | 2009 | 19287503 |
| the arabidopsis thaliana f-box protein fbl17 is essential for progression through the second mitosis during pollen development. | in fungi and metazoans, the scf-type ubiquitin protein ligases (e3s) play a critical role in cell cycle regulation by degrading negative regulators, such as cell cycle-dependent kinase inhibitors (ckis) at the g1-to-s-phase checkpoint. here we report that fbl17, an arabidopsis thaliana f-box protein, is involved in cell cycle regulation during male gametogenesis. fbl17 expression is strongly enhanced in plants co-expressing e2fa and dpa, transcription factors that promote s-phase entry. fbl17 lo ... | 2009 | 19277118 |
| structural similarity of tailed phages and pathogenic bacterial secretion systems. | | 2009 | 19276114 |
| tandem affinity purification and mass spectrometric analysis of ubiquitylated proteins in arabidopsis. | protein ubiquitylation is a central regulatory mechanism that controls numerous processes in plants, including hormone signaling, developmental progression, responses to biotic and abiotic challenges, protein trafficking and chromatin structure. despite data implicating thousands of plant proteins as targets, so far only a few have been conclusively shown to be ubiquitylated in planta. here we describe a method to isolate ubiquitin-protein conjugates from arabidopsis that exploits a stable trans ... | 2009 | 19292762 |
| characterization of genes in the asymmetric leaves2/lateral organ boundaries (as2/lob) family in arabidopsis thaliana, and functional and molecular comparisons between as2 and other family members. | the asymmetric leaves2 (as2) gene is required for the generation of the flat and symmetrical shape of the leaf lamina in arabidopsis. as2 encodes a plant-specific protein with an as2/lateral organ boundaries (as2/lob) domain that includes a cysteine repeat, a conserved single glycine residue and a leucine-zipper-like sequence in its amino-terminal half. the arabidopsis genome contains 42 genes, including as2, that encode proteins with an as2/lob domain in their amino-terminal halves, and these g ... | 2009 | 19154202 |
| disruption of adenosine-5'-phosphosulfate kinase in arabidopsis reduces levels of sulfated secondary metabolites. | plants can metabolize sulfate by two pathways, which branch at the level of adenosine 5'-phosphosulfate (aps). aps can be reduced to sulfide and incorporated into cys in the primary sulfate assimilation pathway or phosphorylated by aps kinase to 3'-phosphoadenosine 5'-phosphosulfate, which is the activated sulfate form for sulfation reactions. to assess to what extent aps kinase regulates accumulation of sulfated compounds, we analyzed the corresponding gene family in arabidopsis thaliana. analy ... | 2009 | 19304933 |
| obligate heterodimerization of arabidopsis phytochromes c and e and interaction with the pif3 basic helix-loop-helix transcription factor. | phytochromes are dimeric chromoproteins that regulate plant responses to red (r) and far-red (fr) light. the arabidopsis thaliana genome encodes five phytochrome apoproteins: type i phya mediates responses to fr, and type ii phyb-phye mediate shade avoidance and classical r/fr-reversible responses. in this study, we describe the complete in vivo complement of homodimeric and heterodimeric type ii phytochromes. unexpectedly, phyc and phye do not homodimerize and are present in seedlings only as h ... | 2009 | 19286967 |
| a single vegetative actin isovariant overexpressed under the control of multiple regulatory sequences is sufficient for normal arabidopsis development. | the relative significance of gene regulation and protein isovariant differences remains unexplored for most gene families, particularly those participating in multicellular development. arabidopsis thaliana encodes three vegetative actins, act2, act7, and act8, in two ancient and highly divergent subclasses. mutations in any of these differentially expressed actins revealed only mild phenotypes. however, double mutants were extremely dwarfed, with altered cell and organ morphology and an aberran ... | 2009 | 19304937 |
| shallot-like1 is a kanadi transcription factor that modulates rice leaf rolling by regulating leaf abaxial cell development. | as an important agronomic trait, rice (oryza sativa l.) leaf rolling has attracted much attention from plant biologists and breeders. moderate leaf rolling increases the photosynthesis of cultivars and hence raises grain yield. however, the relevant molecular mechanism remains unclear. here, we show the isolation and functional characterization of shallot-like1 (sll1), a key gene controlling rice leaf rolling. sll1 mutant plants have extremely incurved leaves due to the defective development of ... | 2009 | 19304938 |
| the wuschel-related homeobox gene wox11 is required to activate shoot-borne crown root development in rice. | in rice (oryza sativa), the shoot-borne crown roots are the major root type and are initiated at lower stem nodes as part of normal plant development. however, the regulatory mechanism of crown root development is poorly understood. in this work, we show that a wuschel-related homeobox (wox) gene, wox11, is involved in the activation of crown root emergence and growth. wox11 was found to be expressed in emerging crown roots and later in cell division regions of the root meristem. the expression ... | 2009 | 19258439 |
| a chloroplastic udp-glucose pyrophosphorylase from arabidopsis is the committed enzyme for the first step of sulfolipid biosynthesis. | plants synthesize a sulfur-containing lipid, sulfoquinovosyldiacylglycerol, which is one of three nonphosphorus glycerolipids that provide the bulk of the structural lipids in photosynthetic membranes. here, the identification of a novel gene, udp-glucose pyrophosphorylase3 (ugp3), required for sulfolipid biosynthesis is described. transcriptome coexpression analysis demonstrated highly correlated expression of ugp3 with known genes for sulfolipid biosynthesis in arabidopsis thaliana. liquid chr ... | 2009 | 19286968 |
| identification and functional analysis of pistil self-incompatibility factor ht-b of petunia. | gametophytic self-incompatibility (gsi) in solanaceae, rosaceae, and plantaginaceae is controlled by a multiallelic s-locus. the specificities of pistil and pollen are controlled by separate s-locus genes, s-rnase and slf/sfb, respectively. although the s-specificity is determined by the s-locus genes, factors located outside the s-locus are also required for expression of gsi. ht-b is one of the pistil non-s-factors identified in nicotiana and solanum, and encodes a small asparagine/aspartate-r ... | 2009 | 19282427 |
| positive fluorescent selection permits precise, rapid, and in-depth overexpression analysis in plant protoplasts. | transient genetic modification of plant protoplasts is a straightforward and rapid technique for the study of numerous aspects of plant biology. recent studies in metazoan systems have utilized cell-based assays to interrogate signal transduction pathways using high-throughput methods. plant biologists could benefit from new tools that expand the use of cell culture for large-scale analysis of gene function. we have developed a system that employs fluorescent positive selection in combination wi ... | 2009 | 19168642 |
| molecular and functional characterization of pebp genes in barley reveal the diversification of their roles in flowering. | five barley (hordeum vulgare) pebp (for phosphatidylethanolamine-binding protein) genes were analyzed to clarify their functional roles in flowering using transgenic, expression, and quantitative trait locus analyses. introduction of hvtfl1 and hvmft1 into rice (oryza sativa) plants did not result in any changes in flowering, suggesting that these two genes have functions distinct from flowering. overexpression of hvft1, hvft2, and hvft3 in rice resulted in early heading, indicating that these f ... | 2009 | 19168644 |
| a small family of chloroplast atypical thioredoxins. | the reduction and the formation of regulatory disulfide bonds serve as a key signaling element in chloroplasts. members of the thioredoxin (trx) superfamily of oxidoreductases play a major role in these processes. we have characterized a small family of plant-specific trxs in arabidopsis (arabidopsis thaliana) that are rich in cysteine and histidine residues and are typified by a variable noncanonical redox active site. we found that the redox midpoint potential of three selected family members ... | 2009 | 19109414 |
| in vivo interference with attcp20 function induces severe plant growth alterations and deregulates the expression of many genes important for development. | attcp20 is a transcription factor belonging to the arabidopsis (arabidopsis thaliana) tcp-p subfamily, characterized by its capacity to bind to site ii motifs (tgggcy). our aim was to understand the role of attcp20 in plant development. the expression pattern of a translational fusion of prom(tcp20):cds20gusgfp suggested a function for attcp20 in several plant organs and stages of development. the role of attcp20 was challenged in planta by inducing expression of attcp20 proteins fused with eith ... | 2009 | 19091878 |
| peroxisome-associated matrix protein degradation in arabidopsis. | peroxisomes are ubiquitous eukaryotic organelles housing diverse enzymatic reactions, including several that produce toxic reactive oxygen species. although understanding of the mechanisms whereby enzymes enter peroxisomes with the help of peroxin (pex) proteins is increasing, mechanisms by which damaged or obsolete peroxisomal proteins are degraded are not understood. we have exploited unique aspects of plant development to characterize peroxisome-associated protein degradation (pexad) in arabi ... | 2009 | 19246395 |
| cytokinin regulates root meristem activity via modulation of the polar auxin transport. | plant development is governed by signaling molecules called phytohormones. typically, in certain developmental processes more than 1 hormone is implicated and, thus, coordination of their overlapping activities is crucial for correct plant development. however, molecular mechanisms underlying the hormonal crosstalk are only poorly understood. multiple hormones including cytokinin and auxin have been implicated in the regulation of root development. here we dissect the roles of cytokinin in modul ... | 2009 | 19246387 |
| the transcription factor osnac4 is a key positive regulator of plant hypersensitive cell death. | the hypersensitive response (hr) is a common feature of plant immune responses and a type of programmed cell death. however, little is known about the induction mechanism of hr cell death. we report that overexpression of osnac4, which encodes a plant-specific transcription factor, leads to hr cell death accompanied by the loss of plasma membrane integrity, nuclear dna fragmentation and typical morphological changes. in osnac4 knock-down lines, hr cell death is markedly decreased in response to ... | 2009 | 19229294 |
| common themes in nutrient acquisition by plant symbiotic microbes, described by the gene ontology. | a critical function for symbionts is the acquisition of nutrients from their host. relationships between hosts and symbionts range from biotrophic mutualism to necrotrophic parasitism, with a corresponding range of structures to facilitate nutrient flow between host and symbiont. here, we review common themes among the nutrient acquisition strategies of a range of plant symbiotic microorganisms, including mutualistic symbionts, biotrophic pathogens that feed from living tissue, necrotrophic path ... | 2009 | 19278554 |
| the lack of floral synthesis and emission of isoeugenol in petunia axillaris subsp. parodii is due to a mutation in the isoeugenol synthase gene. | floral scent has been extensively investigated in plants of the south american genus petunia. flowers of petunia integrifolia emit mostly benzaldehyde, while flowers of petunia axillaris subsp. axillaris emit a mixture of volatile benzenoid and phenylpropanoid compounds that include isoeugenol and eugenol. flowers of the artificial hybrid petunia hybrida, a cross between p. integrifolia and p. axillaris, emit a similar spectrum of volatiles as p. axillaris subsp. axillaris. however, the flowers ... | 2009 | 19222805 |
| crystal structure of kora bound to operator dna: insight into repressor cooperation in rp4 gene regulation. | kora is a global repressor in rp4 which regulates cooperatively the expression of plasmid genes whose products are involved in replication, conjugative transfer and stable inheritance. the structure of kora bound to an 18-bp dna duplex that contains the symmetric operator sequence and incorporates 5-bromo-deoxyuridine nucleosides has been determined by multiple-wavelength anomalous diffraction phasing at 1.96-a resolution. kora is present as a symmetric dimer and contacts dna via a helix-turn-he ... | 2009 | 19190096 |
| a novel fatty acyl-coa synthetase is required for pollen development and sporopollenin biosynthesis in arabidopsis. | acyl-coa synthetase (acos) genes are related to 4-coumarate:coa ligase (4cl) but have distinct functions. the arabidopsis thaliana acos5 protein is in clade a of arabidopsis acos proteins, the clade most closely related to 4cl proteins. this clade contains putative nonperoxisomal acos enzymes conserved in several angiosperm lineages and in the moss physcomitrella patens. although its function is unknown, acos5 is preferentially expressed in the flowers of all angiosperms examined. here, we show ... | 2009 | 19218397 |
| the rab gtpase raba4d regulates pollen tube tip growth in arabidopsis thaliana. | during reproduction in flowering plants, pollen grains form a tube that grows in a polarized fashion through the female tissues to eventually fertilize the egg cell. these highly polarized pollen tubes have a rapid rate of growth that is supported by a tip-focused delivery of membrane and cell wall components. to gain a better understanding of how this growth is regulated, we investigated the function raba4d, a member of the arabidopsis thaliana raba4 subfamily of rab gtpase proteins. here, we s ... | 2009 | 19208902 |
| the cytosolic protein response as a subcomponent of the wider heat shock response in arabidopsis. | in common with a range of environmental and biological stresses, heat shock results in the accumulation of misfolded proteins and a collection of downstream consequences for cellular homeostasis and growth. within this complex array of responses, the sensing of and responses to misfolded proteins in specific subcellular compartments involves specific chaperones, transcriptional regulators, and expression profiles. using biological (ectopic protein expression and virus infection) and chemical tri ... | 2009 | 19244141 |
| arabidopsis photorespiratory serine hydroxymethyltransferase activity requires the mitochondrial accumulation of ferredoxin-dependent glutamate synthase. | the dual affinity of ribulose-1,5-bisphosphate carboxylase/oxygenase for o(2) and co(2) results in the net loss of fixed carbon and energy in a process termed photorespiration. the photorespiratory cycle is complex and occurs in three organelles, chloroplasts, peroxisomes, and mitochondria, which necessitates multiple steps to transport metabolic intermediates. genetic analysis has identified a number of mutants exhibiting photorespiratory chlorosis at ambient co(2), including several with defec ... | 2009 | 19223513 |
| the rpn5 subunit of the 26s proteasome is essential for gametogenesis, sporophyte development, and complex assembly in arabidopsis. | the 26s proteasome is an essential multicatalytic protease complex that degrades a wide range of intracellular proteins, especially those modified with ubiquitin. arabidopsis thaliana and other plants use pairs of genes to encode most of the core subunits, with both of the isoforms often incorporated into the mature complex. here, we show that the gene pair encoding the regulatory particle non-atpase subunit (rpn5) has a unique role in proteasome function and arabidopsis development. homozygous ... | 2009 | 19252082 |
| phytochrome a mediates rapid red light-induced phosphorylation of arabidopsis far-red elongated hypocotyl1 in a low fluence response. | phytochrome a (phya) is the primary photoreceptor for mediating the far-red high irradiance response in arabidopsis thaliana. far-red elongated hypocotyl1 (fhy1) and its homolog fhy1-like (fhl) define two positive regulators in the phya signaling pathway. these two proteins have been reported to be essential for light-regulated phya nuclear accumulation through direct physical interaction with phya. here, we report that fhy1 protein is phosphorylated rapidly after exposure to red light. subseque ... | 2009 | 19208901 |
| ethylene mediates response and tolerance to potassium deprivation in arabidopsis. | potassium deprivation leads to large reductions in plant growth and yields. how plants sense and transduce the stress signals initiated by potassium deprivation is poorly understood. both ethylene production and the transcription of genes involved in ethylene biosynthesis increase when plants are deprived of potassium. to elucidate the role of ethylene in low potassium signaling pathways, we used both genetic and chemical approaches. our results showed that ethylene is important in tolerance to ... | 2009 | 19190240 |
| an arabidopsis gpi-anchor plasmodesmal neck protein with callose binding activity and potential to regulate cell-to-cell trafficking. | plasmodesmata (pds) traverse the cell wall to establish a symplastic continuum through most of the plant. rapid and reversible deposition of callose in the cell wall surrounding the pd apertures is proposed to provide a regulatory process through physical constriction of the symplastic channel. we identified members within a larger family of x8 domain-containing proteins that targeted to pds. this subgroup of proteins contains signal sequences for a glycosylphosphatidylinositol linkage to the ex ... | 2009 | 19223515 |
| a plena-like gene of peach is involved in carpel formation and subsequent transformation into a fleshy fruit. | mads-box genes have been shown to play a role in the formation of fruits, both in arabidopsis and in tomato. in peach, two c-class mads-box genes have been isolated. both of them are expressed during flower and mesocarp development. here a detailed analysis of a gene that belongs to the plena subfamily of mads-box genes is shown. the expression of this plena-like gene (ppplena) increases during fruit ripening, and its ectopic expression in tomato plants causes the transformation of sepals into c ... | 2009 | 19264761 |