| plant smu-1 and smu-2 homologues regulate pre-mrna splicing and multiple aspects of development. | in eukaryotes, alternative splicing of pre-mrnas contributes significantly to the proper expression of the genome. however, the functions of many auxiliary spliceosomal proteins are still unknown. here, we functionally characterized plant homologues of nematode suppressors of mec-8 and unc-52 (smu). we compared transcript profiles of maize (zea mays) smu2 endosperm with those of wild-type plants and identified pre-mrna splicing events that depend on the maize smu2 protein. consistent with a cons ... | 2009 | 19734266 |
| lbd18/asl20 regulates lateral root formation in combination with lbd16/asl18 downstream of arf7 and arf19 in arabidopsis. | the lateral organ boundaries domain/asymmetric leaves2-like (lbd/asl) genes encode proteins harboring a conserved amino acid domain, referred to as the lob (for lateral organ boundaries) domain. while recent studies have revealed developmental functions of some lbd genes in arabidopsis (arabidopsis thaliana) and in crop plants, the biological functions of many other lbd genes remain to be determined. in this study, we have demonstrated that the lbd18 mutant evidenced a reduced number of lateral ... | 2009 | 19717544 |
| a leaky mutation in dwarf4 reveals an antagonistic role of brassinosteroid in the inhibition of root growth by jasmonate in arabidopsis. | the f-box protein coronatine insensitive1 (coi1) plays a central role in jasmonate (ja) signaling and is required for all ja responses in arabidopsis (arabidopsis thaliana). to dissect ja signal transduction, we isolated the partially suppressing coi1 (psc1) mutant, which partially suppressed coi1 insensitivity to ja inhibition of root growth. the psc1 mutant partially restored ja sensitivity in coi1-2 background and displayed ja hypersensitivity in wild-type coi1 background. genetic mapping, se ... | 2009 | 19741050 |
| a wd40 repeat protein from medicago truncatula is necessary for tissue-specific anthocyanin and proanthocyanidin biosynthesis but not for trichome development. | wd40 repeat proteins regulate biosynthesis of anthocyanins, proanthocyanidins (pas), and mucilage in the seed and the development of trichomes and root hairs. we have cloned and characterized a wd40 repeat protein gene from medicago truncatula (mtwd40-1) via a retrotransposon-tagging approach. deficiency of mtwd40-1 expression blocks accumulation of mucilage and a range of phenolic compounds, including pas, epicatechin, other flavonoids, and benzoic acids, in the seed, reduces epicatechin levels ... | 2009 | 19710231 |
| coordination of plastid protein import and nuclear gene expression by plastid-to-nucleus retrograde signaling. | expression of nuclear-encoded plastid proteins and import of those proteins into plastids are indispensable for plastid biogenesis. one possible cellular mechanism that coordinates these two essential processes is retrograde signaling from plastids to the nucleus. however, the molecular details of how this signaling occurs remain elusive. using the plastid protein import2 mutant of arabidopsis (arabidopsis thaliana), which lacks the attoc159 protein import receptor, we demonstrate that the expre ... | 2009 | 19726569 |
| distinct extremely abundant sirnas associated with cosuppression in petunia. | cosuppression is a classical form of eukaryotic post-transcriptional gene silencing. it was first reported in transgenic petunia, where a sense transgene meant to overexpress the host chalcone synthase-a (chs-a) gene caused the degradation of the homologous transcripts and the loss of flower pigmentation. in this work, we used deep sequencing technology to characterize in detail the small rna population generated from the chs-a sequence in cosuppressed transgenic petunia. unexpectedly, two disti ... | 2009 | 19776157 |
| genetic reprogramming of host cells by bacterial pathogens. | during the course of infection, pathogens often induce changes in gene expression in host cells and these changes can be long lasting and global or transient and of limited amplitude. defining how, when, and why bacterial pathogens reprogram host cells represents an exciting challenge that opens up the opportunity to grasp the essence of pathogenesis and its molecular details. | 2009 | 20948607 |
| functional genomics of allergen gene families in fruits. | fruit consumption is encouraged for health reasons; however, fruits may harbour a series of allergenic proteins that may cause discomfort or even represent serious threats to certain individuals. thus, the identification and characterization of allergens in fruits requires novel approaches involving genomic and proteomic tools. since avoidance of fruits also negatively affects the quality of patients' lives, biotechnological interventions are ongoing to produce low allergenic fruits by down regu ... | 2009 | 22253972 |
| cell wall invertase 4 is required for nectar production in arabidopsis. | to date, no genes have been reported to directly affect the de novo production of floral nectar. in an effort to identify genes involved in nectar production, the affymetrix((r)) ath1 genechip was previously used to examine global gene expression profiles in arabidopsis thaliana nectaries. one of the genes displaying highly enriched expression in nectaries was cell wall invertase 4 (atcwinv4, at2g36190), which encodes an enzyme that putatively catalyses the hydrolysis of sucrose into glucose and ... | 2009 | 19861655 |
| a bac-based physical map of brachypodium distachyon and its comparative analysis with rice and wheat. | brachypodium distachyon (brachypodium) has been recognized as a new model species for comparative and functional genomics of cereal and bioenergy crops because it possesses many biological attributes desirable in a model, such as a small genome size, short stature, self-pollinating habit, and short generation cycle. to maximize the utility of brachypodium as a model for basic and applied research it is necessary to develop genomic resources for it. a bac-based physical map is one of them. a phys ... | 2009 | 19860896 |
| integrating elf4 into the circadian system through combined structural and functional studies. | the circadian clock is a timekeeping mechanism that enables anticipation of daily environmental changes. in the plant arabidopsis thaliana, the circadian system is a multiloop series of interlocked transcription-translation feedbacks. several genes have been arranged in these oscillation loops, but the position of the core-clock gene elf4 in this network was previously undetermined. elf4 lacks sequence similarity to known domains, and functional homologs have not yet been identified. here we sho ... | 2009 | 20357892 |
| determination of a chloroplast degron in the regulatory domain of chlorophyllide a oxygenase. | chlorophyll b is one of the major photosynthetic pigments of plants. the regulation of chlorophyll b biosynthesis is important for plants in order to acclimate to changing environmental conditions. in the chloroplast, chlorophyll b is synthesized from chlorophyll a by chlorophyllide a oxygenase (cao), a rieske-type monooxygenase. the activity of this enzyme is regulated at the level of protein stability via a feedback mechanism through chlorophyll b. the clp protease and the n-terminal domain (d ... | 2009 | 19843523 |
| the infective cycle of cabbage leaf curl virus (calcuv) is affected by crumpled leaf (crl) gene in arabidopsis thaliana. | geminiviruses are single-stranded dna viruses that cause serious crop losses worldwide. successful infection by these pathogens depends extensively on virus-host intermolecular interactions that allow them to express their gene products, to replicate their genomes and to move to adjacent cells and throughout the plant. | 2009 | 19840398 |
| a small intergenic region drives exclusive tissue-specific expression of the adjacent genes in arabidopsis thaliana. | transcription initiation by rna polymerase ii is unidirectional from most genes. in plants, divergent genes, defined as non-overlapping genes organized head-to-head, are highly represented in the arabidopsis genome. nevertheless, there is scarce evidence on functional analyses of these intergenic regions. the at5g06290 and at5g06280 loci are head-to-head oriented and encode a chloroplast-located 2-cys peroxiredoxin b (2cpb) and a protein of unknown function (puf), respectively. the 2-cys peroxir ... | 2009 | 19835620 |
| a single amino acid replacement in etc2 shapes trichome patterning in natural arabidopsis populations. | our understanding of the evolution of organismal diversity is restricted by the current resolution of the genotype-phenotype map. in particular, the genetic basis of environmentally relevant phenotypic variation among natural populations remains poorly understood. trichomes are single-cell outgrowths on the surface of plant leaves and other above-ground organs. consistent with trichomes' suggested function to protect plants from predators and abiotic stressors [1-3], trichome density is striking ... | 2009 | 19818620 |
| toc1 functions as a molecular switch connecting the circadian clock with plant responses to drought. | despite our increasing knowledge on the transcriptional networks connecting abscisic acid (aba) signalling with the circadian clock, the molecular nodes in which both pathways converge to translate the environmental information into a physiological response are not known. here, we provide evidence of a feedback mechanism linking the circadian clock with plant responses to drought. a key clock component (toc1, timing of cab expression 1) binds to the promoter of the aba-related gene (abar/chlh/gu ... | 2009 | 19816401 |
| bcmf9, a novel polygalacturonase gene, is required for both brassica campestris intine and exine formation. | the polygalacturonase (pg) gene family has been found to be enriched in pollen of several species; however, little is currently known about the function of the pg gene in pollen development. to investigate the exact role that the pg gene has played in pollen development and about this family in general, one putative pg gene, brassica campestris male fertility 9 (bcmf9), was isolated from chinese cabbage (brassica campestris ssp. chinensis, syn. b. rapa ssp. chinensis) and characterized. | 2009 | 19815569 |
| reverse genetics for functional genomics of phytopathogenic fungi and oomycetes. | sequencing of over 40 fungal and oomycete genomes has been completed. the next major challenge in modern fungal/oomycete biology is now to translate this plethora of genome sequence information into biological functions. reverse genetics has emerged as a seminal tool for functional genomics investigations. techniques utilized for reverse genetics like targeted gene disruption/replacement, gene silencing, insertional mutagenesis, and targeting induced local lesions in genomes will contribute grea ... | 2009 | 19830245 |
| phenotypic plasticity of adventitious rooting in arabidopsis is controlled by complex regulation of auxin response factor transcripts and microrna abundance. | the development of shoot-borne roots, or adventitious roots, is indispensable for mass propagation of elite genotypes. it is a complex genetic trait with a high phenotypic plasticity due to multiple endogenous and environmental regulatory factors. we demonstrate here that a subtle balance of activator and repressor auxin response factor (arf) transcripts controls adventitious root initiation. moreover, microrna activity appears to be required for fine-tuning of this process. thus, arf17, a targe ... | 2009 | 19820192 |
| yabbys and the transcriptional corepressors leunig and leunig_homolog maintain leaf polarity and meristem activity in arabidopsis. | in arabidopsis thaliana, filamentous flower (fil) and yabby3 (yab3) encode yabby domain proteins that regulate abaxial patterning, growth of lateral organs, and inflorescence phyllotaxy. in this study, we show that yabs physically interact with components of a transcriptional repressor complex that include leunig (lug), leunig_homolog (luh), the lug-associated coregulator seuss, and related seuss-like proteins. consistent with the formation of a lug-yab complex, we find that lug mutants enhance ... | 2009 | 19837869 |
| fleshy fruit expansion and ripening are regulated by the tomato shatterproof gene tagl1. | the maturation and ripening of fleshy fruits is a developmental program that synchronizes seed maturation with metabolism, rendering fruit tissues desirable to seed dispersing organisms. through rna interference repression, we show that tomato agamous-like1 (tagl1), the tomato (solanum lycopersicum) ortholog of the duplicated shatterproof (shp) mads box genes of arabidopsis thaliana, is necessary for fruit ripening. tomato plants with reduced tagl1 mrna produced yellow-orange fruit with reduced ... | 2009 | 19880793 |
| domain swapping to assess the mechanistic basis of arabidopsis phototropin 1 receptor kinase activation and endocytosis by blue light. | phototropins (phot1 and phot2) are plasma membrane-associated receptor kinases that respond specifically to blue and uv wavelengths. in addition to a c-terminal ser/thr kinase domain, phototropins contain two n-terminal chromophore binding lov domains that function as photoswitches to regulate a wide range of enzymatic activities in prokaryotes and eukaryotes. through domain swapping, we show that the photochemical properties of arabidopsis thaliana phot1 rely on interactions between lov1 and lo ... | 2009 | 19880798 |
| the ferroportin metal efflux proteins function in iron and cobalt homeostasis in arabidopsis. | relatively little is known about how metals such as iron are effluxed from cells, a necessary step for transport from the root to the shoot. ferroportin (fpn) is the sole iron efflux transporter identified to date in animals, and there are two closely related orthologs in arabidopsis thaliana, iron regulated1 (ireg1/fpn1) and ireg2/fpn2. fpn1 localizes to the plasma membrane and is expressed in the stele, suggesting a role in vascular loading; fpn2 localizes to the vacuole and is expressed in th ... | 2009 | 19861554 |
| owl1: an arabidopsis j-domain protein involved in perception of very low light fluences. | to sense ambient light conditions in order to optimize their growth and development, plants employ a battery of photoreceptors responsive to light quality and quantity. essential for the sensing of red and far-red (fr) light is the phytochrome family of photoreceptors. among them, phytochrome a is special because it mediates responses to different light conditions, including both very low fluences (very low fluence response [vlfr]) and high irradiances (high irradiance response [hir]). in contra ... | 2009 | 19808946 |
| lyrate is a key regulator of leaflet initiation and lamina outgrowth in tomato. | development of the flattened laminar structure in plant leaves requires highly regulated cell division and expansion patterns. although tight regulation of these processes is essential during leaf development, leaf shape is highly diverse across the plant kingdom, implying that patterning of growth must be amenable to evolutionary change. here, we describe the molecular identification of the classical tomato (solanum lycopersicum) mutant lyrate, which is impaired in outgrowth of leaflet primodia ... | 2009 | 19820188 |
| mosaic floral organs1, an agl6-like mads box gene, regulates floral organ identity and meristem fate in rice. | floral organ identity and meristem determinacy in plants are controlled by combinations of activities mediated by mads box genes. agamous-like6 (agl6)-like genes are mads box genes expressed in floral tissues, but their biological functions are mostly unknown. here, we describe an agl6-like gene in rice (oryza sativa), mosaic floral organs1 (mfo1/mads6), that regulates floral organ identity and floral meristem determinacy. in the flower of mfo1 mutants, the identities of palea and lodicule are d ... | 2009 | 19820190 |
| chotto1, a putative double apetala2 repeat transcription factor, is involved in abscisic acid-mediated repression of gibberellin biosynthesis during seed germination in arabidopsis. | the phytohormones abscisic acid (aba) and gibberellins (gas) are the primary signals that regulate seed dormancy and germination. in this study, we investigated the role of a double apetala2 repeat transcription factor, chotto1 (cho1), in seed dormancy, germination, and phytohormone metabolism of arabidopsis (arabidopsis thaliana). wild-type seeds were dormant when freshly harvested seeds were sown, and these seeds were released from dormancy after a particular period of dry storage (after-ripen ... | 2009 | 19648230 |
| the arabidopsis grf-interacting factor gene family performs an overlapping function in determining organ size as well as multiple developmental properties. | previously, the grf-interacting factor1 (gif1)/angustifolia3 (an3) transcription coactivator gene, a member of a small gene family comprising three genes, was characterized as a positive regulator of cell proliferation in lateral organs, such as leaves and flowers, of arabidopsis (arabidopsis thaliana). as yet, it remains unclear how gif1/an3 affects the cell proliferation process. in this study, we demonstrate that the other members of the gif gene family, gif2 and gif3, are also required for c ... | 2009 | 19648231 |
| analysis of photoperiod sensitivity5 sheds light on the role of phytochromes in photoperiodic flowering in rice. | a great number of plants synchronize flowering with day length. in rice (oryza sativa), photoperiod is the primary environmental cue that triggers flowering. here, we show that the s73 mutant, identified in a gamma-irradiated bahia collection, displays early flowering and photoperiodic insensitivity due to a null mutation in the photoperiod sensitivity5 (se5) gene, which encodes an enzyme implicated in phytochrome chromophore biosynthesis. s73 mutant plants show a number of alterations in the ch ... | 2009 | 19675157 |
| plastidial glyceraldehyde-3-phosphate dehydrogenase deficiency leads to altered root development and affects the sugar and amino acid balance in arabidopsis. | glycolysis is a central metabolic pathway that, in plants, occurs in both the cytosol and the plastids. the glycolytic glyceraldehyde-3-phosphate dehydrogenase (gapdh) catalyzes the conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate with concomitant reduction of nad(+) to nadh. both cytosolic (gapcs) and plastidial (gapcps) gapdh activities have been described. however, the in vivo functions of the plastidial isoforms remain unresolved. in this work, we have identified two arabi ... | 2009 | 19675149 |
| ectopic 5' splice sites inhibit gene expression by engaging rna surveillance and silencing pathways in plants. | the quality control of mrna maturation is a highly regulated process that surveys pre-mrna integrity and eliminates improperly matured pre-mrnas. in nature, certain viruses regulate the expression of their genes by hijacking the endogenous rna quality control machinery. we demonstrate that the inclusion of 5' splice sites within the 3'-untranslated region of a reporter gene in plants alters the pre-mrna cleavage and polyadenylation process, resulting in pre-mrna degradation, exemplifying a regul ... | 2009 | 19666706 |
| saur39, a small auxin-up rna gene, acts as a negative regulator of auxin synthesis and transport in rice. | the phytohormone auxin plays a critical role for plant growth by regulating the expression of a set of genes. one large auxin-responsive gene family of this type is the small auxin-up rna (saur) genes, although their function is largely unknown. the expression of the rice (oryza sativa) saur39 gene showed rapid induction by transient change in different environmental factors, including auxin, nitrogen, salinity, cytokinin, and anoxia. transgenic rice plants overexpressing the saur39 gene resulte ... | 2009 | 19700562 |
| arabidopsis putative selenium-binding protein1 expression is tightly linked to cellular sulfur demand and can reduce sensitivity to stresses requiring glutathione for tolerance. | selenium-binding protein1 (sbp1) gene expression was studied in arabidopsis (arabidopsis thaliana) seedlings challenged with several stresses, including cadmium (cd), selenium {selenate [se(vi)] and selenite [se(iv)]}, copper (cu), zinc (zn), and hydrogen peroxide (h(2)o(2)) using transgenic lines expressing the luciferase (luc) reporter gene under the control of the sbp1 promoter. in roots and shoots of sbp1luc lines, luc activity increased in response to cd, se(vi), cu, and h(2)o(2) but not in ... | 2009 | 19710230 |
| imprinting of the polycomb group gene medea serves as a ploidy sensor in arabidopsis. | balanced maternal and paternal genome contributions are a requirement for successful seed development. unbalanced contributions often cause seed abortion, a phenomenon that has been termed "triploid block." misregulation of imprinted regulatory genes has been proposed to be the underlying cause for abnormalities in growth and structure of the endosperm in seeds with deviating parental contributions. we identified a mutant forming unreduced pollen that enabled us to investigate direct effects of ... | 2009 | 19779546 |
| brassica orthologs from banyuls belong to a small multigene family, which is involved in procyanidin accumulation in the seed. | as part of a research programme focused on flavonoid biosynthesis in the seed coat of brassica napus l. (oilseed rape), orthologs of the banyuls gene that encoded anthocyanidin reductase were cloned in b. napus as well as in the related species brassica rapa and brassica oleracea. b. napus genome contained four functional copies of ban, two originating from each diploid progenitor. amino acid sequences were highly conserved between the brassicaceae including b. napus, b. rapa, b. oleracea as wel ... | 2009 | 19760260 |
| a new set of ests and cdna clones from full-length and normalized libraries for gene discovery and functional characterization in citrus. | interpretation of ever-increasing raw sequence information generated by modern genome sequencing technologies faces multiple challenges, such as gene function analysis and genome annotation. indeed, nearly 40% of genes in plants encode proteins of unknown function. functional characterization of these genes is one of the main challenges in modern biology. in this regard, the availability of full-length cdna clones may fill in the gap created between sequence information and biological knowledge. ... | 2009 | 19747386 |
| toc receptor dimerization participates in the initiation of membrane translocation during protein import into chloroplasts. | the post-translational import of nucleus-encoded preproteins into chloroplasts occurs through multimeric translocons in the outer (toc) and inner (tic) membranes. the high fidelity of the protein import process is maintained by specific recognition of the transit peptide of preproteins by the coordinate activities of two homologous gtpase toc receptors, toc34 and toc159. structural and biochemical studies suggest that dimerization of the toc receptors functions as a component of the mechanism to ... | 2009 | 19744928 |
| disruption of the pollen-expressed feronia homologs anxur1 and anxur2 triggers pollen tube discharge. | the precise delivery of male to female gametes during reproduction in eukaryotes requires complex signal exchanges and a flawless communication between male and female tissues. in angiosperms, molecular mechanisms have recently been revealed that are crucial for the dialog between male (pollen tube) and female gametophytes required for successful sperm delivery. when pollen tubes reach the female gametophyte, they arrest growth, burst and discharge their sperm cells. these processes are under th ... | 2009 | 19736323 |
| vx211, a vigorous new walnut hybrid clone with nematode tolerance and a useful resistance mechanism. | vx211 is a highly vigorous paradox hybrid clone that outgrew other walnut seedlings in the presence of nematodes. a four-year macroplot trial involving paradox vx211 and a standard paradox selection, ax1, demonstrated that the damage threshold level of pratylenchus vulnus on commercially available walnut rootstocks is < 1 nematode/250 cm³ of soil. using 1 as the initial population level (pi) within an inoculation zone of 80 l of soil, the p. vulnus population level increased 2,500-fold in the fi ... | 2009 | 22736816 |
| cellular pathways regulating responses to compatible and self-incompatible pollen in brassica and arabidopsis stigmas intersect at exo70a1, a putative component of the exocyst complex. | in the brassicaceae, compatible pollen-pistil interactions result in pollen adhesion to the stigma, while pollen grains from unrelated plant species are largely ignored. there can also be an additional layer of recognition to prevent self-fertilization, the self-incompatibility response, whereby self pollen grains are distinguished from nonself pollen grains and rejected. this pathway is activated in the stigma and involves the arm repeat-containing 1 (arc1) protein, an e3 ubiquitin ligase. in a ... | 2009 | 19789280 |
| a dual role for the s-locus receptor kinase in self-incompatibility and pistil development revealed by an arabidopsis rdr6 mutation. | the coordinate evolution of self-incompatibility (si) and stigma-anther separation, two mechanisms that promote cross-pollination in plants, has been a long-standing puzzle in evolution and development. using a transgenic self-incompatible arabidopsis thaliana model, we performed screens for mutants exhibiting a modified si response. a mutation in the rna-dependent rna polymerase rdr6, which functions in trans-acting short interfering rna (ta-sirna) production, was found that simultaneously enha ... | 2009 | 19767457 |
| replication stress leads to genome instabilities in arabidopsis dna polymerase delta mutants. | impeded dna replication or a deficiency of its control may critically threaten the genetic information of cells, possibly resulting in genome alterations, such as gross chromosomal translocations, microsatellite instabilities, or increased rates of homologous recombination (hr). we examined an arabidopsis thaliana line derived from a forward genetic screen, which exhibits an elevated frequency of somatic hr. these hr events originate from replication stress in endoreduplicating cells caused by r ... | 2009 | 19789281 |
| specific targeting of the arabidopsis resistance protein rpw8.2 to the interfacial membrane encasing the fungal haustorium renders broad-spectrum resistance to powdery mildew. | powdery mildew fungal pathogens penetrate the plant cell wall and develop a feeding structure called the haustorium to steal photosynthetate from the host cell. here, we report that the broad-spectrum mildew resistance protein rpw8.2 from arabidopsis thaliana is induced and specifically targeted to the extrahaustorial membrane (ehm), an enigmatic interfacial membrane believed to be derived from the host cell plasma membrane. there, rpw8.2 activates a salicylic acid (sa) signaling-dependent defen ... | 2009 | 19749153 |
| cryptochromes, phytochromes, and cop1 regulate light-controlled stomatal development in arabidopsis. | in arabidopsis thaliana, the cryptochrome (cry) blue light photoreceptors and the phytochrome (phy) red/far-red light photoreceptors mediate a variety of light responses. cop1, a ring motif-containing e3 ubiquitin ligase, acts as a key repressor of photomorphogenesis. production of stomata, which mediate gas and water vapor exchange between plants and their environment, is regulated by light and involves phyb and cop1. here, we show that, in the loss-of-function mutants of cry and phyb, stomatal ... | 2009 | 19794114 |
| the rice alpha-amylase glycoprotein is targeted from the golgi apparatus through the secretory pathway to the plastids. | the well-characterized secretory glycoprotein, rice (oryza sativa) alpha-amylase isoform i-1 (amyi-1), was localized within the plastids and proved to be involved in the degradation of starch granules in the organelles of rice cells. in addition, a large portion of transiently expressed amyi-1 fused to green fluorescent protein (amyi-1-gfp) colocalized with a simultaneously expressed fluorescent plastid marker in onion (allium cepa) epidermal cells. the plastid targeting of amyi-1 was inhibited ... | 2009 | 19767453 |
| deletion in a quantitative trait gene qpe9-1 associated with panicle erectness improves plant architecture during rice domestication. | rice plant architecture is an important agronomic trait and a major determinant in high productivity. panicle erectness is the preferred plant architecture in japonica rice, but the molecular mechanism underlying domestication of the erect panicle remains elusive. here we report the map-based cloning of a major quantitative trait locus, qpe9-1, which plays an integral role in regulation of rice plant architecture including panicle erectness. the r6547 qpe9-1 gene encodes a 426-amino-acid protein ... | 2009 | 19546322 |
| the paralogous genes radical-induced cell death1 and similar to rcd one1 have partially redundant functions during arabidopsis development. | radical-induced cell death1 (rcd1) and similar to rcd one1 (sro1) are the only two proteins encoded in the arabidopsis (arabidopsis thaliana) genome containing both a putative poly(adp-ribose) polymerase catalytic domain and a wwe protein-protein interaction domain, although similar proteins have been found in other eukaryotes. poly(adp-ribose) polymerases mediate the attachment of adp-ribose units from donor nad(+) molecules to target proteins and have been implicated in a number of processes, ... | 2009 | 19625634 |
| auxin stimulates its own transport by shaping actin filaments. | the directional transport of the plant hormone auxin has been identified as central element of axis formation and patterning in plants. this directionality of transport depends on gradients, across the cell, of auxin-efflux carriers that continuously cycle between plasma membrane and intracellular compartments. this cycling has been proposed to depend on actin filaments. however, the role of actin for the polarity of auxin transport has been disputed. the organization of actin, in turn, has been ... | 2009 | 19633235 |
| wpp-domain proteins mimic the activity of the hsc70-1 chaperone in preventing mistargeting of rangap1-anchoring protein wit1. | arabidopsis (arabidopsis thaliana) tryptophan-proline-proline (wpp)-domain proteins, wpp1 and wpp2, are plant-unique, nuclear envelope-associated proteins of unknown function. they have sequence similarity to the nuclear envelope-targeting domain of plant rangap1, the gtpase activating protein of the small gtpase ran. wpp domain-interacting tail-anchored protein 1 (wit1) and wit2 are two arabidopsis proteins containing a coiled-coil domain and a c-terminal predicted transmembrane domain. they ar ... | 2009 | 19617588 |
| polyphenoloxidase silencing affects latex coagulation in taraxacum species. | latex is the milky sap that is found in many different plants. it is produced by specialized cells known as laticifers and can comprise a mixture of proteins, carbohydrates, oils, secondary metabolites, and rubber that may help to prevent herbivory and protect wound sites against infection. the wound-induced browning of latex suggests that it contains one or more phenol-oxidizing enzymes. here, we present a comprehensive analysis of the major latex proteins from two dandelion species, taraxacum ... | 2009 | 19605551 |
| a phosphofructokinase b-type carbohydrate kinase family protein, nara5, for massive expressions of plastid-encoded photosynthetic genes in arabidopsis. | to date, there have been no reports on screening for mutants defective in the massive accumulation of rubisco in higher plants. here, we describe a screening method based on the toxic accumulation of ammonia in the presence of methionine sulfoximine, a specific inhibitor of glutamine synthetase, during photorespiration initiated by the oxygenase reaction of rubisco in arabidopsis (arabidopsis thaliana). five recessive mutants with decreased amounts of rubisco were identified and designated as na ... | 2009 | 19587101 |
| ribonucleotide reductase regulation in response to genotoxic stress in arabidopsis. | ribonucleotide reductase (rnr) is an essential enzyme that provides dntps for dna replication and repair. arabidopsis (arabidopsis thaliana) encodes three atrnr2-like catalytic subunit genes (attso2, atrnr2a, and atrnr2b). however, it is currently unclear what role, if any, each gene contributes to the dna damage response, and in particular how each gene is transcriptionally regulated in response to replication blocks and dna damage. to address this, we investigated transcriptional changes of 17 ... | 2009 | 19571309 |
| arabidopsis methionine gamma-lyase is regulated according to isoleucine biosynthesis needs but plays a subordinate role to threonine deaminase. | the canonical pathway for isoleucine biosynthesis in plants begins with the conversion of threonine to 2-ketobutyrate by threonine deaminase (omr1). however, demonstration of methionine gamma-lyase (mgl) activity in arabidopsis (arabidopsis thaliana) suggested that production of 2-ketobutyrate from methionine can also lead to isoleucine biosynthesis. rescue of the isoleucine deficit in a threonine deaminase mutant by mgl overexpression, as well as decreased transcription of endogenous arabidopsi ... | 2009 | 19571310 |
| the role of oxophytodienoate reductases in the detoxification of the explosive 2,4,6-trinitrotoluene by arabidopsis. | the explosive 2,4,6-trinitrotoluene (tnt) is a significant environmental pollutant that is both toxic and recalcitrant to degradation. phytoremediation is being increasingly proposed as a viable alternative to conventional remediation technologies to clean up explosives-contaminated sites. despite the potential of this technology, relatively little is known about the innate enzymology of tnt detoxification in plants. to further elucidate this, we used microarray analysis to identify arabidopsis ... | 2009 | 19605548 |
| bobber1 is a noncanonical arabidopsis small heat shock protein required for both development and thermotolerance. | plants have evolved a range of cellular responses to maintain developmental homeostasis and to survive over a range of temperatures. here, we describe the in vivo and in vitro functions of bobber1 (bob1), a nudc domain containing arabidopsis (arabidopsis thaliana) small heat shock protein. bob1 is an essential gene required for the normal partitioning and patterning of the apical domain of the arabidopsis embryo. because bob1 loss-of-function mutants are embryo lethal, we used a partial loss-of- ... | 2009 | 19571304 |
| pleiotropic modulation of carbon and nitrogen metabolism in arabidopsis plants overexpressing the nad kinase2 gene. | nicotinamide nucleotides (nad and nadp) are important cofactors in many metabolic processes in living organisms. in this study, we analyzed transgenic arabidopsis (arabidopsis thaliana) plants that overexpress nad kinase2 (nadk2), an enzyme that catalyzes the synthesis of nadp from nad in chloroplasts, to investigate the impacts of altering nadp level on plant metabolism. metabolite profiling revealed that nadp(h) concentrations were proportional to nadk activity in nadk2 overexpressors and in t ... | 2009 | 19587098 |
| function of arabidopsis hexokinase-like1 as a negative regulator of plant growth. | a recent analysis of the hexokinase (hxk) gene family from arabidopsis revealed that three hexokinase-like (hkl) proteins lack catalytic activity, but share about 50% identity with the primary glucose (glc) sensor/transducer protein athxk1. since the athkl1 protein is predicted to bind glc, although with a relatively decreased affinity, a reverse genetics approach was used to test whether hkl1 might have a related regulatory function in plant growth. by comparing phenotypes of an hkl1 mutant (hk ... | 2009 | 19706780 |
| using small molecules to dissect mechanisms of microbial pathogenesis. | understanding the ways in which pathogens invade and neutralize their hosts is of great interest from both an academic and a clinical perspective. however, in many cases genetic tools are unavailable or insufficient to fully characterize the detailed mechanisms of pathogenesis. small molecule approaches are particularly powerful due to their ability to modulate specific biological functions in a highly controlled manner and their potential to broadly target conserved processes across species. re ... | 2009 | 19606820 |
| an inducible, modular system for spatio-temporal control of gene expression in stomatal guard cells. | stomata, flanked by pairs of guard cells, are small pores on the leaf surfaces of plants and they function to control gas exchange between plants and the atmosphere. stomata will open when water is available to allow for the uptake of carbon dioxide for photosynthesis. during periods of drought, stomata will close to reduce desiccation stress. as such, optimal functioning of stomata will impact on water use efficiency by plants. the development of an inducible, modular system for robust and targ ... | 2009 | 19700494 |
| regulation of seed germination and seedling growth by an arabidopsis phytocystatin isoform, atcys6. | phytocystatins are cysteine proteinase inhibitors in plants that are implicated in the endogenous regulation of protein turnover and defense mechanisms against insects and pathogens. a cdna encoding a phytocystatin called atcys6 (arabidopsis thaliana phytocystatin6) has been isolated. we show that atcys6 is highly expressed in dry seeds and seedlings and that it also accumulates in flowers. the persistence of atcys6 protein expression in seedlings was promoted by abscisic acid (aba), a seed germ ... | 2009 | 19690865 |
| lateral genetic transfer: open issues. | lateral genetic transfer (lgt) is an important adaptive force in evolution, contributing to metabolic, physiological and ecological innovation in most prokaryotes and some eukaryotes. genomic sequences and other data have begun to illuminate the processes, mechanisms, quantitative extent and impact of lgt in diverse organisms, populations, taxa and environments; deep questions are being posed, and the provisional answers sometimes challenge existing paradigms. at the same time, there is an enhan ... | 2009 | 19571244 |
| {alpha}' subunit of soybean {beta}-conglycinin forms complex with rice glutelin via a disulphide bond in transgenic rice seeds. | the alpha' and beta subunits of soybean beta-conglycinin were expressed in rice seeds in order to improve the nutritional and physiological properties of rice as a food. the alpha' subunit accumulated in rice seeds at a higher level than the beta subunit, but no detectable difference in mrna transcription level between subunits was observed. sequential extraction results indicate that the alpha' subunit formed one or more disulphide bonds with glutelin. electron microscopic analysis showed that ... | 2009 | 19656819 |
| restoring a maize root signal that attracts insect-killing nematodes to control a major pest. | when attacked by herbivorous insects, plants emit volatile compounds that attract natural enemies of the insects. it has been proposed that these volatile signals can be manipulated to improve crop protection. here, we demonstrate the full potential of this strategy by restoring the emission of a specific belowground signal emitted by insect-damaged maize roots. the western corn rootworm induces the roots of many maize varieties to emit (e)-beta-caryophyllene, which attracts entomopathogenic nem ... | 2009 | 19666594 |
| suppression of mkk5 reduces ozone-induced signal transmission to both mpk3 and mpk6 and confers increased ozone sensitivity in arabidopsis thaliana. | in arabidopsis thaliana, ozone-induced signaling has been shown to involve the mitogen-activated protein kinases (mapks) mpk3 and mpk6. to identify a possible ozone-induced mitogen-activated protein kinase kinase (mapkk) involved in the activation of these specific mapks, we employed rna interference-(rnai)-based suppression of mkk5, a known cognate mapkk to both mpk3 and mpk6. when exposed to ozone, activation of both mpk3 and mpk6 was markedly reduced in the mkk5-suppressed plants compared to ... | 2009 | 19820329 |
| differential recruitment of wox transcription factors for lateral development and organ fusion in petunia and arabidopsis. | petal fusion in petunia (petunia x hybrida) results from lateral expansion of the five initially separate petal primordia, forming a ring-like primordium that determines further development. here, we show that maewest (maw) and choripetala suzanne (chsu) are required for petal and carpel fusion, as well as for lateral outgrowth of the leaf blade. morphological and molecular analysis of maw and maw chsu double mutants suggest that polarity defects along the adaxial/abaxial axis contribute to the ... | 2009 | 19717616 |
| arabidopsis stn7 kinase provides a link between short- and long-term photosynthetic acclimation. | flowering plants control energy allocation to their photosystems in response to light quality changes. this includes the phosphorylation and migration of light-harvesting complex ii (lhcii) proteins (state transitions or short-term response) as well as long-term alterations in thylakoid composition (long-term response or ltr). both responses require the thylakoid protein kinase stn7. here, we show that the signaling pathways triggering state transitions and ltr diverge at, or immediately downstr ... | 2009 | 19706797 |
| starch granule initiation in arabidopsis requires the presence of either class iv or class iii starch synthases. | the mechanisms underlying starch granule initiation remain unknown. we have recently reported that mutation of soluble starch synthase iv (ssiv) in arabidopsis thaliana results in restriction of the number of starch granules to a single, large, particle per plastid, thereby defining an important component of the starch priming machinery. in this work, we provide further evidence for the function of ssiv in the priming process of starch granule formation and show that ssiv is necessary and suffic ... | 2009 | 19666739 |
| phospholipase dalpha1 and phosphatidic acid regulate nadph oxidase activity and production of reactive oxygen species in aba-mediated stomatal closure in arabidopsis. | we determined the role of phospholipase dalpha1 (pldalpha1) and its lipid product phosphatidic acid (pa) in abscisic acid (aba)-induced production of reactive oxygen species (ros) in arabidopsis thaliana guard cells. the pldalpha1 mutant failed to produce ros in guard cells in response to aba. aba stimulated nadph oxidase activity in wild-type guard cells but not in pldalpha1 cells, whereas pa stimulated nadph oxidase activity in both genotypes. pa bound to recombinant arabidopsis nadph oxidase ... | 2009 | 19690149 |
| a serine carboxypeptidase-like acyltransferase is required for synthesis of antimicrobial compounds and disease resistance in oats. | serine carboxypeptidase-like (scpl) proteins have recently emerged as a new group of plant acyltransferases. these enzymes share homology with peptidases but lack protease activity and instead are able to acylate natural products. several scpl acyltransferases have been characterized to date from dicots, including an enzyme required for the synthesis of glucose polyesters that may contribute to insect resistance in wild tomato (solanum pennellii) and enzymes required for the synthesis of sinapat ... | 2009 | 19684243 |
| aintegumenta and aintegumenta-like6 act redundantly to regulate arabidopsis floral growth and patterning. | an arabidopsis (arabidopsis thaliana) flower consists of four types of organs arranged in a stereotypical pattern. this complex floral structure is elaborated from a small number of floral meristem cells partitioned from the shoot apical meristem during reproductive development. the positioning of floral primordia within the periphery of the shoot apical meristem depends on transport of the phytohormone auxin with floral anlagen arising at sites of auxin maxima. an early marker of lateral organ ... | 2009 | 19542297 |
| the magnesium-chelatase h subunit binds abscisic acid and functions in abscisic acid signaling: new evidence in arabidopsis. | using a newly developed abscisic acid (aba)-affinity chromatography technique, we showed that the magnesium-chelatase h subunit abar/chlh (for putative abscisic acid receptor/chelatase h subunit) specifically binds aba through the c-terminal half but not the n-terminal half. a set of potential agonists/antagonists to aba, including 2-trans,4-trans-aba, gibberellin, cytokinin-like regulator 6-benzylaminopurine, auxin indole-3-acetic acid, auxin-like substance naphthalene acetic acid, and jasmonic ... | 2009 | 19535472 |
| cyp86b1 is required for very long chain omega-hydroxyacid and alpha, omega -dicarboxylic acid synthesis in root and seed suberin polyester. | suberin composition of various plants including arabidopsis (arabidopsis thaliana) has shown the presence of very long chain fatty acid derivatives c20 in addition to the c16 and c18 series. phylogenetic studies and plant genome mining have led to the identification of putative aliphatic hydroxylases belonging to the cyp86b subfamily of cytochrome p450 monooxygenases. in arabidopsis, this subfamily is represented by cyp86b1 and cyp86b2, which share about 45% identity with cyp86a1, a fatty acid o ... | 2009 | 19525321 |
| an archived activation tagged population of arabidopsis thaliana to facilitate forward genetics approaches. | functional genomics tools provide researchers with the ability to apply high-throughput techniques to determine the function and interaction of a diverse range of genes. mutagenized plant populations are one such resource that facilitate gene characterisation. they allow complex physiological responses to be correlated with the expression of single genes in planta, through either reverse genetics where target genes are mutagenized to assay the affect, or through forward genetics where population ... | 2009 | 19646253 |
| ago1 homeostasis involves differential production of 21-nt and 22-nt mir168 species by mir168a and mir168b. | ago1 associates with micrornas (mirnas) and regulates mrnas through cleavage and translational repression. ago1 homeostasis entails dcl1-dependent production of mir168 from mir168a and mir168b transcripts, post-transcriptional stabilization of mir168 by ago1, and ago1-catalyzed mir168-guided cleavage of ago1 mrna. | 2009 | 19649244 |
| the association of homeobox gene expression with stem cell formation and morphogenesis in cultured medicago truncatula. | somatic embryogenesis (se) is induced in vitro in medicago truncatula 2ha by auxin and cytokinin but rarely in wild type jemalong. the putative wuschel (mtwus), clavata3 (mtclv3) and the wuschel-related homeobox gene wox5 (mtwox5) were investigated in m. truncatula (mt) and identified by the similarity to arabidopsis wus, clv3 and wox5 in amino acid sequence, phylogeny and in planta and in vitro expression patterns. mtwus was induced throughout embryogenic cultures by cytokinin after 24-48 h and ... | 2009 | 19639337 |
| plant mitochondria possess a short-patch base excision dna repair pathway. | despite constant threat of oxidative damage, sequence drift in mitochondrial and chloroplast dna usually remains very low in plant species, indicating efficient defense and repair. whereas the antioxidative defense in the different subcellular compartments is known, the information on dna repair in plant organelles is still scarce. focusing on the occurrence of uracil in the dna, the present work demonstrates that plant mitochondria possess a base excision repair (ber) pathway. in vitro and in o ... | 2009 | 19625491 |
| sucrose synthase affects carbon partitioning to increase cellulose production and altered cell wall ultrastructure. | overexpression of the gossypium hirsutum sucrose synthase (susy) gene under the control of 2 promoters was examined in hybrid poplar (populus alba x grandidentata). analysis of rna transcript abundance, enzyme activity, cell wall composition, and soluble carbohydrates revealed significant changes in the transgenic lines. all lines showed significantly increased susy enzyme activity in developing xylem. this activity manifested in altered secondary cell wall cellulose content per dry weight in al ... | 2009 | 19625620 |
| ripening-associated ethylene biosynthesis in tomato fruit is autocatalytically and developmentally regulated. | to investigate the regulatory mechanism(s) of ethylene biosynthesis in fruit, transgenic tomatoes with all known leeil genes suppressed were produced by rna interference engineering. the transgenic tomato exhibited ethylene insensitivity phenotypes such as non-ripening and the lack of the triple response and petiole epinasty of seedlings even in the presence of exogenous ethylene. transgenic fruit exhibited a low but consistent increase in ethylene production beyond 40 days after anthesis (daa), ... | 2009 | 19605457 |
| new sources of soybean seed meal and oil composition traits identified through tilling. | several techniques are available to study gene function, but many are less than ideal for soybean. reverse genetics, a relatively new approach, can be utilized to identify novel mutations in candidate genes; this technique has not produced an allelic variant with a confirmed phenotype in soybean. soybean raffinose synthase genes and microsomal omega-6 fatty acid desaturase genes were screened for novel alleles in mutagenized soybean populations. | 2009 | 19602293 |
| the potato r locus codes for dihydroflavonol 4-reductase. | the potato r locus is required for the production of red pelargonidin-based anthocyanin pigments in potato (solanum tuberosum l.). red color also requires tissue-specific regulatory genes, such as d (for expression in tuber skin) and f (expression in flowers). a related locus, p, is required for production of blue/purple anthocyanins; p is epistatic to r. we have previously reported that the dihydroflavonol 4-reductase gene (dfr) co-segregates with r. to test directly whether r corresponds to df ... | 2009 | 19588118 |
| a novel virus that infecting hypovirulent strain xg36-1 of plant fungal pathogen sclerotinia sclerotiorum. | sclerotinia sclerotiorum is a notorious plant fungal pathogen which spreads across the world. hypovirulence is a phenomenon where the virulence of fungal pathogens is decreased, even lost, due to mycovirus infection. the potential of hypoviruses for biological control of the chestnut blight fungus (cryphonectria parasitica) has attracted much interest, and has led to discovery of new hypovirulent strains in other fungi. | 2009 | 19583873 |
| metabolism and cometabolism of cyclic ethers by a filamentous fungus, a graphium sp. | the filamentous fungus graphium sp. (atcc 58400) grows on gaseous n-alkanes and diethyl ether. n-alkane-grown mycelia of this strain also cometabolically oxidize the gasoline oxygenate methyl tert-butyl ether (mtbe). in this study, we characterized the ability of this fungus to metabolize and cometabolize a range of cyclic ethers, including tetrahydrofuran (thf) and 1,4-dioxane (14d). this strain grew on thf and other cyclic ethers, including tetrahydropyran and hexamethylene oxide. however, mor ... | 2009 | 19581469 |
| development of a gene silencing dna vector derived from a broad host range geminivirus. | gene silencing is proving to be a powerful tool for genetic, developmental, and physiological analyses. the use of viral induced gene silencing (vigs) offers advantages to transgenic approaches as it can be potentially applied to non-model systems for which transgenic techniques are not readily available. however, many vigs vectors are derived from gemini viruses that have limited host ranges. we present a new, unipartite vector that is derived from a curtovirus that has a broad host range and w ... | 2009 | 19573239 |
| posttranslational elevation of cell wall invertase activity by silencing its inhibitor in tomato delays leaf senescence and increases seed weight and fruit hexose level. | invertase plays multiple pivotal roles in plant development. thus, its activity must be tightly regulated in vivo. emerging evidence suggests that a group of small proteins that inhibit invertase activity in vitro appears to exist in a wide variety of plants. however, little is known regarding their roles in planta. here, we examined the function of invinh1, a putative invertase inhibitor, in tomato (solanum lycopersicum). expression of a invinh1:green fluorescent protein fusion revealed its apo ... | 2009 | 19574437 |
| arabidopsis duo pollen3 is a key regulator of male germline development and embryogenesis. | male germline development in angiosperms produces the pair of sperm cells required for double fertilization. a key regulator of this process in arabidopsis thaliana is the male germline-specific transcription factor duo pollen1 (duo1) that coordinates germ cell division and gamete specification. here, we uncover the role of duo3, a nuclear protein that has a distinct, but overlapping role with duo1 in male germline development. duo3 is a conserved protein in land plants and is related to gon-4, ... | 2009 | 19638475 |
| phylogenomic analysis demonstrates a pattern of rare and ancient horizontal gene transfer between plants and fungi. | horizontal gene transfer (hgt) describes the transmission of genetic material across species boundaries and is an important evolutionary phenomenon in the ancestry of many microbes. the role of hgt in plant evolutionary history is, however, largely unexplored. here, we compare the genomes of six plant species with those of 159 prokaryotic and eukaryotic species and identify 1689 genes that show the highest similarity to corresponding genes from fungi. we constructed a phylogeny for all 1689 gene ... | 2009 | 19584142 |
| the maize transcription factor myb-related protein-1 is a key regulator of the differentiation of transfer cells. | transfer cells are highly modified plant cells specialized in the transport of solutes. they differentiate at many plant exchange surfaces, including phloem loading and unloading zones such as those present in the sink organs and seeds. in maize (zea mays) seeds, transfer cells are located at the base of the endosperm. it is currently unknown how apical-basal polarity is established or why the peripheral cells at the base of the endosperm differentiate into transfer instead of aleurone cells. he ... | 2009 | 19574436 |
| aberrant mrna transcripts and the nonsense-mediated decay proteins upf2 and upf3 are enriched in the arabidopsis nucleolus. | the eukaryotic nucleolus is multifunctional and involved in the metabolism and assembly of many different rnas and ribonucleoprotein particles as well as in cellular functions, such as cell division and transcriptional silencing in plants. we previously showed that arabidopsis thaliana exon junction complex proteins associate with the nucleolus, suggesting a role for the nucleolus in mrna production. here, we report that the plant nucleolus contains mrnas, including fully spliced, aberrantly spl ... | 2009 | 19602621 |
| shoot na+ exclusion and increased salinity tolerance engineered by cell type-specific alteration of na+ transport in arabidopsis. | soil salinity affects large areas of cultivated land, causing significant reductions in crop yield globally. the na+ toxicity of many crop plants is correlated with overaccumulation of na+ in the shoot. we have previously suggested that the engineering of na+ exclusion from the shoot could be achieved through an alteration of plasma membrane na+ transport processes in the root, if these alterations were cell type specific. here, it is shown that expression of the na+ transporter hkt1;1 in the ma ... | 2009 | 19584143 |
| cdkb1;1 forms a functional complex with cyca2;3 to suppress endocycle onset. | the mitosis-to-endocycle transition requires the controlled inactivation of m phase-associated cyclin-dependent kinase (cdk) activity. previously, the b-type cdkb1;1 was identified as an important negative regulator of endocycle onset. here, we demonstrate that cdkb1;1 copurifies and associates with the a2-type cyclin cyca2;3. coexpression of cyca2;3 with cdkb1;1 triggered ectopic cell divisions and inhibited endoreduplication. moreover, the enhanced endoreduplication phenotype observed after ov ... | 2009 | 19458112 |
| rna interference of lin5 in tomato confirms its role in controlling brix content, uncovers the influence of sugars on the levels of fruit hormones, and demonstrates the importance of sucrose cleavage for normal fruit development and fertility. | it has been previously demonstrated, utilizing intraspecific introgression lines, that lycopersicum invertase5 (lin5), which encodes a cell wall invertase, controls total soluble solids content in tomato (solanum lycopersicum). the physiological role of this protein, however, has not yet been directly studied, since evaluation of data obtained from the introgression lines is complicated by the fact that they additionally harbor many other wild species alleles. to allow a more precise comparison, ... | 2009 | 19439574 |
| the role of annexin 1 in drought stress in arabidopsis. | annexins act as targets of calcium signals in eukaryotic cells, and recent results suggest that they play an important role in plant stress responses. we found that in arabidopsis (arabidopsis thaliana), annat1 (for annexin 1) mrna levels were up-regulated in leaves by most of the stress treatments applied. plants overexpressing annat1 protein were more drought tolerant and knockout plants were more drought sensitive than ecotype columbia plants. we also observed that hydrogen peroxide accumulat ... | 2009 | 19482919 |
| cis-element- and transcriptome-based screening of root hair-specific genes and their functional characterization in arabidopsis. | understanding the cellular differentiation of multicellular organisms requires the characterization of genes whose expression is modulated in a cell type-specific manner. the arabidopsis (arabidopsis thaliana) root hair cell is one model for studying cellular differentiation. in this study, root hair cell-specific genes were screened by a series of in silico and experimental filtration procedures. this process included genome-wide screening for genes with a root hair-specific cis-element in thei ... | 2009 | 19448035 |
| overexpression of the transcription factor ap37 in rice improves grain yield under drought conditions. | transcription factors with an apetela2 (ap2) domain have been implicated in various cellular processes involved in plant development and stress responses. of the 139 ap2 genes predicted in rice (oryza sativa), we identified 42 genes in our current study that are induced by one or more stress conditions, including drought, high salinity, low temperature, and abscisic acid. phylogenic analysis of these 42 stress-inducible ap2 genes revealed the presence of six subgroups (i-vi) with distinct signat ... | 2009 | 19429605 |
| processing of a dicistronic trna-snorna precursor: combined analysis in vitro and in vivo reveals alternate pathways and coupling to assembly of snornp. | the c/d box small nucleolar rnas (snornas) represent an essential class of small nucleolar rnas that guide 2'-o-rib methylation of ribosomal rnas and other rnas in eukaryotes. in arabidopsis (arabidopsis thaliana), >100 c/d snornas have been identified, most of them encoded by polycistronic gene clusters, but little is known on the factors controlling their biogenesis. here, we focus on the identification of factors controlling the processing of trna-snorna dicistronic precursors (pre-tsnorna) s ... | 2009 | 19420328 |
| senescence-induced serotonin biosynthesis and its role in delaying senescence in rice leaves. | serotonin, which is well known as a pineal hormone in mammals, plays a key role in conditions such as mood, eating disorders, and alcoholism. in plants, although serotonin has been suggested to be involved in several physiological roles, including flowering, morphogenesis, and adaptation to environmental changes, its regulation and functional roles are as yet not characterized at the molecular level. in this study, we found that serotonin is greatly accumulated in rice (oryza sativa) leaves unde ... | 2009 | 19439571 |
| arabidopsis encodes four trnase z enzymes. | functional transfer rna (trna) molecules are a prerequisite for protein biosynthesis. several processing steps are required to generate the mature functional trna from precursor molecules. two of the early processing steps involve cleavage at the trna 5' end and the trna 3' end. while processing at the trna 5' end is performed by rnase p, cleavage at the 3' end is catalyzed by the endonuclease trnase z. in eukaryotes, trnase z enzymes are found in two versions: a short form of about 250 to 300 a ... | 2009 | 19411372 |
| far-red light inhibits germination through della-dependent stimulation of aba synthesis and abi3 activity. | under the canopy, far-red (fr) light represses seed germination by inactivating phytochrome photoreceptors. this elicits a decrease in gibberellins (ga) levels and an increase in abscisic acid (aba) levels. ga promotes germination by enhancing the proteasome-mediated destruction of della repressors. aba prevents germination by stimulating the expression of abi repressors. how phytochromes elicit changes in hormone levels or how ga- and aba-dependent signals are coordinated to repress germination ... | 2009 | 19556968 |
| characterization and isolation of a t-dna tagged banana promoter active during in vitro culture and low temperature stress. | next-generation transgenic plants will require a more precise regulation of transgene expression, preferably under the control of native promoters. a genome-wide t-dna tagging strategy was therefore performed for the identification and characterization of novel banana promoters. embryogenic cell suspensions of a plantain-type banana were transformed with a promoterless, codon-optimized luciferase (luc+) gene and low temperature-responsive luciferase activation was monitored in real time. | 2009 | 19552803 |
| conserved active site sequences in arabidopsis plastid terminal oxidase (ptox): in vitro and in planta mutagenesis studies. | the plastid terminal oxidase (ptox) is distantly related to the mitochondrial alternative oxidase (aox). both are members of the diiron carboxylate quinol oxidase (dox) class of proteins. ptox and aox contain 20 highly conserved amino acids, six of which are fe-binding ligands. we have previously used in vitro and in planta activity assays to examine the functional importance of the fe-binding sites. in this report, we conduct alanine-scanning mutagenesis on the 14 other conserved sites using ou ... | 2009 | 19542226 |