| quantitative multiplex detection of plant pathogens using a novel ligation probe-based system coupled with universal, high-throughput real-time pcr on openarrays. | diagnostics and disease-management strategies require technologies to enable the simultaneous detection and quantification of a wide range of pathogenic microorganisms. most multiplex, quantitative detection methods available suffer from compromises between the level of multiplexing, throughput and accuracy of quantification. here, we demonstrate the efficacy of a novel, high-throughput, ligation-based assay for simultaneous quantitative detection of multiple plant pathogens. the ligation probes ... | 2007 | 17697351 |
| a minimal peach type ii chlorophyll a/b-binding protein promoter retains tissue-specificity and light regulation in tomato. | promoters with tissue-specificity are desirable to drive expression of transgenes in crops to avoid accumulation of foreign proteins in edible tissues/organs. several photosynthetic promoters have been shown to be strong regulators of expression of transgenes in light-responsive tissues and would be good candidates for leaf and immature fruit tissue-specificity, if expression in the mature fruit were minimized. | 2007 | 17697347 |
| antiviral immunity directed by small rnas. | plants and invertebrates can protect themselves from viral infection through rna silencing. this antiviral immunity involves production of virus-derived small interfering rnas (virnas) and results in specific silencing of viruses by virna-guided effector complexes. the proteins required for virna production as well as several key downstream components of the antiviral immunity pathway have been identified in plants, flies, and worms. meanwhile, viral mechanisms to suppress this small rna-directe ... | 2007 | 17693253 |
| cluss: clustering of protein sequences based on a new similarity measure. | the rapid burgeoning of available protein data makes the use of clustering within families of proteins increasingly important. the challenge is to identify subfamilies of evolutionarily related sequences. this identification reveals phylogenetic relationships, which provide prior knowledge to help researchers understand biological phenomena. a good evolutionary model is essential to achieve a clustering that reflects the biological reality, and an accurate estimate of protein sequence similarity ... | 2007 | 17683581 |
| targeted degradation of pseudo-response regulator5 by an scfztl complex regulates clock function and photomorphogenesis in arabidopsis thaliana. | circadian clocks comprise several regulatory feedback loops that control gene transcription. however, recent evidence has shown that posttranslational mechanisms are also required for clock function. in arabidopsis thaliana, members of the pseudo-response regulator (prr) family were proposed to be components of the central oscillator. using a prr5-specific antibody, we characterized changes in prr5 protein levels in relation to its mrna levels under various circadian conditions. under long-day c ... | 2007 | 17693530 |
| the arabidopsis transcription factor myb77 modulates auxin signal transduction. | auxin is a key plant hormone that regulates plant development, apical dominance, and growth-related tropisms, such as phototropism and gravitropism. in this study, we report a new arabidopsis thaliana transcription factor, myb77, that is involved in auxin response. in myb77 knockout plants, we found that auxin-responsive gene expression was greatly attenuated. lateral root density in the myb77 knockout was lower than the wild type at low concentrations of indole-3-acetic acid (iaa) and also unde ... | 2007 | 17675404 |
| myb98 positively regulates a battery of synergid-expressed genes encoding filiform apparatus localized proteins. | the synergid cells within the female gametophyte are essential for reproduction in angiosperms. myb98 encodes an r2r3-myb protein required for pollen tube guidance and filiform apparatus formation by the synergid cells. to test the predicted function of myb98 as a transcriptional regulator, we determined its subcellular localization and examined its dna binding properties. we show that myb98 binds to a specific dna sequence (taac) and that a myb98-green fluorescent protein fusion protein localiz ... | 2007 | 17693534 |
| microrna-mediated regulation of stomatal development in arabidopsis. | the proper number and distribution of stomata are essential for the efficient exchange of gases between the atmosphere and the aerial parts of plants. we show that the density and development of stomatal complexes on the epidermis of arabidopsis thaliana leaves depend, in part, on the microrna-mediated regulation of agamous-like16 (agl16), which is a member of the mads box protein family. agl16 mrna is targeted for sequence-specific degradation by mir824, a recently evolved microrna conserved in ... | 2007 | 17704216 |
| uv-b promotes rapid nuclear translocation of the arabidopsis uv-b specific signaling component uvr8 and activates its function in the nucleus. | arabidopsis thaliana uv resistance locus8 (uvr8) is a uv-b-specific signaling component that binds to chromatin and regulates uv protection by orchestrating expression of a range of genes. here, we studied how uv-b regulates uvr8. we show that uv-b stimulates the nuclear accumulation of both a green fluorescent protein (gfp)-uvr8 fusion and native uvr8. nuclear accumulation leads to uv-b induction of the hy5 gene, encoding a key transcriptional effector of the uvr8 pathway. nuclear accumulation ... | 2007 | 17720867 |
| the in silico map-based cloning of pi36, a rice coiled-coil nucleotide-binding site leucine-rich repeat gene that confers race-specific resistance to the blast fungus. | the indica rice variety kasalath carries pi36, a gene that determines resistance to chinese isolates of rice blast and that has been located to a 17-kb interval on chromosome 8. the genomic sequence of the reference japonica variety nipponbare was used for an in silico prediction of the resistance (r) gene content of the interval and hence for the identification of candidate gene(s) for pi36. three such sequences, which all had both a nucleotide-binding site and a leucine-rich repeat motif, were ... | 2007 | 17507669 |
| a novel nucleus-encoded chloroplast protein, pifi, is involved in nad(p)h dehydrogenase complex-mediated chlororespiratory electron transport in arabidopsis. | a transient rise in chlorophyll fluorescence after turning off actinic light reflects nonphotochemical reduction of the plastoquinone (pq) pool. this process is dependent on the activity of the chloroplast nad(p)h dehydrogenase (ndh) complex, which mediates electron flow from stromal reductants to the pq pool. in this study, we characterized an arabidopsis (arabidopsis thaliana) t-dna insertion mutant pifi (for postillumination chlorophyll fluorescence increase), which possesses an intact ndh co ... | 2007 | 17573537 |
| localization of members of the gamma-glutamyl transpeptidase family identifies sites of glutathione and glutathione s-conjugate hydrolysis. | gamma-glutamyl transpeptidases (ggts) are essential for hydrolysis of the tripeptide glutathione (gamma-glutamate-cysteine-glycine) and glutathione s-conjugates since they are the only enzymes known to cleave the amide bond linking the gamma-carboxylate of glutamate to cysteine. in arabidopsis thaliana, four ggt genes have been identified based on homology with animal ggts. they are designated ggt1 (at4g39640), ggt2 (at4g39650), ggt3 (at1g69820), and ggt4 (at4g29210). by analyzing the expression ... | 2007 | 17545509 |
| silencing of the major salt-dependent isoform of pectinesterase in tomato alters fruit softening. | pectinesterase (pe; e.c. 3.1.1.11) is an enzyme responsible for the demethylation of galacturonyl residues in high-molecular-weight pectin and is believed to play an important role in cell wall metabolism. in this study, pmeu1, a ubiquitously expressed pe gene, has been characterized by antisense suppression in tomato (solanum lycopersicum). transgenic tomato plants showed reduced pe activity levels in both green fruit and leaf tissue to around 65% and 25% of that found in wild-type plants, resp ... | 2007 | 17556513 |
| related arabidopsis serine carboxypeptidase-like sinapoylglucose acyltransferases display distinct but overlapping substrate specificities. | the arabidopsis (arabidopsis thaliana) genome encodes 51 proteins annotated as serine carboxypeptidase-like (scpl) enzymes. nineteen of these scpl proteins are highly similar to one another, and represent a clade that appears to be unique to plants. two of the most divergent proteins within this group have been characterized to date, sinapoyl-glucose (glc):malate sinapoyltransferase and sinapoyl-glc:choline sinapoyltransferase. the fact that two of the least related proteins within this clade ar ... | 2007 | 17600138 |
| transitivity in arabidopsis can be primed, requires the redundant action of the antiviral dicer-like 4 and dicer-like 2, and is compromised by viral-encoded suppressor proteins. | in plants, worms, and fungi, rna-dependent rna polymerases (rdrs) amplify the production of short-interfering rnas (sirnas) that mediate rna silencing. in arabidopsis, rdr6 is thought to copy endogenous and exogenous rna templates into double-stranded rnas (dsrnas), which are subsequently processed into sirnas by one or several of the four dicer-like enzymes (dcl1-->4). this reaction produces secondary sirnas corresponding to sequences outside the primary targeted regions of a transcript, a phen ... | 2007 | 17592042 |
| an analysis of expressed sequence tags of developing castor endosperm using a full-length cdna library. | castor seeds are a major source for ricinoleate, an important industrial raw material. genomics studies of castor plant will provide critical information for understanding seed metabolism, for effectively engineering ricinoleate production in transgenic oilseeds, or for genetically improving castor plants by eliminating toxic and allergic proteins in seeds. | 2007 | 17672910 |
| functional conservation between crabs claw orthologues from widely diverged angiosperms. | crabs claw (crc) encodes a transcription factor of the yabby family that plays important roles in carpel and nectary development in arabidopsis thaliana. combined evolutionary and developmental studies suggest an ancestor of the crc gene to have controlled carpel development in the last common ancestor of the angiosperms. roles for crc orthologues in leaf development and carpel specification in rice, and in nectary development in core eudicots, have accordingly been interpreted as derived. the a ... | 2007 | 17650514 |
| origins of flagellar gene operons and secondary flagellar systems. | forty-one flagellated species representing 11 bacterial phyla were used to investigate the origin of secondary flagellar systems and the structure and formation of flagellar gene operons over the course of bacterial evolution. secondary (i.e., lateral) flagellar systems, which are harbored by five of the proteobacterial species considered, originated twice, once in the alphaproteobacterial lineage and again in the common ancestor of the beta- and gammaproteobacteria. the order and organization o ... | 2007 | 17644605 |
| mutations in a plastid-localized elongation factor g alter early stages of plastid development in arabidopsis thaliana. | proper development of plastids in embryo and seedling tissues is critical for plant development. during germination, plastids develop to perform many critical functions that are necessary to establish the seedling for further growth. a growing body of work has demonstrated that components of the plastid transcription and translation machinery must be present and functional to establish the organelle upon germination. | 2007 | 17629920 |
| assessment of n-glycan heterogeneity of cactus glycoproteins by one-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. | artificial environmental conditions in tissue culture, such as elevated relative humidity and rich nutrient medium, can influence and modify tissue growth and induce spontaneous changes from characteristic organization pattern to unorganized callus. as succulent plants with crassulacean acid metabolism, cacti are particularly susceptible to this altered growth environment. glycosylated proteins of mammillaria gracillis tissues cultivated in vitro, separated by sds-page, were detected with con a ... | 2007 | 17595312 |
| light-independent phytochrome signaling mediated by dominant gaf domain tyrosine mutants of arabidopsis phytochromes in transgenic plants. | the photoreversibility of plant phytochromes enables continuous surveillance of the ambient light environment. through expression of profluorescent, photoinsensitive tyr-to-his mutant alleles of arabidopsis thaliana phytochrome b (phyb(y276h)) and arabidopsis phytochrome a (phya(y242h)) in transgenic arabidopsis plants, we demonstrate that photoconversion is not a prerequisite for phytochrome signaling. phyb(y276h)-expressing plants exhibit chromophore-dependent constitutive photomorphogenesis, ... | 2007 | 17660358 |
| the auxin-regulated ap2/erebp gene puchi is required for morphogenesis in the early lateral root primordium of arabidopsis. | organ primordia develop from founder cells into organs due to coordinated patterns of cell division. how patterned cell division is regulated during organ formation, however, is not well understood. here, we show that the puchi gene, which encodes a putative apetala2/ethylene-responsive element binding protein transcription factor, is required for the coordinated pattern of cell divisions during lateral root formation in arabidopsis thaliana. recessive mutations in puchi disturbed cell division ... | 2007 | 17630277 |
| a unique beta1,3-galactosyltransferase is indispensable for the biosynthesis of n-glycans containing lewis a structures in arabidopsis thaliana. | in plants, the only known outer-chain elongation of complex n-glycans is the formation of lewis a [fuc alpha1-4(gal beta1-3)glcnac-r] structures. this process involves the sequential attachment of beta1,3-galactose and alpha1,4-fucose residues by beta1,3-galactosyltransferase and alpha1,4-fucosyltransferase. however, the exact mechanism underlying the formation of lewis a epitopes in plants is poorly understood, largely because one of the involved enzymes, beta1,3-galactosyltransferase, has not ... | 2007 | 17630273 |
| a functional link between rhythmic changes in chromatin structure and the arabidopsis biological clock. | circadian clocks rhythmically coordinate biological processes in resonance with the environmental cycle. the clock function relies on negative feedback loops that generate 24-h rhythms in multiple outputs. in arabidopsis thaliana, the clock component timing of cab expression1 (toc1) integrates the environmental information to coordinate circadian responses. here, we use chromatin immunoprecipitation as well as physiological and luminescence assays to demonstrate that proper photoperiodic phase o ... | 2007 | 17616736 |
| hawaiian skirt: an f-box gene that regulates organ fusion and growth in arabidopsis. | a fast neutron-mutagenized population of arabidopsis (arabidopsis thaliana) columbia-0 wild-type plants was screened for floral phenotypes and a novel mutant, termed hawaiian skirt (hws), was identified that failed to shed its reproductive organs. the mutation is the consequence of a 28 bp deletion that introduces a premature amber termination codon into the open reading frame of a putative f-box protein (at3g61590). the most striking anatomical characteristic of hws plants is seen in flowers wh ... | 2007 | 17496113 |
| monoacylglycerols are components of root waxes and can be produced in the aerial cuticle by ectopic expression of a suberin-associated acyltransferase. | the interface between plants and the environment is provided for aerial organs by epicuticular waxes that have been extensively studied. by contrast, little is known about the nature, biosynthesis, and role of waxes at the root-rhizosphere interface. waxes isolated by rapid immersion of arabidopsis (arabidopsis thaliana) roots in organic solvents were rich in saturated c18-c22 alkyl esters of p-hydroxycinnamic acids, but also contained significant amounts of both alpha- and beta-isomers of monoa ... | 2007 | 17496107 |
| identification of a novel chloroplast protein atnye1 regulating chlorophyll degradation during leaf senescence in arabidopsis. | a dramatic increase of chlorophyll (chl) degradation occurs during senescence of vegetative plant organs and fruit ripening. although the biochemical pathway of chl degradation has long been proposed, little is known about its regulatory mechanism. identification of chl degradation-disturbed mutants and subsequently isolation of responsible genes would greatly facilitate the elucidation of the regulation of chl degradation. here, we describe a nonyellowing mutant of arabidopsis (arabidopsis thal ... | 2007 | 17468209 |
| rna interference silencing of chalcone synthase, the first step in the flavonoid biosynthesis pathway, leads to parthenocarpic tomato fruits. | parthenocarpy, the formation of seedless fruits in the absence of functional fertilization, is a desirable trait for several important crop plants, including tomato (solanum lycopersicum). seedless fruits can be of great value for consumers, the processing industry, and breeding companies. in this article, we propose a novel strategy to obtain parthenocarpic tomatoes by down-regulation of the flavonoid biosynthesis pathway using rna interference (rnai)-mediated suppression of chalcone synthase ( ... | 2007 | 17478633 |
| transcriptional activation and localization of expression of brassica juncea putative metal transport protein bjmtp1. | metal hyperaccumulators, including various thlaspi species, constitutively express the putative metal transporter mtp1 to high levels in shoots. here we present data on the transcriptional regulation and localization of expression of the homologous gene bjmtp1 in brassica juncea. though b. juncea lacks the ability to hyperaccumulate metals, its relatively high biomass, rapid growth and relatedness to true metal hyperaccumulating plants makes it a promising starting point for the development of p ... | 2007 | 17577406 |
| rice-based mucosal vaccine as a global strategy for cold-chain- and needle-free vaccination. | capable of inducing antigen-specific immune responses in both systemic and mucosal compartments without the use of syringe and needle, mucosal vaccination is considered ideal for the global control of infectious diseases. in this study, we developed a rice-based oral vaccine expressing cholera toxin b subunit (ctb) under the control of the endosperm-specific expression promoter 2.3-kb glutelin glub-1 with codon usage optimization for expression in rice seed. an average of 30 mug of ctb per seed ... | 2007 | 17573530 |
| the two-pore channel tpk1 gene encodes the vacuolar k+ conductance and plays a role in k+ homeostasis. | the arabidopsis thaliana genome contains five genes that encode two pore k+ (tpk) channels. the most abundantly expressed isoform of this family, tpk1, is expressed at the tonoplast where it mediates k+ -selective currents between cytoplasmic and vacuolar compartments. tpk1 open probability depends on both cytoplasmic ca2+ and cytoplasmic ph but not on the tonoplast membrane voltage. the channel shows intrinsic rectification and can be blocked by ba2+, tetraethylammonium, and quinine. tpk1 curre ... | 2007 | 17563365 |
| can clustal-style progressive pairwise alignment of multiple sequences be used in rna secondary structure prediction? | in ribonucleic acid (rna) molecules whose function depends on their final, folded three-dimensional shape (such as those in ribosomes or spliceosome complexes), the secondary structure, defined by the set of internal basepair interactions, is more consistently conserved than the primary structure, defined by the sequence of nucleotides. | 2007 | 17559658 |
| sdir1 is a ring finger e3 ligase that positively regulates stress-responsive abscisic acid signaling in arabidopsis. | ubiquitination plays important roles in plant hormone signal transduction. we show that the ring finger e3 ligase, arabidopsis thaliana salt- and drought-induced ring finger1 (sdir1), is involved in abscisic acid (aba)-related stress signal transduction. sdir1 is expressed in all tissues of arabidopsis and is upregulated by drought and salt stress, but not by aba. plants expressing the prosdir1-beta-glucuronidase (gus) reporter construct confirmed strong induction of gus expression in stomatal g ... | 2007 | 17573536 |
| blade-on-petiole 1 and 2 control arabidopsis lateral organ fate through regulation of lob domain and adaxial-abaxial polarity genes. | we report a novel function for blade-on-petiole1 (bop1) and bop2 in regulating arabidopsis thaliana lateral organ cell fate and polarity, through the analysis of loss-of-function mutants and transgenic plants that ectopically express bop1 or bop2. 35s:bop1 and 35s:bop2 plants exhibit a very short and compact stature, hyponastic leaves, and downward-orienting siliques. we show that the lateral organ boundaries (lob) domain genes asymmetric leaves2 (as2) and lob are upregulated in 35s:bop and down ... | 2007 | 17601823 |
| a heteromeric plastidic pyruvate kinase complex involved in seed oil biosynthesis in arabidopsis. | glycolysis is a ubiquitous pathway thought to be essential for the production of oil in developing seeds of arabidopsis thaliana and oil crops. compartmentation of primary metabolism in developing embryos poses a significant challenge for testing this hypothesis and for the engineering of seed biomass production. it also raises the question whether there is a preferred route of carbon from imported photosynthate to seed oil in the embryo. plastidic pyruvate kinase catalyzes a highly regulated, a ... | 2007 | 17557808 |
| mutations in arabidopsis multidrug resistance-like abc transporters separate the roles of acropetal and basipetal auxin transport in lateral root development. | auxin affects the shape of root systems by influencing elongation and branching. because multidrug resistance (mdr)-like abc transporters participate in auxin transport, they may be expected to contribute to root system development. this reverse genetic study of arabidopsis thaliana roots shows that mdr4-mediated basipetal auxin transport did not affect root elongation or branching. however, impaired acropetal auxin transport due to mutation of the mdr1 gene caused 21% of nascent lateral roots t ... | 2007 | 17557807 |
| increased size exclusion limit 2 encodes a putative devh box rna helicase involved in plasmodesmata function during arabidopsis embryogenesis. | here, we characterize the arabidopsis thaliana embryo-defective mutant increased size exclusion limit2 (ise2). in contrast with wild-type embryos, ise2 mutants continue to traffic 10-kd fluorescent dextran in the mid-torpedo stage of development. ise2 embryos contain branched as well as simple plasmodesmata (pd) compared with wild-type embryos, which only contain simple pd. positional cloning reveals that the ise2 gene encodes a putative devh box rna helicase that shares sequence homology with r ... | 2007 | 17601829 |
| arabidopsis jagged lateral organs is expressed in boundaries and coordinates knox and pin activity. | plant lateral organs are initiated as small protrusions on the flanks of shoot apical meristems. organ primordia are separated from the remainder of the meristem by distinct cell types that create a morphological boundary. the arabidopsis thaliana gain-of-function mutant jagged lateral organs-d (jlo-d) develops strongly lobed leaves, indicative of knox gene misexpression, and the shoot apical meristem arrests organ initiation prematurely, terminating in a pin-like structure. the jlo gene, a memb ... | 2007 | 17557810 |
| suppression of rice telomere binding protein 1 results in severe and gradual developmental defects accompanied by genome instability in rice. | although several potential telomere binding proteins have been identified in higher plants, their in vivo functions are still unknown at the plant level. both knockout and antisense mutants of rice telomere binding protein1 (rtbp1) exhibited markedly longer telomeres relative to those of the wild type, indicating that the amount of functional rtbp1 is inversely correlated with telomere length. rtbp1 plants displayed progressive and severe developmental abnormalities in both germination and postg ... | 2007 | 17586654 |
| zucchini and squash encode two putative nucleases required for rasirna production in the drosophila germline. | rnai is a widespread mechanism by which organisms regulate gene expression and defend their genomes against viruses and transposable elements. here we report the identification of drosophila zucchini (zuc) and squash (squ), which function in germline rnai processes. zuc and squ contain domains with homologies to nucleases. mutant females are sterile and show dorsoventral patterning defects during oogenesis. in addition, oskar protein is ectopically expressed in early oocytes, where it is normall ... | 2007 | 17543859 |
| apyrases (nucleoside triphosphate-diphosphohydrolases) play a key role in growth control in arabidopsis. | expression of two arabidopsis (arabidopsis thaliana) apyrase (nucleoside triphosphate-diphosphohydrolase) genes with high similarity, apy1 and apy2, was analyzed during seedling development and under different light treatments using beta-glucuronidase fusion constructs with the promoters of both genes. as evaluated by beta-glucuronidase staining and independently confirmed by other methods, the highest expression of both apyrases was in rapidly growing tissues and/or tissues that accumulate high ... | 2007 | 17434987 |
| mutation of e1-conjugating enzyme-related1 decreases related to ubiquitin conjugation and alters auxin response and development. | the ubiquitin-like protein related to ubiquitin (rub) is conjugated to cullin (cul) proteins to modulate the activity of skp1-cullin-f-box (scf) ubiquitylation complexes. rub conjugation to specific target proteins is necessary for the development of many organisms, including arabidopsis (arabidopsis thaliana). here, we report the isolation and characterization of e1-conjugating enzyme-related1-1 (ecr1-1), an arabidopsis mutant compromised in rub conjugation. the ecr1-1 mutation causes a missens ... | 2007 | 17449645 |
| arabidopsis inositol polyphosphate 6-/3-kinase (atipk2beta) is involved in axillary shoot branching via auxin signaling. | the arabidopsis (arabidopsis thaliana) inositol polyphosphate 6-/3-kinase gene (atipk2beta) is known to participate in inositol phosphate metabolism. however, little is known about its physiological functions in higher plants. here, we report that atipk2beta regulates arabidopsis axillary shoot branching. by overexpressing atipk2beta in the wild type and mutants, we found that overexpression of atipk2beta leads to more axillary shoot branches. further analysis of atipk2beta overexpression lines ... | 2007 | 17434984 |
| using genomics to study legume seed development. | | 2007 | 17556519 |
| arabidopsis, a model to study biological functions of isoprene emission? | the volatile hemiterpene isoprene is emitted from plants and can affect atmospheric chemistry. although recent studies indicate that isoprene can enhance thermotolerance or quench oxidative stress, the underlying physiological mechanisms are largely unknown. in this work, arabidopsis (arabidopsis thaliana), a natural nonemitter of isoprene and the model plant for functional plant analyses, has been constitutively transformed with the isoprene synthase gene (pcisps) from grey poplar (populus x ca ... | 2007 | 17468218 |
| executer1- and executer2-dependent transfer of stress-related signals from the plastid to the nucleus of arabidopsis thaliana. | shortly after the release of singlet oxygen ((1)o2), drastic changes in nuclear gene expression occur in the conditional flu mutant of arabidopsis that reveal a rapid transfer of signals from the plastid to the nucleus. in contrast to retrograde control of nuclear gene expression by plastid signals described earlier, the primary effect of (1)o2 generation in the flu mutant is not the control of chloroplast biogenesis but the activation of a broad range of signaling pathways known to be involved ... | 2007 | 17540731 |
| zinc finger protein stop1 is critical for proton tolerance in arabidopsis and coregulates a key gene in aluminum tolerance. | acid soil syndrome causes severe yield losses in various crop plants because of the rhizotoxicities of ions, such as aluminum (al(3+)). although protons (h(+)) could be also major rhizotoxicants in some soil types, molecular mechanisms of their tolerance have not been identified yet. one mutant that was hypersensitive to h(+) rhizotoxicity was isolated from ethyl methanesulfonate mutagenized seeds, and a single recessive mutation was found on chromosome 1. positional cloning followed by genomic ... | 2007 | 17535918 |
| characterization of arabidopsis atugt85a and atgus gene families and their expression in rapidly dividing tissues. | in humans, uridine 5'-diphosphate glucuronosyltransferase (ugt) operates in opposition to glucuronidase (gus) to control activity of diverse metabolites such as hormones by reversible conjugation with glucuronic acid. previous data revealed that, as in mammals, these enzymes are required for plant life in that a ugt from pisum sativum (psugt1) controls plant development by opposing endogenous gus activity thereby modulating the duration of the cell cycle. here we report that a small family of ge ... | 2007 | 17498920 |
| conserved domain structure of pentatricopeptide repeat proteins involved in chloroplast rna editing. | the pentatricopeptide repeat (ppr) proteins form one of the largest families in higher plants and are believed to be involved in the posttranscriptional processes of gene expression in plant organelles. it has been shown by using a genetic approach focusing on nad(p)h dehydrogenase (ndh) activity that a ppr protein crr4 is essential for a specific rna editing event in chloroplasts. here, we discovered arabidopsis crr21 mutants that are specifically impaired in the rna editing of the site 2 of nd ... | 2007 | 17483454 |
| specificity and similarity of functions of the aux/iaa genes in auxin signaling of arabidopsis revealed by promoter-exchange experiments among msg2/iaa19, axr2/iaa7, and slr/iaa14. | as indicated by various and some overlapped phenotypes of the dominant mutants, the aux/iaa genes of arabidopsis (arabidopsis thaliana) concomitantly exhibit a functional similarity and differentiation. to evaluate the contributions of their expression patterns determined by promoter activity and molecular properties of their gene products to aux/iaa function, we examined phenotypes of transgenic plants expressing the green fluorescent protein (gfp)-tagged msg2-1/iaa19, axr2-1/iaa7, or slr-1/iaa ... | 2007 | 17369427 |
| arabidopsis cor15am is a chloroplast stromal protein that has cryoprotective activity and forms oligomers. | many plants acquire increased freezing tolerance when they are exposed to nonfreezing temperatures of a certain duration. this process is known as cold acclimation and allows plants to protect themselves from freezing injury. a wide variety of polypeptides are induced during cold acclimation, among which is one encoded by cor15a in arabidopsis (arabidopsis thaliana). previous studies showed that the cor15a gene encodes a small, plastid-targeted polypeptide that is processed to a mature form call ... | 2007 | 17384167 |
| cloning and characterization of unusual fatty acid desaturases from anemone leveillei: identification of an acyl-coenzyme a c20 delta5-desaturase responsible for the synthesis of sciadonic acid. | the seed oil of anemone leveillei contains significant amounts of sciadonic acid (20:3delta(5,11,14); sa), an unusual non-methylene-interrupted fatty acid with pharmaceutical potential similar to arachidonic acid. two candidate cdnas (al10 and al21) for the c(20) delta(5cis)-desaturase from developing seeds of a. leveillei were functionally characterized in transgenic arabidopsis (arabidopsis thaliana) plants. the open reading frames of both delta(5)-desaturases showed some similarity to presump ... | 2007 | 17384161 |
| mam3 catalyzes the formation of all aliphatic glucosinolate chain lengths in arabidopsis. | chain elongated, methionine (met)-derived glucosinolates are a major class of secondary metabolites in arabidopsis (arabidopsis thaliana). the key enzymatic step in determining the length of the chain is the condensation of acetyl-coenzyme a with a series of omega-methylthio-2-oxoalkanoic acids, catalyzed by methylthioalkylmalate (mam) synthases. the existence of two mam synthases has been previously reported in the arabidopsis ecotype columbia: mam1 and mam3 (formerly known as mam-l). here, we ... | 2007 | 17369439 |
| gigantea regulates phytochrome a-mediated photomorphogenesis independently of its role in the circadian clock. | gigantea (gi) is a nuclear protein involved in the promotion of flowering by long days, in light input to the circadian clock, and in seedling photomorphogenesis under continuous red light but not far-red light (fr). here, we report that in arabidopsis (arabidopsis thaliana) different alleles of gi have defects in the hypocotyl-growth and cotyledon-unfolding responses to hourly pulses of fr, a treatment perceived by phytochrome a (phya). this phenotype is rescued by overexpression of gi. the ver ... | 2007 | 17384162 |
| the senescence-induced staygreen protein regulates chlorophyll degradation. | loss of green color in leaves results from chlorophyll (chl) degradation in chloroplasts, but little is known about how chl catabolism is regulated throughout leaf development. using the staygreen (sgr) mutant in rice (oryza sativa), which maintains greenness during leaf senescence, we identified sgr, a senescence-associated gene encoding a novel chloroplast protein. transgenic rice overexpressing sgr produces yellowish-brown leaves, and arabidopsis thaliana pheophorbide a oxygenase-impaired mut ... | 2007 | 17513504 |
| an snf2 protein associated with nuclear rna silencing and the spread of a silencing signal between cells in arabidopsis. | the silencing phenotype in arabidopsis thaliana lines with an inverted repeat transgene under the control of a phloem-specific promoter was manifested in regions around veins due to a mobile signal of silencing. genetic analysis implicates rna-dependent rna polymerase2 (rdr2) and an rna polymerase iva subunit gene (nrpd1a) in the signaling mechanism. we also identified an snf2 domain-containing protein (classy1) that acts together with rdr2 and nrpd1a in the spread of transgene silencing and in ... | 2007 | 17526749 |
| time for coffee encodes a nuclear regulator in the arabidopsis thaliana circadian clock. | the plant circadian clock is required for daily anticipation of the diurnal environment. mutation in arabidopsis thaliana time for coffee (tic) affects free-running circadian rhythms. to investigate how tic functions within the circadian system, we introduced markers for the evening and morning phases of the clock into tic and measured evident rhythms. the phases of evening clock genes in tic were all advanced under light/dark cycles without major expression level defects. with regard to morning ... | 2007 | 17496120 |
| canonical signal recognition particle components can be bypassed for posttranslational protein targeting in chloroplasts. | the chloroplast signal recognition particle (cpsrp) and its receptor (cpftsy) target proteins both cotranslationally and posttranslationally to the thylakoids. this dual function enables cpsrp to utilize its posttranslational activities for targeting a family of nucleus-encoded light-harvesting chlorophyll binding proteins (lhcps), the most abundant membrane proteins in plants. previous in vitro experiments indicated an absolute requirement for all cpsrp pathway soluble components. in agreement, ... | 2007 | 17513500 |
| tomato linalool synthase is induced in trichomes by jasmonic acid. | tomato (lycopersicon esculentum) plants emit a blend of volatile organic compounds, which mainly consists of terpenes. upon herbivory or wounding, the emission of several terpenes increases. we have identified and characterized the first two tomato monoterpene synthases, lemts1 and lemts2. although these proteins were highly homologous, recombinant lemts1 protein produced (r)-linalool from geranyl diphosphate (gpp) and (e)-nerolidol from farnesyl diphosphate (fpp), while recombinant lemts2 produ ... | 2007 | 17440821 |
| discovery of chemically induced mutations in rice by tilling. | rice is both a food source for a majority of the world's population and an important model system. available functional genomics resources include targeted insertion mutagenesis and transgenic tools. while these can be powerful, a non-transgenic, unbiased targeted mutagenesis method that can generate a range of allele types would add considerably to the analysis of the rice genome. tilling (targeting induced local lesions in genomes), a general reverse genetic technique that combines traditional ... | 2007 | 17428339 |
| the nuclear-encoded factor hcf173 is involved in the initiation of translation of the psba mrna in arabidopsis thaliana. | to gain insight into the biogenesis of photosystem ii (psii) and to identify auxiliary factors required for this process, we characterized the mutant hcf173 of arabidopsis thaliana. the mutant shows a high chlorophyll fluorescence phenotype (hcf) and is severely affected in the accumulation of psii subunits. in vivo labeling experiments revealed a drastically decreased synthesis of the reaction center protein d1. polysome association experiments suggest that this is primarily caused by reduced t ... | 2007 | 17435084 |
| roles of arabidopsis cyclin-dependent kinase c complexes in cauliflower mosaic virus infection, plant growth, and development. | the c-terminal domain (ctd) of rna polymerase ii is phosphorylated during the transcription cycle by three cyclin-dependent kinases (cdks): cdk7, cdk8, and cdk9. cdk9 and its interacting cyclin t partners belong to the positive transcription elongation factor b (p-tefb) complexes, which phosphorylate the ctd to promote transcription elongation. we report that arabidopsis thaliana cdk9-like proteins, cdkc;1 and cdkc;2, and their interacting cyclin t partners, cyct1;4 and cyct1;5, play important r ... | 2007 | 17468259 |
| the balance between protein synthesis and degradation in chloroplasts determines leaf variegation in arabidopsis yellow variegated mutants. | an arabidopsis thaliana leaf-variegated mutant yellow variegated2 (var2) results from loss of ftsh2, a major component of the chloroplast ftsh complex. ftsh is an atp-dependent metalloprotease in thylakoid membranes and degrades several chloroplastic proteins. to understand the role of proteolysis by ftsh and mechanisms leading to leaf variegation, we characterized the second-site recessive mutation fu-gaeri1 (fug1) that suppressed leaf variegation of var2. map-based cloning and subsequent chara ... | 2007 | 17416734 |
| rice non-yellow coloring1 is involved in light-harvesting complex ii and grana degradation during leaf senescence. | chlorophyll degradation is an aspect of leaf senescence, which is an active process to salvage nutrients from old tissues. non-yellow coloring1 (nyc1) is a rice (oryza sativa) stay-green mutant in which chlorophyll degradation during senescence is impaired. pigment analysis revealed that degradation of not only chlorophylls but also light-harvesting complex ii (lhcii)-bound carotenoids was repressed in nyc1, in which most lhcii isoforms were selectively retained during senescence. ultrastructura ... | 2007 | 17416733 |
| monodehyroascorbate reductase4 is required for seed storage oil hydrolysis and postgerminative growth in arabidopsis. | hydrogen peroxide is a major by-product of peroxisomal metabolism and has the potential to cause critical oxidative damage. in all eukaryotes, catalase is thought to be instrumental in removing this h(2)o(2). however, plants also contain a peroxisomal membrane-associated ascorbate-dependent electron transfer system, using ascorbate peroxidase and monodehydroascorbate reductase (mdar). here, i report that the conditional seedling-lethal sugar-dependent2 mutant of arabidopsis thaliana is deficient ... | 2007 | 17449810 |
| characterization of the vier f-box proteine genes from arabidopsis reveals their importance for plant growth and development. | e3 ubiquitin ligases (e3s) target proteins for degradation by the 26s proteasome. in skp1/cdc53/f-box protein-type e3s, substrate specificity is conferred by the interchangeable f-box protein subunit. the vast majority of the 694 f-box proteins encoded by the arabidopsis thaliana genome remain to be understood. we characterize the vier f-box proteine (vfb; german for four f-box proteins) genes from arabidopsis that belong to subfamily c of the arabidopsis f-box protein superfamily. this subfamil ... | 2007 | 17435085 |
| heterotrimeric g protein gamma subunits provide functional selectivity in gbetagamma dimer signaling in arabidopsis. | the arabidopsis thaliana heterotrimeric g protein complex is encoded by single canonical galpha and gbeta subunit genes and two ggamma subunit genes (agg1 and agg2), raising the possibility that the two potential g protein complexes mediate different cellular processes. mutants with reduced expression of one or both ggamma genes revealed specialized roles for each ggamma subunit. agg1-deficient mutants, but not agg2-deficient mutants, showed impaired resistance against necrotrophic pathogens, re ... | 2007 | 17468261 |
| mitochondrial complex ii is essential for gametophyte development in arabidopsis. | mitochondrial complex ii (succinate dehydrogenase [sdh]) is part of the tricarboxylic acid cycle and the respiratory electron transport chain. its flavoprotein subunit is encoded by two nuclear genes, sdh1-1 and sdh1-2, in arabidopsis (arabidopsis thaliana). the sdh1-2 gene is significantly expressed only in roots, albeit at very low level, and its disruption has no effect on growth and development of homozygous mutant plants. in contrast, sdh1-1 transcripts are ubiquitously expressed, with high ... | 2007 | 17322334 |
| overexpression of an r1r2r3 myb gene, osmyb3r-2, increases tolerance to freezing, drought, and salt stress in transgenic arabidopsis. | we used a cdna microarray approach to monitor the expression profile of rice (oryza sativa) under cold stress and identified 328 cold-regulated genes. thirteen such genes encoding myb, homeodomain, and zinc finger proteins with unknown functions showed a significant change in expression under 72-h cold stress. among them, osmyb3r-2 was selected for further study. unlike most plant r2r3 myb transcription factors, osmyb3r-2 has three imperfect repeats in the dna-binding domain, the same as in anim ... | 2007 | 17293435 |
| an early nodulin-like protein accumulates in the sieve element plasma membrane of arabidopsis. | membrane proteins within the sieve element-companion cell complex have essential roles in the physiological functioning of the phloem. the monoclonal antibody line rs6, selected from hybridomas raised against sieve elements isolated from california shield leaf (streptanthus tortuosus; brassicaceae) tissue cultures, recognizes an antigen in the arabidopsis (arabidopsis thaliana) ecotype columbia that is associated specifically with the plasma membrane of sieve elements, but not companion cells, a ... | 2007 | 17293437 |
| skb1-mediated symmetric dimethylation of histone h4r3 controls flowering time in arabidopsis. | plant flowering is a crucial developmental transition from the vegetative to reproductive phase and is properly timed by a number of intrinsic and environmental cues. genetic studies have identified that chromatin modification influences the expression of flowering locus c (flc), a mads-box transcription factor that controls flowering time. histone deacetylation and methylation at h3k9 and h3k27 are associated with repression of flc; in contrast, methylation at h3k4 and h3k36 activates flc expre ... | 2007 | 17363895 |
| bacterial conversations: talking, listening and eavesdropping. an introduction. | | 2007 | 17360281 |
| modulating seed beta-ketoacyl-acyl carrier protein synthase ii level converts the composition of a temperate seed oil to that of a palm-like tropical oil. | beta-ketoacyl-acyl carrier protein (acp) synthase ii (kasii) elongates 16:0-acp to 18:0-acp in the plastid, where it competes with three other enzymes at the first major branch point in fatty acid biosynthesis. despite its key metabolic location, the influence of kasii in determining seed oil composition remains unclear, in part because the biochemical consequences of the fab1-1 mutation were unresolved. thus, fab1-1, and a newly identified knockout allele, fab1-2, were analyzed in the context o ... | 2007 | 17360594 |
| synthesis and antitumor activity of substituted succinamides using a potato disc tumor induction assay. | in view of potential biological activities of some succinic acid derivatives, we synthesized some novel n-[4-(4-morpholinosulfonyl)-phenyl]-succinamides (6a, c; 7a, c) and n-[4-(benzylaminosulfonyl) phenyl]-succinamides (6b, d; 7b, d) derivatives as antitumor agents. the antitumor activity of compounds was studied using the potato disk bioassay technique. vincristine at 0.25 mg/ml was employed as positive control and caused -67.24% inhibitions. compound 7b at 1 mg/ml caused -80.50% tumor inhibit ... | 2007 | 23675023 |
| analysis of transcription factor hy5 genomic binding sites revealed its hierarchical role in light regulation of development. | the transcription factor long hypocotyl5 (hy5) acts downstream of multiple families of the photoreceptors and promotes photomorphogenesis. although it is well accepted that hy5 acts to regulate target gene expression, in vivo binding of hy5 to any of its target gene promoters has yet to be demonstrated. here, we used a chromatin immunoprecipitation procedure to verify suspected in vivo hy5 binding sites. we demonstrated that in vivo association of hy5 with promoter targets is not altered under d ... | 2007 | 17337630 |
| single gene-mediated shift in pollinator attraction in petunia. | animal-mediated pollination is essential in plant reproductive biology and is often associated with pollination syndromes, sets of floral traits, such as color, scent, shape, or nectar content. selection by pollinators is often considered a key factor in floral evolution and plant speciation. our aim is the identification and characterization of the genetic changes that caused the evolution of divergent pollination syndromes in closely related plant species. we focus on anthocyanin2 (an2), a wel ... | 2007 | 17337627 |
| rice udp-glucose pyrophosphorylase1 is essential for pollen callose deposition and its cosuppression results in a new type of thermosensitive genic male sterility. | udp-glucose pyrophosphorylase (ugpase) catalyzes the reversible production of glucose-1-phosphate and utp to udp-glucose and pyrophosphate. the rice (oryza sativa) genome contains two homologous ugpase genes, ugp1 and ugp2. we report a functional characterization of rice ugp1, which is expressed throughout the plant, with highest expression in florets, especially in pollen during anther development. ugp1 silencing by rna interference or cosuppression results in male sterility. expressing a doubl ... | 2007 | 17400897 |
| the n-terminal double-stranded rna binding domains of arabidopsis hyponastic leaves1 are sufficient for pre-microrna processing. | arabidopsis thaliana hyponastic leaves1 (hyl1) is a microrna (mirna) biogenesis protein that contains two n-terminal double-stranded rna binding domains (dsrbds), a putative nuclear localization site (nls), and a putative protein-protein interaction domain. the interaction of hyl1 with dicer-like1 is important for the efficient and precise processing of mirna primary transcripts in plant mirna biogenesis. to define the roles of the various domains of hyl1 in mirna processing and the mirna-direct ... | 2007 | 17337628 |
| improperly terminated, unpolyadenylated mrna of sense transgenes is targeted by rdr6-mediated rna silencing in arabidopsis. | rna silencing can be induced by highly transcribed transgenes through a pathway dependent on rna-dependent rna polymerase6 (rdr6) and may function as a genome protection mechanism against excessively expressed genes. whether all transcripts or just aberrant transcripts activate this protection mechanism is unclear. consistent rna silencing induced by a transgene with three direct repeats of the beta-glucuronidase (gus) open reading frame (orf) is associated with high levels of truncated, unpolya ... | 2007 | 17384170 |
| the thylakoid lumen protease deg1 is involved in the repair of photosystem ii from photoinhibition in arabidopsis. | deg1 is a ser protease peripherally attached to the lumenal side of the thylakoid membrane. its physiological function is unknown, but its localization makes it a suitable candidate for participation in photoinhibition repair by degradation of the photosystem ii reaction center protein d1. we transformed arabidopsis thaliana with an rna interference construct and obtained plants with reduced levels of deg1. these plants were smaller than wild-type plants, flowered earlier, were more sensitive to ... | 2007 | 17351117 |
| a mutant of the arabidopsis phosphate transporter pht1;1 displays enhanced arsenic accumulation. | the exceptional toxicity of arsenate [as(v)] is derived from its close chemical similarity to phosphate (pi), which allows the metalloid to be easily incorporated into plant cells through the high-affinity pi transport system. in this study, we identified an as(v)-tolerant mutant of arabidopsis thaliana named pht1;1-3, which harbors a semidominant allele coding for the high-affinity pi transporter pht1;1. pht1;1-3 displays a slow rate of as(v) uptake that ultimately enables the mutant to accumul ... | 2007 | 17400898 |
| dual lipid modification of arabidopsis ggamma-subunits is required for efficient plasma membrane targeting. | posttranslational lipid modifications are important for proper localization of many proteins in eukaryotic cells. however, the functional interrelationships between lipid modification processes in plants remain unclear. here we demonstrate that the two heterotrimeric g-protein gamma-subunits from arabidopsis (arabidopsis thaliana), agg1 and agg2, are prenylated, and agg2 is s-acylated. in wild type, enhanced yellow fluorescent protein-fused agg1 and agg2 are associated with plasma membranes, wit ... | 2007 | 17220359 |
| agf1, an at-hook protein, is necessary for the negative feedback of atga3ox1 encoding ga 3-oxidase. | negative feedback is a fundamental mechanism of organisms to maintain the internal environment within tolerable limits. gibberellins (gas) are essential regulators of many aspects of plant development, including seed germination, stem elongation, and flowering. ga biosynthesis is regulated by the feedback mechanism in plants. ga 3-oxidase (ga3ox) catalyzes the final step of the biosynthetic pathway to produce the physiologically active gas. here, we found that only the atga3ox1 among the atga3ox ... | 2007 | 17277098 |
| isolation of a regulatory gene of anthocyanin biosynthesis in tuberous roots of purple-fleshed sweet potato. | many transcriptional factors harboring the r2r3-myb domain, basic helix-loop-helix domain, or wd40 repeats have been identified in various plant species as regulators of flavonoid biosynthesis in flowers, seeds, and fruits. however, the regulatory elements of flavonoid biosynthesis in underground organs have not yet been elucidated. we isolated the novel myb genes ibmyb1 and ibmyb2s from purple-fleshed sweet potato (ipomoea batatas l. lam. cv ayamurasaki). ibmyb1 was predominantly expressed in t ... | 2007 | 17208956 |
| auxin biosynthesis by the yucca genes in rice. | although indole-3-acetic acid (iaa), the predominant auxin in plants, plays a critical role in various plant growth and developmental processes, its biosynthesis and regulation have not been clearly elucidated. to investigate the molecular mechanisms of iaa synthesis in rice (oryza sativa), we identified seven yucca-like genes (named osyucca1-7) in the rice genome. plants overexpressing osyucca1 exhibited increased iaa levels and characteristic auxin overproduction phenotypes, whereas plants exp ... | 2007 | 17220367 |
| characterization of a plastid triacylglycerol lipase from arabidopsis. | full-length cdna corresponding to arabidopsis (arabidopsis thaliana) gene at2g31690, which has been annotated in genbank as a putative triacylglycerol (tag) lipase, was obtained by reverse transcription-polymerase chain reaction using rna from senescing rosette leaves of arabidopsis as a template. the cognate protein was found to contain the lipase active site sequence, and corresponding recombinant protein proved capable of deesterifying tag. in vitro chloroplast import assays indicated that th ... | 2007 | 17259290 |
| differential binding of calmodulin-related proteins to their targets revealed through high-density arabidopsis protein microarrays. | calmodulins (cams) are the most ubiquitous calcium sensors in eukaryotes. a number of cam-binding proteins have been identified through classical methods, and many proteins have been predicted to bind cams based on their structural homology with known targets. however, multicellular organisms typically contain many cam-like (cml) proteins, and a global identification of their targets and specificity of interaction is lacking. in an effort to develop a platform for large-scale analysis of protein ... | 2007 | 17360592 |
| histone deacetylases and asymmetric leaves2 are involved in the establishment of polarity in leaves of arabidopsis. | we show that two arabidopsis thaliana genes for histone deacetylases (hdacs), hdt1/hd2a and hdt2/hd2b, are required to establish leaf polarity in the presence of mutant asymmetric leaves2 (as2) or as1. treatment of as1 or as2 plants with inhibitors of hdacs resulted in abaxialized filamentous leaves and aberrant distribution of microrna165 and/or microrna166 (mir165/166) in leaves. knockdown mutations of these two hdacs by rna interference resulted in phenotypes like those observed in the as2 ba ... | 2007 | 17293570 |
| identification of two protein kinases required for abscisic acid regulation of seed germination, root growth, and gene expression in arabidopsis. | abscisic acid (aba) is an important phytohormone regulating various plant processes, including seed germination. although phosphorylation has been suggested to be important, the protein kinases required for aba signaling during seed germination and seedling growth remain elusive. here, we show that two protein kinases, snf1-related protein kinase2.2 (snrk2.2) and snrk2.3, control responses to aba in seed germination, dormancy, and seedling growth in arabidopsis thaliana. a snrk2.2 snrk2.3 double ... | 2007 | 17307925 |
| transcriptional profiling of the arabidopsis embryo. | we have used laser-capture microdissection to isolate rna from discrete tissues of globular, heart, and torpedo stage embryos of arabidopsis (arabidopsis thaliana). this was amplified and analyzed by dna microarray using the affymetrix ath1 genechip, representing approximately 22,800 arabidopsis genes. cluster analysis showed that spatial differences in gene expression were less significant than temporal differences. time course analysis reveals the dynamics and complexity of gene expression in ... | 2007 | 17189330 |
| an analysis of univalent segregation in meiotic mutants of arabidopsis thaliana: a possible role for synaptonemal complex. | during first meiotic prophase, homologous chromosomes are normally kept together by both crossovers and synaptonemal complexes (sc). in most eukaryotes, the sc disassembles at diplotene, leaving chromosomes joined by chiasmata. the correct co-orientation of bivalents at metaphase i and the reductional segregation at anaphase i are facilitated by chiasmata and sister-chromatid cohesion. in the absence of meiotic reciprocal recombination, homologs are expected to segregate randomly at anaphase i. ... | 2007 | 17151235 |
| vim1, a methylcytosine-binding protein required for centromeric heterochromatinization. | epigenetic regulation in eukaryotes is executed by a complex set of signaling interactions among small rna species and chromatin marks, including histone modification and dna methylation. we identified vim1 (variant in methylation 1), an arabidopsis mutation causing cytosine hypomethylation and decondensation of centromeres in interphase. vim1 is a member of a small gene family, encoding proteins containing phd, ring, and sra (set- and ring-associated) domains, which are found together in mammal ... | 2007 | 17242155 |
| molecular bases of viral rna targeting by viral small interfering rna-programmed risc. | rna silencing is conserved in a broad range of eukaryotes and operates in the development and maintenance of genome integrity in many organisms. plants have adapted this system for antiviral defense, and plant viruses have in turn developed mechanisms to suppress rna silencing. rna silencing-related rna inactivation is likely based on target rna cleavage or translational arrest. although it is widely assumed that virus-induced gene silencing (vigs) promotes the endonucleolytic cleavage of the vi ... | 2007 | 17267504 |
| arabidopsis thaliana telomeric dna-binding protein 1 is required for telomere length homeostasis and its myb-extension domain stabilizes plant telomeric dna binding. | telomeres are specific protein-dna complexes that protect the ends of eukaryotic chromosomes from fusion and degradation and are maintained by a specialized mechanism exerted by telomerase and telomere-binding proteins (tbps), which are evolutionarily conserved. attbp1 is an arabidopsis thaliana protein that binds plant telomeric dna in vitro. here, we demonstrated that lack of attbp1 results in a deregulation of telomere length control, with mutant telomeres expanding steadily by the fourth gen ... | 2007 | 17272298 |
| a medicago truncatula phosphate transporter indispensable for the arbuscular mycorrhizal symbiosis. | the arbuscular mycorrhizal (am) symbiosis is a mutualistic endosymbiosis formed by plant roots and am fungi. most vascular flowering plants have the ability to form these associations, which have a significant impact on plant health and consequently on ecosystem function. nutrient exchange is a central feature of the am symbiosis, and am fungi obtain carbon from their plant host while assisting the plant with the acquisition of phosphorus (as phosphate) from the soil. in the am symbiosis, the fu ... | 2007 | 17242358 |
| requirement of the c3hc4 zinc ring finger of the arabidopsis pex10 for photorespiration and leaf peroxisome contact with chloroplasts. | plant peroxisomes perform multiple vital metabolic processes including lipid mobilization in oil-storing seeds, photorespiration, and hormone biosynthesis. peroxisome biogenesis requires the function of peroxin (pex) proteins, including pex10, a c(3)hc(4) zn ring finger peroxisomal membrane protein. loss of function of pex10 causes embryo lethality at the heart stage. we investigated the function of pex10 with conditional sublethal mutants. four t-dna insertion lines expressing pex10 with a dysf ... | 2007 | 17215364 |
| metagenomics: a call for bringing a new science into the classroom (while it's still new). | | 2007 | 18056294 |
| sdg714, a histone h3k9 methyltransferase, is involved in tos17 dna methylation and transposition in rice. | although the role of h3k9 methylation in rice (oryza sativa) is unclear, in arabidopsis thaliana the loss of histone h3k9 methylation by mutation of kryptonite [also known as su(var)3-9 homolog] reduces genome-wide dna methylation and increases the transcription of transposable elements. here, we report that rice sdg714 (for set domain group protein714) encodes a histone h3k9-specific methyltransferase. the c terminus of sdg714 confers enzymatic activity and substrate specificity, whereas the n ... | 2007 | 17259261 |
| cryptochrome2 in vascular bundles regulates flowering in arabidopsis. | plants make full use of light signals to determine the timing of flowering. in arabidopsis thaliana, a blue/uv-a photoreceptor, cryptochrome 2 (cry2), and a red/far-red photoreceptor, phytochrome b (phyb), are two major photoreceptors that control flowering. the light stimuli for the regulation of flowering are perceived by leaves. we have recently shown that phyb expression in mesophyll but not in vascular bundles suppresses the expression of a key flowering regulator, flowering locus t (ft), i ... | 2007 | 17259260 |
| arf7 and arf19 regulate lateral root formation via direct activation of lbd/asl genes in arabidopsis. | lateral root formation in arabidopsis thaliana is regulated by two related auxin response factors, arf7 and arf19, which are transcriptional activators of early auxin response genes. the arf7 arf19 double knockout mutant is severely impaired in lateral root formation. target-gene analysis in arf7 arf19 transgenic plants harboring inducible forms of arf7 and arf19 revealed that arf7 and arf19 directly regulate the auxin-mediated transcription of lateral organ boundaries-domain16/asymmetric leaves ... | 2007 | 17259263 |