Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| mapk signaling regulates nitric oxide and nadph oxidase-dependent oxidative bursts in nicotiana benthamiana. | nitric oxide (no) and reactive oxygen species (ros) act as signals in innate immunity in plants. the radical burst is induced by inf1 elicitin, produced by the oomycete pathogen phytophthora infestans. no associated1 (noa1) and nadph oxidase participate in the radical burst. here, we show that mitogen-activated protein kinase (mapk) cascades mek2-sipk/ntf4 and mek1-ntf6 participate in the regulation of the radical burst. no generation was induced by conditional activation of sipk/ntf4, but not b ... | 2008 | 18515503 |
| roles of rna polymerase iv in gene silencing. | eukaryotes typically have three multi-subunit enzymes that decode the nuclear genome into rna: dna-dependent rna polymerases i, ii and iii (pol i, ii and iii). remarkably, higher plants have five multi-subunit nuclear rna polymerases: the ubiquitous pol i, ii and iii, which are essential for viability; plus two non-essential polymerases, pol iva and pol ivb, which specialize in small rna-mediated gene silencing pathways. there are numerous examples of phenomena that require pol iva and/or pol iv ... | 2008 | 18514566 |
| the dark side of the salad: salmonella typhimurium overcomes the innate immune response of arabidopsis thaliana and shows an endopathogenic lifestyle. | salmonella enterica serovar typhimurium contaminated vegetables and fruits are considerable sources of human infections. bacteria present in raw plant-derived nutrients cause salmonellosis, the world wide most spread food poisoning. this facultative endopathogen enters and replicates in host cells and actively suppresses host immune responses. although salmonella survives on plants, the underlying bacterial infection mechanisms are only poorly understood. in this report we investigated the possi ... | 2008 | 18509467 |
| evolution of catalases from bacteria to humans. | excessive hydrogen peroxide is harmful for almost all cell components, so its rapid and efficient removal is of essential importance for aerobically living organisms. conversely, hydrogen peroxide acts as a second messenger in signal-transduction pathways. h(2)o(2) is degraded by peroxidases and catalases, the latter being able both to reduce h(2)o(2) to water and to oxidize it to molecular oxygen. nature has evolved three protein families that are able to catalyze this dismutation at reasonable ... | 2008 | 18498226 |
| functional analysis reveals pleiotropic effects of rice ring-h2 finger protein gene osbirf1 on regulation of growth and defense responses against abiotic and biotic stresses. | ring finger proteins comprise a large family and play key roles in regulating growth/developmental processes, hormone signaling and responses to biotic and abiotic stresses in plants. a rice gene, osbirf1, encoding a putative ring-h2 finger protein, was cloned and identified. osbirf1 encodes a 396 amino acid protein belonging to the atl family characterized by a conserved ring-h2 finger domain (c-x2-c-x15-c-x1-h-x2-h-x2-c-x10-c-x2-c), a transmembrane domain at the n-terminal, a basic amino acid ... | 2008 | 18496756 |
| nitrogen fixation island and rhizosphere competence traits in the genome of root-associated pseudomonas stutzeri a1501. | the capacity to fix nitrogen is widely distributed in phyla of bacteria and archaea but has long been considered to be absent from the pseudomonas genus. we report here the complete genome sequencing of nitrogen-fixing root-associated pseudomonas stutzeri a1501. the genome consists of a single circular chromosome with 4,567,418 bp. comparative genomics revealed that, among 4,146 protein-encoding genes, 1,977 have orthologs in each of the five other pseudomonas representative species sequenced to ... | 2008 | 18495935 |
| photorhabdus luminescens genes induced upon insect infection. | photorhabdus luminescens is a gram-negative luminescent enterobacterium and a symbiote to soil nematodes belonging to the species heterorhabditis bacteriophora. p.luminescens is simultaneously highly pathogenic to insects. this bacterium exhibits a complex life cycle, including one symbiotic stage characterized by colonization of the upper nematode gut, and a pathogenic stage, characterized by release from the nematode into the hemocoel of insect larvae, resulting in rapid insect death caused by ... | 2008 | 18489737 |
| amyloids: friend or foe? | amyloidogenesis is the aggregation of soluble proteins into structurally conserved fibers. amyloid fibers are distinguished by their resistance to proteinase k, tinctorial properties and beta-sheet-rich secondary structure. amyloid formation is a hallmark of many human diseases including alzheimer's, huntington's and the prion diseases. therefore, understanding amyloidogenesis will provide insights into the development of therapeutics that target these debilitating diseases. a new class of ;func ... | 2008 | 18487849 |
| multiple models for rosaceae genomics. | the plant family rosaceae consists of over 100 genera and 3,000 species that include many important fruit, nut, ornamental, and wood crops. members of this family provide high-value nutritional foods and contribute desirable aesthetic and industrial products. most rosaceous crops have been enhanced by human intervention through sexual hybridization, asexual propagation, and genetic improvement since ancient times, 4,000 to 5,000 b.c. modern breeding programs have contributed to the selection and ... | 2008 | 18487361 |
| genes and enzymes of azetidine-2-carboxylate metabolism: detoxification and assimilation of an antibiotic. | l-(-)-azetidine-2-carboxylate (ac) is a toxic, natural product analog of l-proline. this study revealed the genes and biochemical strategy employed by pseudomonas sp. strain a2c to detoxify and assimilate ac as its sole nitrogen source. the gene region from pseudomonas sp. strain a2c required for detoxification was cloned into escherichia coli and sequenced. the 7.0-kb region contained eight identifiable genes. four encoded putative transporters or permeases for gamma-amino acids or drugs. anoth ... | 2008 | 18487339 |
| symbiosis-promoting and deleterious effects of nopt, a novel type 3 effector of rhizobium sp. strain ngr234. | establishment of symbiosis between certain host plants and nitrogen-fixing bacteria ("rhizobia") depends on type 3 effector proteins secreted via the bacterial type 3 secretion system (t3ss). here, we report that the open reading frame y4zc of strain ngr234 encodes a novel rhizobial type 3 effector, termed nopt (for nodulation outer protein t). analysis of secreted proteins from ngr234 and t3ss mutants revealed that nopt is secreted via the t3ss. nopt possessed autoproteolytic activity when expr ... | 2008 | 18487326 |
| structural basis of substrate recognition in thiopurine s-methyltransferase. | thiopurine s-methyltransferase (tpmt) modulates the cytotoxic effects of thiopurine prodrugs such as 6-mercaptopurine by methylating them in a reaction using s-adenosyl- l-methionine as the donor. patients with tpmt variant allozymes exhibit diminished levels of protein and/or enzyme activity and are at risk for thiopurine drug-induced toxicity. we have determined two crystal structures of murine tpmt, as a binary complex with the product s-adenosyl- l-homocysteine and as a ternary complex with ... | 2008 | 18484748 |
| responses of arabidopsis thaliana to challenge by pseudomonas syringae. | plants are continually exposed to a variety of potentially pathogenic microbes, and the interactions between plants and pathogenic invaders determine the outcome, disease or disease resistance. to defend themselves, plants have developed a sophisticated immune system. unlike animals, however, they do not have specialized immune cells and, thus all plant cells appear to have the innate ability to recognize pathogens and turn on an appropriate defense response. using genetic, genomic and biochemic ... | 2008 | 18483469 |
| pseudomonas aeruginosa uses type iii secretion system to kill biofilm-associated amoebae. | bacteria and protozoa coexist in a wide range of biofilm communities of natural, technical and medical importance. generally, this interaction is characterized by the extensive grazing activity of protozoa on bacterial prey populations. we hypothesized that the close spatial coexistence in biofilms should allow opportunistic pathogenic bacteria to utilize their eukaryote-targeting arsenal to attack and exploit protozoan host cells. studying cocultures of the environmental pathogen pseudomonas ae ... | 2008 | 18480848 |
| arabidopsis mrna polyadenylation machinery: comprehensive analysis of protein-protein interactions and gene expression profiling. | the polyadenylation of mrna is one of the critical processing steps during expression of almost all eukaryotic genes. it is tightly integrated with transcription, particularly its termination, as well as other rna processing events, i.e. capping and splicing. the poly(a) tail protects the mrna from unregulated degradation, and it is required for nuclear export and translation initiation. in recent years, it has been demonstrated that the polyadenylation process is also involved in the regulation ... | 2008 | 18479511 |
| invasion of the arabidopsis genome by the tobacco retrotransposon tnt1 is controlled by reversible transcriptional gene silencing. | long terminal repeat (ltr) retrotransposons are generally silent in plant genomes. however, they often constitute a large proportion of repeated sequences in plants. this suggests that their silencing is set up after a certain copy number is reached and/or that it can be released in some circumstances. we introduced the tobacco (nicotiana tabacum) ltr retrotransposon tnt1 into arabidopsis (arabidopsis thaliana), thus mimicking the horizontal transfer of a retrotransposon into a new host species ... | 2008 | 18467467 |
| ecology and genomics of bacillus subtilis. | bacillus subtilis is a remarkably diverse bacterial species that is capable of growth within many environments. recent microarray-based comparative genomic analyses have revealed that members of this species also exhibit considerable genomic diversity. the identification of strain-specific genes might explain how b. subtilis has become so broadly adapted. the goal of identifying ecologically adaptive genes could soon be realized with the imminent release of several new b. subtilis genome sequenc ... | 2008 | 18467096 |
| identification of a xylogalacturonan xylosyltransferase involved in pectin biosynthesis in arabidopsis. | xylogalacturonan (xga) is a class of pectic polysaccharide found in plant cell walls. the arabidopsis thaliana locus at5g33290 encodes a predicted type ii membrane protein, and insertion mutants of the at5g33290 locus had decreased cell wall xylose. immunological studies, enzymatic extraction of polysaccharides, monosaccharide linkage analysis, and oligosaccharide mass profiling were employed to identify the affected cell wall polymer. pectic xga was reduced to much lower levels in mutant than i ... | 2008 | 18460606 |
| coi1 is a critical component of a receptor for jasmonate and the bacterial virulence factor coronatine. | jasmonate (ja) is a lipid-derived hormone that regulates diverse aspects of plant immunity and development. an amino acid-conjugated form of ja, jasmonoyl-isoleucine (ja-ile), stimulates binding of the f-box protein coronatine-insensitive 1 (coi1) to, and subsequent ubiquitin-dependent degradation of, jasmonate zim domain (jaz) proteins that repress transcription of ja-responsive genes. the virulence factor coronatine (cor), which is produced by plant pathogenic strains of pseudomonas syringae, ... | 2008 | 18458331 |
| fungal effector protein avr2 targets diversifying defense-related cys proteases of tomato. | the interaction between the fungal pathogen cladosporium fulvum and its host tomato (solanum lycopersicum) is an ideal model to study suppression of extracellular host defenses by pathogens. secretion of protease inhibitor avr2 by c. fulvum during infection suggests that tomato papain-like cysteine proteases (plcps) are part of the tomato defense response. we show that the tomato apoplast contains a remarkable diversity of plcp activities with seven plcps that fall into four different subfamilie ... | 2008 | 18451324 |
| dellas control plant immune responses by modulating the balance of jasmonic acid and salicylic acid signaling. | in arabidopsis, the flagellin-derived peptide flg22 elevates antibacterial resistance [1] and inhibits growth [2] upon perception via the leucine-rich repeat receptor-like kinase flagellin-sensitive 2 (fls2) [3]. della proteins are plant growth repressors whose degradation is promoted by the phytohormone gibberellin [4]. here, we show that della stabilization contributes to flg22-induced growth inhibition. in addition, we show that dellas promote susceptibility to virulent biotrophs and resistan ... | 2008 | 18450451 |
| cyanogenic pseudomonads influence multitrophic interactions in the rhizosphere. | in the rhizosphere, plant roots cope with both pathogenic and beneficial bacterial interactions. the exometabolite production in certain bacterial species may regulate root growth and other root-microbe interactions in the rhizosphere. here, we elucidated the role of cyanide production in pseudomonad virulence affecting plant root growth and other rhizospheric processes. exposure of arabidopsis thaliana col-0 seedlings to both direct (with kcn) and indirect forms of cyanide from different pseudo ... | 2008 | 18446201 |
| effect of linear alkylbenzene sulfonates on the growth of aerobic heterotrophic cultivable bacteria isolated from an agricultural soil. | an enrichment culture technique was used to isolate soil bacteria capable of growing in the presence of two different concentrations of linear alkylbenzene sulfonates (las) (10 and 500 microg ml(-1)). nine bacterial strains, representatives of the major colony types of aerobic heterotrophic cultivable bacteria in the enriched samples, were isolated and subsequently identified by pcr-amplification and partial sequencing of the 16s rrna gene. amongst the isolates, strains las05 (pseudomonas syring ... | 2008 | 18443905 |
| regulating the regulators: the future prospects for transcription-factor-based agricultural biotechnology products. | 2008 | 18443103 | |
| osbirh1, a dead-box rna helicase with functions in modulating defence responses against pathogen infection and oxidative stress. | dead-box proteins comprise a large protein family with members from all kingdoms and play important roles in all types of processes in rna metabolism. in this study, a rice gene osbirh1, which encodes a dead-box rna helicase protein, was cloned and characterized. the predicted osbirh1 protein contains a dead domain and all conserved motifs that are common characteristics of dead-box rna helicases. recombinant osbirh1 protein purified from escherichia coli was shown to have both rna-dependent atp ... | 2008 | 18441339 |
| regulatory network controlling extracellular proteins in erwinia carotovora subsp. carotovora: flhdc, the master regulator of flagellar genes, activates rsmb regulatory rna production by affecting gaca and hexa (lrha) expression. | erwinia carotovora subsp. carotovora produces an array of extracellular proteins (i.e., exoproteins), including plant cell wall-degrading enzymes and harpin, an effector responsible for eliciting hypersensitive reaction. exoprotein genes are coregulated by the quorum-sensing signal, n-acyl homoserine lactone, plant signals, an assortment of transcriptional factors/regulators (gacs/a, expr1, expr2, kdgr, rpos, hexa, and rsmc) and posttranscriptional regulators (rsma, rsmb rna). rsmb rna productio ... | 2008 | 18441056 |
| induction of the arabidopsis pho1;h10 gene by 12-oxo-phytodienoic acid but not jasmonic acid via a coronatine insensitive1-dependent pathway. | expression of atpho1;h10, a member of the arabidopsis (arabidopsis thaliana) pho1 gene family, is strongly induced following numerous abiotic and biotic stresses, including wounding, dehydration, cold, salt, and pathogen attack. atpho1;h10 expression by wounding was localized to the cells in the close vicinity of the wound site. atpho1;h10 expression was increased by application of the jasmonic acid (ja) precursor 12-oxo-phytodienoic acid (opda), but not by ja or coronatine. surprisingly, induct ... | 2008 | 18434606 |
| a genome-wide functional investigation into the roles of receptor-like proteins in arabidopsis. | receptor-like proteins (rlps) are cell surface receptors that typically consist of an extracellular leucine-rich repeat domain, a transmembrane domain, and a short cytoplasmatic tail. in several plant species, rlps have been found to play a role in disease resistance, such as the tomato (solanum lycopersicum) cf and ve proteins and the apple (malus domestica) hcrvf2 protein that mediate resistance against the fungal pathogens cladosporium fulvum, verticillium spp., and venturia inaequalis, respe ... | 2008 | 18434605 |
| light regulation and daytime dependency of inducible plant defenses in arabidopsis: phytochrome signaling controls systemic acquired resistance rather than local defense. | we have examined molecular and physiological principles underlying the light dependency of defense activation in arabidopsis (arabidopsis thaliana) plants challenged with the bacterial pathogen pseudomonas syringae. within a fixed light/dark cycle, plant defense responses and disease resistance significantly depend on the time of day when pathogen contact takes place. morning and midday inoculations result in higher salicylic acid accumulation, faster expression of pathogenesis-related genes, an ... | 2008 | 18434604 |
| an extensive (co-)expression analysis tool for the cytochrome p450 superfamily in arabidopsis thaliana. | sequencing of the first plant genomes has revealed that cytochromes p450 have evolved to become the largest family of enzymes in secondary metabolism. the proportion of p450 enzymes with characterized biochemical function(s) is however very small. if p450 diversification mirrors evolution of chemical diversity, this points to an unexpectedly poor understanding of plant metabolism. we assumed that extensive analysis of gene expression might guide towards the function of p450 enzymes, and highligh ... | 2008 | 18433503 |
| the 'core' and 'accessory' regulons of pseudomonas-specific extracytoplasmic sigma factors. | pyoverdine is a fluorescent, high-affinity peptide siderophore produced by different pseudomonas species. the genes for pyoverdine biosynthesis depend on pvds, an extracytoplasmic sigma factor. in this issue of molecular microbiology, swingle et al. demonstrate that in the plant pathogen pseudomonas syringae pvds not only regulates the production of pyoverdine (core regulon), but also controls expression of other genes likely to be involved in the adaptation to the environment (accessory regulon ... | 2008 | 18430079 |
| site-directed mutagenesis of the temperature-sensing histidine protein kinase cors from pseudomonas syringae. | several plant pathogenic bacteria belonging to the species pseudomonas syringae produce the phytotoxin coronatine to enhance their virulence. pseudomonas syringae pv. glycinea pg4180 synthesizes coronatine at the virulence-promoting temperature of 18 degrees c, but not at 28 degrees c, its optimal growth temperature. in contrast, temperature has virtually no effect on coronatine synthesis in p. syringae pv. tomato strain dc3000. a modified two-component system controlling coronatine synthesis an ... | 2008 | 18429999 |
| trna modification by gida/mnme is necessary for streptococcus pyogenes virulence: a new strategy to make live attenuated strains. | studies directed at vaccine development and mucosal immunity against streptococcus pyogenes would benefit from the availability of live attenuated strains. our approach for production of candidate live attenuated strains was to identify mutations that did not alter growth in vitro and did not alter the overall complement of virulence factors produced but did result in reduced levels of expression of multiple secreted virulence factors. a global reduction but not elimination of expression would l ... | 2008 | 18426891 |
| arabidopsis tao1 is a tir-nb-lrr protein that contributes to disease resistance induced by the pseudomonas syringae effector avrb. | the type iii effector protein encoded by avirulence gene b (avrb) is delivered into plant cells by pathogenic strains of pseudomonas syringae. there, it localizes to the plasma membrane and triggers immunity mediated by the arabidopsis coiled-coil (cc)-nucleotide binding (nb)-leucine-rich repeat (lrr) disease resistance protein rpm1. the sequence unrelated type iii effector avirulence protein encoded by avirulence gene rpm1 (avrrpm1) also activates rpm1. avrb contributes to virulence after deliv ... | 2008 | 18424557 |
| plant immunity from a to z. | a report of the keystone symposium on plant innate immunity, keystone, usa, 10-15 february 2008. | 2008 | 18423060 |
| soybean defense responses to the soybean aphid. | transcript profiles in aphid (aphis glycines)-resistant (cv. dowling) and -susceptible (cv. williams 82) soybean (glycine max) cultivars using soybean cdna microarrays were investigated. large-scale soybean cdna microarrays representing approx. 18 000 genes or c. 30% of the soybean genome were compared at 6 and 12 h post-application of aphids. in a separate experiment utilizing clip cages, expression of three defense-related genes were examined at 6, 12, 24, 48, and 72 h in both cultivars by qua ... | 2008 | 18422900 |
| role of stomata in plant innate immunity and foliar bacterial diseases. | pathogen entry into host tissue is a critical first step in causing infection. for foliar bacterial plant pathogens, natural surface openings, such as stomata, are important entry sites. historically, these surface openings have been considered as passive portals of entry for plant pathogenic bacteria. however, recent studies have shown that stomata can play an active role in limiting bacterial invasion as part of the plant innate immune system. as a counter-defense, the plant pathogen pseudomon ... | 2008 | 18422426 |
| electron paramagnetic resonance characterization of the copper-resistance protein pcoc from escherichia coli. | continuous-wave and pulsed electron paramagnetic resonance have been applied to the study of the cu(ii) site of the copper-resistance protein pcoc from escherichia coli and certain variant forms. electron spin echo envelope modulation (eseem) experiments confirm the presence of two histidine ligands, his1 and his92, at the cu(ii) site of wild-type pcoc, consistent with the available x-ray crystallographic data for the homolog copc (67% sequence identity) from pseudomonas syringae pv. tomato. the ... | 2008 | 18421485 |
| phenotypic instability of arabidopsis alleles affecting a disease resistance gene cluster. | three mutations in arabidopsis thaliana strain columbia - cpr1, snc1, and bal - map to the rpp5 locus, which contains a cluster of disease resistance genes. the similar phenotypes, gene expression patterns, and genetic interactions observed in these mutants are related to constitutive activation of pathogen defense signaling. however, these mutant alleles respond differently to various conditions. exposure to mutagens, such as ethyl methanesulfonate (ems) and gamma-irradiation, induce high frequ ... | 2008 | 18410684 |
| negative regulation of quorum-sensing systems in pseudomonas aeruginosa by atp-dependent lon protease. | lon protease, a member of the atp-dependent protease family, regulates numerous cellular systems by degrading specific substrates. here, we demonstrate that lon is involved in the regulation of quorum-sensing (qs) signaling systems in pseudomonas aeruginosa, an opportunistic human pathogen. the organism has two acyl-homoserine lactone (hsl)-mediated qs systems, lasr/lasi and rhlr/rhli. many reports have demonstrated that these two systems are regulated and interconnected by global regulators. we ... | 2008 | 18408026 |
| genome-wide search reveals a novel gaca-regulated small rna in pseudomonas species. | small rnas (srnas) are widespread among bacteria and have diverse regulatory roles. most of these srnas have been discovered by a combination of computational and experimental methods. in pseudomonas aeruginosa, a ubiquitous gram-negative bacterium and opportunistic human pathogen, the gacs/gaca two-component system positively controls the transcription of two srnas (rsmy, rsmz), which are crucial for the expression of genes involved in virulence. in the biocontrol bacterium pseudomonas fluoresc ... | 2008 | 18405392 |
| a plant pathogen virulence factor inhibits the eukaryotic proteasome by a novel mechanism. | pathogenic bacteria often use effector molecules to increase virulence. in most cases, the mode of action of effectors remains unknown. strains of pseudomonas syringae pv. syringae (pss) secrete syringolin a (syla), a product of a mixed non-ribosomal peptide/polyketide synthetase, in planta. here we identify syla as a virulence factor because a syla-negative mutant in pss strain b728a obtained by gene disruption was markedly less virulent on its host, phaseolus vulgaris (bean). we show that syla ... | 2008 | 18401409 |
| role of swollenin, an expansin-like protein from trichoderma, in plant root colonization. | swollenin, a protein first characterized in the saprophytic fungus trichoderma reesei, contains an n-terminal carbohydrate-binding module family 1 domain (cbd) with cellulose-binding function and a c-terminal expansin-like domain. this protein was identified by liquid chromatography-mass spectrometry among many other cellulolytic proteins secreted in the coculture hydroponics medium of cucumber (cucumis sativus) seedlings and trichoderma asperellum, a well-known biocontrol agent and inducer of p ... | 2008 | 18400936 |
| identification and regulation of tps04/ges, an arabidopsis geranyllinalool synthase catalyzing the first step in the formation of the insect-induced volatile c16-homoterpene tmtt. | volatile secondary metabolites emitted by plants contribute to plant-plant, plant-fungus, and plant-insect interactions. the c(16)-homoterpene tmtt (for 4,8,12-trimethyltrideca-1,3,7,11-tetraene) is emitted after herbivore attack by a wide variety of plant species, including arabidopsis thaliana, and is assumed to play a role in attracting predators or parasitoids of herbivores. tmtt has been suggested to be formed as a degradation product of the diterpene alcohol (e,e)-geranyllinalool. here, we ... | 2008 | 18398052 |
| discovery of adp-ribosylation and other plant defense pathway elements through expression profiling of four different arabidopsis-pseudomonas r-avr interactions. | a dissection of plant defense pathways was initiated through gene expression profiling of the responses of a single arabidopsis thaliana genotype to isogenic pseudomonas syringae strains expressing one of four different cloned avirulence (avr) genes. differences in the expression profiles elicited by different resistance (r)-avr interactions were observed. a role for poly(adp-ribosyl)ation in plant defense responses was suggested initially by the upregulated expression of genes encoding nudt7 an ... | 2008 | 18393624 |
| characterization of the rnd-type multidrug efflux pump mexab-oprm of the plant pathogen pseudomonas syringae. | in gram-negative bacteria, transporters belonging to the rnd family are the transporters most relevant for resistance to antimicrobial compounds. in pseudomonas aeruginosa, a clinically important pathogen, the rnd-type pump mexab-oprm has been recognized as one of the major multidrug efflux systems. here, homologues of mexab-oprm in the plant pathogens pseudomonas syringae pv. phaseolicola 1448a, p. syringae pv. syringae b728a, and p. syringae pv. tomato dc3000 were identified, and mexab-oprm-de ... | 2008 | 18390672 |
| conserved c-terminal motifs required for avirulence and suppression of cell death by phytophthora sojae effector avr1b. | the sequenced genomes of oomycete plant pathogens contain large superfamilies of effector proteins containing the protein translocation motif rxlr-deer. however, the contributions of these effectors to pathogenicity remain poorly understood. here, we show that the phytophthora sojae effector protein avr1b can contribute positively to virulence and can suppress programmed cell death (pcd) triggered by the mouse bax protein in yeast, soybean (glycine max), and nicotiana benthamiana cells. we ident ... | 2008 | 18390593 |
| jasmonate signaling: toward an integrated view. | 2008 | 18390489 | |
| a fungal-responsive mapk cascade regulates phytoalexin biosynthesis in arabidopsis. | plant recognition of pathogens leads to rapid activation of mpk3 and mpk6, two arabidopsis mitogen-activated protein kinases (mapks), and their orthologs in other species. here, we report that synthesis of camalexin, the major phytoalexin in arabidopsis, is regulated by the mpk3/mpk6 cascade. activation of mpk3/mpk6 by expression of active upstream mapk kinase (mapkk) or mapkk kinase (mapkkk) was sufficient to induce camalexin synthesis in the absence of pathogen attack. induction of camalexin b ... | 2008 | 18378893 |
| role of recombination in the evolution of the model plant pathogen pseudomonas syringae pv. tomato dc3000, a very atypical tomato strain. | pseudomonas syringae pv. tomato strain dc3000 (ptodc3000) is one of the most intensively studied bacterial plant pathogens today. here we report a thorough investigation into ptodc3000 and close relatives isolated from antirrhinum majus (snapdragon), apium graveolens (celery), and solanaceae and brassicaceae species. multilocus sequence typing (mlst) was used to resolve the precise phylogenetic relationship between isolates and to determine the importance of recombination in their evolution. mls ... | 2008 | 18378665 |
| the f-box protein acre189/acif1 regulates cell death and defense responses activated during pathogen recognition in tobacco and tomato. | virus-induced gene silencing identified the avr9/cf-9 rapidly elicited gene acre189 as essential for the cf-9- and cf-4-mediated hypersensitive response (hr) in nicotiana benthamiana. we report a role for acre189 in disease resistance in tomato (solanum lycopersicum) and tobacco (nicotiana tabacum). acre189 (herein renamed avr9/cf-9-induced f-box1 [acif1]) encodes an f-box protein with a leu-rich-repeat domain. acif1 is widely conserved and is closely related to f-box proteins regulating plant h ... | 2008 | 18375657 |
| riboswitches that sense s-adenosylhomocysteine and activate genes involved in coenzyme recycling. | we have identified a highly conserved rna motif that occurs upstream of genes involved in s-adenosyl-l-methionine (sam) recycling in many gram-positive and gram-negative species of bacteria. the phylogenetic distribution and the conserved structural features of representatives of this motif are indicative of riboswitch function. riboswitches are widespread metabolite-sensing gene control elements that are typically found in the 5' untranslated regions (utrs) of bacterial mrnas. we experimentally ... | 2008 | 18374645 |
| polymerizing the fibre between bacteria and host cells: the biogenesis of functional amyloid fibres. | amyloid fibres are proteinaceous aggregates associated with several human diseases, including alzheimer's, huntington's and creutzfeldt jakob's. disease-associated amyloid formation is the result of proteins that misfold and aggregate into beta sheet-rich fibre polymers. cellular toxicity is readily associated with amyloidogenesis, although the molecular mechanism of toxicity remains unknown. recently, a new class of 'functional' amyloid fibres was discovered that demonstrates that amyloids can ... | 2008 | 18373633 |
| locatep: genome-scale subcellular-location predictor for bacterial proteins. | in the past decades, various protein subcellular-location (scl) predictors have been developed. most of these predictors, like tmhmm 2.0, signalp 3.0, predisi and phobius, aim at the identification of one or a few scls, whereas others such as cello and psortb.v.2.0 aim at a broader classification. although these tools and pipelines can achieve a high precision in the accurate prediction of signal peptides and transmembrane helices, they have a much lower accuracy when other sequence characterist ... | 2008 | 18371216 |
| measuring cell-wall-based defenses and their effect on bacterial growth in arabidopsis. | plants are resistant to most potentially pathogenic microbes. frequently, resistance results from defenses activated upon recognition of "non-self." invasion of a variety of pathogens, including gram-negative bacteria, into plants is betrayed by the presence of pathogen-associated molecular patterns (pamps). plants challenged by a non-pathogenic bacterial strain or a purified pamp often form cell wall modifications called papillae. these cell wall thickenings, which can be observed in the electr ... | 2008 | 18370170 |
| impact of transcription units rearrangement on the evolution of the regulatory network of gamma-proteobacteria. | in the past years, several studies begun to unravel the structure, dynamical properties, and evolution of transcriptional regulatory networks. however, even those comparative studies that focus on a group of closely related organisms are limited by the rather scarce knowledge on regulatory interactions outside a few model organisms, such as e. coli among the prokaryotes. | 2008 | 18366643 |
| donor substrate recognition in the raffinose-bound e342a mutant of fructosyltransferase bacillus subtilis levansucrase. | fructans - beta-d-fructofuranosyl polymers with a sucrose starter unit - constitute a carbohydrate reservoir synthesised by a considerable number of bacteria and plant species. biosynthesis of levan (alphaglc(1-2)betafru [(2-6)betafru]n), an abundant form of bacterial fructan, is catalysed by levansucrase (sucrose:2,6-beta-d-fructan-6-beta-d-fructosyl transferase), utilizing sucrose as the sole substrate. previously, we described the tertiary structure of bacillus subtilis levansucrase in the li ... | 2008 | 18366639 |
| genome mapping and molecular breeding of tomato. | the cultivated tomato, lycopersicon esculentum, is the second most consumed vegetable worldwide and a well-studied crop species in terms of genetics, genomics, and breeding. it is one of the earliest crop plants for which a genetic linkage map was constructed, and currently there are several molecular maps based on crosses between the cultivated and various wild species of tomato. the high-density molecular map, developed based on an l. esculentum x l. pennellii cross, includes more than 2200 ma ... | 2007 | 18364989 |
| systems analysis of metabolism in the pathogenic trypanosomatid leishmania major. | systems analyses have facilitated the characterization of metabolic networks of several organisms. we have reconstructed the metabolic network of leishmania major, a poorly characterized organism that causes cutaneous leishmaniasis in mammalian hosts. this network reconstruction accounts for 560 genes, 1112 reactions, 1101 metabolites and 8 unique subcellular localizations. using a systems-based approach, we hypothesized a comprehensive set of lethal single and double gene deletions, some of whi ... | 2008 | 18364711 |
| characterization of the pvds-regulated promoter motif in pseudomonas syringae pv. tomato dc3000 reveals regulon members and insights regarding pvds function in other pseudomonads. | bacteria that survive under variable conditions possess an assortment of genetic regulators to meet these challenges. the group iv or extracytoplasmic function (ecf) sigma factors regulate gene expression in response to specific environmental signals by altering the promoter specificity of rna polymerase. we have undertaken a study of pvds, a group iv sigma factor encoded by pseudomonas syringae pv. tomato dc3000 (dc3000), a plant pathogen that is likely to encounter variations in nutrient avail ... | 2008 | 18363796 |
| ttsi regulates symbiotic genes in rhizobium species ngr234 by binding to tts boxes. | infection of legumes by rhizobium sp. ngr234 and subsequent development of nitrogen-fixing nodules are dependent on the coordinated actions of nod factors, proteins secreted by a type iii secretion system (t3ss) and modifications to surface polysaccharides. the production of these signal molecules is dependent on plant flavonoids which trigger a regulatory cascade controlled by the transcriptional activators nodd1, nodd2, syrm2 and ttsi. ttsi is known to control the genes responsible for t3ss fu ... | 2008 | 18363648 |
| a novel gene, phca from pseudomonas syringae induces programmed cell death in the filamentous fungus neurospora crassa. | the phytopathogen pseudomonas syringae competes with other epiphytic organisms, such as filamentous fungi, for resources. here we characterize a gene in p. syringae pv. syringae b728a and p. syringae pv. tomato dc3000, termed phca, that has homology to a filamentous fungal gene called het-c. phca is conserved in many p. syringae strains, but is absent in one of the major clades, which includes the p. syringae pathovar phaseolicola. in the filamentous fungus neurospora crassa, het-c regulates a c ... | 2008 | 18363647 |
| oxylipin signaling in plant stress responses. | 2008 | 18359852 | |
| differential generation of hydrogen peroxide upon exposure to zinc and cadmium in the hyperaccumulating plant species (sedum alfredii hance). | sedum alfredii hance has been identified as zinc (zn) and cadmium (cd) co-hyperaccumulator. in this paper the relationships of zn or cd hyperaccumulation to the generation and the role of h2o2 in sedum alfredii h. were examined. the results show that zn and cd contents in the shoots of sedum alfredii h. treated with 1000 micromol/l zn2+ and/or 200 micromol/l cd2+ increased linearly within 15 d. contents of total s, glutathione (gsh) and h2o2 in shoots also increased within 15 d, and then decreas ... | 2008 | 18357627 |
| cellulose synthesis in phytophthora infestans is required for normal appressorium formation and successful infection of potato. | cellulose, the important structural compound of cell walls, provides strength and rigidity to cells of numerous organisms. here, we functionally characterize four cellulose synthase genes (cesa) in the oomycete plant pathogen phytophthora infestans, the causal agent of potato (solanum tuberosum) late blight. three members of this new protein family contain pleckstrin homology domains and form a distinct phylogenetic group most closely related to the cellulose synthases of cyanobacteria. expressi ... | 2008 | 18349153 |
| lectr2, a ctr1-like protein kinase from tomato, plays a role in ethylene signalling, development and defence. | arabidopsis atctr1 is a raf-like protein kinase that interacts with etr1 and ers and negatively regulates ethylene responses. in tomato, several ctr1-like proteins could perform this role. we have characterized lectr2, which has similarity to atctr1 and also to edr1, a ctr1-like arabidopsis protein involved in defence and stress responses. protein-protein interactions between lectr2 and six tomato ethylene receptors indicated that lectr2 interacts preferentially with the subfamily i etr1-type et ... | 2008 | 18346193 |
| cold shock exoribonuclease r (vacb) is involved in aeromonas hydrophila pathogenesis. | in this study, we cloned and sequenced a virulence-associated gene (vacb) from a clinical isolate ssu of aeromonas hydrophila. we identified this gene based on our recently annotated genome sequence of the environmental isolate atcc 7966(t) of a. hydrophila and the vacb gene of shigella flexneri. the a. hydrophila vacb protein contained 798 amino acid residues, had a molecular mass of 90.5 kda, and exhibited an exoribonuclease (rnase r) activity. the rnase r of a. hydrophila was a cold-shock pro ... | 2008 | 18344363 |
| identification and onion pathogenicity of burkholderia cepacia complex isolates from the onion rhizosphere and onion field soil. | burkholderia cepacia complex strains are genetically related but phenotypically diverse organisms that are important opportunistic pathogens in patients with cystic fibrosis (cf,) as well as pathogens of onion and banana, colonizers of the rhizospheres of many plant species, and common inhabitants of bulk soil. genotypic identification and pathogenicity characterization were performed on b. cepacia complex isolates from the rhizosphere of onion and organic soils in michigan. a total of 3,798 put ... | 2008 | 18344334 |
| quality control of bacterial mrna decoding and decay. | studies in eukaryotes and prokaryotes have revealed that gene expression is not only controlled through altering the rate of transcription but also through varying rates of translation and mrna decay. indeed, the expression level of a protein is strongly affected by the steady state level of its mrna. rna decay can, along with transcription, play an important role in regulating gene expression by fine-tuning the steady state level of a given transcript and affecting its subsequent decoding durin ... | 2008 | 18342642 |
| atpase activity of recd is essential for growth of the antarctic pseudomonas syringae lz4w at low temperature. | recd is essential for growth at low temperature in the antarctic psychrotrophic bacterium pseudomonas syringae lz4w. to examine the essential nature of its activity, we analyzed wild-type and mutant recd proteins with substitutions of important residues in each of the seven conserved helicase motifs. the wild-type recd displayed dna-dependent atpase and helicase activity in vitro, with the ability to unwind short dna duplexes containing only 5' overhangs or forked ends. five of the mutant protei ... | 2008 | 18336576 |
| general detoxification and stress responses are mediated by oxidized lipids through tga transcription factors in arabidopsis. | 12-oxo-phytodienoic acid and several phytoprostanes are cyclopentenone oxylipins that are formed via the enzymatic jasmonate pathway and a nonenzymatic, free radical-catalyzed pathway, respectively. both types of cyclopentenone oxylipins induce the expression of genes related to detoxification, stress responses, and secondary metabolism, a profile clearly distinct from that of the cyclopentanone jasmonic acid. microarray analyses revealed that 60% of the induction by phytoprostanes and 30% of th ... | 2008 | 18334669 |
| pepper pectin methylesterase inhibitor protein capmei1 is required for antifungal activity, basal disease resistance and abiotic stress tolerance. | pectin is one of the main components of the plant cell wall that functions as the primary barrier against pathogens. among the extracellular pectinolytic enzymes, pectin methylesterase (pme) demethylesterifies pectin, which is secreted into the cell wall in a highly methylesterified form. here, we isolated and functionally characterized the pepper (capsicum annuum l.) gene capmei1, which encodes a pectin methylesterase inhibitor protein (pmei), in pepper leaves infected by xanthomonas campestris ... | 2008 | 18327607 |
| the type iii secretion system of xanthomonas fuscans subsp. fuscans is involved in the phyllosphere colonization process and in transmission to seeds of susceptible beans. | understanding the survival, multiplication, and transmission to seeds of plant pathogenic bacteria is central to study their pathogenesis. we hypothesized that the type iii secretion system (t3ss), encoded by hrp genes, could have a role in host colonization by plant pathogenic bacteria. the seed-borne pathogen xanthomonas fuscans subsp. fuscans causes common bacterial blight of bean (phaseolus vulgaris). directed mutagenesis in strain cfbp4834-r of x. fuscans subsp. fuscans and bacterial popula ... | 2008 | 18326683 |
| a survey of the pseudomonas syringae pv. tomato dc3000 type iii secretion system effector repertoire reveals several effectors that are deleterious when expressed in saccharomyces cerevisiae. | the injection of nearly 30 effector proteins by the type iii secretion system underlies the ability of pseudomonas syringae pv. tomato dc3000 to cause disease in tomato and other host plants. the search for effector functions is complicated by redundancy within the repertoire and by plant resistance (r)-gene sentinels, which may convert effector virulence activities into a monolithic defense response. on the premise that some effectors target universal eukaryotic processes and that yeast (saccha ... | 2008 | 18321194 |
| pathogenicity of pseudomonas syringae pv. tomato on tomato seedlings: phenotypic and gene expression analyses of the virulence function of coronatine. | bacterial speck disease, which is caused by pseudomonas syringae pv. tomato, is an economically important disease on tomato. in the present study, we show that p. syringae pv. tomato dc3000 is a pathogen of tomato seedlings, an aspect of pathogen biology that has not been previously investigated. this resulted in the development of a virulence assay on tomato seedlings that has several advantages over labor-intensive foliar assays, including a shorter growth and incubation period, ease of inocul ... | 2008 | 18321184 |
| a complete collection of single-gene deletion mutants of acinetobacter baylyi adp1. | we have constructed a collection of single-gene deletion mutants for all dispensable genes of the soil bacterium acinetobacter baylyi adp1. a total of 2594 deletion mutants were obtained, whereas 499 (16%) were not, and are therefore candidate essential genes for life on minimal medium. this essentiality data set is 88% consistent with the escherichia coli data set inferred from the keio mutant collection profiled for growth on minimal medium, while 80% of the orthologous genes described as esse ... | 2008 | 18319726 |
| cross talk in defense signaling. | 2008 | 18316638 | |
| new weapons and a rapid response against insect attack. | 2008 | 18316637 | |
| basic blue skies research in the uk: are we losing out? | the term blue skies research implies a freedom to carry out flexible, curiosity-driven research that leads to outcomes not envisaged at the outset. this research often challenges accepted thinking and introduces new fields of study. science policy in the uk has given growing support for short-term goal-oriented scientific research projects, with pressure being applied on researchers to demonstrate the future application of their work. these policies carry the risk of restricting freedom, curbing ... | 2008 | 18312612 |
| enterohemorrhagic escherichia coli exploits espa filaments for attachment to salad leaves. | enterohemorrhagic escherichia coli (ehec) strains are important food-borne pathogens that use a filamentous type iii secretion system (ft3ss) for colonization of the gut epithelium. in this study we have shown that ehec o157 and o26 strains use the ft3ss apparatus for attachment to leaves. leaf attachment was independent of effector protein translocation. | 2008 | 18310437 |
| leaf age as a risk factor in contamination of lettuce with escherichia coli o157:h7 and salmonella enterica. | outbreaks of escherichia coli o157:h7 infections have been linked increasingly to leafy greens, particularly to lettuce. we present here the first evidence that this enteric pathogen can multiply on the leaves of romaine lettuce plants. the increases in population size of e. coli o157:h7 in the phyllosphere of young lettuce plants ranged from 16- to 100-fold under conditions of warm temperature and the presence of free water on the leaves and varied significantly with leaf age. the population si ... | 2008 | 18310433 |
| differential regulation of root arginine catabolism and polyamine metabolism in clubroot-susceptible and partially resistant arabidopsis genotypes. | the hypertrophy and hyperplasia of infected roots into clubs are the intrinsic characteristics of clubroot, one of the economically most important diseases in brassica crops worldwide. polyamines, arginine (arg)-derived metabolites, have long been recognized as cell proliferation and differentiation regulators in plants and consequently are suitable candidates for potential gall development factors. furthermore, arg catabolism, through arginase, which is strongly connected to polyamine metabolis ... | 2008 | 18305204 |
| natural variation in arabidopsis thaliana as a tool for highlighting differential drought responses. | to test whether natural variation in arabidopsis could be used to dissect out the genetic basis of responses to drought stress, we characterised a number of accessions. most of the accessions belong to a core collection that was shown to maximise the genetic diversity captured for a given number of individual accessions in arabidopsis thaliana. we measured total leaf area (tla), electrolyte leakage (el), relative water content (rwc), and cut rosette water loss (crwl) in control and mild water de ... | 2008 | 18301780 |
| origin and evolution of gala-lrr, a new member of the cc-lrr subfamily: from plants to bacteria? | the phytopathogenic bacterium ralstonia solanacearum encodes type iii effectors, called gala proteins, which contain f-box and lrr domains. the gala lrrs do not perfectly fit any of the previously described lrr subfamilies. by applying protein sequence analysis and structural prediction, we clarify this ambiguous case of lrr classification and assign gala-lrrs to cc-lrr subfamily. we demonstrate that side-by-side packing of lrrs in the 3d structures may control the limits of repeat variability w ... | 2008 | 18301771 |
| role of soil, crop debris, and a plant pathogen in salmonella enterica contamination of tomato plants. | in the u.s., tomatoes have become the most implicated vehicle for produce-associated salmonellosis with 12 outbreaks since 1998. although unconfirmed, trace backs suggest pre-harvest contamination with salmonella enterica. routes of tomato crop contamination by s. enterica in the absence of direct artificial inoculation have not been investigated. | 2008 | 18301739 |
| calmodulin-binding transcription activator (camta) 3 mediates biotic defense responses in arabidopsis. | calmodulin-binding transcription activator (camta) 3 (also called sr1) is a calmodulin-binding transcription factor in arabidopsis. two homozygous t-dna insertion mutants (camta3-1, camta3-2) showed enhanced spontaneous lesions. transcriptome analysis of both mutants revealed 6 genes with attenuated expression and 99 genes with elevated expression. of the latter, 32 genes are related to defense against pathogens (e.g. wrky33, pr1 and chitinase). propagation of a virulent strain of the bacterial ... | 2008 | 18298954 |
| [composition, structure, and biological properties of lipopolysaccharides from different strains of pseudomonas syringae pv. atrofaciens]. | the composition, structure, and certain biological properties of lipopolysaccharides (lps) isolated from six strains of bacteria pseudomonas syringae pv. atrofaciens pathogenic for grain-crops (wheat, rye) are presented. the lps-protein complexes were isolated by a sparing procedure (extraction from microbial cells with a weak salt solution). they reacted with the homologous o sera and contained one to three antigenic determinants. against the cells of warm-blooded animals (mice, humans) they ex ... | 2007 | 18297868 |
| temporal gene expression profiling of the wheat leaf rust pathosystem using cdna microarray reveals differences in compatible and incompatible defence pathways. | in this study, we detail the construction of a custom cdna spotted microarray containing 7728 wheat ests and the use of the array to identify host genes that are differentially expressed upon challenges with leaf rust fungal pathogens. wheat cultivar rl6003 (thatcher lr1) was inoculated with puccinia triticina virulence phenotypes bbb (incompatible) or tjb (7-2) (compatible) and sampled at four different time points (3, 6, 12, and 24 hours) after inoculation. transcript expression levels relativ ... | 2007 | 18288238 |
| initial location of the rna-dependent rna polymerase in the bacteriophage phi6 procapsid determined by cryo-electron microscopy. | the rna-dependent rna polymerases (rdrps) of cystoviridae bacteriophages, like those of eukaryotic viruses of the reoviridae, function inside the inner capsid shell in both replication and transcription. in bacteriophage phi6, this inner shell is first assembled as an icosahedral procapsid with recessed 5-fold vertices that subsequently undergoes major structural changes during maturation. the tripartite genome is packaged as single-stranded rna molecules via channels on the 5-fold vertices, and ... | 2008 | 18287088 |
| quorum size of pseudomonas syringae is small and dictated by water availability on the leaf surface. | the paradigm of bacterial quorum sensing (qs), which mediates cell-density-dependent gene expression, usually has been studied in high-cell-density planktonic liquid cultures or in biofilms in which signal concentrations accumulate to sufficiently high levels to induce qs. presumably under conditions with restricted diffusion of the signal molecule, smaller population sizes could achieve such a state of qs induction. the plant-pathogenic bacterium pseudomonas syringae, in which qs controls trait ... | 2008 | 18287070 |
| comparative analysis of intestinal microbial community diversity between healthy and orally infected ducklings with salmonella enteritidis by eric-pcr. | to analyze the difference of intestinal microbial community diversity between healthy and (s. enteritidis) orally infected ducklings. | 2008 | 18286697 |
| interactions between cdsd, cdsq, and cdsl, three putative chlamydophila pneumoniae type iii secretion proteins. | chlamydophila pneumoniae is a gram-negative obligate intracellular bacterial pathogen that causes pneumonia and bronchitis and may contribute to atherosclerosis. the developmental cycle of c. pneumoniae includes a morphological transition from an infectious extracellular elementary body (eb) to a noninfectious intracellular reticulate body (rb) that divides by binary fission. the c. pneumoniae genome encodes a type iii secretion (t3s) apparatus that may be used to infect eukaryotic cells and to ... | 2008 | 18281400 |
| a place for thioether chemistry in cellular copper ion recognition and trafficking. | over the last decade, cysteine thiolate ligands have been shown to be critical to the cu(i) (cuprous) binding chemistry of many cytosolic metallochaperone and metalloregulatory proteins involved in copper physiology. more recently, the thioether group of methionine has begun to emerge as an important cu(i) ligand for trafficking proteins in more oxidizing cellular environments. | 2008 | 18277969 |
| chloroplastic protein nrip1 mediates innate immune receptor recognition of a viral effector. | plant innate immunity relies on the recognition of pathogen effector molecules by nucleotide-binding-leucine-rich repeat (nb-lrr) immune receptor families. previously we have shown the n immune receptor, a member of tir-nb-lrr family, indirectly recognizes the 50 kda helicase (p50) domain of tobacco mosaic virus (tmv) through its tir domain. we have identified an n receptor-interacting protein, nrip1, that directly interacts with both n's tir domain and p50. nrip1 is a functional rhodanese sulfu ... | 2008 | 18267075 |
| arabidopsis proteins important for modulating defense responses to pseudomonas syringae that secrete hopw1-1. | plant infection responses result from the interaction of pathogen-derived molecules with host components. for the bacterial pathogen pseudomonas syringae, these molecules are often effector proteins (hops) that are injected into plant cells. p. syringae carrying hopw1-1 have restricted host range on some arabidopsis thaliana accessions. at least two arabidopsis genomic regions are important for the natural variation that conditions resistance to p. syringae/hopw1-1. hopw1-1 elicits a resistance ... | 2008 | 18266921 |
| a lysm receptor-like kinase plays a critical role in chitin signaling and fungal resistance in arabidopsis. | chitin, a polymer of n-acetyl-d-glucosamine, is found in fungal cell walls but not in plants. plant cells can perceive chitin fragments (chitooligosaccharides) leading to gene induction and defense responses. we identified a lysm receptor-like protein (lysm rlk1) required for chitin signaling in arabidopsis thaliana. the mutation in this gene blocked the induction of almost all chitooligosaccharide-responsive genes and led to more susceptibility to fungal pathogens but had no effect on infection ... | 2008 | 18263776 |
| naturally occurring nonpathogenic isolates of the plant pathogen pseudomonas syringae lack a type iii secretion system and effector gene orthologues. | pseudomonas syringae causes plant diseases, and the main virulence mechanism is a type iii secretion system (t3ss) that translocates dozens of effector proteins into plant cells. here we report the existence of a subgroup of p. syringae isolates that do not cause disease on any plant species tested. this group is monophyletic and most likely evolved from a pathogenic p. syringae ancestor through loss of the t3ss. in the nonpathogenic isolate p. syringae 508 the genomic region that in pathogenic ... | 2008 | 18263729 |
| the hopz family of pseudomonas syringae type iii effectors require myristoylation for virulence and avirulence functions in arabidopsis thaliana. | pseudomonas syringae utilizes the type iii secretion system to translocate effector proteins into plant cells, where they can contribute to the pathogen's ability to infect and cause disease. recognition of these effectors by resistance proteins induces defense responses that typically include a programmed cell death reaction called the hypersensitive response. the yopj/hopz family of type iii effector proteins is a common family of effector proteins found in animal- and plant-pathogenic bacteri ... | 2008 | 18263728 |
| secretome analysis uncovers an hcp-family protein secreted via a type vi secretion system in agrobacterium tumefaciens. | agrobacterium tumefaciens is a plant-pathogenic bacterium capable of secreting several virulence factors into extracellular space or the host cell. in this study, we used shotgun proteomics analysis to investigate the secretome of a. tumefaciens, which resulted in identification of 12 proteins, including 1 known secretory protein (virb1*) and 11 potential secretory proteins. interestingly, one unknown protein, which we designated hemolysin-coregulated protein (hcp), is a predicted soluble protei ... | 2008 | 18263727 |
| lcrg secretion is not required for blocking of yops secretion in yersinia pestis. | lcrg, a negative regulator of the yersinia type iii secretion apparatus has been shown to be primarily a cytoplasmic protein, but is secreted at least in y. pestis. lcrg secretion has not been functionally analyzed and the relevance of lcrg secretion on lcrg function is unknown. | 2008 | 18261225 |