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a mutation in arabidopsis that leads to constitutive expression of systemic acquired resistance.systemic acquired resistance (sar) is a nonspecific defense response in plants that is associated with an increase in the endogenous level of salicylic acid (sa) and elevated expression of pathogenesis-related (pr) genes. to identify mutants involved in the regulation of pr genes and the onset of sar, we transformed arabidopsis with a reporter gene containing the promoter of a beta-1,3-glucanase-encoding pr gene (bgl2) and the coding region of beta-glucuronidase (gus). the resulting transgenic l ...19947866028
arabidopsis mutants compromised for the control of cellular damage during pathogenesis and aging.mutants of arabidopsis thaliana which exhibit accelerated cell death in response to pathogens were isolated and characterized to gain insight into how symptom severity and disease resistance are modulated. this paper describes mutants that fall into one of two complementation groups that were identified. a novel feature of these mutants is that they are unable to control the rate and extent of cell death after exposure to a variety of stimuli that induce senescence responses. thus, accelerated c ...19938220484
recognition of the avirulence gene avrb from pseudomonas syringae pv. glycinea by arabidopsis thaliana.the response of arabidopsis thaliana land race columbia to the bacterial pathogen pseudomonas syringae pv. maculicola 4326 harboring cloned avirulence genes avrb and avrc from p. syringae pv. glycinea and avra and avrd from p. syringae pv. tomato was examined. only avrb was recognized by columbia, as evidenced by attenuation of disease symptoms, slower bacterial multiplication in planta, and differentially greater induction of mrna for several defense-related genes. this contrasts with two a. th ...19938274772
isolation of arabidopsis genes that differentiate between resistance responses mediated by the rps2 and rpm1 disease resistance genes.the arabidopsis disease resistance gene rps2 is involved in recognition of bacterial pathogens carrying the avirulence gene avrrpt2, and the rpm1 resistance gene is involved in recognition of pathogens carrying avrrpm1 or avrb. we identified and cloned two arabidopsis genes, aig1 and aig2 (for avrrpt2-induced gene), that exhibit rps2- and avrrpt2-dependent induction early after infection with pseudomonas syringae pv maculicola strain es4326 carrying avrrpt2. however, es4326 carrying avrrpm1 or a ...19968742710
mode of action of the arabidopsis thaliana phytoalexin camalexin and its role in arabidopsis-pathogen interactions.the virulent arabidopsis thaliana pathogen pseudomonas syringae pv. maculicola strain es4326 (psm es4326) and other gram-negative bacteria are sensitive to camalexin (3-thiazol-2'-yl-indole), the arabidopsis phytoalexin. furthermore, psm es4326 is unable to degrade camalexin or to become tolerant to it. apparently, psm es4326 is a successful pathogen even though it elicits synthesis of a host phytoalexin to which it is sensitive. assays of membrane integrity revealed that, like other phytoalexin ...19968870273
pad4 functions upstream from salicylic acid to control defense responses in arabidopsis.the arabidopsis pad4 gene was previously shown to be required for synthesis of camalexin in response to infection by the virulent bacterial pathogen pseudomonas syringae pv maculicola es4326 but not in response to challenge by the non-host fungal pathogen cochliobolus carbonum. in this study, we show that pad4 mutants exhibit defects in defense responses, including camalexin synthesis and pathogenesis-related pr-1 gene expression, when infected by p. s. maculicola es4 326. no such defects were o ...19989634589
arabidopsis thaliana pad4 encodes a lipase-like gene that is important for salicylic acid signaling.the arabidopsis pad4 gene previously was found to be required for expression of multiple defense responses including camalexin synthesis and pr-1 gene expression in response to infection by the bacterial pathogen pseudomonas syringae pv. maculicola. this report describes the isolation of pad4. the predicted pad4 protein sequence displays similarity to triacyl glycerol lipases and other esterases. the pad4 transcript was found to accumulate after p. syringae infection or treatment with salicylic ...199910557364
virulence of the phytopathogen pseudomonas syringae pv. maculicola is rpon dependent.we cloned the rpon (ntra and glnf) gene encoding sigma(54) from the phytopathogen pseudomonas syringae pv. maculicola strain es4326. the p. syringae es4326 rpon gene complemented pseudomonas aeruginosa, escherichia coli, and klebsiella aerogenes rpon mutants for a variety of rpon mutant phenotypes, including the inability to utilize nitrate as sole nitrogen source. dna sequence analysis of the p. syringae es4326 rpon gene revealed that the deduced amino acid sequence was most similar (86% identi ...200010852883
the alternative sigma factor rpon is required for hrp activity in pseudomonas syringae pv. maculicola and acts at the level of hrpl transcription.beta-glucuronidase (uida) reporter gene fusions were constructed for the hrpz, hrpl, and hrps genes from the phytopathogen pseudomonas syringae pv. maculicola strain es4326. these reporters, as well as an avrrpt2-uida fusion, were used to measure transcriptional activity in es4326 and a es4326 rpon mutant. rpon was required for the expression of avrrpt2, hrpz, and hrpl in vitro in minimal media and in vivo when infiltrated into arabidopsis thaliana leaves. in contrast, the expression of hrps was ...200010852884
three unique mutants of arabidopsis identify eds loci required for limiting growth of a biotrophic fungal pathogen.to identify components of the defense response that limit growth of a biotrophic fungal pathogen, we isolated arabidopsis mutants with enhanced disease susceptibility to erysiphe orontii. our initial characterization focused on three mutants, eds14, eds15, and eds16. none of these is considerably more susceptible to a virulent strain of the bacterial pathogen pseudomonas syringae pv. maculicola (psm). all three mutants develop a hypersensitive response when infiltrated with psm expressing the av ...200011069695
a pathogen-responsive cdna from potato encodes a protein with homology to a phosphate starvation-induced phosphatase.infiltration of potato leaves with the phytopathogenic bacteria pseudomonas syringae pv. maculicola induces local and systemic defense gene expression as well as increased resistance against subsequent pathogen attacks. by cdna-aflp a gene was identified that is activated locally in potato leaves in response to bacterial infiltration and after infection with phytophthora infestans, the causal agent of late blight disease. the encoded protein has high homology to a phosphate starvation-induced ac ...200212354923
xopc and xopj, two novel type iii effector proteins from xanthomonas campestris pv. vesicatoria.pathogenicity of the gram-negative plant pathogen xanthomonas campestris pv. vesicatoria depends on a type iii secretion (tts) system which translocates bacterial effector proteins into the plant cell. previous transcriptome analysis identified a genome-wide regulon of putative virulence genes that are coexpressed with the tts system. in this study, we characterized two of these genes, xopc and xopj. both genes encode xanthomonas outer proteins (xops) that were shown to be secreted by the tts sy ...200314645268
nucleotide sequence and evolution of the five-plasmid complement of the phytopathogen pseudomonas syringae pv. maculicola es4326.plasmids are transmissible, extrachromosomal genetic elements that are often responsible for environmental or host-specific adaptations. in order to identify the forces driving the evolution of these important molecules, we determined the complete nucleotide sequence of the five-plasmid complement of the radish and arabidopsis pathogen pseudomonas syringae pv. maculicola es4326 and conducted an intraspecific comparative genomic analysis. to date, this is the most complex fully sequenced plasmid ...200415262947
arabidopsis rin4 negatively regulates disease resistance mediated by rps2 and rpm1 downstream or independent of the ndr1 signal modulator and is not required for the virulence functions of bacterial type iii effectors avrrpt2 or avrrpm1.bacterial pathogens deliver type iii effector proteins into the plant cell during infection. on susceptible (r) hosts, type iii effectors can contribute to virulence. some trigger the action of specific disease resistance (r) gene products. the activation of r proteins can occur indirectly via modification of a host target. thus, at least some type iii effectors are recognized at site(s) where they may act as virulence factors. these data indicate that a type iii effector's host target might be ...200415361584
involvement of the small gtpase rac in the defense responses of tobacco to pathogens.during the hypersensitive response (hr), plants accumulate reactive oxygen species (ros) that are likely generated at least in part by an nadph oxidase similar to that found in mammalian neutrophils. an essential regulator of mammalian nadph oxidase is the small gtp-binding protein rac. to investigate whether rac also regulates the pathogen-induced oxidative burst in plants, a dominant negative form of the rice osrac1 gene was overexpressed in tobacco carrying the n resistance gene. following in ...200515720080
arabidopsis ssi2-conferred susceptibility to botrytis cinerea is dependent on eds5 and pad4.loss of a stearoyl-acp desaturase activity in the arabidopsis thaliana ssi2 mutant confers susceptibility to the necrotroph, botrytis cinerea. in contrast, the ssi2 mutant exhibits enhanced resistance to pseudomonas syringae, peronospora parasitica, and cucumber mosaic virus. the altered basal resistance to these pathogens in the ssi2 mutant plant is accompanied by the constitutive accumulation of elevated salicylic acid (sa) level and expression of the pathogenesis-related 1 (pr1) gene, the ina ...200515828688
nitrite as the major source of nitric oxide production by arabidopsis thaliana in response to pseudomonas syringae.the origin of nitric oxide (*no) in plants is unclear and an *no synthase (nos)-like enzyme and nitrate reductase (nr) are claimed as potential sources. here we used wild-type and nr-defective double mutant plants to investigate *no production in arabidopsis thaliana in response to pseudomonas syringae pv maculicola. nos activity increased substantially in leaves inoculated with p. syringae. however, electron paramagnetic resonance experiments showed a much higher *no formation that was dependen ...200515978583
molecular and physiological characterization of pseudomonas syringae pv. tomato and pseudomonas syringae pv. maculicola strains that produce the phytotoxin coronatine.the chlorosis-inducing phytotoxin coronatine is produced by several pseudomonas syringae pathovars, including glycinea, morsprunorum, atropurpurea, and the closely related tomato and maculicola. to date, all coronatine-producing pv. glycinea, morsprunorum, and atropurpurea strains that have been examined carry the gene cluster that controls toxin production on a large plasmid. in the present study the genomic location of the coronatine gene cluster was determined for coronatine-producing strains ...199516535140
a putative nucleoporin 96 is required for both basal defense and constitutive resistance responses mediated by suppressor of npr1-1,constitutive 1.the arabidopsis thaliana suppressor of npr1-1, constitutive 1 (snc1) mutant contains a gain-of-function mutation in a toll interleukin1 receptor-nucleotide binding-leu-rich repeat-type resistance gene (r-gene), which leads to constitutive activation of disease resistance response against pathogens. in a screen for suppressors of snc1, a recessive mutation, designated mos3 (for modifier of snc1,3), was found to suppress the constitutive pathogenesis-related gene expression and resistance to virul ...200515772285
[chemical and biological characterization of lipopolysaccharides from the pseudomonas syringae pv. maculicola imv 381 collection culture and its dissociants].lipopolysaccharides (lps) were isolated from the crude bacterial mass of the pseudomonas syringae pv. maculicola imv 381 collection culture and its virulent and avirulent subcultures isolated earlier from the heterogeneous collection culture due to its natural variability during long-term storage. the composition, immunochemical properties, and certain parameters of the biological activity of the lps preparations obtained were studied. the structural parts of the lps macromolecule--lipid a, the ...200415688938
extracellular pyridine nucleotides induce pr gene expression and disease resistance in arabidopsis.although it is well known that the pyridine nucleotides nad and nadp function inside the cell to regulate intracellular signaling processes, recent evidence from animal studies suggests that nad(p) also functions in the extracellular compartment (ecc). extracellular nad(p) [enad(p)] can either directly bind to plasma membrane receptors or be metabolized by ecto-enzymes to produce cyclic adp-ribose and nicotinic acid adenine dinucleotide phosphate, and/or may adp-ribosylate cell-surface receptors ...200918798871
light conditions influence specific defence responses in incompatible plant-pathogen interactions: uncoupling systemic resistance from salicylic acid and pr-1 accumulation.in incompatible plant-pathogen interactions, disease resistance is generated by rapid activation of a multitude of plant defence reactions. little is known about the dependency of these resistance responses on external factors. the plasticity of plant defence mechanisms in terms of light conditions is studied here. interaction of arabidopsis thaliana (l.) heynh. with an avirulent strain of pseudomonas syringae pv. maculicola in the dark resulted in increased apoplastic bacterial growth and there ...200415098125
the arabidopsis thaliana dihydroxyacetone phosphate reductase gene suppresssor of fatty acid desaturase deficiency1 is required for glycerolipid metabolism and for the activation of systemic acquired resistance.systemic acquired resistance (sar) is a broad-spectrum resistance mechanism in plants that is activated in naive organs after exposure of another organ to a necrotizing pathogen. the organs manifesting sar exhibit an increase in levels of salicylic acid (sa) and expression of the pathogenesis-related1 (pr1) gene. sa signaling is required for the manifestation of sar. we demonstrate here that the arabidopsis thaliana suppressor of fatty acid desaturase deficiency1 (sfd1) mutation compromises the ...200414729910
a gain-of-function mutation in a plant disease resistance gene leads to constitutive activation of downstream signal transduction pathways in suppressor of npr1-1, constitutive 1.plants have evolved sophisticated defense mechanisms against pathogen infections, during which resistance (r) genes play central roles in recognizing pathogens and initiating defense cascades. most of the cloned r genes share two common domains: the central domain, which encodes a nucleotide binding adaptor shared by apaf-1, certain r proteins, and ced-4 (nb-arc), plus a c-terminal region that encodes leu-rich repeats (lrr). in arabidopsis, a dominant mutant, suppressor of npr1-1, constitutive 1 ...200314576290
arabidopsis sfd mutants affect plastidic lipid composition and suppress dwarfing, cell death, and the enhanced disease resistance phenotypes resulting from the deficiency of a fatty acid desaturase.a loss-of-function mutation in the arabidopsis ssi2/fab2 gene, which encodes a plastidic stearoyl-acyl-carrier protein desaturase, has pleiotropic effects. the ssi2 mutant plant is dwarf, spontaneously develops lesions containing dead cells, accumulates increased salicylic acid (sa) levels, and constitutively expresses sa-mediated, npr1-dependent and -independent defense responses. in parallel, jasmonic acid-regulated signaling is compromised in the ssi2 mutant. in an effort to discern the invol ...200314507997
the pattern of systemic acquired resistance induction within the arabidopsis rosette in relation to the pattern of translocation.local leaf infections by a necrogenic pathogen can lead to systemic acquired resistance (sar) in untreated leaves. we reasoned that, whatever the nature of the long-distance signal, if it is transported in the phloem, the pattern of sar induced within the plant by treatment of a single leaf should match the pattern of translocation out of that leaf. the source-sink relationships (orthostichies) in the arabidopsis rosette were established with [14c]suc or phloem-mobile 3-aminotriazole at herbicid ...200312805614
nucleotide sequence, functional characterization and evolution of pfkn, a virulence plasmid in pseudomonas syringae pathovar maculicola.pseudomonas syringae pv. maculicola strain m6 (psm m6) carries the avrrpm1 gene, encoding a type iii effector, on a 40 kb plasmid, pfkn. we hypothesized that this plasmid might carry additional genes required for pathogenesis on plants. we report the sequence and features of pfkn. in addition to avrrpm1, pfkn carries an allele of another type iii effector, termed avrpphe, and a gene of unknown function (orf8), expression of which is induced in planta, suggesting a role in the plant-pathogen inte ...200312622811
[some characteristics of pseudomonas syringae pv. maculicola dissociants].pseudomonas syringae pv. maculicola dissociants producing colonies of different morphotype were found to possess similar biochemical and serological properties but different virulence to the host plant. the heterogeneous extracellular and intracellular lipopolysaccharide-protein complexes of the dissociants differed in their chemical composition and biological activity towards test plants.200212024826
lignification induced by pseudomonads harboring avirulent genes on arabidopsis.the responses of arabidopsis thaliana ecotypes to the bacterial pathogen pseudomonas syringae pv. maculicola 4326 (psm4326) harboring cloned avirulence genes avrb and avrrpt2 from p. syringae pv. glycinea were examined. psm4326 containing avirulent genes, avrb and avrrpt2 induced lignification and peroxidase activities in the bacteria infiltrated leaves of col-o only and not in mt-o, bla-2 and po-1. however, arabidopsis ecotypes infiltrated with psm4326 harboring with and without avirulent genes ...200111561727
metal hyperaccumulation armors plants against disease.metal hyperaccumulation, in which plants store exceptional concentrations of metals in their shoots, is an unusual trait whose evolutionary and ecological significance has prompted extensive debate. hyperaccumulator plants are usually found on metalliferous soils, and it has been proposed that hyperaccumulation provides a defense against herbivores and pathogens, an idea termed the 'elemental defense' hypothesis. we have investigated this hypothesis using the crucifer thlaspi caerulescens, a hyp ...201020838462
a high-throughput method for isolation of salicylic acid metabolic mutants.abstract:201020863393
the role for the exocyst complex subunits exo70b2 and exo70h1 in the plant-pathogen interaction.recently, the octameric vesicle-tethering complex exocyst was found in plants and its importance for arabidopsis morphogenesis was demonstrated. exo70 exocyst subunits in plants, unlike in yeasts and mammals, are represented by a multigene family, comprising 23 members in arabidopsis. for exo70b2 and exo70h1 paralogues, transcriptional up-regulation was confirmed on treatment with an elicitor peptide, elf18, derived from the bacterial elongation factor. their ability to participate in the exocys ...201121199889
arabidopsis dth9 mutation identifies a gene involved in regulating disease susceptibility without affecting salicylic acid-dependent responses.to determine which components of the plant defense response make important contributions to limiting pathogen attack, an m(2) mutagenized population of a transgenic arabidopsis line was screened for mutants showing constitutive expression of beta-glucuronidase activity driven by the promoter region of the cevi-1 gene. the cevi-1 gene originally was isolated from tomato plants and has been shown to be induced in susceptible varieties of tomato plants by virus infection in a salicylic acid-indepen ...200011090213
arabidopsis thaliana eds4 contributes to salicylic acid (sa)-dependent expression of defense responses: evidence for inhibition of jasmonic acid signaling by sa.the arabidopsis enhanced disease susceptibility 4 (eds4) mutation causes enhanced susceptibility to infection by the bacterial pathogen pseudomonas syringae pv. maculicola es4326 (psm es4326). gene-for-gene resistance to bacteria carrying the avirulence gene avrrpt2 is not significantly affected by eds4. plants homozygous for eds4 exhibit reduced expression of the pathogenesis-related gene pr-1 after infection by psm es4326, weakened responses to treatment with the signal molecule salicylic acid ...200010796016
camalexin accumulation in arabis lyrata.inoculation of leaves of arabis lyrata with either a bacterial pathogen pseudomonas syringae pv. maculicola strain es4326 or cochliobolus carbonum, a fungal nonpathogen of a. lyrata, resulted in the accumulation of a compound with similar chromatographic and fluorescent properties to that of camalexin (i), a phytoalexin produced by arabidopsis thaliana. a. lyrata is closely related to a. thaliana. high resolution electron impact mass spectroscopic and proton nmr analysis confirmed that the compo ...19989887527
isolation of new arabidopsis mutants with enhanced disease susceptibility to pseudomonas syringae by direct screening.to identify plant defense components that are important in restricting the growth of virulent pathogens, we screened for arabidopsis mutants in the accession columbia (carrying the transgene bgl2-gus) that display enhanced disease susceptibility to the virulent bacterial pathogen pseudomonas syringae pv. maculicola (psm) es4326. among six (out of a total of 11 isolated) enhanced disease susceptibility (eds) mutants that were studied in detail, we identified one allele of the previously described ...19989611172
uncoupling pr gene expression from npr1 and bacterial resistance: characterization of the dominant arabidopsis cpr6-1 mutant.in arabidopsis, npr1 mediates the salicylic acid (sa)-induced expression of pathogenesis-related (pr) genes and systemic acquired resistance (sar). here, we report the identification of another component, cpr 6, that may function with npr1 in regulating pr gene expression. the dominant cpr 6-1 mutant expresses the sa/npr1-regulated pr genes (pr-1, bgl 2, and pr-5) and displays enhanced resistance to pseudomonas syringae pv maculicola es4326 and peronospora parasitica noco2 in the absence of sar ...19989548982
the cpr5 mutant of arabidopsis expresses both npr1-dependent and npr1-independent resistance.the cpr5 mutant was identified from a screen for constitutive expression of systemic acquired resistance (sar). this single recessive mutation also leads to spontaneous expression of chlorotic lesions and reduced trichome development. the cpr5 plants were found to be constitutively resistant to two virulent pathogens, pseudomonas syringae pv maculicola es4326 and peronospora parasitica noco2; to have endogenous expression of the pathogenesis-related gene 1 (pr-1); and to have an elevated level o ...19979338960
phytoalexin-deficient mutants of arabidopsis reveal that pad4 encodes a regulatory factor and that four pad genes contribute to downy mildew resistance.we are working to determine the role of the arabidopsis phytoalexin, camalexin, in protecting the plant from pathogen attack by isolating phytoalexin-deficient (pad) mutants in the accession columbia (col-0) and examining their response to pathogens. mutations in pad1, pad2, and pad4 caused enhanced susceptibility to the bacterial pathogen pseudomonas syringae pv. maculicola strain es4326 (psmes4326), while mutations in pad3 or pad5 did not. camalexin was not detected in any of the double mutant ...19979136026
arabidopsis enhanced disease susceptibility mutants exhibit enhanced susceptibility to several bacterial pathogens and alterations in pr-1 gene expression.to identify plant defense responses that limit pathogen attack, arabidopsis eds mutants that exhibit enhanced disease susceptibility to the virulent bacterial pathogen pseudomonas syringae pv maculicola es4326 were previously identified. in this study, we show that each of four eds mutants (eds5-1, eds6-1, eds7-1, and eds9-1) has a distinguishable phenotype with respect to the degree of susceptibility to a panel of bacterial phytopathogens and the ability to activate pathogenesis-related pr-1 ge ...19979090877
isolation of arabidopsis mutants with enhanced disease susceptibility by direct screening.to discover which components of plant defense responses make significant contributions to limiting pathogen attack, we screened a mutagenized population of arabidopsis thaliana for individuals that exhibit increased susceptibility to the moderately virulent bacterial pathogen pseudomonas syringae pv. maculicola es4326 (psm es4326). the 12 enhanced disease susceptibility (eds) mutants isolated included alleles of two genes involved in phytoalexin biosynthesis (pad2, which had been identified prev ...19968725243
the avrrpm1 gene of pseudomonas syringae pv. maculicola is required for virulence on arabidopsis.we demonstrate that the avirulence gene avrrpm1, isolated from pseudomonas syringae pv. maculicola strain psm m2 via interaction with the arabidopsis resistance gene rpm1, is also required for maximal virulence on this host. two avrrpm1::tn3-spice marker-exchange mutants do not elicit a hypersensitive reaction on rpm1-containing arabidopsis accessions col-0 and oy-0. surprisingly, these mutants neither generate disease symptoms, nor grow in planta, after inoculation onto susceptible accessions n ...19957655064
the arabidopsis thaliana 4-coumarate:coa ligase (4cl) gene: stress and developmentally regulated expression and nucleotide sequence of its cdna.an arabidopsis cdna clone encoding 4-coumarate:coa ligase (4cl), a key enzyme of phenylpropanoid metabolism, was identified and sequenced. the predicted amino acid sequence is similar to those of other cloned 4cl genes. southern blot analysis indicated that 4cl is single-copy gene in arabidopsis. northern blots showed that 4cl expression was activated early during seedling development. the onset of 4cl expression was correlated with the onset of lignin deposition in cotyledons and roots 2-3 days ...19957640359
constitutive activation of jasmonate signaling in an arabidopsis mutant correlates with enhanced resistance to erysiphe cichoracearum, pseudomonas syringae, and myzus persicae.in arabidopsis spp., the jasmonate (ja) response pathway generally is required for defenses against necrotrophic pathogens and chewing insects, while the salicylic acid (sa) response pathway is generally required for specific, resistance (r) gene-mediated defenses against both biotrophic and necrotrophic pathogens. for example, sa-dependent defenses are required for resistance to the biotrophic fungal pathogen erysiphe cichoracearum ucsc1 and the bacterial pathogen pseudomonas syringae pv. macul ...200212437300
oxylipin profiling in pathogen-infected potato leaves.plants respond to pathogen attack with a multicomponent defense response. synthesis of oxylipins via the lipoxygenase (lox) pathway appears to be an important factor for establishment of resistance in a number of pathosystems. in potato cells, pathogen-derived elicitors preferentially stimulate the 9-lox-dependent metabolism of polyunsaturated fatty acids (pufas). here we show by oxylipin profiling that potato plants react to pathogen infection with increases in the amounts of the 9-lox-derived ...200212213493
the arabidopsis flavin-dependent monooxygenase fmo1 is an essential component of biologically induced systemic acquired resistance.upon localized attack by necrotizing pathogens, plants gradually develop increased resistance against subsequent infections at the whole-plant level, a phenomenon known as systemic acquired resistance (sar). to identify genes involved in the establishment of sar, we pursued a strategy that combined gene expression information from microarray data with pathological characterization of selected arabidopsis (arabidopsis thaliana) t-dna insertion lines. a gene that is up-regulated in arabidopsis lea ...200616778014
systemic acquired resistance in canola is linked with pathogenesis-related gene expression and requires salicylic acid.abstract systemic acquired resistance (sar) is an induced defense response that confers long-lasting protection against a broad range of microbial pathogens. here we show that treatment of brassica napus plants with the sar-inducing chemical benzo-(1,2,3)-thiadiazole-7-carbothioic acid s-methyl ester (bth) significantly enhanced resistance against virulent strains of the bacterial pathogen pseudomonas syringae pv. maculicola and the fungal pathogen leptosphaeria maculans. localized preinoculatio ...200718943928
characterization of arabidopsis 6-phosphogluconolactonase t-dna insertion mutants reveals an essential role for the oxidative section of the plastidic pentose phosphate pathway in plant growth and development.arabidopsis pgl1, pgl2, pgl4 and pgl5 are predicted to encode cytosolic isoforms of 6-phosphogluconolactonase (6pgl), whereas pgl3 is predicted to encode a 6pgl that has been shown to localize in both plastids and peroxisomes. therefore, 6pgl may exist in the cytosol, plastids and peroxisomes. however, the function of 6pgl in these three subcellular locations has not been well defined. here we show that pgl3 is essential, whereas pgl1, pgl2 and pgl5 are individually dispensable for plant growth ...200919457984
simulation of fungal-mediated cell death by fumonisin b1 and selection of fumonisin b1-resistant (fbr) arabidopsis mutants.fumonisin b1 (fb1), a programmed cell death-eliciting toxin produced by the necrotrophic fungal plant pathogen fusarium moniliforme, was used to simulate pathogen infection in arabidopsis. plants infiltrated with 10 microm fb1 and seedlings transferred to agar media containing 1 microm fb1 develop lesions reminiscent of the hypersensitive response, including generation of reactive oxygen intermediates, deposition of phenolic compounds and callose, accumulation of phytoalexin, and expression of p ...200011041878
overexpression of arabidopsis map kinase kinase 7 leads to activation of plant basal and systemic acquired resistance.there is a growing body of evidence indicating that mitogen-activated protein kinase (mapk) cascades are involved in plant defense responses. analysis of the completed arabidopsis thaliana genome sequence has revealed the existence of 20 mapks, 10 mapkks and 60 mapkkks, implying a high level of complexity in mapk signaling pathways, and making the assignment of gene functions difficult. the map kinase kinase 7 (mkk7) gene of arabidopsis has previously been shown to negatively regulate polar auxi ...200717908155
the genetic network controlling the arabidopsis transcriptional response to pseudomonas syringae pv. maculicola: roles of major regulators and the phytotoxin coronatine.expression profiling of wild-type plants and mutants with defects in key components of the defense signaling network was used to model the arabidopsis network 24 h after infection by pseudomonas syringae pv. maculicola es4326. results using the affymetrix ath1 array revealed that expression levels of most pathogen-responsive genes were affected by mutations in coi1, ein2, npr1, pad4, or sid2. these five mutations defined a small number of different expression patterns displayed by the majority o ...200818842091
compost and compost water extract-induced systemic acquired resistance in cucumber and arabidopsis.abstract a biocontrol agent-fortified compost mix, suppressive to several diseases caused by soilborne plant pathogens, induced systemic acquired resistance (sar) in cucumber against anthracnose caused by colletotrichum orbiculare and in arabidopsis against bacterial speck caused by pseudomonas syringae pv. maculicola kd4326. a peat mix conducive to soilborne diseases did not induce sar. the population size of p. syringae pv. maculicola kd4326 was significantly lower in leaves of arabidopsis pla ...199818944926
combining subproteome enrichment and rubisco depletion enables identification of low abundance proteins differentially regulated during plant defense.transgenic arabidopsis conditionally expressing the bacterial avrrpm1 type iii effector under the control of a dexamethasone-responsive promoter were used for proteomics studies. this model system permits study of an individual effector without interference from additional bacterial components. coupling of different prefractionation approaches to high resolution 2-de facilitated the discovery of low abundance proteins - enabling the identification of proteins that have escaped detection in simil ...200919053141
pseudomonas cannabina pv. cannabina pv. nov., and pseudomonas cannabina pv. alisalensis (cintas koike and bull, 2000) comb. nov., are members of the emended species pseudomonas cannabina (ex sutic & dowson 1959) gardan, shafik, belouin, brosch, grimont & grimont 1999.sequence similarity in the 16s rdna gene confirmed that crucifer pathogen pseudomonas syringae pv. alisalensis belongs to p. syringae sensu lato. in reciprocal dna/dna hybridization experiments, dna relatedness was high (69-100%) between p. syringae pv. alisalensis strains and the type strain of p. cannabina (genomospecies 9). in contrast, dna relatedness was low (below 48%) between p. syringae pv. alisalensis and reference strains from the remaining genomospecies of p. syringae including the ty ...201020227217
cbp60g and sard1 play partially redundant, critical roles in salicylic acid signaling.the arabidopsis thaliana calmodulin binding protein 60 g (cbp60g) contributes to production of salicylic acid (sa) in response to recognition of microbe associated molecular patterns (mamps) such as flg22, a fragment of bacterial flagellin. calmodulin (cam) binding is required for the functions of cbp60g in limiting growth of the bacterial pathogen pseudomonas syringae pv. maculicola (pma) es4326 and in activation of sa synthesis. here, we describe a closely-related protein, sard1. unlike cbp60g ...201121615571
arabidopsis harmless to ozone layer protein methylates a glucosinolate breakdown product and functions in resistance to pseudomonas syringae pv. maculicola.almost all of the chlorine-containing gas emitted from natural sources is methyl chloride (ch(3)cl), which contributes to the destruction of the stratospheric ozone layer. tropical and subtropical plants emit substantial amounts of ch(3)cl. a gene involved in ch(3)cl emission from arabidopsis was previously identified and designated harmless to ozone layer (hereafter athol1) based on the mutant phenotype. our previous studies demonstrated that athol1 and its homologs, athol2 and athol3, have s-a ...200919419967
primary structure and tissue-specific expression of the pathogenesis-related protein pr-1b in potatodagger.summary the infection of potato (solanum tuberosum) leaves with the late blight pathogen phytophthora infestans, or treatment with fungal elicitor, leads to the massive accumulation of pathogenesis-related (pr) proteins in the extracellular leaf space. the most abundant of these proteins was purified to apparent homogeneity and identified as a new, basic member of the pr-1 family of defence proteins, designated pr-1b. antibodies raised against the protein and a cdna isolated by differential scre ...200220569341
vitis vinifera vvnpr1.1 is the functional ortholog of atnpr1 and its overexpression in grapevine triggers constitutive activation of pr genes and enhanced resistance to powdery mildew.studying grapevine (vitis vinifera) innate defense mechanisms is a prerequisite to the development of new protection strategies, based on the stimulation of plant signaling pathways to trigger pathogen resistance. two transcriptional coactivators (vvnpr1.1 and vvnpr1.2) with similarity to arabidopsis thaliana npr1 (non-expressor of pr genes 1), a well-characterized and key signaling element of the salicylic acid (sa) pathway, were recently isolated in vitis vinifera. in this study, functional ch ...201121505863
parallel loss-of-function at the rpm1 bacterial resistance locus in arabidopsis thaliana.dimorphism at the resistance to pseudomonas syringae pv. maculicola 1 (rpm1) locus is well documented in natural populations of arabidopsis thaliana and has been portrayed as a long-term balanced polymorphism. the haplotype from resistant plants contains the rpm1 gene, which enables these plants to recognize at least two structurally unrelated bacterial effector proteins (avrb and avrrpm1) from bacterial crop pathogens. a complete deletion of the rpm1 coding sequence has been interpreted as a si ...201223272006
plant intracellular innate immune receptor resistance to pseudomonas syringae pv. maculicola 1 (rpm1) is activated at, and functions on, the plasma membrane.plants deploy intracellular innate immune receptors to recognize pathogens and initiate disease resistance. these nucleotide-binding, leucine-rich repeat (nb-lrr) proteins are activated by pathogen effector proteins that are delivered into the host cell to suppress host defense responses. little is known about the sites and mechanisms of nb-lrr activation, but some nb-lrr proteins can function inside the plant nucleus. we demonstrate that rpm1 is activated on the plasma membrane and does not rel ...201121490299
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