Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| the pseudomonas syringae avrrpt2 gene product promotes pathogen virulence from inside plant cells. | several bacterial avr genes have been shown to contribute to virulence on susceptible plants lacking the corresponding resistance (r) gene. the mechanisms by which avr genes promote parasitism and disease, however, are not well understood. we investigated the role of the pseudomonas syringae pv. tomato avrrpt2 gene in pathogenesis by studying the interaction of p. syringae pv. tomato strain pstdc3000 expressing avrrpt2 with several arabidopsis thaliana lines lacking the corresponding r gene, rps ... | 2000 | 11106023 |
| elicitation of hypersensitive cell death by extracellularly targeted hrpzpsph produced in planta. | the ability of the pseudomonas syringae pv. phaseolicola harpin (hrpzpsph) to elicit hypersensitive response was investigated in three nicotiana genotypes. the hrpzpsph gene was placed under chemical regulation (tetracycline induction) in tetr+ nicotiana tabacum cv. wisconsin 38 (w38) or was transiently expressed in n. benthamiana following infection with a pvx-derived vector and in three nicotiana genotypes by agroinfiltration. the constructs were designed to express either the canonical form o ... | 2000 | 11106029 |
| signal recognition and transduction mediated by the tomato pto kinase: a paradigm of innate immunity in plants. | plant disease resistance is the result of an innate host defense mechanism, which relies on the ability of the plant to recognize pathogen invasion and to efficiently mount defense responses. in tomato, resistance to the pathogen pseudomonas syringae is mediated by the specific interaction between the plant serine/threonine kinase pto and the bacterial protein avrpto. this article reviews molecular and biochemical properties that confer to pto the capability to function as an intracellular recep ... | 2000 | 11113378 |
| negative regulation of defense responses in plants by a conserved mapkk kinase. | the enhanced disease resistance 1 (edr1) mutation of arabidopsis confers resistance to powdery mildew disease caused by the fungus erysiphe cichoracearum. resistance mediated by the edr1 mutation is correlated with induction of several defense responses, including host cell death. double mutant analysis revealed that all edr1-associated phenotypes are suppressed by mutations that block salicylic acid (sa) perception (nim1) or reduce sa production (pad4 and eds1). the nahg transgene, which lowers ... | 2001 | 11114160 |
| negative regulation of defense responses in plants by a conserved mapkk kinase. | the enhanced disease resistance 1 (edr1) mutation of arabidopsis confers resistance to powdery mildew disease caused by the fungus erysiphe cichoracearum. resistance mediated by the edr1 mutation is correlated with induction of several defense responses, including host cell death. double mutant analysis revealed that all edr1-associated phenotypes are suppressed by mutations that block salicylic acid (sa) perception (nim1) or reduce sa production (pad4 and eds1). the nahg transgene, which lowers ... | 2001 | 11114160 |
| phzo, a gene for biosynthesis of 2-hydroxylated phenazine compounds in pseudomonas aureofaciens 30-84. | certain strains of root-colonizing fluorescent pseudomonas spp. produce phenazines, a class of antifungal metabolites that can provide protection against various soilborne root pathogens. despite the fact that the phenazine biosynthetic locus is highly conserved among fluorescent pseudomonas spp., individual strains differ in the range of phenazine compounds they produce. this study focuses on the ability of pseudomonas aureofaciens 30-84 to produce 2-hydroxyphenazine-1-carboxylic acid (2-oh-pca ... | 2001 | 11114932 |
| fatty acid ketodienes and fatty acid ketotrienes: michael addition acceptors that accumulate in wounded and diseased arabidopsis leaves. | physical damage and disease are known to lead to changes in the oxylipin signature of plants. we searched for oxylipins produced in response to both wounding and pathogenesis in arabidopsis leaves. linoleic acid 9- and 13-ketodienes (kodes) were found to accumulate in wounded leaves as well as in leaves infected with the pathogen pseudomonas syringae pv. tomato (pst). quantification of the compounds showed that they accumulated to higher levels during the hypersensitive response to pst avrrpm1 t ... | 2000 | 11115128 |
| pathogenesis of the human opportunistic pathogen pseudomonas aeruginosa pa14 in arabidopsis. | the human opportunistic pathogen pseudomonas aeruginosa strain pa14 is a multihost pathogen that can infect arabidopsis. we found that pa14 pathogenesis in arabidopsis involves the following steps: attachment to the leaf surface, congregation of bacteria at and invasion through stomata or wounds, colonization of intercellular spaces, and concomitant disruption of plant cell wall and membrane structures, basipetal movement along the vascular parenchyma, and maceration and rotting of the petiole a ... | 2000 | 11115892 |
| defence gene expression in soybean is linked to the status of the cell death program. | soybean cell cultures (cv. williams 82) respond to pseudomonas syringae bacteria expressing the avirulence gene avra with a hypersensitive reaction, a programmed cell death (pcd) of plant cells to pathogen attack. this pcd is under control of salicylic acid (sa) via an unknown mechanism. in the presence of low concentrations of sa, the cells undergo a very rapid cell death, which needs only half of the time required for the normal hypersensitive reaction (hr). northern blot studies for defence-r ... | 2000 | 11117264 |
| stress induces peroxisome biogenesis genes. | peroxisomes are the cellular location of many antioxidants and are themselves significant producers of reactive oxygen species. in this report we demonstrate the induction of peroxisome biogenesis genes in both plant and animal cells by the universal stress signal molecule hydrogen peroxide. using pex1-luc transgenic plants, rapid local and systemic induction of pex1-luciferase could be demonstrated in vivo in response to physiological levels of hydrogen peroxide. pex1-luciferase was also induce ... | 2000 | 11118212 |
| a phaseolus vulgaris lipoxygenase gene expressed in nodules and in rhizobium tropici inoculated roots. | a genomic clone encoding a common bean lipoxygenase (pvlox5) was isolated from a phaseolus vulgaris library. reverse transcription-polymerase chain reaction analysis revealed that pvlox5 is expressed during nodule development and in rhizobium tropici inoculated roots. there was no detectable expression of pvlox5 in non-inoculated roots, healthy leaves, leaves after pseudomonas syringae pv. tabaci infection, floral buds or dry seeds. | 2000 | 11118627 |
| release of cell-free ice nuclei from halomonas elongata expressing the ice nucleation gene inaz of pseudomonas syringae. | release of ice nuclei in the growth medium of recombinant halomonas elongata cells expressing the inaz gene of pseudomonas syringae was studied in an attempt to produce cell-free active ice nuclei for biotechnological applications. cell-free ice nuclei were not retained by cellulose acetate filters of 0.2 microm pore size. highest activity of cell-free ice nuclei was obtained when cells were grown in low salinity (0.5-5% nacl, w/v). freezing temperature threshold, estimated to be below -7 degree ... | 2000 | 11119152 |
| structure-function analysis of the tobacco mosaic virus resistance gene n. | the tobacco n gene is a member of the toll-interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (tir-nbs-lrr) class of plant resistance (r) genes and confers resistance to tobacco mosaic virus (tmv). we investigated the importance of specific domains of n in inducing tmv resistance, by examining various n deletion and point mutations that introduce single amino acid substitution mutants in vivo. our deletion analysis suggests that the tir, nbs, and lrr domains play an indispensable ... | 2000 | 11121079 |
| simultaneous ethanol and bacterial ice nuclei production from sugar beet molasses by a zymomonas mobilis cp4 mutant expressing the inaz gene of pseudomonas syringae in continuous culture. | the aim of this work was to construct a zymomonas mobilis mutant capable of simultaneous ethanol and ice nuclei production from agricultural by-product such as sugar beet molasses, in steady-state continuous culture. | 2000 | 11123473 |
| oxidative burst and cognate redox signalling reported by luciferase imaging: identification of a signal network that functions independently of ethylene, sa and me-ja but is dependent on mapkk activity. | recognition of avirulent microbial pathogens activates an oxidative burst leading to the accumulation of reactive oxygen intermediates (rois), which are thought to integrate a diverse set of defence mechanisms resulting in the establishment of plant disease resistance. a novel transgenic arabidopsis line containing a gst1:luc transgene was developed and employed to report the temporal and spatial dynamics of roi accumulation and cognate redox signalling in response to attempted infection by avir ... | 2000 | 11123796 |
| membrane-permeabilizing activities of cyclic lipodepsipeptides, syringopeptin 22a and syringomycin e from pseudomonas syringae pv. syringae in human red blood cells and in bilayer lipid membranes. | the pore-forming activities of cyclic lipodepsipeptides (clps), syringopeptin 22a (sp22a) and syringomycin e (sre) were compared on the human red blood cell (rbc) membrane and on bilayer lipid membranes (blms). sp22a above a concentration of 4 x 10(5) molecules/cell significantly increased the rbc membrane permeability for 86rb. with electric current measurements on blm, it was proved that like sre, the sp22a formed two types of ion channels in the membrane, small and large, the latter having si ... | 2000 | 11129239 |
| novel tellurite-amended media and specific chromosomal and ti plasmid probes for direct analysis of soil populations of agrobacterium biovars 1 and 2. | ecology and biodiversity studies of agrobacterium spp. require tools such as selective media and dna probes. tellurite was tested as a selective agent and a supplement of previously described media for agrobacteria. the known biodiversity within the genus was taken into account when the selectivity of k(2)teo(3) was analyzed and its potential for isolating agrobacterium spp. directly from soil was evaluated. a k(2)teo(3) concentration of 60 ppm was found to favor the growth of agrobacteria and r ... | 2001 | 11133429 |
| direct cloning from enrichment cultures, a reliable strategy for isolation of complete operons and genes from microbial consortia. | enrichment cultures of microbial consortia enable the diverse metabolic and catabolic activities of these populations to be studied on a molecular level and to be explored as potential sources for biotechnology processes. we have used a combined approach of enrichment culture and direct cloning to construct cosmid libraries with large (>30-kb) inserts from microbial consortia. enrichment cultures were inoculated with samples from five environments, and high amounts of avidin were added to the cu ... | 2001 | 11133432 |
| pantoea agglomerans strain eh318 produces two antibiotics that inhibit erwinia amylovora in vitro. | pantoea agglomerans (synonym: erwinia herbicola) strain eh318 produces through antibiosis a complex zone of inhibited growth in an overlay seeded with erwinia amylovora, the causal agent of fire blight. this zone is caused by two antibiotics, named pantocin a and b. using a genomic library of eh318, two cosmids, pcpp702 and pcpp704, were identified that conferred on escherichia coli the ability to inhibit growth of e. amylovora. the two cosmids conferred different antibiotic activities on e. col ... | 2001 | 11133457 |
| gene cloning and functional characterization by heterologous expression of the fructosyltransferase of aspergillus sydowi iam 2544. | we have purified a fructosyltransferase from conidia of the inulin-producing fungus aspergillus sydowi iam 2544 and obtained peptide sequences from proteolytic fragments of the protein. with degenerated primers, we amplified a pcr fragment that was used to screen a cdna library. the fructosyltransferase gene from aspergillus sydowi (embl accession no. aj289046) is expressed in conidia, while no expression could be detected in mycelia by northern blot analysis of mycelial rna. the gene encodes a ... | 2001 | 11133467 |
| genetic and molecular organization of the alkylbenzene catabolism operon in the psychrotrophic strain pseudomonas putida 01g3. | the 11-kb sequence encompassing the alkylbenzene upper pathway in pseudomonas putida 01g3, a psychrotrophic strain able to degrade alkylbenzenes at low temperatures, was characterized. together with a potential regulator (ebdr), six putative enzymes (ebdaaabacadbc) were identified, and they exhibited highly significant similarities with enzymes implicated in the equivalent pathway in p. putida re204. ebd genes appeared to be preferentially induced by ethylbenzene. multiple-alignment data and gro ... | 2001 | 11133479 |
| hrpz(psph) from the plant pathogen pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore in vitro. | the hrp gene clusters of plant pathogenic bacteria control pathogenicity on their host plants and ability to elicit the hypersensitive reaction in resistant plants. some hrp gene products constitute elements of the type iii secretion system, by which effector proteins are exported and delivered into plant cells. here, we show that the hrpz gene product from the bean halo-blight pathogen, pseudomonas syringae pv. phaseolicola (hrpz(psph)), is secreted in an hrp-dependent manner in p. syringae pv. ... | 2001 | 11134504 |
| hrpz(psph) from the plant pathogen pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore in vitro. | the hrp gene clusters of plant pathogenic bacteria control pathogenicity on their host plants and ability to elicit the hypersensitive reaction in resistant plants. some hrp gene products constitute elements of the type iii secretion system, by which effector proteins are exported and delivered into plant cells. here, we show that the hrpz gene product from the bean halo-blight pathogen, pseudomonas syringae pv. phaseolicola (hrpz(psph)), is secreted in an hrp-dependent manner in p. syringae pv. ... | 2001 | 11134504 |
| the release of alginate lyase from growing pseudomonas syringae pathovar phaseolicola. | pseudomonas syringae pathovar phaseolicola, which produces alginate during stationary growth phase, displayed elevated extracellular alginate lyase activity during both mid-exponential and late-stationary growth phases of batch growth. intracellular activity remained below 22% of the total activity during exponential growth, suggesting that alginate lyase has an extracellular function for this organism. extracellular enzyme activity in continuous cultures, grown in either nutrient broth or gluco ... | 2001 | 11136126 |
| accumulation of soluble and wall-bound indolic metabolites in arabidopsis thaliana leaves infected with virulent or avirulent pseudomonas syringae pathovar tomato strains. | the chemical structures and accumulation kinetics of several major soluble as well as wall-bound, alkali-hydrolyzable compounds induced upon infection of arabidopsis thaliana leaves with pseudomonas syringae pathovar tomato were established. all identified accumulating products were structurally related to tryptophan. most prominent among the soluble substances were tryptophan, beta-d-glucopyranosyl indole-3-carboxylic acid, 6-hydroxyindole-3-carboxylic acid 6-o-beta-d-glucopyranoside, and the i ... | 2001 | 11136235 |
| induction of ltp (lipid transfer protein) and pal (phenylalanine ammonia-lyase) gene expression in rice roots colonized by the arbuscular mycorrhizal fungus glomus mosseae. | the expression of a lipid transfer protein (ltp) gene is regulated in oryza sativa roots in response to colonization by the mycorrhizal fungus glomus mosseae. transcript levels increased when the fungus forms appressoria and penetrates the root epidermis and decreased at the onset of the intercellular colonization of the root cortex. the analysis of histochemical gus staining in transgenic rice plants carrying the ltp/gus construct confirm the induction of ltp: gene associated with fungal appres ... | 2000 | 11141171 |
| the pseudomonas avrpto protein is differentially recognized by tomato and tobacco and is localized to the plant plasma membrane. | the avrpto gene of pseudomonas syringae pv tomato triggers race-specific resistance in tomato plants carrying pto, a resistance gene encoding a protein kinase. when introduced into p. s. tabaci, avrpto triggers resistance in tobacco w38 plants that carry the corresponding r gene. the avrpto protein is believed to be secreted into host cells through the bacterial type iii secretion pathway, where it activates disease resistance in tomato by interacting with pto. we report here the identification ... | 2000 | 11148281 |
| nuclear localization of npr1 is required for activation of pr gene expression. | systemic acquired resistance (sar) is a broad-spectrum resistance in plants that involves the upregulation of a battery of pathogenesis-related (pr) genes. npr1 is a key regulator in the signal transduction pathway that leads to sar. mutations in npr1 result in a failure to induce pr genes in systemic tissues and a heightened susceptibility to pathogen infection, whereas overexpression of the npr1 protein leads to increased induction of the pr genes and enhanced disease resistance. we analyzed t ... | 2000 | 11148282 |
| mutational analysis of the arabidopsis nucleotide binding site-leucine-rich repeat resistance gene rps2. | disease resistance proteins containing a nucleotide binding site (nbs) and a leucine-rich repeat (lrr) region compose the largest class of disease resistance proteins. these so-called nbs-lrr proteins confer resistance against a wide variety of phytopathogens. to help elucidate the mechanism by which nbs-lrr proteins recognize and transmit pathogen-derived signals, we analyzed mutant versions of the arabidopsis nbs-lrr protein rps2. the rps2 gene confers resistance against pseudomonas syringae s ... | 2000 | 11148296 |
| the arabidopsis-accelerated cell death gene acd2 encodes red chlorophyll catabolite reductase and suppresses the spread of disease symptoms. | accelerated cell death 2 (acd2) mutants of arabidopsis have spontaneous spreading cell death lesions and constitutive activation of defenses in the absence of pathogen infection. lesion formation in acd2 plants can be triggered by the bacterial toxin coronatine through a light-dependent process. coronatine-triggered and spontaneous lesion spreading in acd2 plants also requires protein translation, indicating that cell death occurs by an active process. we have cloned the acd2 gene; its predicted ... | 2001 | 11149948 |
| cloning and characterization of estc from burkholderia gladioli, a novel-type esterase related to plant enzymes. | by screening a genomic library of burkholderia gladioli (formerly pseudomonas marginata) for clones exhibiting esterolytic activity, the gene for a novel-type esterase (estc) showing significant homology to plant enzymes could be isolated. high homology was found to two hydroxynitrile lyases originating from hevea brasiliensis (tropical rubber tree) and manihot esculenta (cassava), and to two proteins from oryza sativa (rice) that are specifically induced upon infection by pseudomonas syringae p ... | 2000 | 11152069 |
| freezing of barley studied by infrared video thermography. | freezing of barley (hordeum vulgare), hordeum murinum, and holcus lanatus was studied using infrared video thermography. in the field, ice could enter h. lanatus leaves through hydathodes. in laboratory tests with barley, initially 0.4% of the leaf water froze, spreading in alternate strips of high and low freezing intensity longitudinally at 1 to 4 cm s(-1), and simultaneously spreading laterally at 0.3 cm s(-1). similar results were obtained in the field with h. lanatus. a distinct second, mor ... | 2001 | 11154332 |
| tomato allene oxide synthase and fatty acid hydroperoxide lyase, two cytochrome p450s involved in oxylipin metabolism, are targeted to different membranes of chloroplast envelope. | allene oxide synthase (aos) and hydroperoxide lyase (hpl) are related cytochrome p450s that metabolize a common fatty acid hydroperoxide substrate to different classes of bioactive oxylipins within chloroplasts. here, we report the use of in vitro import assays to investigate the targeting of tomato (lycopersicon esculentum) aos (leaos) and hpl (lehpl) to isolated chloroplasts. leaos, which contains a typical n-terminal transit peptide, was targeted to the inner envelope membrane by a route that ... | 2001 | 11154338 |
| pseudomonas frederiksbergensis sp. nov., isolated from soil at a coal gasification site. | phenotypic and genotypic characterization indicated that a group of 29 closely related phenanthrene-degrading bacteria from a coal gasification site in frederiksberg, copenhagen, denmark, belonged to the genus pseudomonas. the strains were isolated at two sampling occasions 2 years apart. the isolates were phenotypically different from any known species of the genus pseudomonas and were therefore subject to further identification. colonies were smooth and pale yellowish and did not produce pigme ... | 2000 | 11155968 |
| analysis of the type iv fimbrial-subunit gene fima of xanthomonas hyacinthi: application in pcr-mediated detection of yellow disease in hyacinths. | a sensitive and specific detection method was developed for xanthomonas hyacinthi; this method was based on amplification of a subsequence of the type iv fimbrial-subunit gene fima from strain s148. the fima gene was amplified by pcr with degenerate dna primers designed by using the n-terminal and c-terminal amino acid sequences of trypsin fragments of fima. the nucleotide sequence of fima was determined and compared with the nucleotide sequences coding for the fimbrial subunits in other type iv ... | 2001 | 11157222 |
| iron-binding compounds from agrobacterium spp.: biological control strain agrobacterium rhizogenes k84 produces a hydroxamate siderophore. | iron-binding compounds were produced in various amounts in response to iron starvation by a collection of agrobacterium strains belonging to the species a. tumefaciens, a. rhizogenes, and a. vitis. the crown gall biocontrol agent a. rhizogenes strain k84 produced a hydroxamate iron chelator in large amounts. production of this compound, and also of a previously described antibiotic-like substance called als84, occurred only in cultures of strain k84 grown in iron-deficient medium. similarly, sen ... | 2001 | 11157228 |
| the adna transcriptional factor affects persistence and spread of pseudomonas fluorescens under natural field conditions. | a soil plot was inoculated with a mixture of pseudomonas fluorescens pf0-2, the wild type, and pf0-5a, a tn5 insertion mutant in adna, at 7.84 log cfu/g of soil. over a period of 231 days, culturable populations of both strains were measured at selected times below and away from the point of inoculation. pf0-5a did not spread as fast and attained significantly lower populations than pf0-2. at sample depths below the inoculation site, the adna mutant showed a significant decrease in cfu/g of soil ... | 2001 | 11157254 |
| potential symbiosis-specific genes uncovered by sequencing a 410-kilobase dna region of the bradyrhizobium japonicum chromosome. | the physical and genetic map of the bradyrhizobium japonicum chromosome revealed that nitrogen fixation and nodulation genes are clustered. because of the complex interactions between the bacterium and the plant, we expected this chromosomal sector to contain additional genes that are involved in the maintenance of an efficient symbiosis. therefore, we determined the nucleotide sequence of a 410-kb region. the overall g+c nucleotide content was 59.1%. using a minimum gene length of 150 nucleotid ... | 2001 | 11157954 |
| syringolin reprograms wheat to undergo hypersensitive cell death in a compatible interaction with powdery mildew. | we had previously isolated and characterized syringolin a, one of the molecular determinants secreted by pseudomonas syringae pv syringae that is perceived by nonhost plant species such as rice. here, we show that syringolin a is recognized by wheat and that it induces the accumulation of gene transcripts and increases protection against powdery mildew when applied before inoculation. moreover, syringolin a essentially eradicates powdery mildew from infected wheat if applied after inoculation. t ... | 2001 | 11158536 |
| six amino acid changes confined to the leucine-rich repeat beta-strand/beta-turn motif determine the difference between the p and p2 rust resistance specificities in flax. | at least six rust resistance specificities (p and p1 to p5) map to the complex p locus in flax. the p2 resistance gene was identified by transposon tagging and transgenic expression. p2 is a member of a small multigene family and encodes a protein with nucleotide binding site (nbs) and leucine-rich repeat (lrr) domains and an n-terminal toll/interleukin-1 receptor (tir) homology domain, as well as a c-terminal non-lrr (cnl) domain of approximately 150 amino acids. a related cnl domain was detect ... | 2001 | 11158537 |
| hydrogen peroxide acts as a second messenger for the induction of defense genes in tomato plants in response to wounding, systemin, and methyl jasmonate. | the systemic accumulation of both hydrogen peroxide (h(2)o(2)) and proteinase inhibitor proteins in tomato leaves in response to wounding was inhibited by the nadph oxidase inhibitors diphenylene iodonium (dpi), imidazole, and pyridine. the expression of several defense genes in response to wounding, systemin, oligosaccharides, and methyl jasmonate also was inhibited by dpi. these genes, including those of four proteinase inhibitors and polyphenol oxidase, are expressed within 4 to 12 hr after w ... | 2001 | 11158538 |
| plant mitogen-activated protein kinase cascades: negative regulatory roles turn out positive. | 2001 | 11158543 | |
| the arabidopsis isr1 locus controlling rhizobacteria-mediated induced systemic resistance is involved in ethylene signaling. | in arabidopsis, the rhizobacterial strain pseudomonas fluorescens wcs417r triggers an induced systemic resistance (isr) response that is effective against different types of pathogens. the isr signaling pathway functions independent of salicylic acid, but requires responsiveness to jasmonate (ja) and ethylene. using the genetic variability of isr inducibility between arabidopsis accessions, we recently identified a locus (isr1) on chromosome iii that is involved in isr signaling. accessions rld ... | 2001 | 11161023 |
| a comparison of the effects of dna-damaging agents and biotic elicitors on the induction of plant defense genes, nuclear distortion, and cell death. | pea (pisum sativum l. cv alcan) endocarp tissue challenged with an incompatible fungal pathogen, fusarium solani f. sp. phaseoli or fungal elicitors results in the induction of pathogenesis-related (pr) genes and the accumulation of pisatin, a phytoalexin. essentially the same response occurs in pea tissue exposed to dna-specific agents that crosslink or intercalate dna. in this study, the effects of dna-damaging agents were assessed relative to the inducible expression of several pea pr genes: ... | 2001 | 11161032 |
| molecular responses to aphid feeding in arabidopsis in relation to plant defense pathways. | little is known about molecular responses in plants to phloem feeding by insects. the induction of genes associated with wound and pathogen response pathways was investigated following green peach aphid (myzus persicae) feeding on arabidopsis. aphid feeding on rosette leaves induced transcription of two genes associated with salicylic acid (sa)-dependent responses to pathogens (pr-1 and bgl2) 10- and 23-fold, respectively. induction of pr-1 and bgl2 mrna was reduced in npr1 mutant plants, which ... | 2001 | 11161062 |
| the use of 16s and 16s-23s rdna to easily detect and differentiate common gram-negative orchard epiphytes. | the identification of gram-negative pathogenic and non-pathogenic bacteria commonly isolated from an orchard phylloplane may result in a time consuming and tedious process for the plant pathologist. the paper provides a simple "one-step" protocol that uses the polymerase chain reaction (pcr) to amplify intergenic spacer regions between 16s and 23s genes and a portion of 16s gene in the prokaryotic rrna genetic loci. amplified 16s rdna, and restriction fragment length polymorphisms (rflp) followi ... | 2001 | 11166101 |
| cell surface display of salmobin, a thrombin-like enzyme from agkistrodon halys venom on escherichia coli using ice nucleation protein. | cell surface display on escherichia coli using ice nucleation protein was performed in order to develop a new expression system for recombinant eukaryotic proteins. salmobin, the thrombin-like enzyme obtained from korean snake (agkistrodon halys) venom was displayed on the surface of escherichia coli fused to the c-terminus of the ice nucleation protein (inp), an outer membrane protein of pseudomonas syringae. the thrombin cleavage site was inserted between salmobin and inp. the presence of salm ... | 2001 | 11166806 |
| probenazole induces systemic acquired resistance in arabidopsis with a novel type of action. | probenazole (pbz; 3-allyloxy-1,2-benzisothiazole-1,1-dioxide), which is the active ingredient in oryzemate, has been used widely in asia to protect rice plants against the rice blast fungus magnaporthe grisea. to study pbz's mode of action, we analyzed its ability, as well as that of its active metabolite 1, 2-benzisothiazol-3 (2h)-one 1,1-dioxide (bit) to induce defense gene expression and resistance in arabidopsis mutants that are defective in various defense signaling pathways. wild-type arab ... | 2001 | 11169191 |
| cell surface display of organophosphorus hydrolase using ice nucleation protein. | a new anchor system based on the ice nucleation protein (inav) from pseudomonas syringae ina5 was developed for cell surface display of functional organophosphorus hydrolase (oph). the activity and stability of cells expressing the truncated inav (inpnc)-oph fusions were compared to cells with surface-expressed oph using two other fusion anchors based on lpp-ompa and the truncated inak protein. whole cell activity was as much as 5-fold higher using the inav anchor. majority of the oph activity w ... | 2001 | 11170483 |
| bacterial menageries inside insects. | 2001 | 11171951 | |
| the insect endosymbiont sodalis glossinidius utilizes a type iii secretion system for cell invasion. | sodalis glossinidius is a maternally transmitted secondary endosymbiont residing intracellularly in tissues of the tsetse flies, glossina spp. in this study, we have used tn5 mutagenesis and a negative selection procedure to derive a s. glossinidius mutant that is incapable of invading insect cells in vitro and is aposymbiotic when microinjected into tsetse. this mutant strain harbors tn5 integrated into a chromosomal gene sharing high sequence identity with a type iii secretion system invasion ... | 2001 | 11172045 |
| ancient origin of pathogen recognition specificity conferred by the tomato disease resistance gene pto. | we have investigated the origin of the pto disease resistance (r) gene that was previously identified in the wild tomato species lycopersicon pimpinellifolium and isolated by map-based cloning. pto encodes a serine-threonine protein kinase that specifically recognizes strains of pseudomonas syringae pv. tomato (pst) that express the avirulence gene avrpto. we examined an accession of the distantly related wild species lycopersicon hirsutum var. glabratum that exhibits avrpto-specific resistance ... | 2001 | 11172075 |
| arabidopsis genome sequence as a tool for functional genomics in tomato. | tomato is a well-established model organism for studying many biological processes including resistance and susceptibility to pathogens and the development and ripening of fleshy fruits. the availability of the complete arabidopsis genome sequence will expedite map-based cloning in tomato on the basis of chromosomal synteny between the two species, and will facilitate the functional analysis of tomato genes. | 2001 | 11178283 |
| an active role for a structured b-linker in effector control of the sigma54-dependent regulator dmpr. | the activities of many prokaryotic sigma54-dependent transcriptional activators are controlled by the n-terminal a-domain of the protein, which is linked to the central transcriptional activation domain via a short b-linker. it used to be thought that these b-linkers simply serve as flexible tethers. here we show that the b-linker of the aromatic-responsive regulator dmpr and many other regulators of the family contain signature heptad repeats with regularly spaced hydrophobic amino acids. mutan ... | 2001 | 11179226 |
| cloning and characterization of a bean udp-glucosyltransferase cdna expressed during plant-bacterial interactions. | a cdna clone, which corresponds to an rna transcript that accumulates in bean during the hypersensitive reaction, was isolated and designated hra25 (for hypersensitive reaction associated). hra25 is predicted to encode a udp-glucosyltransferase. northern analysis was used to study hra25 transcript accumulation in bean in response to incompatible and compatible strains of pseudomonas syringae, an hrp- mutant, and wounding. our data suggest that the hra25 transcript is activated in response to spe ... | 2001 | 11194877 |
| functional analysis of the type iii effectors avrrpt2 and avrrpm1 of pseudomonas syringae with the use of a single-copy genomic integration system. | gram-negative phytopathogenic bacteria require a type iii secretion apparatus for pathogenesis, presumably to deliver avr effector proteins directly into plant cells. to extend previous studies of avr effectors that employed plasmids encoding avr proteins, we developed a system that permits the integration of any gene into the pseudomonas syringae genome in single copy. with this system, we confirmed earlier findings showing that p. syringae pv. maculicola strain psmes4326 expressing the avrrpt2 ... | 2001 | 11204777 |
| mutational analysis of the arabidopsis rps2 disease resistance gene and the corresponding pseudomonas syringae avrrpt2 avirulence gene. | plants have evolved a large number of disease resistance genes that encode proteins containing conserved structural motifs that function to recognize pathogen signals and to initiate defense responses. the arabidopsis rps2 gene encodes a protein representative of the nucleotide-binding site-leucine-rich repeat (nbs-lrr) class of plant resistance proteins. rps2 specifically recognizes pseudomonas syringae pv. tomato strains expressing the avrrpt2 gene and initiates defense responses to bacteria c ... | 2001 | 11204781 |
| the induction of tomato leucine aminopeptidase genes (lapa) after pseudomonas syringae pv. tomato infection is primarily a wound response triggered by coronatine. | tomato plants constitutively express a neutral leucine aminopeptidase (lap-n) and an acidic lap (lap-a) during floral development and in leaves in response to insect infestation, wounding, and pseudomonas syringae pv. tomato infection. to assess the physiological roles of lap-a, a lapa-antisense construct (35s:aslapa1) was introduced into tomato. the 35s:aslapa1 plants had greatly reduced or showed undetectable levels of lap-a and lap-n proteins in healthy and wounded leaves and during floral de ... | 2001 | 11204785 |
| immunogold labeling of hrp pili of pseudomonas syringae pv. tomato assembled in minimal medium and in planta. | hypersensitive reaction and pathogenicity (hrp) genes are required for pseudomonas syringae pv. tomato (pst) dc3000 to cause disease in susceptible tomato and arabidopsis thaliana plants and to elicit the hypersensitive response in resistant plants. the hrp genes encode a type iii protein secretion system known as the hrp system, which in pst dc3000 secretes hrpa, hrpz, hrpw, and avrpto and assembles a surface appendage, named the hrp pilus, in hrp-gene-inducing minimal medium. hrpa has been sug ... | 2001 | 11204787 |
| functional analysis of the pseudomonas syringae rulab determinant in tolerance to ultraviolet b (290-320 nm) radiation and distribution of rulab among p. syringae pathovars. | the effect of the plasmid-encoded rulab (resistance to ultraviolet radiation) determinant on responses of pseudomonas syringae to ultraviolet-b (uv-b) radiation and the distribution of rulab among pathovars of p. syringae were determined. the cloned rulab determinant and the native rulab+ plasmid ppsr1 both conferred approximately a 10-fold increase in survival on p. syringae pv. syringae ff5 following increasing doses of uv-b radiation. rulab+ p. syringae strains also maintained significantly l ... | 1999 | 11207720 |
| exchange of xcp (gsp) secretion machineries between pseudomonas aeruginosa and pseudomonas alcaligenes: species specificity unrelated to substrate recognition. | pseudomonas aeruginosa and pseudomonas alcaligenes are gram-negative bacteria that secrete proteins using the type ii or general secretory pathway, which requires at least 12 xcp gene products (xcpa and xcpp to -z). despite strong conservation of this secretion pathway, gram-negative bacteria usually cannot secrete exoproteins from other species. based on results obtained with erwinia, it has been proposed that the xcpp and/or xcpq homologs determine this secretion specificity (m. linderberg, g. ... | 2001 | 11208795 |
| activation of a mitogen-activated protein kinase pathway is involved in disease resistance in tobacco. | hypersensitive response (hr), a form of programmed cell death, is frequently associated with plant disease resistance. it has been proposed that mitogen-activated protein kinase (mapk) cascades regulate hr cell death based on pharmacological studies by using kinase inhibitors. however, direct evidence is lacking. here, we demonstrate that ntmek2, a mapk kinase, is upstream of salicylic acid-induced protein kinase (sipk) and wounding-induced protein kinase (wipk), two tobacco mapks that are activ ... | 2001 | 11209069 |
| structural determination of the phytotoxic mannan exopolysaccharide from pseudomonas syringae pv. ciccaronei. | the structural determination was performed of a mannan exopolysaccharide from the gram negative bacterium pseudomonas syringae pv. ciccaronei, which is the pathogenic agent responsible for the leaf spots of carob plants. the structure, obtained by chemical, enzymatic and spectroscopic methods, consisted of a backbone of alpha-(1-->6)-linked mannopyranose units with 80% substituted at c-2 by mono-, di- and trisaccharide side chains. in addition, terminal glucose units and phosphate groups were fo ... | 2001 | 11217981 |
| modeling pseudomonas syringae ice-nucleation protein as a beta-helical protein. | antifreeze proteins (afps) inhibit the growth of ice, whereas ice-nucleation proteins (inps) promote its formation. although the structures of several afps are known, the structure of inp has been modeled thus far because of the difficulty in determining membrane protein structures. here, we present a novel model of an inp structure from pseudomonas syringae based on comparison with two newly determined insect afp structures. the results suggest that both this class of afps and inps may have a s ... | 2001 | 11222281 |
| phase-variable expression of an operon encoding extracellular alkaline protease, a serine protease homolog, and lipase in pseudomonas brassicacearum. | the rhizobacterium pseudomonas brassicacearum forms phenotypic variants which do not show extracellular protease and lipase activity. the operon encoding these enzymes, a serine protease homolog, and a type i secretion machinery was characterized. transcriptional lacz gene fusions revealed that the expression of the operon is under the control of phase variation. | 2001 | 11222613 |
| genes involved in copper homeostasis in escherichia coli. | recently, genes for two copper-responsive regulatory systems were identified in the escherichia coli chromosome. in this report, data are presented that support a hypothesis that the putative multicopper oxidase cueo and the transenvelope transporter cuscfba are involved in copper tolerance in e. coli. | 2001 | 11222619 |
| arabidopsis nho1 is required for general resistance against pseudomonas bacteria. | nonhost interactions are prevalent between plants and specialized phytopathogens. although it has great potential for providing crop plants with durable resistance, nonhost resistance is poorly understood. here, we show that nonhost resistance is controlled, at least in part, by general resistance. arabidopsis plants are resistant to the nonhost pathogen pseudomonas syringae pv phaseolicola nps3121 and completely arrest bacterial multiplication in the plant. ten arabidopsis mutants were isolated ... | 2001 | 11226196 |
| acyl-homoserine lactone production is more common among plant-associated pseudomonas spp. than among soilborne pseudomonas spp. | a total of 137 soilborne and plant-associated bacterial strains belonging to different pseudomonas species were tested for their ability to synthesize n-acyl-homoserine lactones (nahl). fifty-four strains synthesized nahl. interestingly, nahl production appears to be more common among plant-associated than among soilborne pseudomonas spp. indeed, 40% of the analyzed pseudomonas syringae strains produced nahl which were identified most often as the short-chain nahl, n-hexanoyl-l-homoserine lacton ... | 2001 | 11229911 |
| biological sensor for sucrose availability: relative sensitivities of various reporter genes. | a set of three sucrose-regulated transcriptional fusions was constructed. fusions p61rytir, p61rylac, and p61ryice contain the scrr sucrose repressor gene and the promoterless gfp, lacz, and inaz reporter genes, respectively, fused to the scry promoter from salmonella enterica serovar typhimurium. cells of erwinia herbicola containing these fusions are induced only in media amended with sucrose, fructose, or sorbose. while a large variation in sucrose-dependent reporter gene activity was observe ... | 2001 | 11229926 |
| genetic evidence that loss of virulence associated with gacs or gaca mutations in pseudomonas syringae b728a does not result from effects on alginate production. | mutations in the global regulatory genes gacs and gaca render pseudomonas syringae pv. syringae strain b728a completely nonpathogenic in foliar infiltration assays on bean plants. it had been previously demonstrated that gac genes regulate alginate production in pseudomonas species, while other published work indicated that alginate is involved in the pathogenic interaction of p. syringae on bean plants. together, these results suggested that the effects of gacs and gaca mutations on virulence i ... | 2001 | 11229941 |
| cadmium-regulated gene fusions in pseudomonas fluorescens. | to study the mechanisms soil bacteria use to cope with elevated concentrations of heavy metals in the environment, a mutagenesis with the lacz-based reporter gene transposon tn5b20 was performed. random gene fusions in the genome of the common soil bacterium pseudomonas fluorescens strain atcc 13525 were used to create a bank of 5,000 p. fluorescens mutants. this mutant bank was screened for differential gene expression in the presence of the toxic metal cadmium. fourteen mutants were identified ... | 2000 | 11234925 |
| sira orthologs affect both motility and virulence. | the sira gene of salmonella enterica serovar typhimurium encodes a two-component response regulator of the fixj family that has a positive regulatory influence on the expression of type iii secretion genes involved with epithelial cell invasion and the elicitation of bovine gastroenteritis. sira orthologs in pseudomonas, vibrio, and erwinia control the expression of distinct virulence genes in these genera, but an evolutionarily conserved target of sira regulation has never been identified. in t ... | 2001 | 11244064 |
| [properties of bacteria of pathovars of pseudomonas syringae affecting cereals]. | antigenic properties of pseudomonas syringae pv. coronafaciens isolated from the oats have been studied for the first time, and serologic grouping of the strains of p. syringae pv. coronafaciens and p. syringae pv. atrofaciens has been carried out. it has been determined that the strains of p. syringae pv. coronafaciens, as to availability of specific antigenic complexes belong to two serological groups i and v, and thus they are differed from the strains of the pathovar atrofaciens which includ ... | 2000 | 11247339 |
| agricultural microbes genome 2: first glimpses into the genomes of plant-associated microbes. | 2001 | 11251088 | |
| spa33, a cell surface-associated subunit of the mxi-spa type iii secretory pathway of shigella flexneri, regulates ipa protein traffic. | the mxi-spa type iii secretion system of shigella flexneri directs the host cell contact-induced secretion of a set of invasins, referred to as ipas. in this study, we examined the role of spa33 in ipa secretion. a spa33-null mutant was both noninvasive and unable to translocate the ipas from inner membrane to outer membrane (om) positions of the mxi-spa transmembrane channel. spa33 was found to be a mxi-spa substrate that is translocated to the bacterial cell surface upon the induction of ipa s ... | 2001 | 11254573 |
| complete dna sequence and comparative analysis of the 50-kilobase virulence plasmid of salmonella enterica serovar choleraesuis. | the complete nucleotide sequence of pkdsc50, a large virulence plasmid from salmonella enterica serovar choleraesuis strain rf-1, has been determined. we identified 48 of the open reading frames (orfs) encoded by the 49,503-bp molecule. pkdsc50 encodes a known virulence-associated operon, the spv operon, which is composed of genes essential for systemic infection by nontyphoidal salmonella. analysis of the genetic organization of pkdsc50 suggests that the plasmid is composed of several virulence ... | 2001 | 11254626 |
| detection of tabtoxin-producing strains of pseudomonas syringae by pcr. | the present study describes a system based on pcr to distinguish tabtoxin-producing strains of pseudomonas syringae from other ps. syringae plant pathogens that produce chlorosis-inducing phytotoxins. | 2001 | 11264746 |
| location of the o-methyl groups in the o polysaccharide of pseudomonas syringae pv. phaseolicola. | the o-methylation pattern of the o polysaccharide (ops) of the lipopolysaccharide of pseudomonas syringae pv. phaseolicola gspb 1552 was revealed by methylation (cd3i) analysis, smith degradation, and nmr spectroscopy. together with the major o repeats consisting of d-rhamnopyranose (d-rhap) and d-fucofuranose (d-fucf), there are minor repeats (approximately 30%) containing 3-o-methyl-d-rhamnose (d-acofriose), which is 2-substituted in the interior repeats and occupies the terminal non-reducing ... | 2001 | 11269402 |
| glnd and mvin are genes of an essential operon in sinorhizobium meliloti. | to evaluate the role of uridylyl-transferase, the sinorhizobium meliloti glnd gene was isolated by heterologous complementation in azotobacter vinelandii. the glnd gene is cotranscribed with a gene homologous to salmonella mvin. glnd1::omega or mvin1::omega mutants could not be isolated by a powerful sucrose counterselection procedure unless a complementing cosmid was provided, indicating that glnd and mvin are members of an indispensable operon in s. meliloti. | 2001 | 11274131 |
| the dna-repair protein alkb, egl-9, and leprecan define new families of 2-oxoglutarate- and iron-dependent dioxygenases. | protein fold recognition using sequence profile searches frequently allows prediction of the structure and biochemical mechanisms of proteins with an important biological function but unknown biochemical activity. here we describe such predictions resulting from an analysis of the 2-oxoglutarate (2og) and fe(ii)-dependent oxygenases, a class of enzymes that are widespread in eukaryotes and bacteria and catalyze a variety of reactions typically involving the oxidation of an organic substrate usin ... | 2001 | 11276424 |
| the contribution of syringopeptin and syringomycin to virulence of pseudomonas syringae pv. syringae strain b301d on the basis of sypa and syrb1 biosynthesis mutant analysis. | sequencing of an approximately 3.9-kb fragment downstream of the syrd gene of pseudomonas syringae pv. syringae strain b301d revealed that this region, designated sypa, codes for a peptide synthetase, a multifunctional enzyme involved in the thiotemplate mechanism of peptide biosynthesis. the translated protein sequence encompasses a complete amino acid activation module containing the conserved domains characteristic of peptide synthetases. analysis of the substrate specificity region of this m ... | 2001 | 11277431 |
| immunocytochemical localization of hrpa and hrpz supports a role for the hrp pilus in the transfer of effector proteins from pseudomonas syringae pv. tomato across the host plant cell wall. | the hrp pilus, composed of hrpa subunits, is an essential component of the type iii secretion system in pseudomonas syringae. we used electron microscopy (em) and immunocytochemistry to examine production of the pilus in vitro from p. syringae pv. tomato strain dc3000 grown under hrp-inducing conditions on em grids. pili, when labeled with antibodies to hrpa, developed rapidly in a nonpolar manner shortly after the detection of the hrpa transcript and extended up to 5 microm into surrounding med ... | 2001 | 11277437 |
| construction and analysis of photolyase mutants of pseudomonas aeruginosa and pseudomonas syringae: contribution of photoreactivation, nucleotide excision repair, and mutagenic dna repair to cell survival and mutability following exposure to uv-b radiation. | based on nucleotide sequence homology with the escherichia coli photolyase gene (phr), the phr sequence of pseudomonas aeruginosa pao1 was identified from the genome sequence, amplified by pcr, cloned, and shown to complement a known phr mutation following expression in escherichia coli sy2. stable, insertional phr mutants containing a tetracycline resistance gene cassette were constructed in p. aeruginosa pao1 and p. syringae pv. syringae ff5 by homologous recombination and sucrose-mediated cou ... | 2001 | 11282583 |
| chromosomal locus for cadmium resistance in pseudomonas putida consisting of a cadmium-transporting atpase and a merr family response regulator. | pseudomonads from environmental sources vary widely in their sensitivity to cadmium, but the basis for this resistance is largely uncharacterized. a chromosomal fragment encoding cadmium resistance was cloned from pseudomonas putida 06909, a rhizosphere bacterium, and sequence analysis revealed two divergently transcribed genes, cada and cadr. cada was similar to cadmium-transporting atpases known mostly from gram-positive bacteria, and to znta, a lead-, zinc-, and cadmium-transporting atpase fr ... | 2001 | 11282588 |
| characterization of fluorescent and nonfluorescent peptide siderophores produced by pseudomonas syringae strains and their potential use in strain identification. | nonfluorescent highly virulent strains of pseudomonas syringae pv. aptata isolated in different european countries and in uruguay produce a nonfluorescent peptide siderophore, the production of which is iron repressed and specific to these strains. the amino acid composition of this siderophore is identical to that of the dominant fluorescent peptide siderophore produced by fluorescent p. syringae strains, and the molecular masses of the respective fe(iii) chelates are 1,177 and 1,175 atomic mas ... | 2001 | 11282626 |
| complete dna sequence and analysis of the large virulence plasmid of shigella flexneri. | the complete sequence analysis of the 210-kb shigella flexneri 5a virulence plasmid was determined. shigella spp. cause dysentery and diarrhea by invasion and spread through the colonic mucosa. most of the known shigella virulence determinants are encoded on a large plasmid that is unique to virulent strains of shigella and enteroinvasive escherichia coli; these known genes account for approximately 30 to 35% of the virulence plasmid. in the complete sequence of the virulence plasmid, 286 open r ... | 2001 | 11292750 |
| characterization of the plesiomonas shigelloides genes encoding the heme iron utilization system. | plesiomonas shigelloides is a gram-negative pathogen which can utilize heme as an iron source. in previous work, p. shigelloides genes which permitted heme iron utilization in a laboratory strain of escherichia coli were isolated. in the present study, the cloned p. shigelloides sequences were found to encode ten potential heme utilization proteins: huga, the putative heme receptor; tonb and exbbd; hugb, the putative periplasmic binding protein; hugcd, the putative inner membrane permease; and t ... | 2001 | 11292789 |
| characterization of the d-xylulose 5-phosphate/d-fructose 6-phosphate phosphoketolase gene (xfp) from bifidobacterium lactis. | a d-xylulose 5-phosphate/d-fructose 6-phosphate phosphoketolase (xfp) from the probiotic bifidobacterium lactis was purified to homogeneity. the specific activity of the purified enzyme with d-fructose 6-phosphate as a substrate is 4.28 units per mg of enzyme. k(m) values for d-xylulose 5-phosphate and d-fructose 6-phosphate are 45 and 10 mm, respectively. the native enzyme has a molecular mass of 550,000 da. the subunit size upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (90,000 ... | 2001 | 11292814 |
| transgenic rice plants expressing the ferredoxin-like protein (ap1) from sweet pepper show enhanced resistance to xanthomonas oryzae pv. oryzae. | we used particle bombardment to cotransform mature seed-derived rice callus (oryza sativa l., ssp. japonica, cv. eyi 105) with plasmids containing the linked marker genes gusa and hpt, and the ap1 gene encoding an amphipathic protein previously shown to delay the hypersensitive response induced in non-host plants by the pathogen pseudomonas syringae pv. syringae (pss). thirty-two independent lines of transgenic rice plants were regenerated, and 27 of these lines carried all three transgenes as s ... | 2001 | 11297801 |
| study of the role of antimicrobial glucosinolate-derived isothiocyanates in resistance of arabidopsis to microbial pathogens. | crude aqueous extracts from arabidopsis leaves were subjected to chromatographic separations, after which the different fractions were monitored for antimicrobial activity using the fungus neurospora crassa as a test organism. two major fractions were obtained that appeared to have the same abundance in leaves from untreated plants versus leaves from plants challenge inoculated with the fungus alternaria brassicicola. one of both major antimicrobial fractions was purified to homogeneity and iden ... | 2001 | 11299350 |
| evidence for the involvement of an oxidative stress in the initiation of infection of pear by erwinia amylovora. | involvement of an oxidative burst, usually related to incompatible plant/pathogen interactions leading to hypersensitive reactions, was investigated with erwinia amylovora, the causal agent of fire blight of maloideae subfamily of rosaceae, in interaction with pear (pyrus communis; compatible situation) and tobacco (nicotiana tabacum; incompatible situation). as expected, this necrogenic bacterium induced in tobacco a sustained production of superoxide anion, lipid peroxidation, electrolyte leak ... | 2001 | 11299395 |
| effects of urate, a natural inhibitor of peroxynitrite-mediated toxicity, in the response of arabidopsis thaliana to the bacterial pathogen pseudomonas syringae. | urate, a natural peroxynitrite scavenger, has been used to investigate the possible role of peroxynitrite during plant-pathogen interactions. urate greatly reduced lesion formation in arabidopsis leaves treated with an abiotic peroxynitrite-generating system or with a peroxynitrite solution, indicating that it can act as an effective scavenger in planta. in the interaction with the avirulent pseudomonas syringae pv. phaseolicola (avrrpm1+), cell death in the inoculated area was strongly reduced ... | 2001 | 11309143 |
| a recessive mutation in the arabidopsis ssi2 gene confers sa- and npr1-independent expression of pr genes and resistance against bacterial and oomycete pathogens. | the arabidopsis thaliana npr1 gene is required for salicylic acid (sa)-induced expression of pathogenesis-related (pr) genes and systemic acquired resistance. however, loss-of-function mutations in npr1 do not confer complete loss of pr gene expression or disease resistance. thus these responses also can be activated via an npr1-independent pathway that currently remain to be elucidated. the ssi2-1 mutant, identified in a genetic screen for suppressors of npr1-5, affects signaling through the np ... | 2001 | 11309146 |
| functional studies of the bacterial avirulence protein avrpto by mutational analysis. | pseudomonas syringae pathovars expressing avrpto are avirulent on plants expressing the resistance gene pto. over 85 mutants of avrpto were generated with multiple strategies, and several assays were used to characterize avrpto function. only a core of 95 amino acids of the 164 residues was sufficient for binding pto in the yeast two-hybrid system. only nine of 65 mutant proteins of avrpto with amino acid substitutions, created in planta and in vitro, did not interact with pto in the gal4 yeast ... | 2001 | 11310732 |
| effects of the two-component system comprising gaca and gacs of erwinia carotovora subsp. carotovora on the production of global regulatory rsmb rna, extracellular enzymes, and harpinecc. | posttranscriptional regulation mediated by the regulator of secondary metabolites (rsm) rsma-rsmb pair is the most important factor in the expression of genes for extracellular enzymes and harpinecc in erwinia carotovora subsp. carotovora. rsma is a small rna-binding protein, which acts by lowering the half-life of a mrna species. rsmb specifies an untranslated regulatory rna and neutralizes the rsma effect. it has been speculated that gaca-gacs, members of a two-component system, may affect gen ... | 2001 | 11310739 |
| isolation and characterization of the gene coding for the amidinotransferase involved in the biosynthesis of phaseolotoxin in pseudomonas syringae pv. phaseolicola. | pseudomonas syringae pv. phaseolicola is the causal agent of the "halo blight" disease of beans. a key component in the development of the disease is a nonhost-specific toxin, ndelta-(n'-sulphodiaminophosphinyl)-ornithyl-alanyl-homoarginine, known as phaseolotoxin. the homoarginine residue in this molecule has been suggested to be the product of l-arginine:lysine amidinotransferase activity, previously detected in extracts of p. syringae pv. phaseolicola grown under conditions of phaseolotoxin p ... | 2001 | 11310742 |
| analysis of bacterial lipodepsipeptides by matrix-assisted laser desorption/ionisation time-of-flight and high-performance liquid chromatography with electrospray mass spectrometry. | strains of certain plant pathogenic bacteria, in particular several pathovars of pseudomonas syringae, are known to produce cyclic lipodepsipeptides (ldps) endowed with peculiar structural features and noticeable biological activities. in this study, a mass spectrometry procedure is proposed for screening ldp-producing bacterial strains and for identifying and assessing individual ldps. after matrix-assisted laser desorption/ionisation time-of-flight (maldi-tof) screening of thirteen p. syringae ... | 2001 | 11312513 |
| stable transformation of the xylella fastidiosa citrus variegated chlorosis strain with oric plasmids. | xylella fastidiosa is a gram-negative, xylem-limited bacterium affecting economically important crops (e.g., grapevine, citrus, and coffee). the citrus variegated chlorosis (cvc) strain of x. fastidiosa is the causal agent of this severe disease of citrus in brazil and represents the first plant-pathogenic bacterium for which the genome sequence was determined. plasmids for the cvc strain of x. fastidiosa were constructed by combining the chromosomal replication origin (oric) of x. fastidiosa wi ... | 2001 | 11319110 |
| the cela gene, encoding a glycosyl hydrolase family 3 beta-glucosidase in azospirillum irakense, is required for optimal growth on cellobiosides. | the cela beta-glucosidase of azospirillum irakense, belonging to glycosyl hydrolase family 3 (ghf3), preferentially hydrolyzes cellobiose and releases glucose units from the c(3), c(4), and c(5) oligosaccharides. the growth of a deltacela mutant on these cellobiosides was affected. in a. irakense, the ghf3 beta-glucosidases appear to be functional alternatives for the ghf1 beta-glucosidases in the assimilation of beta-glucosides by other bacteria. | 2001 | 11319128 |
| highly conserved sequences flank avirulence genes: isolation of novel avirulence genes from pseudomonas syringae pv. pisi. | dna sequences flanking two avr genes (avrppia1 and avrppib1) from pseudomonas syringae pv. pisi show a high degree of similarity. specific primers designed from the conserved regions were used in pcr amplifications with all p. syringae pv. pisi races. as well as amplifying the expected avrppia- and avrppib-containing fragments, two additional fragments were amplified: one contained a single open reading frame (orf1) and was found in races of genomic group ii (2, 3a, 4a and 6); the second fragmen ... | 2001 | 11320120 |