Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| transcriptional activity at supraoptimal temperature of growth in the antarctic psychrotrophic bacterium pseudomonas syringae. | transcriptional activity was monitored in cells of the antarctic psychrotrophic bacterium pseudomonas syringae (lz4w), which does not grow above 30 degrees c. it was observed that the bacterium was capable of synthesising rna at a temperature range of 0-37 degrees c, both in vitro and in vivo. the net incorporation of the radioactive precursor, [3h]uridine, into rna was found to be affected at 37 degrees c. a pulse-chase experiment following a 32p labeling of rna in vivo indicated that the ribos ... | 1999 | 9922464 |
| fungal lethality, binding, and cytotoxicity of syringomycin-e. | syringomycin-e (se) was significantly lethal to aspergillus and fusarium species at between 1.9 and 7.8 micrograms/ml. se complexed with the following fungal wall constituents (in order of binding): beta-1,3-glucan > chitin > mannan > ergosterol = cholesterol. cytotoxicity in hela cells was proportional to the se concentration, while the amount required for cytotoxicity was 3 to 20 times that needed to kill 95% of the fungi tested. | 1999 | 9925536 |
| the arabidopsis ssi1 mutation restores pathogenesis-related gene expression in npr1 plants and renders defensin gene expression salicylic acid dependent. | the arabidopsis npr1 gene was previously shown to be required for the salicylic acid (sa)- and benzothiadiazole (bth)-induced expression of pathogenesis-related (pr) genes and systemic acquired resistance. the dominant ssi1 (for suppressor of sa insensitivity) mutation characterized in this study defines a new component of the sa signal transduction pathway that bypasses the requirement of npr1 for expression of the pr genes and disease resistance. the ssi1 mutation caused pr (pr-1, bgl2 [pr-2], ... | 1999 | 9927638 |
| cell-specific production and antimicrobial activity of naphthoquinones in roots of lithospermum erythrorhizon | pigmented naphthoquinone derivatives of shikonin are produced at specific times and in specific cells of lithospermum erythrorhizon roots. normal pigment development is limited to root hairs and root border cells in hairy roots grown on "noninducing" medium, whereas induction of additional pigment production by abiotic (cuso4) or biotic (fungal elicitor) factors increases the amount of total pigment, changes the ratios of derivatives produced, and initiates production of pigment de novo in epide ... | 1999 | 9952436 |
| hybrid frequencies confirm limit to coinfection in the rna bacteriophage phi6. | coinfection of the same host cell by multiple viruses may lead to increased competition for limited cellular resources, thus reducing the fitness of an individual virus. selection should favor viruses that can limit or prevent coinfection, and it is not surprising that many viruses have evolved mechanisms to do so. here we explore whether coinfection is limited in the rna bacteriophage phi6 that infects pseudomonas phaseolicola. we estimated the limit to coinfection in phi6 by comparing the freq ... | 1999 | 9971826 |
| characterization of insertions of is476 and two newly identified insertion sequences, is1478 and is1479, in xanthomonas campestris pv. campestris. | thirty-two plasmid insertion mutants were independently isolated from two strains of xanthomonas campestris pv. campestris in taiwan. of the 32 mutants, 14 (44%), 8 (25%), and 4 (12%) mutants resulted from separate insertions of an is3 family member, is476, and two new insertion sequences (is), is1478 and is1479. while is1478 does not have significant sequence homology with any is elements in the embl/genbank/ddbj database, is1479 demonstrated 73% sequence homology with is1051 in x. campestris p ... | 1999 | 9973349 |
| auxins upregulate expression of the indole-3-pyruvate decarboxylase gene in azospirillum brasilense. | transcription of the azospirillum brasilense ipdc gene, encoding an indole-3-pyruvate decarboxylase involved in the biosynthesis of indole-3-acetic acid (iaa), is induced by iaa as determined by ipdc-gusa expression studies and northern analysis. besides iaa, exogenously added synthetic auxins such as 1-naphthaleneacetic acid, 2,4-dichlorophenoxypropionic acid, and p-chlorophenoxyacetic acid were also found to upregulate ipdc expression. no upregulation was observed with tryptophan, acetic acid, ... | 1999 | 9973364 |
| the virulence plasmid-encoded impcab operon enhances survival and induced mutagenesis in shigella flexneri after exposure to uv radiation. | upon exposure to uv radiation, shigella flexneri sa100 displayed survival and mutation frequencies comparable to those of escherichia coli ab1157, which contains a functional umudc error-prone dna repair system. survival of sa100 after uv irradiation was associated with the presence of the 220-kb virulence plasmid, pvp. this plasmid encodes homologues of impa and impb, which comprise an error-prone dna repair system encoded on plasmid tp110 that was initially identified in salmonella typhimurium ... | 1999 | 10024589 |
| diversity and molecular evolution of the rps2 resistance gene in arabidopsis thaliana. | the rps2 gene in arabidopsis thaliana governs resistance to strains of the bacterial pathogen, pseudomonas syringae pv. tomato, that express the avrrpt2 gene. the two loci are involved in a gene-for-gene interaction. seventeen accessions of a. thaliana were sequenced to explore the diversity present in the coding region of the rps2 locus. an unusually high level of nucleotide polymorphisms was found (1.26%), with nearly half of the observed polymorphisms resulting in amino acid changes in the rp ... | 1999 | 9874813 |
| overexpression of pto activates defense responses and confers broad resistance. | the tomato disease resistance (r) gene pto specifies race-specific resistance to the bacterial pathogen pseudomonas syringae pv tomato carrying the avrpto gene. pto encodes a serine/threonine protein kinase that is postulated to be activated by a physical interaction with the avrpto protein. here, we report that overexpression of pto in tomato activates defense responses in the absence of the pto-avrpto interaction. leaves of three transgenic tomato lines carrying the cauliflower mosaic virus 35 ... | 1999 | 9878629 |
| cloning and characterization of a tetracycline resistance determinant present in agrobacterium tumefaciens c58. | agrobacterium tumefaciens c58 and its derivatives give rise to spontaneous mutants resistant to tetracycline at a high frequency. we observed that a mutation affecting a trna processing function significantly affected the emergence of such mutants, suggesting that c58 contained a positively acting gene conferring resistance to tetracycline. a cosmid clone conferring resistance to tetracycline in escherichia coli and agrobacterium was isolated from a genomic bank of one such mutant. subcloning, t ... | 1999 | 9882678 |
| control of herbaspirillum seropedicae nifa activity by ammonium ions and oxygen. | the activity of a truncated form of herbaspirillum seropedicae nifa in different genetic backgrounds showed that its regulatory domain is involved in nitrogen control but not in o2 sensitivity or fe dependence. the model for nitrogen control involving pii could thus apply to the proteobacteria at large. nifa may have a role in controlling adp-ribosylation of nitrogenase in azospirillum brasilense. | 1999 | 9882688 |
| identification of an escherichia coli pepa homolog and its involvement in suppression of the algb phenotype in mucoid pseudomonas aeruginosa. | strains of pseudomonas aeruginosa isolated from the respiratory tracts of patients with cystic fibrosis often display a mucoid morphology due to high levels of expression of the exopolysaccharide alginate. the response regulator algb is required for full transcription of the alginate biosynthetic operon. repeated attempts to demonstrate a direct interaction between algb and the promoter region of algd, the first gene in the alginate operon, have thus far been unsuccessful. the possibility that a ... | 1999 | 9864319 |
| adaptation of mycobacterium smegmatis to stationary phase. | mycobacterium tuberculosis can persist for many years within host lung tissue without causing clinical disease. little is known about the state in which the bacilli survive, although it is frequently referred to as dormancy. some evidence suggests that cells survive in nutrient-deprived stationary phase. therefore, we are studying stationary-phase survival of mycobacterium smegmatis as a model for mycobacterial persistence. m. smegmatis cultures could survive 650 days of either carbon, nitrogen, ... | 1999 | 9864340 |
| cloning and expression in escherichia coli of 2-hydroxypropylphosphonic acid epoxidase from the fosfomycin-producing organism, pseudomonas syringae pb-5123. | the fosfomycin resistance gene, fosc, has been cloned from the fosfomycin-producing organism, pseudomonas syringae pb-5123. sequence analysis upstream of this gene found a new orf showing significant homology to 2-hydroxypropylphosphonic acid epoxidase from fosfomycin-producing streptomyces wedmorensis. the purified recombinant protein of this orf converted 2-hydroxypropylphosphonic acid to fosfomycin. this result clearly showed the orf to encode 2-hydroxypropylphosphonic acid epoxidase in pb-51 ... | 1999 | 10664856 |
| cell surface display of hepatitis b virus surface antigen by using pseudomonas syringae ice nucleation protein. | a new system designed for cell surface display of recombinant proteins on escherichia coli was evaluated for expression of eukaryotic viral antigens. the major surface antigen of hepatitis b virus (hbsag) was fused to the ice nucleation protein (inp), an outer membrane protein of pseudomonas syringae. western blotting, immunofluorescence microscopy, whole-cell elisa, and ice nucleation activity assay confirmed expression of recombinant proteins on the surface of escherichia coli. this study indi ... | 1999 | 10664968 |
| 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 |
| [vascular bundle specific expression of iaal gene affects the generation frequencies of transgenic tobacco]. | a vascular bundles specific expressing vector pbal1 with a promoter aq630 from rice phenylalanine ammonialyase gene and a gene encoding indoleacetic-lysine synthytase from pseudomonas syringae subsp. savastanoi was constructed. affirmed by southern blotting and rtpcr analysis, the aq630-iaal transgenic plants show increasing shoots-regeneration frequency of young stem explants on hormone-free 1/2 ms medium and lower sensibility to iaa when roots were induced from the root explants on the media c ... | 1999 | 12548796 |
| reciprocal secretion of proteins by the bacterial type iii machines of plant and animal pathogens suggests universal recognition of mrna targeting signals. | bacterial pathogens of both animals and plants use type iii secretion machines to inject virulence proteins into host cells. although many components of the secretion machinery are conserved among different bacterial species, the substrates for their type iii pathways are not. the yersinia type iii machinery recognizes some secretion substrates via a signal that is encoded within the first 15 codons of yop mrna. these signals can be altered by frameshift mutations without affecting secretion of ... | 1999 | 10536009 |
| stable packaging of phage prd1 dna requires adsorption protein p2, which binds to the incp plasmid-encoded conjugative transfer complex. | the double-stranded dna bacteriophage prd1 uses an incp plasmid-encoded conjugal transfer complex as a receptor. plasmid functions in the prd1 life cycle are restricted to phage adsorption and dna entry. a single phage structural protein, p2, located at the fivefold capsid vertices, is responsible for prd1 attachment to its host. the purified recombinant adsorption protein was judged to be monomeric by gel filtration, rate zonal centrifugation, analytical ultracentrifugation, and chemical cross- ... | 1999 | 10542170 |
| role of crotonyl coenzyme a reductase in determining the ratio of polyketides monensin a and monensin b produced by streptomyces cinnamonensis. | the ccr gene, encoding crotonyl coenzyme a (coa) reductase (ccr), was cloned from streptomyces cinnamonensis c730.1 and shown to encode a protein with 90% amino acid sequence identity to the ccrs of streptomyces collinus and streptomyces coelicolor. a ccr-disrupted mutant, s. cinnamonensis l1, was constructed by inserting the hyg resistance gene into a unique bglii site within the ccr coding region. by use of the erme* promoter, the s. collinus ccr gene was expressed from plasmids in s. cinnamon ... | 1999 | 10542184 |
| distribution of tetracycline resistance genes and transposons among phylloplane bacteria in michigan apple orchards. | the extent and nature of tetracycline resistance in bacterial populations of two apple orchards with no or a limited history of oxytetracycline usage were assessed. tetracycline-resistant (tc(r)) bacteria were mostly gram negative and represented from 0 to 47% of the total bacterial population on blossoms and leaves (versus 26 to 84% for streptomycin-resistant bacteria). a total of 87 isolates were screened for the presence of specific tc(r) determinants. tc(r) was determined to be due to the pr ... | 1999 | 10543801 |
| characterization of plasmids encoding the phytotoxin coronatine in pseudomonas syringae. | coronatine (cor) is a nonhost-specific phytotoxin that substantially contributes to the virulence of several pathovars (pvs.) of pseudomonas syringae. the cor gene cluster in p. syringae is generally plasmid-encoded in pvs. atropurpurea, glycinea, morsprunorum, and tomato but chromosomally encoded in pv. maculicola. in the present study, we investigated whether the cor plasmids in four pathovars shared other traits including self-transmissibility, conserved oriv/par loci, and insertion sequences ... | 1999 | 10545263 |
| a novel virus-host cell membrane interaction. membrane voltage-dependent endocytic-like entry of bacteriophage straight phi6 nucleocapsid. | studies on the virus-cell interactions have proven valuable in elucidating vital cellular processes. interestingly, certain virus-host membrane interactions found in eukaryotic systems seem also to operate in prokaryotes (bamford, d.h., m. romantschuk, and p. j. somerharju, 1987. embo (eur. mol. biol. organ.) j. 6:1467-1473; romantschuk, m., v.m. olkkonen, and d.h. bamford. 1988. embo (eur. mol. biol. organ.) j. 7:1821-1829). straight phi6 is an enveloped double-stranded rna virus infecting a gr ... | 1999 | 10545509 |
| lsd1 regulates salicylic acid induction of copper zinc superoxide dismutase in arabidopsis thaliana. | we characterized the accumulation patterns of arabidopsis thaliana proteins, two cuznsods, fesod, mnsod, pr1, pr5, and gst1, in response to various pathogen-associated treatments. these treatments included inoculation with virulent and avirulent pseudomonas syringae strains, spontaneous lesion formation in the lsd1 mutant, and treatment with the salicylic acid (sa) analogs ina (2,6-dichloroisonicotinic acid) and bth (benzothiadiazole). the pr1, pr5, and gst1 proteins were inducible by all treatm ... | 1999 | 10550898 |
| phylogenetic analysis of pseudomonas syringae pathovars suggests the horizontal gene transfer of argk and the evolutionary stability of hrp gene cluster. | pseudomonas syringae are differentiated into approximately 50 pathovars with different plant pathogenicities and host specificities. to understand its pathogenicity differentiation and the evolutionary mechanisms of pathogenicity-related genes, phylogenetic analyses were conducted using 56 strains belonging to 19 pathovars. gyrb and rpod were adopted as the index genes to determine the course of bacterial genome evolution, and hrpl and hrps were selected as the representatives of the pathogenici ... | 1999 | 10552044 |
| assembly dynamics of the nucleocapsid shell subunit (p8) of bacteriophage phi6. | phi6 is an enveloped dsrna bacteriophage of pseudomonas syringae. the viral envelope encloses a nucleocapsid, consisting of an rna-dependent rna polymerase complex within an icosahedral shell assembled from approximately 800 copies of a 16 kda subunit (protein p8, encoded by viral gene 8). during infection, the nucleocapsid penetrates the host plasma membrane and enters the cytosol, whereupon the p8 shell disassembles and the polymerase complex is activated. to understand the molecular mechanism ... | 1999 | 10555985 |
| 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 ... | 1999 | 10557364 |
| immunochemical characterization and taxonomic evaluation of the o polysaccharides of the lipopolysaccharides of pseudomonas syringae serogroup o1 strains. | the o polysaccharide (ops) of the lipopolysaccharide (lps) of pseudomonas syringae pv. atrofaciens imv 7836 and some other strains that are classified in serogroup o1 was shown to be a novel linear alpha-d-rhamnan with the tetrasaccharide o repeat -->3)-alpha-d-rhap-(1-->3)-alpha-d-rhap-(1-->2)-alpha-d-r hap-(1-->2)- alpha-d-rhap-(1--> (chemotype 1a). the same alpha-d-rhamnan serves as the backbone in branched opss with lateral (alpha1-->3)-linked d-rhap, (beta1-->4)-linked d-glcpnac, and (alpha ... | 1999 | 10559159 |
| a novel lipolytic enzyme located in the outer membrane of pseudomonas aeruginosa. | a lipase-negative deletion mutant of pseudomonas aeruginosa pao1 still showed extracellular lipolytic activity toward short-chain p-nitrophenylesters. by screening a genomic dna library of p. aeruginosa pao1, an esterase gene, esta, was identified, cloned, and sequenced, revealing an open reading frame of 1,941 bp. the product of esta is a 69.5-kda protein, which is probably processed by removal of an n-terminal signal peptide to yield a 67-kda mature protein. a molecular mass of 66 kda was dete ... | 1999 | 10559163 |
| mutational analysis of the pseudomonas syringae pv. tomato hrpa gene encoding hrp pilus subunit. | plant pathogenic pseudomonas syringae strains harbour a type iii secretion pathway suggested to be involved in the delivery of effector proteins from the bacteria into plant cells. during plant interaction, the bacteria apparently produce surface appendages, termed hrp pili, that are indispensable for the secretion process. we have created an insertion mutation library, as well as deletion mutations to hrpa, the structural gene encoding hrp pilin. analysis of the mutants revealed gene regions im ... | 1999 | 10564513 |
| global gaca-steered control of cyanide and exoprotease production in pseudomonas fluorescens involves specific ribosome binding sites. | the conserved two-component regulatory system gacs/gaca determines the expression of extracellular products and virulence factors in a variety of gram-negative bacteria. in the biocontrol strain cha0 of pseudomonas fluorescens, the response regulator gaca is essential for the synthesis of extracellular protease (apra) and secondary metabolites including hydrogen cyanide. gaca was found to exert its control on the hydrogen cyanide biosynthetic genes (hcnabc) and on the apra gene indirectly via a ... | 1999 | 10570200 |
| transgenic tobacco plants with reduced capability to detoxify reactive oxygen intermediates are hyperresponsive to pathogen infection. | reactive oxygen intermediates (roi) play a critical role in the defense of plants against invading pathogens. produced during the "oxidative burst," they are thought to activate programmed cell death (pcd) and induce antimicrobial defenses such as pathogenesis-related proteins. it was shown recently that during the interaction of plants with pathogens, the expression of roi-detoxifying enzymes such as ascorbate peroxidase (apx) and catalase (cat) is suppressed. it was suggested that this suppres ... | 1999 | 10570216 |
| a novel myb oncogene homologue in arabidopsis thaliana related to hypersensitive cell death. | a novel myb oncogene homologue (atmyb30) has been isolated by differential screening of a cdna library prepared from xanthomonas campestris pv. campestris (x. campestris)-inoculated arabidopsis thaliana cells cultured in the presence of cycloheximide. atmyb30 is a single-copy gene, and the encoded protein contains a myb domain highly homologous to other plant and animal myb proteins. analyses of transcript levels in a. thaliana plants, or in cultured a. thaliana cells infected with either virule ... | 1999 | 10571865 |
| harpin induces disease resistance in arabidopsis through the systemic acquired resistance pathway mediated by salicylic acid and the nim1 gene. | harpin, the product of the hrpn gene of erwinia amylovora, elicits the hypersensitive response and disease resistance in many plants. harpin and known inducers of systemic acquired resistance (sar) were tested on five genotypes of arabidopsis thaliana to assess the role of sar in harpin-induced resistance. in wild-type plants, harpin elicited systemic resistance to peronospora parasitica and pseudomonas syringae pv. tomato, accompanied by induction of the sar genes pr-1 and pr-2. however, in exp ... | 1999 | 10571880 |
| the arabidopsis rps4 bacterial-resistance gene is a member of the tir-nbs-lrr family of disease-resistance genes. | plant-disease resistance (r) genes mediate the specific recognition of invading pathogens carrying cognate avirulence (avr) determinants. rps4 is a disease-resistance locus on chromosome 5 of arabidopsis thaliana specifying resistance to strains of pseudomonas syringae pv. tomato expressing avrrps4. we have isolated the rps4 gene using a map-based cloning approach. rps4 encodes a predicted protein of 1217 amino acids that contains an n-terminus with homology to the intracellular domains of the d ... | 1999 | 10571887 |
| algt (sigma22) controls alginate production and tolerance to environmental stress in pseudomonas syringae. | pseudomonas aeruginosa and the phytopathogen p. syringae produce the exopolysaccharide alginate, which is a copolymer of d-mannuronic and l-guluronic acids. one of the key regulatory genes controlling alginate biosynthesis in p. aeruginosa is algt, which encodes the alternate sigma factor, sigma(22). in the present study, the algt gene product from p. syringae pv. syringae showed 90% amino acid identity with its p. aeruginosa counterpart, and sequence analysis of the region flanking algt in p. s ... | 1999 | 10572118 |
| biosynthetic origin of syringomycin and syringopeptin 22, toxic secondary metabolites of the phytopathogenic bacterium pseudomonas syringae pv. syringae. | the biosynthesis of syringomycin (sr) and syringopeptin 22 (sp22), bioactive lipodepsipeptides of the phytopathogenic bacterium pseudomonas syringae pv. syringae, was studied by feeding (14)c-labeled precursors to chloramphenicol-containing bacterial suspensions. the preferential sites of incorporation were determined by comparing the specific activities of the intact radiolabeled metabolites and their single structural elements, obtained by hydrolytic degradation followed by derivatization and ... | 1999 | 10580109 |
| utilization of heterologous siderophores enhances levels of iron available to pseudomonas putida in the rhizosphere. | pseudomonas spp. have the capacity to utilize siderophores produced by diverse species of bacteria and fungi, and the present study was initiated to determine if siderophores produced by rhizosphere microorganisms enhance the levels of iron available to a strain of pseudomonas putida in this natural habitat. we used a previously described transcriptional fusion (pvd-inaz) between an iron-regulated promoter (pvd) and the ice nucleation reporter gene (inaz) to detect alterations in iron availabili ... | 1999 | 10583989 |
| requirement for phosphoglucose isomerase of xanthomonas campestris in pathogenesis of citrus canker. | a mutant (xt906) of xanthomonas campestris pv. citri, the causal agent of citrus canker, was induced by insertion of the transposon tn5tac1 and isolated. this mutant did not grow or elicit canker disease in citrus leaves but was still able to induce a hypersensitive response in a nonhost plant (the common bean). the mutant was also unable to grow on minimal medium containing fructose or glycerol as the sole carbon source. a 2.5-kb fragment of wild-type dna that complemented the mutant phenotype ... | 1999 | 10584018 |
| arabidopsis pad3, a gene required for camalexin biosynthesis, encodes a putative cytochrome p450 monooxygenase. | phytoalexins are low molecular weight antimicrobial compounds that are synthesized in response to pathogen attack. the phytoalexin camalexin, an indole derivative, is produced by arabidopsis in response to infection with the bacterial pathogen pseudomonas syringae. the phytoalexin deficient 3 (pad3) mutation, which causes a defect in camalexin production, has no effect on resistance to p. syringae but compromises resistance to the fungal pathogen alternaria brassicicola. we have now isolated pad ... | 1999 | 10590168 |
| harpin induces mitogen-activated protein kinase activity during defence responses in arabidopsis thaliana suspension cultures. | elicitation of arabidopsis thaliana (l.) heynh. suspension cultures with the bacterial protein harpin (from pseudomonas syringae pv. syringae) induced the activation of two kinases of 39 and 44 kda, as demonstrated by in-gel kinase assays using myelin basic protein (mbp) as a substrate. both these kinases appeared to be tyrosine-phosphorylated upon activation, as demonstrated by treatment with tyrosine phosphatase and immunoprecipitation using an anti-phosphotyrosine monoclonal antibody. an inhi ... | 1999 | 10592037 |
| requirement of functional ethylene-insensitive 2 gene for efficient resistance of arabidopsis to infection by botrytis cinerea. | inoculation of wild-type arabidopsis plants with the fungus alternaria brassicicola results in systemic induction of genes encoding a plant defensin (pdf1.2), a basic chitinase (pr-3), and an acidic hevein-like protein (pr-4). pathogen-induced induction of these three genes is almost completely abolished in the ethylene-insensitive arabidopsis mutant ein2-1. this indicates that a functional ethylene signal transduction component (ein2) is required in this response. the ein2-1 mutants were found ... | 1999 | 10594097 |
| n-acylethanolamines in signal transduction of elicitor perception. attenuation of alkalinization response and activation of defense gene expression | in a recent study of n-acylphosphatidylethanolamine (nape) metabolism in elicitor-treated tobacco (nicotiana tabacum l.) cells, we identified a rapid release and accumulation of medium-chain n-acylethanolamines (naes) (e.g. n-myristoylethanolamine or nae 14:0) and a compensatory decrease in cellular nape (k.d. chapman, s. tripathy, b. venables, a.d. desouza [1998] plant physiol 116: 1163-1168). in the present study, we extend this observation and report a 10- to 50-fold increase in nae 14:0 cont ... | 1999 | 10594117 |
| vir proteins stabilize virb5 and mediate its association with the t pilus of agrobacterium tumefaciens. | three virb proteins (virb1*, virb2, and virb5) have been implicated as putative components of the t pilus from agrobacterium tumefaciens, which likely mediates binding to plant cells followed by transfer of genetic material. recently, virb2 was indeed shown to be its major component (e.-m. lai and c. i. kado, j. bacteriol. 180:2711-2717, 1998). here, the influence of other vir proteins on the stability and cellular localization of virb1*, virb2, and virb5 was analyzed. solubility of virb1* and m ... | 1999 | 10601205 |
| citrate synthase mutants of sinorhizobium meliloti are ineffective and have altered cell surface polysaccharides. | the glta gene, encoding sinorhizobium meliloti 104a14 citrate synthase, was isolated by complementing an escherichia coli glta mutant. the s. meliloti glta gene was mutated by inserting a kanamycin resistance gene and then using homologous recombination to replace the wild-type glta with the glta::kan allele. the resulting strain, csdx1, was a glutamate auxotroph, and enzyme assays confirmed the absence of a requirement for glutamate. csdx1 did not grow on succinate, malate, aspartate, pyruvate, ... | 1999 | 10601220 |
| biological control of postharvest decays of apple can prevent growth of escherichia coli o157:h7 in apple wounds. | fresh cells of the antagonist pseudomonas syringae at 2.4 x 10(8) cfu/ml inoculated into wounds of 'golden delicious' apple prevented escherichia coli o157:h7 (concentrations ranging from 2.4 x 10(5) to 2.4 x 10(7) cfu/ml) from growing in the wounds. this occurred when the two microorganisms were co-inoculated or inoculation with e. coli o157:h7 was conducted 1 or 2 days after inoculation with the antagonist. in similar tests, application of the commercial formulation of this antagonist prevente ... | 1999 | 10606139 |
| pseudomonas syringae pv tomato induces the expression of tomato erebp-like genes pti4 and pti5 independent of ethylene, salicylate and jasmonate | the tomato genes pti4 and pti5 encode ethylene-responsive element binding protein-like transcription factors that bind to the gcc box, a conserved cis-element in many defense-related genes. the pti proteins have previously been shown to interact with the tomato disease resistance protein pto. here we report that the expression of both pti4 and pti5 are induced by a virulent strain of pseudomonas syringae pv tomato. the expression of pti5 is further enhanced by the interaction of the pto gene in ... | 1999 | 10607299 |
| rhizobacteria-mediated induced systemic resistance (isr) in arabidopsis is not associated with a direct effect on expression of known defense-related genes but stimulates the expression of the jasmonate-inducible gene atvsp upon challenge. | selected strains of nonpathogenic rhizobacteria from the genus pseudomonas are capable of eliciting broad-spectrum induced systemic resistance (isr) in plants that is phenotypically similar to pathogen-induced systemic acquired resistance (sar). in arabidopsis, the isr pathway functions independently of salicylic acid (sa) but requires responsiveness to jasmonate and ethylene. here, we demonstrate that known defense-related genes, i.e. the sa-responsive genes pr-1, pr-2, and pr-5, the ethylene-i ... | 1999 | 10608663 |
| cloning of chlorophyllase, the key enzyme in chlorophyll degradation: finding of a lipase motif and the induction by methyl jasmonate. | chlorophyllase (chlase) is the first enzyme involved in chlorophyll (chl) degradation and catalyzes the hydrolysis of ester bond to yield chlorophyllide and phytol. in the present study, we isolated the chlase cdna. we synthesized degenerate oligo dna probes based on the internal amino acid sequences of purified chlase from chenopodium album, screened the c. album cdna library, and cloned a cdna (caclh, c. album chlorophyll-chlorophyllido hydrolase). the deduced amino acid sequence (347 aa resid ... | 1999 | 10611389 |
| molecular cloning of a defense-response-related cytochrome p450 gene from tobacco. | plant defenses against pathogen attack involve a series of inducible responses that contribute to resistance. tobacco leaves injected with hwc (hyphal wall components prepared from phytophthora infestans) elicitor showed typical defense responses, including the induction of localized necrosis and the accumulation of pathogenesis-related proteins. in order to elucidate the molecular mechanisms by which plant defense systems are activated, we screened tobacco plants for genes differentially expres ... | 1999 | 10682345 |
| serological and molecular size characterization of flagellins of pseudomonas syringae pathovars and related bacteria | flagella from a total of 118 strains representing mostly pathovars of the phytopathogenic group pseudomonas syringae, but also p. chlororaphis, p. cichorii, p. corrugata, p. fluorescens, p. fuscovaginae, p. stutzeri, p. viridiflava, as well as related phytopathogenic genera (burkholderia cepacia and ralstonia solanacearum) were characterized by immuno-fluorescent staining, sds-page, and immunoblotting. eighty-six strains of the p. syringae group pathovars, p. cichorii and p. viridiflava were sho ... | 1999 | 10794141 |
| antifungal peptides: novel therapeutic compounds against emerging pathogens. | 1999 | 9869556 | |
| antiseptics and disinfectants: activity, action, and resistance. | antiseptics and disinfectants are extensively used in hospitals and other health care settings for a variety of topical and hard-surface applications. a wide variety of active chemical agents (biocides) are found in these products, many of which have been used for hundreds of years, including alcohols, phenols, iodine, and chlorine. most of these active agents demonstrate broad-spectrum antimicrobial activity; however, little is known about the mode of action of these agents in comparison to ant ... | 1999 | 9880479 |
| epiphytic colonization of pear stigmas and hypanthia by bacteria during primary bloom. | abstract pear blossoms were sampled during various stages of bloom in 1991 and 1992 from orchards at cashmere, wa, and corvallis and medford, or, for epiphytic populations of culturable bacteria. on stigmatic surfaces, bacteria were isolated from 2 to 32% of blossoms prior to petal expansion and from 47 to 94% of blossoms by petal fall. in general, a lower percentage of hypanthia than stigmas supported bacterial populations. randomly selected bacteria isolated at population levels of >/=10(4) cf ... | 1999 | 18944640 |
| influence of stem diameter, water content, and freezing-thawing on bacterial canker development in excised stems of dormant stone fruit. | abstract in excised dormant stems of peach (prunus persica), prune (prunus domestica), and almond (prunus dulcis), stem diameter, stem hydration, and freezing-thawing influenced the extent of infection caused by pseudomonas syringae pv. syringae. bacterial lesion length increased with increasing stem diameter, demonstrating the need to account for the effects of stem diameter when lesion length data are analyzed. lesion length increased or decreased with stem hydration or dehydration, respective ... | 1999 | 18944742 |
| comparison of ethylene production by pseudomonas syringae and ralstonia solanacearum. | abstract strains of pseudomonas syringae pv. pisi and ralstonia solanacearum produced ethylene at rates 20- and 200-fold lower, respectively, than strains of p. syringae pvs. cannabina, glycinea, phaseolicola, and sesami. in the current study, we investigated which ethylene biosynthetic pathways were used by p. syringae pv. pisi and r. solanacearum. neither the activity of an ethylene-forming enzyme nor a corresponding efe gene homolog could be detected in r. solanacearum, suggesting synthesis o ... | 1999 | 18944747 |
| adding the third dimension to virus life cycles: three-dimensional reconstruction of icosahedral viruses from cryo-electron micrographs. | viruses are cellular parasites. the linkage between viral and host functions makes the study of a viral life cycle an important key to cellular functions. a deeper understanding of many aspects of viral life cycles has emerged from coordinated molecular and structural studies carried out with a wide range of viral pathogens. structural studies of viruses by means of cryo-electron microscopy and three-dimensional image reconstruction methods have grown explosively in the last decade. here we revi ... | 1999 | 10585969 |
| programmed cell death in castor bean endosperm is associated with the accumulation and release of a cysteine endopeptidase from ricinosomes. | the cells of the endosperm of castor bean seeds (ricinus communis) undergo programmed cell death during germination, after their oil and protein reserves have been mobilized. nuclear dna fragmentation first was observed at day 3 in the endosperm cells immediately adjacent to the cotyledons and progressed across to the outermost cell layers by day 5. we also detected the accumulation of small organelles known as ricinosomes, by using an antibody against a cysteine endoprotease. by the time the nu ... | 1999 | 10570215 |
| fungal resistance to plant antibiotics as a mechanism of pathogenesis. | many plants produce low-molecular-weight compounds which inhibit the growth of phytopathogenic fungi in vitro. these compounds may be preformed inhibitors that are present constitutively in healthy plants (also known as phytoanticipins), or they may be synthesized in response to pathogen attack (phytoalexins). successful pathogens must be able to circumvent or overcome these antifungal defenses, and this review focuses on the significance of fungal resistance to plant antibiotics as a mechanism ... | 1999 | 10477313 |
| differential induction of plant volatile biosynthesis in the lima bean by early and late intermediates of the octadecanoid-signaling pathway. | plants are able to respond to herbivore damage with de novo biosynthesis of an herbivore-characteristic blend of volatiles. the signal transduction initiating volatile biosynthesis may involve the activation of the octadecanoid pathway, as exemplified by the transient increase of endogenous jasmonic acid (ja) in leaves of lima bean (phaseolus lunatus) after treatment with the macromolecular elicitor cellulysin. within this pathway lima bean possesses at least two different biologically active si ... | 1999 | 10482670 |
| subcellular localization studies indicate that lipoxygenases 1 to 6 are not involved in lipid mobilization during soybean germination | soybean (glycine max) lipoxygenase (lox) has been proposed to be involved in reserve lipid mobilization during germination. here, subcellular fractionation studies show that lox1, -2, -3, -4, -5, and -6 isozymes were associated with the soluble fraction but not with purified oil bodies. the purified oil bodies contained small amounts of lox1 (<0.01% total activity), which apparently is an artifact of the purification process. immunogold labeling indicated that, in cotyledon parenchyma cells of l ... | 1999 | 10318700 |
| the relationship between photosynthesis and a mastoparan-induced hypersensitive response in isolated mesophyll cells | the g-protein activator mastoparan (mp) was found to elicit the hypersensitive response (hr) in isolated asparagus sprengeri mesophyll cells at micromolar concentrations. the hr was characterized by cell death, extracellular alkalinization, and an oxidative burst, indicated by the reduction of molecular o2 to o2. to our knowledge, this study was the first to monitor photosynthesis during the hr. mp had rapid and dramatic effects on photosynthetic electron transport and excitation energy transfer ... | 1999 | 10198081 |
| the involvement of hydrogen peroxide in the differentiation of secondary walls in cotton fibers | h2o2 is a widespread molecule in many biological systems. it is created enzymatically in living cells during various oxidation reactions and by leakage of electrons from the electron transport chains. depending on the concentration h2o2 can induce cell protective responses, programmed cell death, or necrosis. here we provide evidence that h2o2 may function as a developmental signal in the differentiation of secondary walls in cotton (gossypium hirsutum) fibers. three lines of evidence support th ... | 1999 | 10069824 |
| the polymerase subunit of a dsrna virus plays a central role in the regulation of viral rna metabolism. | bacteriophage φ6 has a three-segmented double-stranded (ds) rna genome, which resides inside a polymerase complex particle throughout the entire life cycle of the virus. the polymerase subunit p2, a minor constituent of the polymerase complex, has previously been reported to replicate both φ6-specific and heterologous single-stranded (ss) rnas, giving rise to dsrna products. in this study, we show that the enzyme is also able to use dsrna templates to perform semi-conservative rna transc ... | 2000 | 11080173 |
| impact of post-anoxia stress on membrane lipids of anoxia-pretreated potato cells. a re-appraisal. | the importance of lipid peroxidation and its contributing pathways (via reactive oxygen species and lipoxygenase) during post-anoxia was evaluated with respect to the biphasic behavior of membrane lipids under anoxia (a. rawyler, d. pavelic, c. gianinazzi, j. oberson, r. brändle [1999] plant physiol 120: 293-300), using potato (solanum tuberosum cv bintje) cell cultures. when anoxic cells in the pre-lytic phase were re-oxygenated for 2 h, superoxide anion was not detectable, the hydrogen peroxid ... | 2000 | 11080304 |
| sensing of osmotic pressure changes in tomato cells. | cells of tomato (lycopersicon esculentum) growing in suspension gradually depleted their culture medium and caused a steady decrease in its osmolality. when confronted with a sudden change in medium osmolality (a hypo-osmotic or hyperosmotic shock), respectively, these cells responded with volume changes and stress symptoms such as rapid extracellular alkalinization, efflux of k(+)-ions, and induction of 1-aminocyclopropane-1-carboxylate synthase acid, the key enzyme of ethylene biosynthesis. th ... | 2000 | 11080294 |
| ozone-sensitive arabidopsis rcd1 mutant reveals opposite roles for ethylene and jasmonate signaling pathways in regulating superoxide-dependent cell death. | we have isolated a codominant arabidopsis mutant, radical-induced cell death1 (rcd1), in which ozone (o(3)) and extracellular superoxide (o(2)(*)-), but not hydrogen peroxide, induce cellular o(2)(*)- accumulation and transient spreading lesions. the cellular o(2)(*)- accumulation is ethylene dependent, occurs ahead of the expanding lesions before visible symptoms appear, and is required for lesion propagation. exogenous ethylene increased o(2)(*)--dependent cell death, whereas impairment of eth ... | 2000 | 11041881 |
| fumonisin b1-induced cell death in arabidopsis protoplasts requires jasmonate-, ethylene-, and salicylate-dependent signaling pathways. | we have established an arabidopsis protoplast model system to study plant cell death signaling. the fungal toxin fumonisin b1 (fb1) induces apoptosis-like programmed cell death (pcd) in wild-type protoplasts. fb1, however, only marginally affects the viability of protoplasts isolated from transgenic nahg plants, in which salicylic acid (sa) is metabolically degraded; from pad4-1 mutant plants, in which an sa amplification mechanism is thought to be impaired; or from jar1-1 or etr1-1 mutant plant ... | 2000 | 11041879 |
| local and systemic changes in squash gene expression in response to silverleaf whitefly feeding. | squash genes (slw1 and slw3) induced systemically after silverleaf whitefly feeding were identified. differences in the local and systemic expression of slw1 and slw3 after feeding by the closely related silverleaf and sweetpotato whiteflies were observed. temporal and spatial studies showed that slw1 and slw3 were induced when second, third, and fourth nymphal instars were feeding. although only barely detected after wounding and bacterial infection, slw1 and slw3 rnas were abundant during wate ... | 2000 | 10948259 |
| characterization and expression of dna sequences encoding putative type-ii metallothioneins in the seagrass posidonia oceanica. | posidonia oceanica is a marine phanerogam, largely widespread in the mediterranean sea, representing an important food substrate for many marine organisms. a progressive reduction of p. oceanica meadows has been reported, due to anthropogenic coastal activity. studying mechanisms by which this species responds to environmental stresses, three dna sequences putatively encoding metallothioneins (mts) have been isolated, by pcr. two sequences, pomt2a (accession no. aj249603) and pomt2b (accession n ... | 2000 | 10938373 |
| the mid-pericarp cell layer in soybean pod walls is a multicellular compartment enriched in specific lipoxygenase isoforms. | specific lipoxygenase isoforms immunolocalize to the cytosol of a single cell layer in the soybean (glycine max l.) pod wall. the cells of this layer, termed the mid-pericarp layer (mpl), are larger than adjacent cells and are highly branched. the entire mpl appears to form an elaborate interdigitated network within the pod wall. a particularly striking feature of the mpl is the presence of extensive regions of very thin, approximately 30 nm, cell wall, which connect the cells of the mpl. it was ... | 2000 | 10938347 |
| genetic complexity of pathogen perception by plants: the example of rcr3, a tomato gene required specifically by cf-2. | genetic analysis of plant-pathogen interactions has demonstrated that resistance to infection is often determined by the interaction of dominant plant resistance (r) genes and dominant pathogen-encoded avirulence (avr) genes. it was postulated that r genes encode receptors for avr determinants. a large number of r genes and their cognate avr genes have now been analyzed at the molecular level. r gene loci are extremely polymorphic, particularly in sequences encoding amino acids of the leucine-ri ... | 2000 | 10922039 |
| gene genealogies and population variation in plants. | early in the development of plant evolutionary biology, genetic drift, fluctuations in population size, and isolation were identified as critical processes that affect the course of evolution in plant species. attempts to assess these processes in natural populations became possible only with the development of neutral genetic markers in the 1960s. more recently, the application of historically ordered neutral molecular variation (within the conceptual framework of coalescent theory) has allowed ... | 2000 | 10860966 |
| ozone sensitivity in hybrid poplar correlates with insensitivity to both salicylic acid and jasmonic acid. the role of programmed cell death in lesion formation. | our earlier studies demonstrated that the ozone-sensitive hybrid poplar clone ne-388 displays an attenuated level of ozone-, wound-, and phytopathogen-induced defense gene expression. to determine if this reduced gene activation involves signal transduction pathways dependent on salicylic acid (sa) and/or jasmonic acid (ja), we compared the responses of ne-388 and an ozone-tolerant clone, ne-245, to these signal molecules. ja levels increased in both clones in response to ozone, but only minimal ... | 2000 | 10859179 |
| octadecanoid-derived alteration of gene expression and the "oxylipin signature" in stressed barley leaves. implications for different signaling pathways. | stress-induced gene expression in barley (hordeum vulgare cv salome) leaves has been correlated with temporally changing levels of octadecanoids and jasmonates, quantified by means of gas chromatography/mass spectrometry-single ion monitoring. application of sorbitol-induced stress led to a low and transient rise of jasmonic acid (ja), its precursor 12-oxophytodienoic acid (opda), and the methyl esters jame and opdame, respectively, followed by a large increase in their levels. ja and jame peake ... | 2000 | 10806235 |
| genome organization in dicots: genome duplication in arabidopsis and synteny between soybean and arabidopsis. | synteny between soybean and arabidopsis was studied by using conceptual translations of dna sequences from loci that map to soybean linkage groups a2, j, and l. synteny was found between these linkage groups and all four of the arabidopsis chromosomes, where genbank contained enough sequence for synteny to be identified confidently. soybean linkage group a2 (soya2) and arabidopsis chromosome i showed significant synteny over almost their entire lengths, with only 2-3 chromosomal rearrangements r ... | 2000 | 10759555 |
| reply. establishing a paradigm for the generation of new s alleles | 2000 | 10715318 | |
| characterization of p69e and p69f, two differentially regulated genes encoding new members of the subtilisin-like proteinase family from tomato plants. | subtilisin-like proteins represent an ancient family of serine proteases that are extremely widespread in living organisms. we report here the structure and genomic organization of two new transcriptionally active genes encoding proteins that belong to the p69 family of subtilisin-like proteases from tomato (lycopersicon esculentum) plants. the two new members, p69e and p69f, are organized in a cluster and arranged in a tandem form. mrna expression analysis and studies of transgenic arabidopsis ... | 2000 | 10631250 |
| population dynamics of postharvest decay antagonists growing epiphytically and within wounds on grapefruit. | abstract coating formulations of shellac, sucrose ester, and cellulose were tested that support populations of bacterial and yeast antagonists of postharvest penicillium decay of grapefruit. surface populations of pseudomonas syringae, p. fluorescens, and p. putida were stable between 10(3) and 10(4) cfu/cm(2) on shellacked fruit over 4 months at 13 degrees c, but numbers of the yeast candida oleophila rose steadily from 2.35 x 10(3) to nearly 10(5). through the first 15 days of cold storage, su ... | 2000 | 18944423 |
| riboflavin induces disease resistance in plants by activating a novel signal transduction pathway. | abstract the role of riboflavin as an elicitor of systemic resistance and an activator of a novel signaling process in plants was demonstrated. following treatment with riboflavin, arabidopsis thaliana developed systemic resistance to peronospora parasitica and pseudomonas syringae pv. tomato, and tobacco developed systemic resistance to tobacco mosaic virus (tmv) and alternaria alternata. riboflavin, at concentrations necessary for resistance induction, did not cause cell death in plants or dir ... | 2000 | 18944500 |
| the relationship of host range, physiology, and genotype to virulence on cantaloupe in pseudomonas syringae from cantaloupe blight epidemics in france. | abstract in 1993, a bacterial blight caused important losses of cantaloupe (cucumis melo var. cantalupensis) in southwestern france and has now been reported in all cantaloupe-growing regions of france. the causal agent of this blight is pseudomonas syringae, although on a worldwide basis this bacterium has not been a major pathogen of melon for over 50 years. to identify the pathovar of the cantaloupe pathogen, we employed biochemical tests, plasmid and chromosomal profiling, and host range stu ... | 2000 | 18944544 |
| biological control of pseudomonas syringae pv. syringae, the causal agent of basal kernel blight of barley, by antagonistic pantoea agglomerans. | abstract strains of pantoea agglomerans (synanamorph erwinia herbicola) suppressed the development of basal kernel blight of barley, caused by pseudomonas syringae pv. syringae, when applied to heads prior to the pseudomonas syringae pv. syringae infection window at the soft dough stage of kernel development. field experiments in 1994 and 1995 revealed 45 to 74% kernel blight disease reduction, whereas glasshouse studies resulted in 50 to 100% disease control depending on the isolate used and ba ... | 2000 | 18944586 |
| impact of wheat cultivation on microbial communities from replant soils and apple growth in greenhouse trials. | abstract studies were conducted to assess the impact of short-term rotations of wheat on microbial community composition and growth of apple in soils from replant orchard sites. soils from two orchards were cultivated with three successive 28-day growth cycles of 'eltan', 'penewawa', or 'rely' wheat in the greenhouse and subsequently planted to 'gala' apple seedlings. cultivation of orchard replant soils with any of the three wheat cultivars enhanced growth of apple relative to that achieved in ... | 2000 | 18944598 |
| evaluation of proposed amended names of several pseudomonads and xanthomonads and recommendations. | abstract in 1980, over 90% of all plant-pathogenic pseudomonads and xanthomonads were lumped into pseudomonas syringae and xanthomonas campestris, respectively, as pathovars. the term "pathovar" was created to preserve the name of plant pathogens, but has no official standing in nomenclature. proposals to elevate and rename several pathovars of the genera pseudomonas and xanthomonas to the rank of species has caused great confusion in the literature. we believe the following changes have merit a ... | 2000 | 18944610 |
| a dsba mutant of pseudomonas syringae exhibits reduced virulence and partial impairment of type iii secretion. | abstract to identify virulence genes of p. syringae pv. tomato strain dc3000 we screened for mutants with reduced virulence on its plant hosts, arabidopsis thaliana and tomato. we isolated a tn5-insertion mutant that exhibited reduced virulence on both hosts. further characterization showed that this mutant carried a single tn5 insertion in the dsba gene, which encodes a periplasmic disulphide bond-forming protein. in addition to reduced virulence, the dsba mutant exhibits mucoid colony morpholo ... | 2000 | 20572960 |
| evidence for the mobility of an avirulence gene, avrppia1, between the chromosome and plasmids of races of pseudomonas syringae pv. pisi. | abstract an 8.5-kb dna fragment containing the avirulence gene avrppia1 is present in the chromosome of race 2 but not present in race 4b of pseudomonas syringae pv. pisi. the likely acquisition of avrppia1 in race 2 at some time in the past was indicated by the presence of direct repeat sequences at the boundaries of the 8.5-kb region, which was amplified by polymerase chain reaction (pcr), cloned and sequenced. the sequence analysis of the 8.5-kb fragment revealed the presence of rulab genes, ... | 2000 | 20572966 |
| expression of the shpx2 peroxidase gene of stylosanthes humilis in transgenic tobacco leads to enhanced resistance to phytophthora parasitica pv. nicotianae and cercospora nicotianae. | abstract previous research indicated that the constitutive expression of a pathogen-inducible peroxidase gene (shpx6a) from stylosanthes humilis in transgenic plants resulted in enhanced resistance to fungal pathogens ( kazan, k., goulter, k.c., way, h.m. and manners, j.m. (1998) expression of a pathogenesis-related peroxidase of stylosanthes humilis in transgenic tobacco and canola and its effect on disease development. plant sci. 136, 207-217). we have now investigated another pathogen-inducib ... | 2000 | 20572969 |
| domain switching between hrpr and hrps affects the regulatory function of the hybrid genes in pseudomonas syringae pv. phaseolicola. | abstract in prokaryotes, a diverse set of physiological processes is regulated by transcription factors which belong to the well-conserved, enhancer-binding protein (ebp) family. these regulatory proteins function together with the alternate sigma factor (sigma(54)). structurally, the ebps are characterized by a central activator domain, containing the recognition motif for the rna polymerase/sigma(54) complex (esigma(54)), and the c-terminal domain, containing a dna-binding helix-turn-helix mot ... | 2000 | 20572970 |
| pseudomonas syringae pv. tomato: the right pathogen, of the right plant, at the right time. | abstract pseudomonas syringae pv. tomato and the closely related pathovar p. s. pv. maculicola have been the focus of intensive research in recent years, not only because of the diseases they cause on tomato and crucifers, but because strains such as p. s. pv. tomato dc3000 and p. s. pv. maculicola es4326 are pathogens of the model plant arabidopsis thaliana. consequently, both p. s. pv. tomato and p. s. pv. maculicola have been widely used to study the molecular mechanisms of host responses to ... | 2000 | 20572973 |
| the bacterial enhancer-dependent sigma(54) (sigma(n)) transcription factor. | 2000 | 10894718 | |
| roles of salicylic acid, jasmonic acid, and ethylene in cpr-induced resistance in arabidopsis. | disease resistance in arabidopsis is regulated by multiple signal transduction pathways in which salicylic acid (sa), jasmonic acid (ja), and ethylene (et) function as key signaling molecules. epistasis analyses were performed between mutants that disrupt these pathways (npr1, eds5, ein2, and jar1) and mutants that constitutively activate these pathways (cpr1, cpr5, and cpr6), allowing exploration of the relationship between the sa- and ja/et-mediated resistance responses. two important findings ... | 2000 | 11090217 |
| how novel methods can help discover more information about foodborne pathogens. | considerable emphasis is being placed on quantitative risk assessment modelling as a basis for regulation of trade in food products. however, for models to be accurate, information about the behaviour of potential pathogens in foods needs to be available. the question is how to obtain this knowledge in a simple and cost effective way. one technique that has great potential is the use of reporter bacteria which have been genetically modified to express a phenotype that can be easily monitored, su ... | 2000 | 18159282 |
| 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 ... | 2000 | 10796016 |
| decreased inositol 1,4,5-trisphosphate content in pathogen-challenged soybean cells. | phosphoinositide-specific phospholipase c (pi-plc) has been shown to be transiently activated when plant cells were treated with elicitors. we thus investigated the activity of pi-plc when soybean cells were infected with the bacterial pathogen pseudomonas syringae pv. glycinea, by measuring cellular cytosolic inositol 1,4,5-trisphosphate (ip3) levels. we observed that ip3 content decreased in both compatible and incompatible interactions. in vitro phosphatase activities were similar in both wat ... | 2000 | 10796022 |
| avrpto enhances growth and necrosis caused by pseudomonas syringae pv.tomato in tomato lines lacking either pto or prf. | avrpto was introduced into three tomato genotypes with two biotic agents to study its role in compatible interactions. avrpto enhanced the capacity of the pseudomonas syringae pv. tomato strain t1 to induce necrotic symptoms on tomato plants that lacked either pto or prf genes. the enhanced necrosis correlated with a small increase in bacterial growth. in planta expression of avrpto in isolation did not elicit necrosis in the absence of a functional prf gene. | 2000 | 10796023 |
| ethylene formation and phenotypic analysis of transgenic tobacco plants expressing a bacterial ethylene-forming enzyme. | a bacterial ethylene-forming enzyme (efe) catalyzes oxygenation of 2-oxoglutarate to produce ethylene and carbon dioxide in contrast to a plant enzyme which uses 1-aminocyclopropane-1-carboxylic acid as a substrate. we constructed several lines of transgenic tobacco plants which expressed an efe from pseudomonas syringae pv. phaseolicola pk2. the gene encoding a chimeric protein consisting of efe and beta-glucuronidase (gus) was introduced into the tobacco genome using a binary vector which dire ... | 2000 | 10805596 |
| response to xanthomonas campestris pv. vesicatoria in tomato involves regulation of ethylene receptor gene expression. | although ethylene regulates a wide range of defense-related genes, its role in plant defense varies greatly among different plant-microbe interactions. we compared ethylene's role in plant response to virulent and avirulent strains of xanthomonas campestris pv. vesicatoria in tomato (lycopersicon esculentum mill.). the ethylene-insensitive never ripe (nr) mutant displays increased tolerance to the virulent strain, while maintaining resistance to the avirulent strain. expression of the ethylene r ... | 2000 | 10806227 |
| differential regulation of plastidial and cytosolic isoforms of peptide methionine sulfoxide reductase in arabidopsis. | we report the characterization of two members of a gene family from arabidopsis that encode, respectively, cytosolic (cpmsr) and plastid-targeted (ppmsr) isoforms of the oxidative-stress-repair enzyme peptide methionine sulfoxide reductase. overexpression of these proteins in escherichia coli confirmed that each had pmsr enzyme activity with a synthetic substrate, n-acetyl-[(3)h]-methionine sulfoxide, or a biological substrate, alpha-1 proteinase inhibitor. the ppmsr was imported into intact chl ... | 2000 | 10806242 |
| cloning and expression of ntnd, encoding a novel nad(p)(+)-independent 4-nitrobenzyl alcohol dehydrogenase from pseudomonas sp. strain tw3. | pseudomonas sp. strain tw3 is able to metabolize 4-nitrotoluene to 4-nitrobenzoate and toluene to benzoate aerobically via a route analogous to the upper pathway of the tol plasmids. we report the cloning and characterization of a benzyl alcohol dehydrogenase gene (ntnd) which encodes the enzyme for the catabolism of 4-nitrobenzyl alcohol and benzyl alcohol to 4-nitrobenzaldehyde and benzaldehyde, respectively. the gene is located downstream of the previously reported ntn gene cluster. ntnd bear ... | 2000 | 10809692 |