Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| isolation of phytoalexin-deficient mutants of arabidopsis thaliana and characterization of their interactions with bacterial pathogens. | a genetic approach was used to assess the extent to which a particular plant defense response, phytoalexin biosynthesis, contributes to arabidopsis thaliana resistance to pseudomonas syringae pathogens. the a. thaliana phytoalexin, camalexin, accumulated in response to infection by various p. syringae strains. no correlation between pathogen avirulence and camalexin accumulation was observed. a biochemical screen was used to isolate three mutants of a. thaliana ecotype columbia that were phytoal ... | 1994 | 8090752 |
| rps2 of arabidopsis thaliana: a leucine-rich repeat class of plant disease resistance genes. | plant disease resistance genes function is highly specific pathogen recognition pathways. prs2 is a resistance gene of arabidopsis thaliana that confers resistance against pseudomonas syringae bacteria that express avirulence gene avrrpt2. rps2 was isolated by the use of a positional cloning strategy. the derived amino acid sequence of rps2 contains leucine-rich repeat, membrane-spanning, leucine zipper, and p loop domains. the function of the rps2 gene product in defense signal transduction is ... | 1994 | 8091210 |
| two different classes of avrd alleles occur in pathovars of pseudomonas syringae. | considerable variation was observed in the occurrence of avirulence gene d (avrd) in different isolates and pathovars of pseudomonas syringae. three functional alleles of avrd were cloned and characterized from p. s. pv. phaseolicola and p. s. pv. lachrymans. these avrd genes occurred on indigenous plasmids in both pathovars, like the allele originally cloned from p. s. pv. tomato. p. s. pv. lachrymans was unique in that it carried two different alleles on plasmids of different sizes. these alle ... | 1994 | 8167364 |
| amino acid residues required for the activity of avrd alleles. | certain pseudomonas syringae pathovars harbor avrd alleles belonging to two different homology classes. the nonfunctional avrd allele of p. s. pv. glycinea is highly homologous to active class ii avrd alleles but has five unique amino acid substitutions. three of these five amino acid changes were shown to be absolutely required for restoration of avrd activity to the p. s. pv. glycinea allele by oligonucleotide site-directed mutagenesis. they were cysteine 19 to arginine, alanine 280 to valine, ... | 1994 | 8167365 |
| synthesis and expression of a gene encoding a 48-residue repeat in the pseudomonas syringae ice nucleation protein. | the aim of this work was to construct short analogues of the repetitive water-binding domain of the pseudomonas syringae ice nucleation protein, inaz. structural analysis of these analogues might provide data pertaining to the protein-water contacts that underlie ice nucleation. an artificial gene coding for a 48-mer repeat sequence from inaz was synthesized from four oligodeoxyribonucleotides and ligated into the expression vector, pgex2t. the recombinant vector was cloned in escherichia coli a ... | 1994 | 8181760 |
| a single promoter sequence recognized by a newly identified alternate sigma factor directs expression of pathogenicity and host range determinants in pseudomonas syringae. | a conserved sequence motif associated with transcription of avr genes was identified in the promoter regions of six pseudomonas syringae pv. syringae pss61 hrp operons. a 34-bp fragment carrying this motif was cloned from the hrpz promoter region and was shown to confer hrpl-dependent promoter activity. expression of pathogenicity and host range determinants in p. syringae strains is thus directed by the apparent alternate sigma factor hrpl. | 1994 | 8188613 |
| the pseudomonas phytotoxin coronatine mimics octadecanoid signalling molecules of higher plants. | the phytotoxic principle, coronatine, which is present in several pathovars of the plant pathogen, pseudomonas syringae was shown to be highly active in completely different, jasmonate-selective bioassays. at nanomolar to micromolar concentrations, coronatine induced the accumulation of defense-related secondary metabolites in several plant cell cultures, induced transcript accumulation of the elicitor-responsive gene encoding the berberine bridge enzyme of eschscholtzia californica, as well as ... | 1994 | 8194607 |
| identification of a putative alternate sigma factor and characterization of a multicomponent regulatory cascade controlling the expression of pseudomonas syringae pv. syringae pss61 hrp and hrma genes. | the pseudomonas syringae hrp and hrma genes controlling pathogenicity and elicitation of the hypersensitive response and the avr genes controlling host range have been shown previously to be regulated by carbon, nitrogen, ph, osmolarity, and hypothetical plant factors. in p. syringae pv. syringae pss61, inactivation of hrp complementation groups ii and xiii reduced expression of a plasmid-borne hrma'-lacz fusion. the hrp regions ii and xiii were cloned on separate plasmids and shown to enhance t ... | 1994 | 8106313 |
| a mutation in the indole-3-acetic acid biosynthesis pathway of pseudomonas syringae pv. syringae affects growth in phaseolus vulgaris and syringomycin production. | homologs of the genes for indole-3-acetic acid (iaa) biosynthesis from pseudomonas syringae pv. savastanoi were retrieved from a genomic library of p. syringae pv. syringae, and their nucleotide sequences were determined. sequence relatedness between the p. syringae pv. syringae and p. syringae pv. savastanoi iaa operons is greater than 90% within the iaam and iaah loci but declines dramatically at a position approximately 200 bp 5' of the iaam translation initiation codon. a third open reading ... | 1994 | 8113177 |
| relevance of chlorine-substituent for the antifungal activity of syringomycin and syringotoxin, metabolites of the phytopathogenic bacterium pseudomonas syringae pv. syringae. | structural analogues of syringomycin and syringotoxin were produced by fermentation, characterized by fab-ms and amino acid analysis and compared to the parent compounds in the antibiosis test against rhodotorula pilimanae. the c-terminal residue was shown to be important for the activity. | 1994 | 8125171 |
| syringomycin production among strains of pseudomonas syringae pv. syringae: conservation of the syrb and syrd genes and activation of phytotoxin production by plant signal molecules. | the syrb and syrd genes of pseudomonas syringae pv. syringae are predicted to encode proteins that function in the synthesis and export of syringomycin, respectively. using portions of the syr genes as dna probes, both genes were shown to be conserved as single copies within a 15-kb or smaller dna region among a broad spectrum of p. s. pv. syringae strains that produce syringomycin or one of its amino acid analogs, syringotoxin and syringostatin. strains representative of p. viridiflava and six ... | 1994 | 7909458 |
| characterization of high-frequency deletions in the iaa-containing plasmid, piaa2, of pseudomonas syringae pv. savastanoi. | the phytopathogenic bacterium pseudomonas syringae pv. savastanoi causes olive and oleander knot disease. the bacterium induces the formation of tumorous galls by the synthesis and secretion of the plant hormones trans-zeatin riboside and indole-3-acetic acid into host intercellular spaces. an italian oleander isolate, pb213, has been observed to lose the ability to synthesize iaa at high frequency, thus becoming non-pathogenic. the iaa genes, located on the 72-kb iaa-containing plasmid, piaa2 w ... | 1994 | 7909615 |
| tomato mutants altered in bacterial disease resistance provide evidence for a new locus controlling pathogen recognition. | we have employed a genetic approach to study the resistance of tomato to the phytopathogenic bacterium pseudomonas syringae pv tomato. resistance to p. s. tomato depends upon expression of the pto locus in tomato, which encodes a protein with similarity to serine/threonine protein kinases and recognizes pathogen strains expressing the avirulence gene avrpto. eleven tomato mutants were isolated with altered resistance to p. s. tomato strains expressing avrpto. we identified mutations both in the ... | 1994 | 7911348 |
| restriction fragment length polymorphism evidence for genetic homology within a pathovar of pseudomonas syringae. | pseudomonas syringae pv. phaseolicola nps3121 hrp sequences were used as hybridization probes in a restriction fragment length polymorphism (rflp) analysis of 24 p. syringae pv. tabaci strains as a means to evaluate the genetic and taxonomic relationship of pathovars of p. syringae. southern blot analyses of genomic restriction digests, with hrpa-s sequences as hybridization probes, and restriction analyses of pcr-amplified dna of regions within hrpd were conducted. the resulting rflp patterns w ... | 1994 | 7912500 |
| identification and relatedness of coronatine-producing pseudomonas syringae pathovars by pcr analysis and sequence determination of the amplification products. | production of the chlorosis-inducing phytotoxin coronatine in the pseudomonas syringae pathovars atropurpurea, glycinea, maculicola, morsprunorum, and tomato has been previously reported. dna hybridization studies previously indicated that the coronatine biosynthetic gene cluster is highly conserved among p. syringae strains which produce the toxin. in the present study, two 17-bp oligonucleotide primers derived from the coronatine biosynthetic gene cluster of p. syringae pv. glycinea pg4180 wer ... | 1994 | 7916181 |
| molecular mechanisms of copper resistance and accumulation in bacteria. | an unusual mechanism of metal resistance is found in certain plant pathogenic strains of pseudomonas syringae that are exposed to high levels of copper compounds used in disease control on agricultural crops. these bacteria accumulate blue cu2+ ions in the periplasm and outer membrane. at least part of this copper sequestering activity is determined by copper-binding protein products of the copper resistance operon (cop). potential copper-binding sites of the periplasmic copa protein show conser ... | 1994 | 7917425 |
| genetic and plasmid diversity within natural populations of pseudomonas syringae with various exposures to copper and streptomycin bactericides. | we examined the genetic and plasmid diversity within natural populations of pseudomonas syringae isolated from three ornamental pear nurseries in eastern oklahoma. the bactericide spray regimen differed at each nursery; copper and streptomycin, only copper, and no bactericides were applied at nurseries i, ii, and iii respectively. resistance to copper (cur) and resistance to streptomycin (smr) were determined for 1,938 isolates of p. syringae; isolates from nurseries i and ii were generally cur ... | 1994 | 7811082 |
| a member of the tomato pto gene family confers sensitivity to fenthion resulting in rapid cell death. | leaves of tomato cultivars that contain the pto bacterial resistance locus develop small necrotic lesions within 24 hr after exposure to fenthion, an organophosphorous insecticide. recently, the pto gene was isolated and shown to be a putative serine/threonine protein kinase. pto is one member of a multigene family that is clustered within a 400-kb region on chromosome 5. here, we report that another member of this gene family, termed fen, is responsible for the sensitivity to fenthion. fen was ... | 1994 | 7827490 |
| newer systems for bacterial resistances to toxic heavy metals. | bacterial plasmids contain specific genes for resistances to toxic heavy metal ions including ag+, aso2-, aso4(3-), cd2+, co2+, cro4(2-), cu2+, hg2+, ni2+, pb2+, sb3+, and zn2+. recent progress with plasmid copper-resistance systems in escherichia coli and pseudomonas syringae show a system of four gene products, an inner membrane protein (pcod), an outer membrane protein (pcob), and two periplasmic cu(2+)-binding proteins (pcoa and pcoc). synthesis of this system is governed by two regulatory p ... | 1994 | 7843081 |
| erwinia chrysanthemi and pseudomonas syringae: plant pathogens trafficking in extracellular virulence proteins. | 1994 | 7859513 | |
| a mutation in arabidopsis that leads to constitutive expression of systemic acquired resistance. | systemic acquired resistance (sar) is a nonspecific defense response in plants that is associated with an increase in the endogenous level of salicylic acid (sa) and elevated expression of pathogenesis-related (pr) genes. to identify mutants involved in the regulation of pr genes and the onset of sar, we transformed arabidopsis with a reporter gene containing the promoter of a beta-1,3-glucanase-encoding pr gene (bgl2) and the coding region of beta-glucuronidase (gus). the resulting transgenic l ... | 1994 | 7866028 |
| characterization of avrpphe, a gene for cultivar-specific avirulence from pseudomonas syringae pv. phaseolicola which is physically linked to hrpy, a new hrp gene identified in the halo-blight bacterium. | the avirulence gene matching the r2 gene for resistance to halo-blight disease in phaseolus was cloned and sequenced from race 4 strain 1302a of pseudomonas syringae pv. phaseolicola. the predicted 41-kda avrpphe protein is hydrophilic, has no features that indicate function, and no similarity to other protein sequences. the promoter region of avrpphe contains a "harp box" motif. the gene was expressed more strongly in minimal than in nutrient-rich media. lower concentrations of the phytoalexin ... | 1994 | 7873779 |
| phosphorylation of membrane proteins in response to temperature in an antarctic pseudomonas syringae. | temperature-dependent phosphorylation and dephosphorylation of membrane proteins was studied in vitro in a number of psychrotrophic antarctic bacteria which grow between 0 and 30 degrees c. one of them, a pseudomonas syringae isolate, was studied in detail and was found to have three membrane proteins of molecular mass 30, 65 and 85 kda which were phosphorylated differently in response to low and high temperatures. the 65 kda protein was phosphorylated only at lower temperatures (between 0 and 1 ... | 1994 | 7881543 |
| cloning and sequencing of an ice nucleation active gene of erwinia uredovora. | an ice nucleation activity gene, named inau, of the bacterium erwinia uredovora kuin-3 has been sequenced. this gene encodes a protein of 1034 amino acid residues, and its expression product, inau protein, has an 832-amino acid residue segment consisting of 52 repeats of closely related 16-amino acid motifs (r-domain), flanked by n- and c-terminal sequences (n- and c-domains, respectively). the primary structure of the inau protein is similar to those of the inaa, inaw, and inaz gene products of ... | 1994 | 7764866 |
| ccd-monitoring of bioluminescence during the induction of the cell wall-deficient, l-form state of a genetically modified strain of pseudomonas syringae pv. phaseolicola. | bioluminescence from developing l-form colonies of the plant pathogen, pseudomonas syringae pv. phaseolicola, was monitored using the enhanced light-detecting capabilities of a charge-coupled device. during l-form induction, the bacteria entered a prolonged period during which the level of light output and hence metabolic activity, was very low. a relatively small number of highly bioluminescent l-form colonies were then observed to develop against a background of non-bioluminescent bacteria. wh ... | 1994 | 7765223 |
| extensin gene expression is induced by mechanical stimuli leading to local cell wall strengthening in nicotiana plumbaginifolia. | nicotiana plumbaginifolia viv. harbors a single extensin gene, although related hydroxyproline-rich sequences are present in the genome. northern analysis showed that the gene is highly expressed in roots and to a lesser extent in stems. expression in leaves is low but mrna levels are increased upon infection with the incompatible bacterium pseudomonas syringae. extensin transcript levels in leaves were slightly enhanced after wounding and salicylic acid treatment. in-situ hybridization experime ... | 1994 | 7765795 |
| structural studies of the side chain of outer membrane lipopolysaccharide from pseudomonas syringae pv. coriandricola w-43. | the lipopolysaccharide (lps) was isolated from pseudomonas syringae pv. coriandricola w-43 by hot phenol-water extraction. rhamnose and 3-n-acetyl-3-deoxyfucose were found to be the major sugar constituents of the lps together with n-acetylglucosamine, n-acetylgalactosamine, heptose, and 3-deoxy-d-manno-octulosonic acid (kdo). the main fatty acids of lipid a of the lps were 3-oh-c:10, c12:0, 2-oh-c12:0, and 3-oh-c12:0. the o-specific polysaccharide liberated from the lps by mild-acid hydrolysis ... | 1994 | 7525536 |
| a biological sensor for iron available to bacteria in their habitats on plant surfaces. | a sensor responsive to iron was constructed by fusing a promoterless ice nucleation activity gene (inaz) to an iron-regulated promoter of a genomic region involved in pyoverdine (fluorescent siderophore) (pvd) production in pseudomonas syringae. cells of pseudomonas fluorescens and p. syringae that contained the pvd-inaz fusion expressed iron-responsive ice nucleation activity in the bean rhizosphere and phyllosphere, respectively, and in culture. addition of fe(iii) to leaves or soil reduced th ... | 1994 | 16349283 |
| inoculum density-dependent mortality and colonization of the phyllosphere by pseudomonas syringae. | pseudomonas syringae inocula containing cell concentrations ranging from 10 to 10 cells per ml were applied to the primary leaves of bean plants. the plants were incubated under conditions of high temperature and illumination and low relative humidity. bacterial mortality rates and the proportional population decline of the inoculum were lowest at the highest inoculum concentrations. addition of a high concentration of heat-killed cells to the inoculum containing a low concentration of viable ce ... | 1994 | 16349313 |
| enhancement of biocontrol of blue mold with the nutrient analog 2-deoxy-d-glucose on apples and pears. | the glucose analog, 2-deoxy-d-glucose (2-dog) enhanced biocontrol of blue mold (caused by penicillium expansum), the most important postharvest disease of apples and pears. 2-dog strongly inhibited p. expansum, and of the two antagonists investigated, pseudomonas syringae was resistant to 2-dog at 10 mg/ml whereas sporobolomyces roseus was susceptible. a mutant of s. roseus resistant to 2-dog was developed. addition of 2-dog at 4 mg/ml allowed more than a 10-fold reduction in the concentration o ... | 1994 | 16349342 |
| cloning and expression of genes required for coronamic acid (2-ethyl-1-aminocyclopropane 1-carboxylic acid), an intermediate in the biosynthesis of the phytotoxin coronatine. | coronamic acid (cma; 2-ethyl-1-aminocyclopropane 1-carboxylic acid) is an intermediate in the biosynthesis of coronatine (cor), a chlorosis-inducing phytotoxin produced by pseudomonas syringae pv. glycinea pg4180. tn5 mutagenesis and substrate feeding studies were previously used to characterize regions of the cor biosynthetic gene cluster required for synthesis of coronafacic acid and cma, which are the only two characterized intermediates in the cor biosynthetic pathway. in the present study, ... | 1994 | 16349356 |
| ecological similarity and coexistence of epiphytic ice-nucleating (ice) pseudomonas syringae strains and a non-ice-nucleating (ice) biological control agent. | de wit replacement series were used to study competitive interactions between epiphytic icepseudomonas syringae strains and the biological frost control agents icep. syringae tlp2del1 and pseudomonas fluorescens a506. mixtures containing two strains in different proportions but at a constant total population size were inoculated onto potato leaves. the population sizes of each strain and the total population size were determined when the community had reached equilibrium. a near-isogenic p. syri ... | 1994 | 16349371 |
| survival, growth, and localization of epiphytic fitness mutants of pseudomonas syringae on leaves. | among 82 epiphytic fitness mutants of a pseudomonas syringae pv. syringae strain that were characterized in a previous study, 4 mutants were particularly intolerant of the stresses associated with dry leaf surfaces. these four mutants each exhibited distinctive behaviors when inoculated onto and into plant leaves. for example, while none showed measurable growth on dry potato leaf surfaces, they grew to different population sizes in the intercellular spaces of bean leaves and on dry bean leaf su ... | 1994 | 16349417 |
| comparison of the behavior of epiphytic fitness mutants of pseudomonas syringae under controlled and field conditions. | the epiphytic fitness of four tn5 mutants of pseudomonas syringae that exhibited reduced epiphytic fitness in the laboratory was evaluated under field conditions. the mutants differed more from the parental strain under field conditions than under laboratory conditions in their survival immediately following inoculation onto bean leaves and in the size of the epiphytic populations that they established, demonstrating that their fitness was reduced more under field conditions than in the laborato ... | 1994 | 16349418 |
| coexistence among epiphytic bacterial populations mediated through nutritional resource partitioning. | the levels of coexistence between pseudomonas syringae and various nonpathogenic epiphytic species in the phyllosphere of beans (phaseolus vulgaris) were assessed by using replacement series. the epiphytic species pseudomonas fluorescens, pantoea agglomerans, stenotrophomonas maltophilia, and methylobacterium organophilum were all capable of exhibiting higher levels of coexistence with p. syringae than was observed with a near-isogenic p. syringae strain pair. the ecological similarity of the ep ... | 1994 | 16349462 |
| characterization of an arabidopsis mutant that is nonresponsive to inducers of systemic acquired resistance. | systemic acquired resistance (sar) is a general defense response in plants that is characterized by the expression of pathogenesis-related (pr) genes. sar can be induced after a hypersensitive response to an avirulent pathogen or by treatment with either salicylic acid (sa) or 2,6-dichloroisonicotinic acid (ina). to dissect the signal transduction pathway of sar, we isolated an arabidopsis mutant that lacks the expression of an sa-, ina-, and pathogen-responsive chimeric reporter gene composed o ... | 1994 | 12244227 |
| function of oxidative cross-linking of cell wall structural proteins in plant disease resistance. | elicitation of soybean cells causes a rapid insolubilization of two cell wall structural proteins, p33 and p100. likewise, a short elicitation of 30 min rendered cell walls more refractory to enzyme digestion as assayed by the yield of protoplasts released. this effect could be ascribed to protein cross-linking because of its insensitivity to inhibitors of transcription (actinomycin d) and translation (cycloheximide) and its induction by exogenous h2o2. moreover, the induced loss of protoplasts ... | 1994 | 12244231 |
| arabidopsis mutants selected for resistance to the phytotoxin coronatine are male sterile, insensitive to methyl jasmonate, and resistant to a bacterial pathogen. | the phytotoxin coronatine and the plant growth regulator methyl jasmonate (meja) caused similar growth-inhibitory effects on arabidopsis seedlings. to test whether these two compounds have similar action, 14 independent coi1 (coronatine-insensitive) mutants of arabidopsis were selected. the mutants segregated as single recessive mendelian markers, and all were alleles at the coi1 locus. all coi1 mutants were also insensitive to meja and were male sterile. both coronatine and meja inhibited root ... | 1994 | 12244256 |
| pto3 and pto4: novel genes from lycopersicon hirsutum var. glabratum that confer resistance to pseudomonas syringae pv tomato. | accessions of wild lycopersicon germplasm were screened for resistance to pseudomonas syringae pv tomato (p.s. tomato). resistance to both race-0 and race-1 strains of p.s. tomato was identified in l. pimpinellifolium, l. peruvianum and l. hirsutum var. glabratum. resistance to race-0 derived from l. hirsutum var. glabratum (pto3) appeared to be inherited independently of pto1 and pto2. filial and backcross generations derived from interspecific crosses between l. esculentum and l. hirsutum var. ... | 1994 | 24178099 |
| the expression of cecropin peptide in transgenic tobacco does not confer resistance to pseudomonas syringae pv tabaci. | we used in vitro growth inhibition assays to demonstrate that synthetic cecropin protein has potent activity against a range of plant pathogenic bacteria. we then prepared transgenic tobacco plants which express cecropin mrna and protein. we have used pseudomonas syringae pv tabaci infection of these transgenic tobacco as a model system to evaluate whether the plants which express cecropin protein also have increased tolerance to infection. we found no dramatic difference in disease response bet ... | 1994 | 24193769 |
| the ice nucleation gene from pseudomonas syringae as a sensitive gene reporter for promoter analysis in zymomonas mobilis. | the expression of the ice nucleation gene inaz from pseudomonas syringae in zymomonas mobilis strains under the control of three different promoters was investigated to establish the utility of the gene as a reporter and examine the possible use of the organism as a source of ice nuclei for biotechnological applications. a promoterless version of the inaz gene was placed under the control of three different promoters: p(infpdc) (pyruvate decarboxylase), a homologous strong promoter from z. mobil ... | 1995 | 16534909 |
| bioacetylation of seaweed alginate. | seaweed alginate was acetylated by intact, resting cells of pseudomonas syringae atcc 19304. maximum acetylation of this polymer occurred at a ph of 6.0 and a temperature of 25 deg c. aeration and gluconic acid were required for an optimal reaction. a reactor which contained carbon-immobilized cells was constructed to continuously acetylate alginate. the maximal yield of acetylation was about 90%, and the half-life of this system was 6.5 days. | 1995 | 16534934 |
| altered epiphytic colonization of mannityl opine-producing transgenic tobacco plants by a mannityl opine-catabolizing strain of pseudomonas syringae. | the plasmid pydh208, which confers the ability to catabolize the mannityl opines mannopine and agropine, was mobilized into the nonpathogenic pseudomonas syringae strain cit7. the growth of the mannityl opine-catabolizing strain cit7(pydh208) was compared with that of the near-isogenic non-opine-catabolizing strain cit7xyle on leaves of wild-type tobacco (nicotiana tabacum cv. xanthi) and transgenic mannityl opine-producing tobacco plants (n. tabacum cv. xanthi, line 2-26). the population size o ... | 1995 | 16535040 |
| molecular and physiological characterization of pseudomonas syringae pv. tomato and pseudomonas syringae pv. maculicola strains that produce the phytotoxin coronatine. | the chlorosis-inducing phytotoxin coronatine is produced by several pseudomonas syringae pathovars, including glycinea, morsprunorum, atropurpurea, and the closely related tomato and maculicola. to date, all coronatine-producing pv. glycinea, morsprunorum, and atropurpurea strains that have been examined carry the gene cluster that controls toxin production on a large plasmid. in the present study the genomic location of the coronatine gene cluster was determined for coronatine-producing strains ... | 1995 | 16535140 |
| role of the phytotoxin coronatine in the infection of arabidopsis thaliana by pseudomonas syringae pv. tomato. | the role of the phytotoxin coronatine in the virulence of pseudomonas syringae pv. tomato in arabidopsis thaliana was evaluated by comparing symptom development, in planta bacterial multiplication, and the induction of defense-related genes in arabidopsis plants inoculated with the coronatine-producing (cor+) p. s. pv. tomato strain dc3000 and the coronatine-defective (cor-) strain dc3661 by either infiltration or dipping methods. the cor+ strain, p. s. pv. tomato dc3000, caused severe disease s ... | 1995 | 7539639 |
| cloning, characterization and phenotypic expression in escherichia coli of catf, which encodes the catalytic subunit of catalase isozyme catf of pseudomonas syringae. | the phytophathogenic, gram-negative bacterium pseudomonas syringae pv. syringae 61 contains three isozymes of catalase (ec 1.11.1.6), which have been proposed to play a role in the bacterium's responses to various environmental stresses. to study the role of individual isozymes, the gene coding for the catalytic subunit of one catalase isozyme was cloned from a cosmid library hosted in escherichia coli dh5 alpha by using a designed catalase-specific dna probe for the screening. one out of four c ... | 1995 | 7546603 |
| saprophytic pseudomonas syringae strain m1 of wheat produces cyclic lipodepsipeptides. | a saprophytic fluorescent bacterium (strain m1) isolated from wheat was identified as pseudomonas syringae and shown to produce the cyclic lipodepsipeptides, syringomycin e and syringopeptin sp25a. m1 grew in planta but did not affect germination or cause disease symptoms in wheat. the findings show that the production of these metabolites, generally regarded as plant virulence factors, does not correlate with plant pathogenicity. | 1995 | 7557311 |
| development of a microbial community of bacterial and yeast antagonists to control wound-invading postharvest pathogens of fruits. | two antagonists, the bacterium pseudomonas syringae and the pink yeast sporobolomyces roseus, against blue mold (caused by penicillium expansum) on apple controlled this disease more effectively when combined at approximately equal biomass (50:50 of the same turbidity) than in individual applications. addition of l-asparagine enhanced the biocontrol effectiveness of p. syringae but decreased that of s. roseus and had no significant effect when the antagonists were combined. populations of both a ... | 1995 | 7574636 |
| molecular characterization of the pseudomonas syringae pv. pisi plasmid-borne avirulence gene avrppib which matches the r3 resistance locus in pea. | an avirulence gene (designated avrppib) from race 3 of pseudomonas syringae pv. pisi was cloned and sequenced. the gene corresponded to a single open reading frame of 831 nt identified by transposon mutagenesis and subcloning. this orf encodes a predicted hydrophilic protein of 276 amino acids (mw 31,300). it effects the expression of a resistance mechanism governed by a single genetic locus in pea. cosegregation of resistance at the r3 locus of pea was observed towards race 3 and a transconjuga ... | 1995 | 7579614 |
| the hrpz proteins of pseudomonas syringae pvs. syringae, glycinea, and tomato are encoded by an operon containing yersinia ysc homologs and elicit the hypersensitive response in tomato but not soybean. | the pseudomonas syringae pathovars are composed of host-specific plant pathogens that characteristically elicit the defense-associated hypersensitive response (hr) in nonhost plants. p. s. pv. syringae 61 secretes an hr elicitor, harpinpss (hrpzpss), in a hrp-dependent manner. an internal fragment of the p. s. pv. syringae 61 hrpz gene was used to clone the hrpz locus from p. s. pv. glycinea race 4 (bacterial blight of soybean) and p. s. pv. tomato dc3000 (bacterial speck of tomato). dna sequenc ... | 1995 | 7579616 |
| the complete hrp gene cluster of pseudomonas syringae pv. syringae 61 includes two blocks of genes required for harpinpss secretion that are arranged colinearly with yersinia ysc homologs. | pseudomonas syringae pv. syringae 61 contains a 25-kb hrp cluster that is sufficient to elicit the hypersensitive response (hr) in nonhost plants. previous studies have shown that mutations in complementation groups viii, ix, and xi in the hrp cluster abolished the ability of the bacterium to cause the hr. the sequence of a 3.7-kb smai-ssti fragment covering groups viii and ix now reveals five open reading frames (orfs) in the same transcript, designated as hrpu, hrpw, hrpo, hrpx, and hrpy, and ... | 1995 | 7579617 |
| synthetic antimicrobial peptide design. | to guide the design of potential plant pathogen-resistance genes, synthetic variants of naturally occurring antimicrobial gene products were evaluated. five 20-amino acid (esf1, esf4, esf5, esf6, esf13), one 18-amino acid (esf12), and one 17-amino acid (esf17) amphipathic peptide sequences were designed, synthesized, and tested with in vitro bioassays. positive charges on the hydrophilic side of the peptide were shown to be essential for antifungal activity, yet the number of positive charges co ... | 1995 | 7579625 |
| intergeneric transfer and functional expression of the tomato disease resistance gene pto. | plant disease resistance loci have been used successfully in breeding programs to transfer traits from resistant germplasm to susceptible plant cultivars. the molecular cloning of plant disease resistance genes now permits the transfer of such traits across species boundaries by genetic transformation of recipient hosts. the tomato disease resistance gene pto confers resistance to strains of the bacterial pathogen pseudomonas syringae pv tomato expressing the avirulence gene avrpto. transformati ... | 1995 | 7580250 |
| high frequency of conjugation versus plasmid segregation of rp1 in epiphytic pseudomonas syringae populations. | the maintenance and transfer of the broad host-range plasmid rp1 in epiphytically growing populations of pseudomonas syringae was monitored in the phyllosphere of bush bean (phaseolus vulgaris). when foliage was inoculated with plasmid-containing bacteria, the plasmid was lost from the majority of the cells within 2 d but was stably maintained in 0.8% of the population. a high frequency of conjugation between added donors and recipients was observed under high humidity conditions. in 1 d, the nu ... | 1995 | 7582033 |
| sequence of a gene encoding periplasmic pseudomonas syringae ankyrin. | a gene encoding ankyrin (ank) was isolated from a genomic library of the plant pathogen pseudomonas syringae pathovar syringae strain 61 (pss61). the gene encodes an 183-amino-acid (aa) polypeptide which has homology to the 33-aa repeat domain of mammalian ank and ank homologs from other bacteria, animals and plants. | 1995 | 7590314 |
| antibacterial polyphenols from olive oil mill waste waters. | olive oil vegetation waters (vw) were highly toxic to both phytopathogenic pseudomonas syringae (smith, yung et al.) pv. savastanoi (gram-negative) and corynebacterium michiganense (gram-positive) and showed bactericidal activity in their original concentration (in raw form). among the main polyphenols, present in the waste waters, methylcatechol proved to be the most toxic to ps. savastanoi at 10(-4) mol l-1, and also demonstrated bactericidal activity, while on coryne. michiganense it was only ... | 1995 | 7592132 |
| a modified two-component regulatory system is involved in temperature-dependent biosynthesis of the pseudomonas syringae phytotoxin coronatine. | biosynthesis of the phytotoxin coronatine (cor) in pseudomonas syringae pv. glycinea pg4180 is regulated by temperature at the transcriptional level. a 3.4-kb dna fragment from the cor biosynthetic gene cluster restored temperature-regulated phytotoxin production to tn5 mutants defective in cor production. nucleotide sequence analysis of this fragment revealed three genes, cors, corp, and corr, which encode a modified two-component regulatory system consisting of one sensor protein, cors, and tw ... | 1995 | 7592381 |
| hrpl activates erwinia amylovora hrp gene transcription and is a member of the ecf subfamily of sigma factors. | hrpl of erwinia amylovora ea321 encodes a 21.7-kda regulatory protein, similar to members of the ecf (extra cytoplasmic functions) subfamily of eubacterial rna polymerase sigma factors. hrpl is a single-gene operon in complementation group vi of the e. amylovora hrp gene cluster. its product is required by ea321 to elicit the hypersensitive response (hr) and to cause disease. hrpl controls the expression of five independent hrp loci, including hrpn, which encodes harpin, a proteinaceous elicitor ... | 1995 | 7592386 |
| a global regulator of secondary metabolite production in pseudomonas fluorescens pf-5. | mutations in the apda (for antibiotic production) gene of the plant root-colonizing bacterium pseudomonas fluorescens pf-5 pleiotropically abolish the production of an array of antibiotics, including pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol, as well as the production of tryptophan side chain oxidase, hydrogen cyanide, and an extracellular protease. the lack of production of secondary metabolites by apda- mutants was correlated with the loss of inhibition of the phytopathogenic f ... | 1995 | 7592389 |
| cloning and characterization of the katb gene of pseudomonas aeruginosa encoding a hydrogen peroxide-inducible catalase: purification of katb, cellular localization, and demonstration that it is essential for optimal resistance to hydrogen peroxide. | pseudomonas aeruginosa is an obligate aerobe that is virtually ubiquitous in the environment. during aerobic respiration, the metabolism of dioxygen can lead to the production of reactive oxygen intermediates, one of which includes hydrogen peroxide. to counteract the potentially toxic effects of this compound, p. aeruginosa possesses two heme-containing catalases which detoxify hydrogen peroxide. in this study, we have cloned katb, encoding one catalase gene of p. aeruginosa. the gene was clone ... | 1995 | 7592431 |
| analysis of the syrb and syrc genes of pseudomonas syringae pv. syringae indicates that syringomycin is synthesized by a thiotemplate mechanism. | the syrb and syrc genes are required for synthesis of syringomycin, a lipodepsipeptide phytotoxin produced by pseudomonas syringae pv. syringae, and are induced by plant-derived signal molecules. a 4,842-bp chromosomal region containing the syrb and syrc genes of strain b301d was sequenced and characterized. the open reading frame (orf) of syrb was 2,847 bp in length and was predicted to encode an approximately 105-kda protein, syrb, with 949 amino acids. searches of databases revealed that syrb ... | 1995 | 7608074 |
| structure of the arabidopsis rpm1 gene enabling dual specificity disease resistance. | plants can recognize pathogens through the action of disease resistance (r) genes, which confer resistance to pathogens expressing unique corresponding avirulence (avr) genes. the molecular basis of this gene-for-gene specificity is unknown. the arabidopsis thaliana rpm1 gene enables dual specificity to pathogens expressing either of two unrelated pseudomonas syringae avr genes. despite this function, rpm1 encodes a protein sharing molecular features with recently described single-specificity r ... | 1995 | 7638602 |
| the arabidopsis thaliana 4-coumarate:coa ligase (4cl) gene: stress and developmentally regulated expression and nucleotide sequence of its cdna. | an arabidopsis cdna clone encoding 4-coumarate:coa ligase (4cl), a key enzyme of phenylpropanoid metabolism, was identified and sequenced. the predicted amino acid sequence is similar to those of other cloned 4cl genes. southern blot analysis indicated that 4cl is single-copy gene in arabidopsis. northern blots showed that 4cl expression was activated early during seedling development. the onset of 4cl expression was correlated with the onset of lignin deposition in cotyledons and roots 2-3 days ... | 1995 | 7640359 |
| the avrrpm1 gene of pseudomonas syringae pv. maculicola is required for virulence on arabidopsis. | we demonstrate that the avirulence gene avrrpm1, isolated from pseudomonas syringae pv. maculicola strain psm m2 via interaction with the arabidopsis resistance gene rpm1, is also required for maximal virulence on this host. two avrrpm1::tn3-spice marker-exchange mutants do not elicit a hypersensitive reaction on rpm1-containing arabidopsis accessions col-0 and oy-0. surprisingly, these mutants neither generate disease symptoms, nor grow in planta, after inoculation onto susceptible accessions n ... | 1995 | 7655064 |
| [the genetic aspects of the study of pseudomonas syringae bacteria]. | the work is a review of the state-of-art of molecular-genetic examination of bacteria p. syringae. the questions concerning new approaches to the study of determinants of pathogenicity, endogenic plasmids, toxins, resistance to antibiotics, avirulence, genes and insertion sequence elements of p. syringae are stated. | 1995 | 7655660 |
| pseudomonas syringae pv. syringae phytotoxins reversibly inhibit the plasma membrane h(+)-atpase and disrupt unilamellar liposomes. | the pseudomonas syringae pv. syringae phytotoxins syringomycin-e and syringopeptins 22-a and 25-a reversibly and noncompetitively inhibit purified h(+)-atpase solubilized from plasma membrane of maize roots. moreover, they increase the passive permeability to protons in phosphatidylcholine/phosphatidylethanolamine liposomes. both effects are more pronounced with syringopeptins than with syringomycin-e. activity on phospholipid bilayers is detectable at phytotoxin concentrations not affecting h(+ ... | 1995 | 7669032 |
| structural analysis of new syringopeptins by tandem mass spectrometry. | new syringopeptins sp(sc)-1 and -2 were isolated from culture filtrates of phytopathogenic bacterium strain sc1 of pseudomonas syringae pv. syringae. these syringopeptins were composed of a beta-hydroxy fatty acid, a long sequence of aliphatic amino acids. and a lactone moiety of eight amino acids. the amino acid sequences were deduced from a comparison of their tandem mass sepctra with those of known syringopeptins sp-22a and sp-25a. sp(sc)-1 and sp(sc)-2 resembled sp-22a, but differed from the ... | 1995 | 7670202 |
| hydrogen peroxide does not function downstream of salicylic acid in the induction of pr protein expression. | the roles of salicylic acid (sa) and h2o2 in the induction of pr proteins in tobacco have been examined. studies were conducted on wild-type tobacco and plants engineered to express a bacterial salicylate hydroxylase capable of metabolizing sa to catechol (sh-l plants). wild-type and pr-1a-gus-transformed plants express pr-1a following challenge with pseudomonas syringae pathovar syringae, sa or 2,6-dichloro-isonicotinic acid (ina). in contrast, sh-l plants failed to respond to sa but did expres ... | 1995 | 7670505 |
| cloning of genes required for hypersensitivity and pathogenicity in pseudomonas syringae pv. aptata. | a genomic library of pseudomonas syringae pv. aptata strain ncppb 2664, which causes bacterial blight of sugar beet, lettuce and other plants, was constructed in the cosmid vector pcpp31. the 13.4 kb ecori fragment of the cosmid phir11, containing the hrp (hypersensitive response and pathogenicity) gene cluster of the closely related bacterium pseudomonas syringae pv. syringae strain 61, was used as a probe to identify a homologous hrp gene cluster in p. syringae pv. aptata. thirty of 2500 cosmi ... | 1995 | 7771767 |
| characterization of avre from pseudomonas syringae pv. tomato: a hrp-linked avirulence locus consisting of at least two transcriptional units. | cosmid clone ppt10e9 from pseudomonas syringae pv. tomato caused p. s pv. glycinea to elicit the hr on leaves of all tested soybean cultivars. the avirulence function of ppt10e9, called avre, occurred on an 11.3-kb dna fragment located immediately adjacent to the p. s. pv. tomato hrp gene cluster. tn3-gus saturation mutagenesis of the avre locus and adjacent dna revealed at least four transcriptional units occurring immediately adjacent to the hrprs locus that were all regulated in a manner simi ... | 1995 | 7772803 |
| membrane fluidity as a factor in production and stability of bacterial ice nuclei active at high subfreezing temperatures. | detailed measurements were made of the rate of appearance of bacterial ice nuclei upon cooling of suspensions of pseudomonas syringae cells and the disappearance of ice nuclei upon warming of the cells before assay for ice nucleation activity. while no substantial change in numbers of ice nuclei active at either -5 or at -9 degrees c was observed in cells that were grown at temperatures lower than 24 degrees c and cooled to 21 degrees c before assay, large increases in -5 but not -9 degrees c ic ... | 1995 | 7781327 |
| copper as a signal for alginate synthesis in pseudomonas syringae pv. syringae. | plant-associated pseudomonads are commonly exposed to copper bactericides, which are applied to reduce the disease incidence caused by these bacteria. consequently, many of these bacteria have acquired resistance or tolerance to copper salts. we recently conducted a survey of 37 copper-resistant (cur) pseudomonas spp., including p. cepacia, p. fluorescens, p. syringae, and p. viridiflava, and found that a subset of the p. syringae strains showed a dramatic increase in exopolysaccharide (eps) pro ... | 1995 | 7793938 |
| differential in vitro dna binding activity to a promoter element of the gn1 beta-1,3-glucanase gene in hypersensitively reacting tobacco plants. | in a hypersensitive reaction to pathogen infection, expression of the beta-1,3-glucanase gn1 gene is induced in cells surrounding the necrotic lesions. the 5'-flanking sequence of gn1 was examined to investigate the molecular basis controlling activation of gene expression during this plant defense response. studies on transgenic tobacco plants containing gn1 promoter deletions fused to the beta-glucuronidase reporter gene revealed the presence of negative and positive regulatory sequences media ... | 1995 | 7704049 |
| use of a gene expression system based on potato virus x to rapidly identify and characterize a tomato pto homolog that controls fenthion sensitivity. | a novel transient gene expression system was used to study both the tomato disease resistance gene pto and a pto homolog designated fen. the gene expression system was based on potato virus x (pvx). tomato plants that were both susceptible to strains of pseudomonas syringae pv tomato carrying the corresponding avirulence gene avrpto and insensitive to the insecticide fenthion were infected with in vitro-generated transcripts of pvx derivatives containing either pto or fen. expression of the pto ... | 1995 | 7734960 |
| differential effects of growth temperature on ice nuclei active at different temperatures that are produced by cells of pseudomonas syringae. | the temperature at which ice-nucleating bacteria are grown causes differences of 100- to 10,000-fold in the fraction of cells that nucleate ice at a given temperature (ice nucleation frequency). ice nucleation frequencies of cells of pseudomonas syringae grown at temperatures that ranged from 9 to 33 degrees c were examined in order to more accurately characterize physiological effects on ice nuclei active at temperatures of from about -2 to -10 degrees c, the temperature range for this phenotyp ... | 1995 | 7743815 |
| purification and characterization of an extracellular levansucrase from pseudomonas syringae pv. phaseolicola. | levansucrase (ec 2.4.1.10), an exoenzyme of pseudomonas syringae pv. phaseolicola, was purified to homogeneity from the cell supernatant by chromatography on tmae-fraktogel and butyl-fraktogel. the enzyme has molecular masses of 45 kda under denaturing conditions and 68 kda during gel filtration of the native form. in isoelectric focusing, active bands appeared at ph 3.55 and 3.6. maximum sucrose cleaving activities were measured at ph 5.8 to 6.6 and 60 degrees c. the enzyme was highly tolerant ... | 1995 | 7751294 |
| the hrprs locus of pseudomonas syringae pv. phaseolicola constitutes a complex regulatory unit. | the right part of the hrp cluster of pseudomonas syringae pv. phaseolicola contains two regulatory genes, the previously described hrps gene and an adjacent locus, hrpr. in this study we determined the sequence of hrpr and analysed the functional organization of the two genes. hrpr and hrps show high sequence similarities to each other and to other response regulators of the two-component regulatory system. this has recently also been described for the hrprs system of the closely related pathoge ... | 1995 | 7752891 |
| use of arabidopsis thaliana defense-related mutants to dissect the plant response to pathogens. | the plant defense response to microbial pathogens had been studied primarily by using biochemical and physiological techniques. recently, several laboratories have developed a variety of pathosystems utilizing arabidopsis thaliana as a model host so that genetic analysis could also be used to study plant defense responses. utilizing a pathosystem that involves the infection of arabidopsis with pathogenic pseudomonads, we have cloned the arabidopsis disease-resistance gene rps2, which corresponds ... | 1995 | 7753782 |
| resistance to antifungal agents. | the marked increase in the number of patients with aids and other forms of immunocompromise has resulted in the emergence of fungi as predominant pathogens in many institutions. unfortunately, with the widespread use of antifungal agents to combat these infections, reports of resistance to antifungal agents have proliferated. in the present environment, the occurrence of resistance to antifungal agents is neither rare nor of negligible clinical importance. the expanding demand for antifungal age ... | 1995 | 7761146 |
| sequence, expression and transcriptional analysis of the coronafacate ligase-encoding gene required for coronatine biosynthesis by pseudomonas syringae. | pseudomonas syringae pv. glycinea pg4180 produces the chlorosis-inducing phytotoxin coronatine (cor), which consists of a polyketide component, coronafacic acid (cfa), ligated by an amide bond to coronamic acid (cma), an ethylcyclopropyl amino-acid derived from isoleucine. we report the nucleotide sequence of a 2.37-kb region containing the coronafacate ligase-encoding gene (cfl) which is required for the amide linkage of cfa and cma. the transcription start point for cfl was identified, and the ... | 1995 | 7883180 |
| isolation and sequence analysis of the pseudomonas syringae pv. tomato gene encoding a 2,3-diphosphoglycerate-independent phosphoglyceromutase. | pseudomonas syringae pv. tomato dc3481, a tn5-induced mutant of the tomato pathogen dc3000, cannot grow and elicit disease symptoms on tomato seedlings. it also cannot grow on minimal medium containing malate, citrate, or succinate, three of the major organic acids found in tomatoes. we report here that this mutant also cannot use, as a sole carbon and/or energy source, a wide variety of hexoses and intermediates of hexose catabolism. uptake studies have shown that dc3481 is not deficient in tra ... | 1995 | 7896694 |
| expression of the stra-strb streptomycin resistance genes in pseudomonas syringae and xanthomonas campestris and characterization of is6100 in x. campestris. | expression of the stra-strb streptomycin resistance (smr) genes was examined in pseudomonas syringae pv. syringae and xanthomonas campestris pv. vesicatoria. the stra-strb genes in p. syringae and x. campestris were encoded on elements closely related to tn5393 from erwinia amylovora and designated tn5393a and tn5393b, respectively. the putative recombination site (res) and resolvase-repressor (tnpr) genes of tn5393 from e. amylovora, p syringae, and x. campestris were identical; however, is6100 ... | 1995 | 7487022 |
| product of fosc, a gene from pseudomonas syringae, mediates fosfomycin resistance by using atp as cosubstrate. | pseudomonas syringe pb-5123, a producer of fosfomycin, is resistant to high concentrations of the antibiotic. two possible mechanisms of resistance have been detected: (i) impermeability to exogenous fosfomycin, even in the presence of sugar phosphate uptake inducers, and (ii) antibiotic phosphorylation. the gene responsible for this last activity, fosc, encodes a ca. 19,000-da protein and is immediately followed by a second open reading frame, which shows sequence similarities to glutathione s- ... | 1995 | 7492106 |
| development of a gene reporter system in moderately halophilic bacteria by employing the ice nucleation gene of pseudomonas syringae. | the expression of the ice nucleation gene inaz of pseudomonas syringae in several moderate halophiles was investigated to establish its utility as a reporter for promoter activity and gene expression studies in these biotechnologically and environmentally important bacteria. a promoterless version of inaz was introduced in two different restriction sites and at both orientations in a recombinant plasmid able to replicate in moderate halophiles and, in particular, within the sequence of its phe1 ... | 1995 | 8526492 |
| characterization and transcriptional analysis of the gene cluster for coronafacic acid, the polyketide component of the phytotoxin coronatine. | coronafacic acid (cfa), the polyketide component of the phytotoxin coronatine (cor), is activated and coupled to coronamic acid via amide bond formation, a biosynthetic step presumably catalyzed by the cfa ligase (cfl) gene product. the cor biosynthetic gene cluster in pseudomonas syringae pv. glycinea pg4180 is located within a 32-kb region of a 90-kb plasmid designated p4180a. in the present study, a cloned region of p4180a complemented all cfa- mutants spanning an 18.8-kb region of the cor bi ... | 1995 | 8526495 |
| an open reading frame in the approximately 28-kb tox-argk gene cluster encodes a polypeptide with homology to fatty acid desaturases. | part of an apparent open reading frame in the tox-argk gene cluster of pseudomonas syringae pathovar phaseolicola (psp) potentially encodes a polypeptide with sequence similarity to fatty acid desaturases (des). escherichia coli b expressing this segment under t7 promoter control produced a 34-kda polypeptide. the possible involvement of a des in facilitating phaseolotoxin (ptx) secretion at the low temperatures normally required for its synthesis and the evolutionary implications about the orig ... | 1995 | 8529898 |
| genetic analysis of the minimal replicon of plasmid pip417 and comparison with the other encoding 5-nitroimidazole resistance plasmids from bacteroides spp. | the nucleotide sequence of the dna replication origin region of a bacteroides vulgatus plasmid, pip417, encoding 5-nitroimidazole resistance has been determined. this region of 1934 bp presents some characteristics similar to those of other replication protein-dependent origins. it contains a large open reading frame which could encode a basic rep protein (repa) of 36.8 kda. upstream of this orf exist an at-rich region, three direct repeats (iterons) of 21 bp, multiple dnaa binding sites, and si ... | 1995 | 8559801 |
| characterization of lipopolysaccharides from pseudomonas syringae (serogroup ii). | lipopolysaccharides (lps) from the strains of pseudomonas syringae pv.syringae 90a, 435, pv. atrofaciens k-1025, pv. morsprunorum cf-4 referred by pastushenko and simonovich (1979) to serogroup ii have been studied. the strains were shown to be heterogeneous by chemical composition of core and lipid a and structure of o-specific polysaccharide. the preparations heterogeneity in serological cross reactions were also detected. o-specific polysaccharides of the strains having similar structures wer ... | 1995 | 8563943 |
| [the characteristics of the lipid a of the lipopolysaccharides in pseudomonas syringae strains]. | component composition of lipid a of pseudomonas syringae pv. syringae 218 and p-55, pv. syringae (holci) 8299, pv. phaseolicola 120a, pv. atrofaciens 2399 has been studied. the lipid a composition of all the strains studied includes 3-hydroxydecanoic fatty acid (3-oh-c10:0), 2-hydroxydodecanoic (2-oh-c12:0), 3-hydroxydodecanoic (3-oh-c12:0), dodecanoic (c12:0), hexadecanoic (c16:0), octadecanoioc (c18:0), hexadecenic (c16:1), octadecenic (c18:1) fatty acids. the carbohydrate part of the lipid a ... | 1995 | 8563945 |
| solution conformation of the pseudomonas syringae pv. syringae phytotoxic lipodepsipeptide syringopeptin 25-a. two-dimensional nmr, distance geometry and molecular dynamics. | syringopeptin 25-a is a phytotoxic amphiphilic lipodepsipeptide containing 25 amino acid residues, produced by some isolates of the plant pathogenic bacterium pseudomonas syringae pv. syringae. previous papers have reported its covalent structure and some of its biological properties. attention has now been directed to define its conformation in solution, a structural feature regarded as important for understanding its possible role in the bacterial colonization of host plants, and its toxic act ... | 1995 | 8575431 |
| role of biosurfactant and ion channel-forming activities of syringomycin in transmembrane ion flux: a model for the mechanism of action in the plant-pathogen interaction. | syringomycin is a necrosis-inducing lipopeptide toxin synthesized and secreted by the phytopathogen, pseudomonas syringae pv. syringae. although small quantities of syringomycin are known to activate a cascade of physiological events in plasma membranes, the mechanism of action of the phytotoxin has never been fully characterized. the objective of this study was to test the hypothesis that the primary mode of action of syringomycin is to form transmembrane pores that are permeable to cations. ac ... | 1995 | 8589416 |
| a disease resistance gene in arabidopsis with specificity for the avrpph3 gene of pseudomonas syringae pv. phaseolicola. | the avirulence gene avrpph3 from pseudomonas syringae pv. phaseolicola was tested for its ability to convert virulent p. syringae pv. tomato strain dc3000 to avirulence on arabidopsis. in f2 plants from a cross between resistant and susceptible ecotypes, the ratio of resistant to susceptible plants was approximately 3:1, indicating that resistance to dc3000(avrpph3) is determined by a single dominant locus, which we have designated rps5. rps5 was mapped to chromosome 1, between restriction fragm ... | 1995 | 8589418 |
| viability and respiratory activity of pseudomonas syringae cells starved in buffer. | pseudomonas syringae cells starved in buffer released orcinol-reactive molecules and materials that absorbed ultraviolet light. the number of cells culturable in nutrient medium decreased more rapidly than the number of intact particles determined by microscopy. the results suggested that starvation resulted in the lysis of an increasing number of cells, and that a fraction of the intact particles were not culturable. starvation also resulted in a decrease in the rate of oxygen consumption with ... | 1995 | 8590414 |
| molecular genetics and transport analysis of the copper-resistance determinant (pco) from escherichia coli plasmid prj1004. | the copper-resistance determinant (pco) of escherichia coli plasmid prj1004 was cloned and sequenced. tn1000 transposon mutagenesis identified four complementation groups, mutations in any of which eliminated copper resistance. dna sequence analysis showed that the four complementation groups contained six open reading frames, designated pco-abcdrs. the protein product sequences derived from the nucleotide sequence show close homology between this copper-resistance system and the cop system of a ... | 1995 | 8594334 |
| soybean resistance genes specific for different pseudomonas syringae avirulence genes are allelic, or closely linked, at the rpg1 locus. | rpg1 and rpm1 are disease resistance genes in soybean and arabidopsis, respectively, that confer resistance to pseudomonas syringae strains expressing the avirulence gene avrb. rpm1 has recently been demonstrated to have a second specificity, also conferring resistance to p. syringae strains expressing avrrpm1. here we show that alleles, or closely linked genes, exist at the rpg1 locus in soybean that are specific for either avrb or avrrpm1 and thus can distinguish between these two avirulence g ... | 1995 | 8601497 |
| analysis of sweet cherry (prunus avium l.) leaves for plant signal molecules that activate the syrb gene required for synthesis of the phytotoxin, syringomycin, by pseudomonas syringae pv syringae. | an important aspect of the interaction of pseudomonas syringae pv syringae with plant hosts is the perception of plant signal molecules that regulate expression of genes, such as syrb, required for synthesis of the phytotoxin, syringomycin. in this study, the leaves of sweet cherry (prunus avium l.) were analyzed to determine the nature of the syrb-inducing activity associated with tissues of a susceptible host. crude leaf extracts yielded high amounts of total signal activity of more than 12,00 ... | 1995 | 12228385 |
| a noninvasive technique for monitoring peroxidative and h2o2-scavenging activities during interactions between bacterial plant pathogens and suspension cells. | stimulation of active oxygen metabolism occurs during the early stages of interactions involving bacteria and plant cell suspensions. although many cellular processes are known to affect active oxygen metabolism in plants, it is not known which of these factors affect active oxygen levels during plant-bacteria interactions. extracellular peroxidases have been shown to participate in both the production and utilization of active oxygen species such as h2o2 and superoxide. catalase and other scave ... | 1995 | 12228480 |
| hrp mutant of pseudomonas syringae pv phaseolicola induces cell wall alterations but not membrane damage leading to the hypersensitive reaction in lettuce. | both wild-type (s21-wt) and hrpd- (s21-533) strains of pseudomonas syringae pv phaseolicola induced the formation of large paramural papillae in lettuce (lactuca sativa) mesophyll cells adjacent to bacterial colonies. localized alterations to the plant cell wall included deposition of hydroxyproline-rich glycoproteins, phe-nolics, and callose, and were associated with proliferation of the endoplasmic reticulum and multivesicular bodies. tissue collapse during the hypersensitive reaction caused b ... | 1995 | 12228488 |
| salicylic acid in rice (biosynthesis, conjugation, and possible role). | salicylic acid (sa) is a natural inducer of disease resistance in some dicotyledonous plants. rice seedlings (oryza sativa l.) had the highest levels of sa among all plants tested for sa content (between 0.01 and 37.19 [mu]g/g fresh weight). the second leaf of rice seedlings had slightly lower sa levels than any younger leaves. to investigate the role of sa in rice disease resistance, we examined the levels of sa in rice (cv m-201) after inoculation with bacterial and fungal pathogens. sa levels ... | 1995 | 12228500 |
| systemic responses in arabidopsis thaliana infected and challenged with pseudomonas syringae pv syringae. | attack of plants by necrotizing pathogens leads to acquired resistance to the same or other pathogens in tissues adjacent to or remotely located from the site of initial attack. we have used arabidopsis thaliana inoculated with the incompatible pathogen pseudomonas syringae pv syringae on the lower leaves to test the induction of systemic reactions. when plants were challenged with pseudomonas syringae pv syringae in the upper leaves, bacterial titers remained stable in those preinfected on the ... | 1995 | 12228548 |