Publications

toxicity of smoke to epiphytic ice nucleation-active bacteria.	wheat straw smoke aerosols and liquid smoke condensates reduced significantly both the viability and the ice-nucleating activity of pseudomonas syringae pv. syringae and erwinia herbicola in vitro and on leaf surfaces in vivo. highly significant reductions in numbers of bacterial ice nuclei on the surface of both corn and almond were observed after exposure to smoke aerosols. at -5 degrees c, frost injury to corn seedlings colonized by ice nucleation-active bacteria was reduced after exposure to ...	1983	16346333
generalized transduction in the phytopathogen pseudomonas syringae.	bacteriophages isolated from culture supernatants of pseudomonas syringae pv. syringae and from sewage transferred various chromosomal genes to p. syringae ps224. linkage between arginine and tryptophan loci was demonstrated. the number of transductants recovered per milliliter was not altered appreciably by uv irradiation of selected phage isolates. in addition, the presence of the incp2 plasmid r38 in a p. syringae ps224 arginine auxotroph did not increase the transduction frequency as it does ...	1983	16346318
isolation and partial characterization of bacteriophages of the phytopathogen pseudomonas syringae.	bacteriophages isolated from culture supernatants of pseudomonas syringae pv. syringae and from sewage were identified. the dna from each phage was isolated and digested with the restriction endonuclease ecori. eight isolates were determined to be different, with two phage isolates from sewage having restriction patterns identical to two phages from culture supernatants. the sizes of the phage dna ranged from 24 to49 kilobases for isolates from sewage and from 39 to 52.5 kilobases for the isolat ...	1983	16346319
isolation and characterization of tn5 insertion mutants of pseudomonas syringae pv. syringae altered in the production of the peptide phytotoxin syringotoxin.	a syringotoxin-producing strain of pseudomonas syringae pv. syringae (b457) was subjected to tn5 mutagenesis by the transposon vector psup1011. analyses of auxotrophs obtained suggested simple random insertions of tn5. syringotoxin-negative mutants arose at a frequency of about 0.28%. in a southern blot analysis, the loss of toxin production was associated with tn5 insertions into chromosomal ecori fragments of about 10.5, 17.8, and 19.3 kilobases. data from a southern blot analysis of ssti-dige ...	1985	2995307
indigenous plasmids in pseudomonas syringae pv. tomato: conjugative transfer and role in copper resistance.	twenty strains of pseudomonas syringae pv. tomato were examined for the presence of plasmid dna. p. syringae pv. tomato plasmids were grouped into five size classes: class a ranged from 95 to 103 kilobases (kb); class b ranged from 71 to 83 kb; class c ranged from 59 to 67 kb; class d ranged from 37 to 39 kb; and class e was 29 kb. all strains contained at least two plasmids in classes a and b. the conjugative ability of p. syringae pv. tomato plasmids in three strains was demonstrated by mobili ...	1986	3003029
auxin production by plant-pathogenic pseudomonads and xanthomonads.	pathogenic strains of xanthomonas campestris pv. glycines which cause hypertrophy of leaf cells of susceptible soybean cultivars and nonpathogenic strains which do not cause hypertrophy were compared for their ability to produce indole compounds, including the plant hormone indole-3-acetic acid (iaa) in liquid media with or without supplementation with l-tryptophan. several additional strains of plant-pathogenic xanthomonads and pseudomonads were also tested for iaa production to determine wheth ...	1987	16347409
outer membrane protein mediating iron uptake via pyoverdinpss, the fluorescent siderophore produced by pseudomonas syringae pv. syringae.	in an iron-limited environment pseudomonas syringae pv. syringae b301d produces a yellow-green fluorescent siderophore called pyoverdinpss which functions in high-affinity iron transport. two-dimensional electrophoretic comparisons of the outer membrane proteins of strain b301d identified nine proteins which were expressed at low (50 nm) but not at high (10 microm) iron concentrations. except for the minor protein 8e, the iron-regulated proteins exhibited high molecular weights ranging from appr ...	1987	3032911
characterization of pyoverdin(pss), the fluorescent siderophore produced by pseudomonas syringae pv. syringae.	pseudomonas syringae pv. syringae b301d produces a yellow-green, fluorescent siderophore, pyoverdin(pss), in large quantities under iron-limited growth conditions. maximum yields of pyoverdin(pss) of approximately 50 mug/ml occurred after 24 h of incubation in a deferrated synthetic medium. increasing increments of fe(iii) coordinately repressed siderophore production until repression was complete at concentrations of >/= 10 mum. pyoverdin(pss) was isolated, chemically characterized, and found t ...	1987	16347352
bacterial phytotoxin, syringomycin, induces a protein kinase-mediated phosphorylation of red beet plasma membrane polypeptides.	syringomycin, a peptide toxin and a virulence factor produced by the bacterial phytopathogen pseudomonas syringae pv. syringae, stimulated the phosphorylation of several plasma membrane polypeptides of red beet storage tissue. among these was a 100-kda polypeptide, which corresponds in size to the proton pump atpase. the phosphorylations were insensitive to hydroxylamine, indicating that the polypeptide phosphorylated intermediates involved phosphate ester bonds characteristic of protein kinase- ...	1987	16578820
mechanism of action of pseudomonas syringae phytotoxin, syringomycin : stimulation of red beet plasma membrane atpase activity.	syringomycin, a peptide toxin produced by the phytopathogen pseudomonas syringae pv syringae preferentially stimulated (2-fold) the vanadate-sensitive atpase activity associated with the plasma membrane of red beet storage tissue. the toxin had a very slight effect on the tonoplast atpase and had no detectable effect on the mitochondrial atpase. optimal stimulation was achieved with 10 to 50 micrograms of syringomycin per 25 micrograms of membrane protein. treatment of membranes with 0.1% (weigh ...	1987	16665211
evaluation of the role of syringomycin in plant pathogenesis by using tn5 mutants of pseudomonas syringae pv. syringae defective in syringomycin production.	syringomycin is a necrosis-inducing phytotoxin produced by pseudomonas syringae pv. syringae. to determine whether syringomycin production is a determinant in virulence or pathogenicity, we isolated nontoxigenic (tox) tn5-containing mutants and then quantitatively evaluated them for the ability to multiply and cause disease in immature sweet-cherry fruits. transposon tn5 was delivered to tox strain b301d-r by using the suicide vector, pgs9, and the resultant kanamycin-resistant (km) colonies wer ...	1988	16347644
molecular analysis of a pathogenicity locus in pseudomonas syringae pv. syringae.	one of the chromosomal regions of pseudomonas syringae pv. syringae encoding pathogenicity factors had been mapped into a 3.9-kilobase-pair fragment in previous studies. promoter probe analysis indicated the existence of a promoter near one end of the fragment. dna sequencing of this fragment revealed the existence of a consensus promoter sequence in the region of the promoter activity and two open reading frames (orfs) downstream. these orfs, orf1 and orf2, encoded putative polypeptides of 40 a ...	1988	3192509
molecular cloning of a pseudomonas syringae pv. syringae gene cluster that enables pseudomonas fluorescens to elicit the hypersensitive response in tobacco plants.	a cosmid clone isolated from a genomic library of pseudomonas syringae pv. syringae 61 restored to all tn5 mutants of this strain studied the ability to elicit the hypersensitive response (hr) in tobacco. cosmid phir11 also enabled escherichia coli tb1 to elicit an hr-like reaction when high levels of inoculum (10(9) cells per ml) were infiltrated into tobacco leaves. the cosmid, which contains a 31-kilobase dna insert, was mobilized by triparental matings into pseudomonas fluorescens 55 (a nonp ...	1988	3139635
physical and functional analyses of the syra and syrb genes involved in syringomycin production by pseudomonas syringae pv. syringae.	the syra and syrb genes involved in syringomycin production in pseudomonas syringae pv. syringae b301d were identified from an ecori-plafr3 cosmid library and then physically and functionally analyzed in relation to plant pathogenicity. homologous recombination of the genes required for syringomycin production from cosmids pgx183 (syra) and pgx56 (syrb), respectively, introduced into nontoxigenic (tox-) tn5 mutants w4s2545 and w4s770 resulted in the concomitant restoration of toxin production an ...	1988	2848010
genetic organization and regulation of proteins associated with production of syringotoxin by pseudomonas syringae pv. syringae.	many strains of pseudomonas syringae pv. syringae produce one of two low-molecular-weight, peptide-containing phytotoxins, either syringomycin (sr) or syringotoxin (st). an analysis of tn5-induced st-mutants revealed alterations in the presence of two large proteins (ca. 470 and 435 kilodaltons). apparent truncated forms of the 470 (st1)- or 435 (st2)-kilodalton proteins were observed in some mutants. mapping of the tn5 insertions and size determinations of truncated proteins suggested that both ...	1988	2848011
scanning electron microscopy of invasion of apple leaves and blossoms by pseudomonas syringae pv. syringae.	scanning electron microscopy indicated that pseudomonas syringae pv. syringae l795 entered leaves through stomata and multiplied in the substomatal chambers. strain l195 applied to blossoms colonized stigmas and also occurred in intercellular spaces of styles. nonpathogenic strain l796 failed to colonize blossoms. this study suggests that inoculum of pathogenic p. syringae pv. syringae builds up on apple leaves and blossoms.	1989	16347862
role of the plasmalemma h-atpase in pseudomonas syringae-induced k/h exchange in suspension-cultured tobacco cells.	activation of a host plasma membrane k(+) efflux/net h(+) uptake exchange by pathogenic pseudomonads plays an important role in the development of hypersensitivity in tobacco (nicotiana tabacum). involvement of the plasmalemma h(+)-pumping atpase in this response was investigated. the exchange response of suspension-cultured tobacco cells to pseudomonas syringae pv syringae was reduced 90% or more by atpase inhibitors including vanadate, n-ethylmaleimide, and n,n'-dicyclohexylcarbodiimide. the e ...	1989	16667014
involvement of plasma membrane calcium influx in bacterial induction of the k/h and hypersensitive responses in tobacco.	an early event in the hypersensitive response of tobacco to pseudomonas syringae pv syringae is the initiation of a k(+)/h(+) response characterized by specific plasma membrane k(+) efflux, extracellular alkalinization, and intracellular acidification. we investigated the role of calcium in induction of these host responses. suspension-cultured tobacco cells exhibited a baseline ca(2+) influx of 0.02 to 0.06 micromole per gram per hour as determined from (45)ca(2+) uptake. following bacterial in ...	1990	16667249
construction of a stable shuttle vector for high-frequency transformation in pseudomonas syringae pv. syringae.	a cryptic 80.3-kilobase plasmid, posu900, in pseudomonas syringae pv. syringae strain j900 could be cured by treatment with mitomycin without affecting the pathogenicity of j900 on the host, phaseolus vulgaris l. the replication region of posu900 was identified, subcloned, and modified for construction of a high-copy cloning vector. this vector could be transformed into pseudomonas strains with high efficiency (ca. 10(6) transformants per microgram of dna) and was very stable during growth of th ...	1990	2294094
plant signal molecules activate the syrb gene, which is required for syringomycin production by pseudomonas syringae pv. syringae.	the syrb gene is required for syringomycin production by pseudomonas syringae pv. syringae and full virulence during plant pathogenesis. strain b3ar132 containing a syrb::lacz fusion was used to detect transcriptional activation of the syrb gene in syringomycin minimal medium by plant metabolites with signal activity. among 34 plant phenolic compounds tested, arbutin, phenyl-beta-d-glucopyranoside, and salicin were shown to be strong inducers of syrb, giving rise to approximately 1,200 u of beta ...	1991	1885550
systemic induction of salicylic acid accumulation in cucumber after inoculation with pseudomonas syringae pv syringae.	inoculation of one true leaf of cucumber (cucumis sativus l.) plants with pseudomonas syringae pathovar syringae results in the systemic appearance of salicylic acid in the phloem exudates from petioles above, below, and at the site of inoculation. analysis of phloem exudates from the petioles of leaves 1 and 2 demonstrated that the earliest increases in salicylic acid occurred 8 hours after inoculation of leaf 1 in leaf 1 and 12 hours after inoculation of leaf 1 in leaf 2. detaching leaf 1 at i ...	1991	16668554
phytoalexin accumulation in arabidopsis thaliana during the hypersensitive reaction to pseudomonas syringae pv syringae.	inoculation of leaves of arabidopsis thaliana (l.) heynh. with the wheat pathogen, pseudomonas syringae pv syringae, resulted in the expression of the hypersensitive reaction and in phytoalexin accumulation. no phytoalexin accumulation was detected after infiltration of leaves with a mutant of p. s. syringae deficient in the ability to elicit a hypersensitive reaction; with the crucifer pathogen, xanthomonas campestris pv campestris; or with 10 millimolar potassium phosphate buffer (ph 6.9). phy ...	1992	16668792
phenotypic expression of the pseudomonas syringae pv. syringae 61 hrp/hrm gene cluster in escherichia coli mc4100 requires a functional porin.	plants, in general, appear to be able to detect the presence of incompatible pseudomonas syringae strains by a hypothetical cell-cell recognition process to initiate inducible defense mechanisms that contribute to disease resistance. a 25-kb hrp/hrm gene cluster isolated from p. syringae pv. syringae 61(phir11) enables escherichia coli to elicit a hypersensitive response (hr), a plant response generally considered to be a manifestation of recognition and resistance. to identify the nature of the ...	1992	1312527
the lema gene required for pathogenicity of pseudomonas syringae pv. syringae on bean is a member of a family of two-component regulators.	the lema gene of the plant pathogen pseudomonas syringae pv. syringae is required for disease lesion formation on bean plants. cosmid clones that complemented a lema mutant in trans were isolated previously. the lema gene was localized by subcloning and transposon mutagenesis. the lema region and flanking dna were sequenced, and an open reading frame of 2.7 kb was identified. the nucleotide and predicted amino acid sequences of the lema gene showed sequence similarity to a family of prokaryotic ...	1992	1314807
the pseudomonas syringae pv. syringae 61 hrph product, an envelope protein required for elicitation of the hypersensitive response in plants.	pseudomonas syringae pv. syringae 61 contains a 25-kb cluster of hrp genes that are required for elicitation of the hypersensitive response (hr) in tobacco. tnphoa mutagenesis of cosmid phir11, which contains the hrp cluster, revealed two genes encoding exported or inner-membrane-spanning proteins (h.-c. huang, s. w. hutcheson, and a. collmer, mol. plant-microbe interact. 4:469-476, 1991). the gene in complementation group x, designated hrph, was subcloned on a 3.1-kb sali fragment into pcpp30, ...	1992	1400238
organization and environmental regulation of the pseudomonas syringae pv. syringae 61 hrp cluster.	the ability of pseudomonas syringae pv. syringae 61 to elicit the hypersensitive response in nonhost plant species has been linked to a cluster of hrp/hrm genes whose expression appears to be environmentally regulated. to understand the genetic organization of this hrp/hrm gene cluster and its expression during the interaction with nonhost plant species better, we constructed a set of chromosomal hrp-uida fusions in p. syringae pv. syringae 61 by tn5-gusa1 mutagenesis of the cloned hrp/hrm gene ...	1992	1548225
a lipoxygenase from leaves of tomato (lycopersicon esculentum mill.) is induced in response to plant pathogenic pseudomonads.	lipoxygenase (lox) mrna, enzyme protein, and enzyme activity were found to be induced in leaves of tomato (lycopersicon esculentum mill. cv moneymaker) on inoculation with plant pathogenic bacteria. the rate of enzyme activity with linoleic or linolenic acid as substrate was approximately 10 times greater than that with arachidonic acid. optimum activity was at ph 7.0. in the incompatible interaction, which was associated with a hypersensitive reaction (hr), a single band with relative molecular ...	1992	16668924
expression of a bacterial ice nucleation gene in plants.	we have introduced an ice nucleation gene (inaz) from pseudomonas syringae pv. syringae into nicotiana tabacum, a freezing-sensitive species, and solanum commersonii, a freezing-tolerant species. transformants of both species showed increased ice nucleation activity over untransformed controls. the concentration of ice nuclei detected at -10.5 degrees c in 15 different primary transformants of s. commersonii varied by over 1000-fold, and the most active transformant contained over 100 ice nuclei ...	1992	16653190
ecological and genetic analysis of copper and streptomycin resistance in pseudomonas syringae pv. syringae.	strains of pseudomonas syringae pv. syringae resistant to copper, streptomycin, or both compounds were recovered from symptomless and diseased tissue of four woody hosts in three nurseries in oklahoma. in strains resistant to copper and streptomycin (cur smr), resistance to both compounds was cotransferred with a single plasmid which was either 68, 190, or 220 kilobase pairs (kb). all cus smr strains contained a 68-kb conjugative plasmid. cur sms strains contained one plasmid which varied in siz ...	1993	8476279
dna sequence variation and phylogenetic relationships among strains of pseudomonas syringae pv. syringae inferred from restriction site maps and restriction fragment length polymorphism.	we evaluated the restriction fragment length polymorphism of genomic dna among 53 strains of the phytopathogenic bacterium pseudomonas syringae pv. syringae. twenty-nine strains were isolated from beans, and the rest were isolated from 11 other hosts. southern blots of dna digested with ecori or hindiii were hybridized to two random probes from a cosmid library of p. syringae pv. syringae and a hrp (hypersensitive reaction and pathogenicity) cluster cloned from p. syringae pv. syringae. the size ...	1993	7904440
hrpi of erwinia amylovora functions in secretion of harpin and is a member of a new protein family.	hrpi, a 78-kda protein, functions in the secretion of harpin, a proteinaceous elicitor of the hypersensitive response from erwinia amylovora. the predicted amino acid sequence of hrpi is remarkably similar to that of lcrd of yersinia species, the first member of a recently described protein family. other proteins of the family are mixa from shigella flexneri, inva from salmonella typhimurium, flha from caulobacter crescentus, hrpi from pseudomonas syringae pv. syringae, hrpo from pseudomonas sol ...	1993	8253684
genetic evidence that the gaca gene encodes the cognate response regulator for the lema sensor in pseudomonas syringae.	mutational analysis of the bean-pathogenic pseudomonas syringae pv. syringae strain b728a has led to the genetic identification of the gaca gene as encoding the response regulator for the unlinked lema sensor kinase. the analysis of a collection of spontaneous mutants of p. syringae pv. syringae suggested that the gaca gene was involved in lesion formation and the production of protease and syringomycin. the gaca gene originally was identified as a regulator of extracellular antibiotic productio ...	1994	8002569
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
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
periplasmic glucans of pseudomonas syringae pv. syringae.	we report the initial characterization of glucans present in the periplasmic space of pseudomonas syringae pv. syringae (strain r32). these compounds were found to be neutral, unsubstituted, and composed solely of glucose. their size ranges from 6 to 13 glucose units/mol. linkage studies and nuclear magnetic resonance analyses demonstrated that the glucans are linked by beta-1,2 and beta-1,6 glycosidic bonds. in contrast to the periplasmic glucans found in other plant pathogenic bacteria, the gl ...	1994	7961404
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
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
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
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
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
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
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
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
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
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
in vitro antifungal and fungicidal activities and erythrocyte toxicities of cyclic lipodepsinonapeptides produced by pseudomonas syringae pv. syringae.	recent increases in fungal infections, the few available antifungal drugs, and increasing fungal resistance to the available antifungal drugs have resulted in a broadening of the search for new antifungal agents. strains of pseudomonas syringae pv. syringae produce cyclic lipodepsinonapeptides with antifungal activity. the in vitro antifungal and fungicidal activities of three cyclic lipodepsinonapeptides (syringomycin e, syringotoxin b, and syringostatin a) against medically important isolates ...	1996	9124827
the active oxygen response of cell suspensions to incompatible bacteria is not sufficient to cause hypersensitive cell death.	the inoculation of tobacco (nicotiana tabacum l.) suspension cells with bacterial pathogens that elicit the hypersensitive response (hr) in leaves has been shown to elicit production of active oxygen. this response occurs in two phases, the second of which occurs 1 to 3 h after bacterial addition and is unique to hr-causing interactions. the relationship between the phase ii active oxygen response and the hr was characterized using pseudomonas syringae pv syringae and p. fluorescens (phir11), wh ...	1996	12226215
isolation and characterization of a tobacco mosaic virus-inducible myb oncogene homolog from tobacco.	salicylic acid (sa) plays an important role in signaling the activation of plant defense responses against pathogen attack including induction of pathogenesis-related (pr) proteins. to gain further insight into the sa-mediated signal transduction pathway, we have isolated and characterized a tobacco mosaic virus (tmv)-inducible myb oncogene homolog (myb1) from tobacco. the myb1 gene was induced upon tmv infection during both the hypersensitive response and development of systemic acquired resist ...	1996	8962166
suppression of a sensor kinase-dependent phenotype in pseudomonas syringae by ribosomal proteins l35 and l20.	the lema gene of pseudomonas syringae pv. syringae encodes the sensor kinase of a bacterial two-component signal transduction system. phenotypes that are lema dependent in p. syringae include lesion formation on bean and production of extracellular protease and the antibiotic syringomycin. recently, the gaca gene has been identified as encoding the response regulator of the lema regulon. to identify additional components that interact with lema, suppressors of a lema mutation were sought. a locu ...	1996	8626280
raindrop momentum triggers growth of leaf-associated populations of pseudomonas syringae on field-grown snap bean plants.	observational and microclimate modification experiments were conducted under field conditions to determine the role of the physical environment in effecting large increases in phyllosphere population sizes of pseudomonas syringae pv. syringae, the causal agent of bacterial brown spot disease of snap bean (phaseolus vulgaris l.). comparisons of daily changes in population sizes of p. syringae on three plantings of snap bean cultivar cascade and one of cultivar eagle with weather conditions indica ...	1996	16535362
contribution of the regulatory gene lema to field fitness of pseudomonas syringae pv. syringae.	in pseudomonas syringae pv. syringae, lema is required for brown spot lesion formation on snap bean and for production of syringomycin and extracellular proteases (e. m. hrabak and d. k. willis, j. bacteriol. 174: 3011-3022, 1992; e. m. hrabak and d. k. willis, mol. plant-microbe interact. 6:368-375, 1993; d. k. willis, e. m. hrabak, j. j. rich, t. m. barta, s. e. lindow, and n. j. panopoulos, mol. plant-microbe interact. 3:149-156, 1990). the lema mutant nps3136 (lema1::tn5) was previously foun ...	1997	16535727
multiple loci of pseudomonas syringae pv. syringae are involved in pathogenicity on bean: restoration of one lesion-deficient mutant requires two trna genes.	a mutational analysis of lesion-forming ability was undertaken in pseudomonas syringae pv. syringae b728a, causal agent of bacterial brown spot disease of bean. following a screen of 6,401 tn5-containing derivatives of b728a on bean pods, 26 strains that did not form disease lesions were identified. nine of the mutant strains were defective in the ability to elicit the hypersensitive reaction (hr) and were shown to contain tn5 insertions within the p. syringae pv. syringae hrp region. ten hr+ mu ...	1997	9079910
characterization of the alginate biosynthetic gene cluster in pseudomonas syringae pv. syringae.	alginate, a copolymer of d-mannuronic acid and l-guluronic acid, is produced by a variety of pseudomonads, including pseudomonas syringae. alginate biosynthesis has been most extensively studied in p. aeruginosa, and a number of structural and regulatory genes from this species have been cloned and characterized. in the present study, an alginate-defective (alg-) mutant of p. syringae pv. syringae ff5 was shown to contain a tn5 insertion in algl, a gene encoding alginate lyase. a cosmid clone de ...	1997	9226254
analysis of the syrp gene, which regulates syringomycin synthesis by pseudomonas syringae pv. syringae.	syringomycin is a lipodepsinonapeptide phytotoxin synthesized by pseudomonas syringae pv. syringae on multienzymatic peptide synthetases. sequence analysis of the interval between the syrb and syrd genes of p. syringae pv. syringae strain b301d revealed a 1,059-bp open reading frame (orf), designated syrp. the predicted product of this orf was a 39.6-kda protein consisting of 353 amino acid residues. searches of protein sequence databases demonstrated that syrp was most similar to histidine kina ...	1997	9212424
altered localization of hrpz in pseudomonas syringae pv. syringae hrp mutants suggests that different components of the type iii secretion pathway control protein translocation across the inner and outer membranes of gram-negative bacteria.	pseudomonas syringae pv. syringae 61 (pss61) secretes the hrpz harpin by a type iii protein secretion pathway encoded by a cluster of hrp (hypersensitive response and pathogenicity) and hrc genes. the nine hrc genes represent a subset of hrp genes that are also conserved in the type iii virulence protein secretion systems of animal pathogenic yersinia, shigella, and salmonella spp. the hrpj and hrpu operons contain seven hrc genes (counting hrcq(a) and hrcq(b) as one gene), all with additional h ...	1997	9190801
gene-expression patterns and levels of jasmonic acid in rice treated with the resistance inducer 2,6-dichloroisonicotinic acid.	acquired disease resistance can be induced in rice (oryza sativa) by a number of synthetic or natural compounds, but the molecular mechanisms behind the phenomenon are poorly understood. one of the synthetic inducers of resistance, 2,6-dichloroisonicotinic acid (ina), efficiently protected rice leaves from infection by the rice blast fungus magnaporthe grisea (hebert) barr. a comparison of gene-expression patterns in plants treated with ina versus plants inoculated with the compatible pathogen m ...	1997	12223792
negative regulation of hrp genes in pseudomonas syringae by hrpv.	mutations in the five hrp and hrc genes in the hrpc operon of the phytopathogen pseudomonas syringae pv. syringae 61 have different effects on bacterial interactions with host and nonhost plants. the hrcc gene within the hrpc operon encodes an outer membrane component of the hrp secretion system that is conserved in all type iii protein secretion systems and is required for most pathogenic phenotypes and for secretion of the hrpz harpin to the bacterial milieu. the other four genes (in order), h ...	1998	9721292
molecular characterization and sequence of a methionine biosynthetic locus from pseudomonas syringae.	two methionine biosynthetic genes in pseudomonas syringae pv. syringae, metx and metw, were isolated, sequenced, and evaluated for their roles in methionine biosynthesis and bacterial fitness on leaf surfaces. the metxw locus was isolated on a 1.8-kb dna fragment that was required for both methionine prototrophy and wild-type epiphytic fitness. sequence analysis identified two consecutive open reading frames (orfs), and in vitro transcription-translation experiments provided strong evidence that ...	1998	9721288
accumulation of salicylic acid and 4-hydroxybenzoic acid in phloem fluids of cucumber during systemic acquired resistance is preceded by a transient increase in phenylalanine ammonia-lyase activity in petioles and stems.	cucumber (cucumis sativa) leaves infiltrated with pseudomonas syringae pv. syringae cells produced a mobile signal for systemic acquired resistance between 3 and 6 h after inoculation. the production of a mobile signal by inoculated leaves was followed by a transient increase in phenylalanine ammonia-lyase (pal) activity in the petioles of inoculated leaves and in stems above inoculated leaves; with peaks in activity at 9 and 12 h, respectively, after inoculation. in contrast, pal activity in in ...	1998	9449843
genetic characterization of pseudomonas syringae pv. syringae strains from stone fruits in california	strains of pseudomonas syringae pv. syringae were isolated from healthy and diseased stone fruit tissues sampled from 43 orchard sites in california in 1995 and 1996. these strains, together with p. syringae strains from other hosts and pathovars, were tested for pathogenicity and the presence of the syrb and syrc genes and were genetically characterized by using enterobacterial repetitive intergenic consensus (eric) primers and pcr. all 89 strains of p. syringae pv. syringae tested were moderat ...	1998	9758805
pcr detection of cyclic lipodepsinonapeptide-producing pseudomonas syringae pv. syringae and similarity of strains.	many strains of pseudomonas syringae pv. syringae produce one of four classes of small cyclic lipodepsinonapeptides: syringomycins, syringostatins, syringotoxins, or pseudomycins. these metabolites are phytotoxic and growth inhibitory against a broad spectrum of fungi. their production is dependent upon the expression of conserved biosynthesis and export genes syrb and syrd, respectively. pcr and oligonucleotide primers specific for a 752-bp fragment of syrb were used to identify cyclic lipodeps ...	1998	16349482
cellular locations of pseudomonas syringae pv. syringae hrcc and hrcj proteins, required for harpin secretion via the type iii pathway.	the complete hrp-hrc-hrma cluster of pseudomonas syringae pv. syringae 61 encodes 28 polypeptides. a saprophytic bacterium carrying this cluster is capable of secreting hrpz-a harpin encoded by hrpz-in an hrp-dependent manner, which suggests that this cluster contains sufficient components to assemble functional type iii secretion machinery. sequence data show that hrcj and hrcc are putative outer membrane proteins, and nonpolar mutagenesis demonstrates they are all required for hrpz secretion. ...	1999	10094714
two-component transcriptional regulation of n-acyl-homoserine lactone production in pseudomonas aureofaciens.	production of phenazine antibiotics by the biological control bacterium pseudomonas aureofaciens 30-84 is regulated in part by the phzi/phzr n-acyl-homoserine lactone (ahl) response system (l. s. pierson iii, v. d. keppenne, and d. w. wood, j. bacteriol. 176:3966-3974, 1994; d. w. wood and l. s. pierson iii, gene 168:49-53, 1996). two mutants, 30-84w and 30-84.a2, were isolated and were found to be deficient in the production of phenazine, protease, hydrogen cyanide (hcn), and the ahl signal n-h ...	1999	10347004
regulation of alginate biosynthesis in pseudomonas syringae pv. syringae.	both pseudomonas aeruginosa and the phytopathogen p. syringae produce the exopolysaccharide alginate. however, the environmental signals that trigger alginate gene expression in p. syringae are different from those in p. aeruginosa with copper being a major signal in p. syringae. in p. aeruginosa, the alternate sigma factor encoded by algt (sigma22) and the response regulator algr1 are required for transcription of algd, a gene which encodes a key enzyme in the alginate biosynthetic pathway. in ...	1999	10348861
swarming by pseudomonas syringae b728a requires gacs (lema) and gaca but not the acyl-homoserine lactone biosynthetic gene ahli.	pseudomonas syringae pv. syringae b728a, a causal agent of bacterial brown spot on snap beans, swarms with a characteristic dendritic pattern on semisolid (0.4%) agar plates. filamentation of swarming cells of b728a was not observed. mutations in either the gacs (formerly lema) or gaca gene of b728a eliminate the ability of this p. syringae isolate to swarm without obvious effects on bacterial motility. three field isolates showed a similar dependence on gacs for swarming. since gacs and gaca mu ...	1999	10383988
role of the hrp type iii protein secretion system in growth of pseudomonas syringae pv. syringae b728a on host plants in the field.	hrp genes are reportedly required for pathogenicity in pseudomonas syringae pv. syringae (pss) and other phytopathogenic bacterial species. a subset of these genes encodes a type iii secretion system through which virulence factors are thought to be delivered to plant cells. in this study, we sought to better understand the role that hrp genes play in interactions of pss with its host as they occur naturally under field conditions. population sizes of hrp mutants with defects in genes that encod ...	1999	10449783
characterization of alginate lyase from pseudomonas syringae pv. syringae.	the gene encoding alginate lyase (algl) in pseudomonas syringae pv. syringae was cloned, sequenced, and overexpressed in escherichia coli. alginate lyase activity was optimal when the ph was 7.0 and when assays were conducted at 42 degrees c in the presence of 0.2 m nacl. in substrate specificity studies, algl from p. syringae showed a preference for deacetylated polymannuronic acid. sequence alignment with other alginate lyases revealed conserved regions within algl likely to be important for t ...	2000	11029455
use of an intergenic region in pseudomonas syringae pv. syringae b728a for site-directed genomic marking of bacterial strains for field experiments.	to construct differentially-marked derivatives of our model wild-type strain, pseudomonas syringae pv. syringae b728a (a causal agent of bacterial brown spot disease in snap bean plants), for field experiments, we selected a site in the gacs-cysm intergenic region for site-directed insertion of antibiotic resistance marker cassettes. in each of three field experiments, population sizes of the site-directed chromosomally marked b728a derivatives in association with snap bean plants were not signi ...	2001	11472957
isolation and in vivo and in vitro antifungal activity of phenylacetic acid and sodium phenylacetate from streptomyces humidus.	the antifungal substances sh-1 and sh-2 were isolated from streptomyces humidus strain s5-55 cultures by various purification procedures and identified as phenylacetic acid and sodium phenylacetate, respectively, based on the nuclear magnetic resonance, electron ionization mass spectral, and inductively coupled plasma mass spectral data. sh-1 and sh-2 completely inhibited the growth of pythium ultimum, phytophthora capsici, rhizoctonia solani, saccharomyces cerevisiae, and pseudomonas syringae p ...	2001	11472958
harpin induces activation of the arabidopsis mitogen-activated protein kinases atmpk4 and atmpk6.	mitogen-activated protein kinases (mapks) are key enzymes that mediate adaptive responses to various abiotic and biotic stresses, including pathogen challenge. the proteinaceous bacterial elicitor harpin (secreted by pseudomonas syringae pv syringae) activates two mapks in suspension cultures of arabidopsis var. landsberg erecta. in this study, we show that harpin and exogenous hydrogen peroxide (h(2)o(2)) activate myelin basic protein kinases in arabidopsis leaves. using anti-atmpk4 and anti-at ...	2001	11500556
genetic evidence that loss of virulence associated with gacs or gaca mutations in pseudomonas syringae b728a does not result from effects on alginate production.	mutations in the global regulatory genes gacs and gaca render pseudomonas syringae pv. syringae strain b728a completely nonpathogenic in foliar infiltration assays on bean plants. it had been previously demonstrated that gac genes regulate alginate production in pseudomonas species, while other published work indicated that alginate is involved in the pathogenic interaction of p. syringae on bean plants. together, these results suggested that the effects of gacs and gaca mutations on virulence i ...	2001	11229941
syringolin reprograms wheat to undergo hypersensitive cell death in a compatible interaction with powdery mildew.	we had previously isolated and characterized syringolin a, one of the molecular determinants secreted by pseudomonas syringae pv syringae that is perceived by nonhost plant species such as rice. here, we show that syringolin a is recognized by wheat and that it induces the accumulation of gene transcripts and increases protection against powdery mildew when applied before inoculation. moreover, syringolin a essentially eradicates powdery mildew from infected wheat if applied after inoculation. t ...	2001	11158536
bacteria associated with hazelnut (corylus avellana l.) decline are of two groups: pseudomonas avellanae and strains resembling p. syringae pv. syringae.	a total of 118 fluorescent pseudomonads associated with hazelnut decline, which has been occurring for many years in different areas of northern greece and italy, were assessed by performing a repetitive pcr analysis with enterobacterial repetitive intergenic consensus, box element, and repetive extragenic palindromic primer sets, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) of whole-cell protein extracts, a carbon compound utilization analysis, and an analysis to determi ...	2002	11823181
hydrogen peroxide activates cell death and defense gene expression in birch.	the function of hydrogen peroxide (h(2)o(2)) as a signal molecule regulating gene expression and cell death induced by external stresses was studied in birch (betula pendula). ozone (o(3)), pseudomonas syringae pv syringae (pss), and wounding all induced cell death of various extents in birch leaves. this was temporally preceded and closely accompanied by h(2)o(2) accumulation at, and especially surrounding, the lesion sites. o(3) and pss, along with an artificial h(2)o(2) producing system gluco ...	2002	12376624
differences between pseudomonas syringae pv. syringae b728a and pantoea agglomerans brt98 in epiphytic and endophytic colonization of leaves.	the leaf colonization strategies of two bacterial strains were investigated. the foliar pathogen pseudomonas syringae pv. syringae strain b728a and the nonpathogen pantoea agglomerans strain brt98 were marked with a green fluorescent protein, and surface (epiphytic) and subsurface (endophytic) sites of bean and maize leaves in the laboratory and the field were monitored to see if populations of these strains developed. the populations were monitored using both fluorescence microscopy and counts ...	2003	12571050
characterization of the arga gene required for arginine biosynthesis and syringomycin production by pseudomonas syringae pv. syringae.	two types of necrosis-inducing lipodepsipeptide toxins, called syringomycin and syringopeptin, are major virulence factors of pseudomonas syringae pv. syringae strain b301d. a previous study showed that a locus, called syra, was required for both syringomycin production and plant pathogenicity, and the syra locus was speculated to encode a regulator of toxin production. in this study, sequence analysis of the 8-kb genomic dna fragment that complements the syra phenotype revealed high conservatio ...	2003	14660376
frequency, size, and localization of bacterial aggregates on bean leaf surfaces.	using epifluorescence microscopy and image analysis, we have quantitatively described the frequency, size, and spatial distribution of bacterial aggregates on leaf surfaces of greenhouse-grown bean plants inoculated with the plant-pathogenic bacterium pseudomonas syringae pv. syringae strain b728a. bacterial cells were not randomly distributed on the leaf surface but occurred in a wide range of cluster sizes, ranging from single cells to over 10(4) cells per aggregate. the average cluster size i ...	2004	14711662
fatty acid hydroperoxides and h2o2 in the execution of hypersensitive cell death in tobacco leaves.	we initially compared lipid peroxidation profiles in tobacco (nicotiana tabacum) leaves during different cell death events. an upstream oxylipin assay was used to discriminate reactive oxygen species (ros)-mediated lipid peroxidation from 9- and 13-lipoxygenase (lox)-dependent lipid peroxidation. free radical-mediated membrane peroxidation was measured during h(2)o(2)-dependent cell death in leaves of catalase-deficient plants. taking advantage of these transgenic plants, we demonstrate that, un ...	2005	15980200
syrb2 in syringomycin e biosynthesis is a nonheme feii alpha-ketoglutarate- and o2-dependent halogenase.	the nine-residue lipodepsipeptide syringomycin e, elaborated as a phytotoxin by pseudomonas syringae pv. syringae b301d contains a 4-cl-l-thr-9 moiety where failure to chlorinate results in a 3-fold drop in biological activity. the proteins syrb1 and syrb2 encoded by the biosynthetic cluster are shown to act as a substrate and enzyme pair for syrb2-mediated chlorination of the aminoacyl-s-enzyme l-thr-s-syrb1. syrb2 is a member of the nonheme fe(ii) alpha-ketoglutarate-dependent enzyme superfami ...	2005	16002467
comparison of the complete genome sequences of pseudomonas syringae pv. syringae b728a and pv. tomato dc3000.	the complete genomic sequence of pseudomonas syringae pv. syringae b728a (pss b728a) has been determined and is compared with that of p. syringae pv. tomato dc3000 (pst dc3000). the two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and pst dc3000 having a more pronounced apoplastic growth habitat. the pss b728a ge ...	2005	16043691
characterization of a resistance-nodulation-cell division transporter system associated with the syr-syp genomic island of pseudomonas syringae pv. syringae.	a tripartite resistance-nodulation-cell division (rnd) transporter system, called the pseabc efflux system, was identified at the left border of the syr-syp genomic island of pseudomonas syringae pv. syringae strain b301d. the pseabc efflux system was located within a 5.7-kb operon that encodes an outer membrane protein (psea), a periplasmic membrane fusion protein (pseb), and an rnd-type cytoplasmic membrane protein (psec). the pseabc efflux system exhibited amino acid homology to a putative rn ...	2005	16151087
identification of the syr-syp box in the promoter regions of genes dedicated to syringomycin and syringopeptin production by pseudomonas syringae pv. syringae b301d.	the phytotoxins syringopeptin and syringomycin are synthesized by nonribosomal peptide synthetases which are encoded by the syringomycin (syr) and syringopeptin (syp) genomic island of pseudomonas syringae pv. syringae. previous studies demonstrated that expression of the syr-syp genes was controlled by the sala-syrf regulatory pathway, which in turn was induced by plant signal molecules. in this study, the 132-kb syr-syp genomic island was found to be organized into five polycistronic operons a ...	2006	16352832
characterization of the transcriptional activators sala and syrf, which are required for syringomycin and syringopeptin production by pseudomonas syringae pv. syringae.	production of the phytotoxins syringomycin and syringopeptin by pseudomonas syringae pv. syringae is controlled by the regulatory genes sala and syrf. analysis with 70-mer oligonucleotide microarrays established that the syr-syp genes responsible for synthesis and secretion of syringomycin and syringopeptin belong to the syrf regulon. vector pmekm12 was successfully used to express both sala and syrf proteins fused to a maltose-binding protein (mbp) in escherichia coli and p. syringae pv. syring ...	2006	16621822
identification of pseudomonas syringae pv. syringae 61 type iii secretion system hrp proteins that can travel the type iii pathway and contribute to the translocation of effector proteins into plant cells.	pseudomonas syringae translocates effector proteins into plant cells via an hrp1 type iii secretion system (t3ss). t3ss components hrpb, hrpd, hrpf, and hrpp were shown to be pathway substrates and to contribute to elicitation of the plant hypersensitive response and to translocation and secretion of the model effector avrpto1.	2007	17526708
alginate production by pseudomonas putida creates a hydrated microenvironment and contributes to biofilm architecture and stress tolerance under water-limiting conditions.	biofilms exist in a variety of habitats that are routinely or periodically not saturated with water, and residents must integrate cues on water abundance (matric stress) or osmolarity (solute stress) into lifestyle strategies. here we examine this hypothesis by assessing the extent to which alginate production by pseudomonas putida strain mt-2 and by other fluorescent pseudomonads occurs in response to water limitations and how the presence of alginate in turn influences biofilm development and ...	2007	17601783
biosynthesis of the proteasome inhibitor syringolin a: the ureido group joining two amino acids originates from bicarbonate.	syringolin a, an important virulence factor in the interaction of the phytopathogenic bacterium pseudomonas syringae pv. syringae b728a with its host plant phaseolus vulgaris (bean), was recently shown to irreversibly inhibit eukaryotic proteasomes by a novel mechanism. syringolin a is synthesized by a mixed non-ribosomal peptide synthetase/polyketide synthetase and consists of a tripeptide part including a twelve-membered ring with an n-terminal valine that is joined to a second valine via a ve ...	2009	19863801
airborne induction and priming of plant defenses against a bacterial pathogen.	herbivore-induced plant volatiles affect the systemic response of plants to local damage and hence represent potential plant hormones. these signals can also lead to "plant-plant communication," a defense induction in yet undamaged plants growing close to damaged neighbors. we observed this phenomenon in the context of disease resistance. lima bean (phaseolus lunatus) plants in a natural population became more resistant against a bacterial pathogen, pseudomonas syringae pv syringae, when located ...	2009	19812184
pea aphid as both host and vector for the phytopathogenic bacterium pseudomonas syringae.	aphids are widespread agricultural pests that are capable of disseminating plant viral diseases; however, despite coming into frequent contact with epiphytic bacteria, aphids are considered to have no role in bacterial transmission. here, we demonstrate the ability of pea aphids to vector the phytopathogen pseudomonas syringae pv. syringae b728a (psyb728a). while feeding on plants colonized by epiphytic bacteria, aphids acquire the bacteria, which colonize the digestive tract, multiply, and are ...	2009	19201955
genomics of plant-associated microbes.		2009	21255272
analysis of achromobactin biosynthesis by pseudomonas syringae pv. syringae b728a.	pseudomonas syringae pv. syringae b728a is known to produce the siderophore pyoverdine under iron-limited conditions. it has also been proposed that this pathovar has the ability to produce a second siderophore, achromobactin. here we present genetic and biochemical evidence supporting the hypothesis that p. syringae pv. syringae b728a produces both of these siderophores. we show that strains unable to synthesize either pyoverdine or achromobactin are unable to grow under iron-limiting condition ...	2009	19482931
novel high-throughput detection method to assess bacterial surfactant production.	a novel biosurfactant detection assay was developed for the observation of surfactants on agar plates. by using an airbrush to apply a fine mist of oil droplets, surfactants can be observed instantaneously as halos around biosurfactant-producing colonies. this atomized oil assay can detect a wide range of different synthetic and bacterially produced surfactants. this method could detect much lower concentrations of many surfactants than a commonly used water drop collapse method. it is semiquant ...	2010	20562275
identification of the biosynthetic gene cluster for 3-methylarginine, a toxin produced by pseudomonas syringae pv. syringae 22d/93.	the epiphyte pseudomonas syringae pv. syringae 22d/93 (pss22d) produces the rare amino acid 3-methylarginine (mearg), which is highly active against the closely related soybean pathogen pseudomonas syringae pv. glycinea. since these pathogens compete for the same habitat, pss22d is a promising candidate for biocontrol of p. syringae pv. glycinea. the mearg biosynthesis gene cluster codes for the s-adenosylmethionine (sam)-dependent methyltransferase mrsa, the putative aminotransferase mrsb, and ...	2010	20190091
recombineering using recte from pseudomonas syringae.	in this report, we describe the identification of functions that promote genomic recombination of linear dna introduced into pseudomonas cells by electroporation. the genes encoding these functions were identified in pseudomonas syringae pv. syringae b728a based on similarity to the lambda red exo/beta and recet proteins encoded by the lambda and rac bacteriophages of escherichia coli. the ability of the pseudomonad-encoded proteins to promote recombination was tested in p. syringae pv. tomato d ...	2010	20543050
proteasome activity imaging and profiling characterizes bacterial effector syringolin a.	syringolin a (syla) is a nonribosomal cyclic peptide produced by the bacterial pathogen pseudomonas syringae pv syringae that can inhibit the eukaryotic proteasome. the proteasome is a multisubunit proteolytic complex that resides in the nucleus and cytoplasm and contains three subunits with different catalytic activities: β1, β2, and β5. here, we studied how syla targets the plant proteasome in living cells using activity-based profiling and imaging. we further developed this technology by intr ...	2010	21045122
impact of siderophore production by pseudomonas syringae pv. syringae 22d/93 on epiphytic fitness and biocontrol activity against pseudomonas syringae pv. glycinea 1a/96.	the use of naturally occurring microbial antagonists to suppress plant diseases offers a favorable alternative to classical methods of plant protection. the soybean epiphyte pseudomonas syringae pv. syringae strain 22d/93 shows great potential for controlling p. syringae pv. glycinea, the causal agent of bacterial blight of soybean. its activity against p. syringae pv. glycinea is highly reproducible even in field trials, and the suppression mechanisms involved are of special interest. in this w ...	2010	20208028
sensor kinases rets and lads regulate pseudomonas syringae type vi secretion and virulence factors.	pseudomonas syringae pv. syringae b728a is a resident on leaves of common bean, where it utilizes several well-studied virulence factors, including secreted effectors and toxins, to develop a pathogenic interaction with its host. the b728a genome was recently sequenced, revealing the presence of 1,297 genes with unknown function. this study demonstrates that a 29.9-kb cluster of genes in the b728a genome shares homology to the novel type vi secretion system (t6ss) locus recently described for ot ...	2010	20472799
genome-driven investigation of compatible solute biosynthesis pathways of pseudomonas syringae pv. syringae and their contribution to water stress tolerance.	the foliar pathogen pseudomonas syringae pv. syringae exhibits an exceptional ability to survive on asymptomatic plants as an epiphyte. intermittent wetting events on plants lead to osmotic and matric stresses which must be tolerated for survival as an epiphyte. in this study, we have applied bioinformatic, genetic, and biochemical approaches to address water stress tolerance in p. syringae pv. syringae strain b728a, for which a complete genome sequence is available. p. syringae pv. syringae b72 ...	2010	20581190
improvement of the efficacy of linear undecapeptides against plant-pathogenic bacteria by incorporation of d-amino acids.	a set of 31 undecapeptides, incorporating 1 to 11 d-amino acids and derived from the antimicrobial peptide bp100 (kklfkkilkyl-nh(2)), was designed and synthesized. this set was evaluated for inhibition of growth of the plant-pathogenic bacteria erwinia amylovora, pseudomonas syringae pv. syringae, and xanthomonas axonopodis pv. vesicatoria, hemolysis, and protease degradation. two derivatives were as active as bp100, and 10 peptides displayed improved activity, with the all-d isomer being the mo ...	2011	21335383
within-genome evolution of repins: a new family of miniature mobile dna in bacteria.	repetitive sequences are a conserved feature of many bacterial genomes. while first reported almost thirty years ago, and frequently exploited for genotyping purposes, little is known about their origin, maintenance, or processes affecting the dynamics of within-genome evolution. here, beginning with analysis of the diversity and abundance of short oligonucleotide sequences in the genome of pseudomonas fluorescens sbw25, we show that over-represented short sequences define three distinct groups ...	2011	21698139
fungicidal activities and mechanisms of action of pseudomonas syringae pv. syringae lipodepsipeptide syringopeptins 22a and 25a.	the plant-associated bacterium pseudomonas syringae pv. syringae simultaneously produces two classes of metabolites: the small cyclic lipodepsinonapeptides such as the syringomycins and the larger cyclic lipodepsipeptide syringopeptins sp22 or sp25. the syringomycins inhibit a broad spectrum of fungi (but particularly yeasts) by lipid-dependent membrane interaction. the syringopeptins are phytotoxic and inhibitory to gram-positive bacteria. in this study, the fungicidal activities of two major s ...	2011	22046175