| evaluation of determinative tests for pathovars of pseudomonas syringae van hall 1902. | the utility of 36 presumptive determinative tests for 32 pathovars of pseudomonas syringae was investigated. a total of 395 strains was examined. most strains of 12 of these pathovars (ps. syringae pv. cannabina, ps. syr. delphinii, ps. syr. glycinea, ps. syr. helianthi, ps. syr. lachrymans, ps. syr. mori, ps. syr. morsprunorum, ps. syr. phaseolicola, ps. syr. 'porri', ps. syr. papulans, ps. syr. savastanoi and ps. syr. tabaci) formed clusters when test data were compared by centroid analysis. p ... | 1994 | 7961191 |
| 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 |
| 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 |
| the biosynthetic gene cluster for coronamic acid, an ethylcyclopropyl amino acid, contains genes homologous to amino acid-activating enzymes and thioesterases. | coronamic acid (cma), an ethylcyclopropyl amino acid derived from isoleucine, functions as an intermediate in the biosynthesis of coronatine, a chlorosis-inducing phytotoxin produced by pseudomonas syringae pv. glycinea pg4180. the dna required for cma biosynthesis (6.9 kb) was sequenced, revealing three distinct open reading frames (orfs) which share a common orientation for transcription. the deduced amino acid sequence of a 2.7-kb orf designated cmaa contained six core sequences and two conse ... | 1994 | 8002582 |
| plasmid-directed assembly of the lipid-containing membrane of bacteriophage phi 6. | the nucleocapsid of bacteriophage phi 6 is enveloped within a lipid-containing membrane. the membrane is composed of proteins p3, p6, p9, p10, and p13 and phospholipids. the relationship between membrane protein p9 and morphogenetic protein p12 was studied in the absence of phage infection. cdna copies of genes 9 and 12 were expressed on plasmids in pseudomonas syringae pv. phaseolicola. immunoblotting demonstrated the presence of protein p9 in strains carrying both gene 9 and gene 12 but not in ... | 1994 | 8021194 |
| phosphorylation of lipopolysaccharides in the antarctic psychrotroph pseudomonas syringae: a possible role in temperature adaptation. | phosphorylation of lipopolysaccharide (lps) from a psychrotrophic bacterium, pseudomonas syringae, from antarctica was studied by using sucrose gradient-separated membrane fractions. the bacterium was found to possess an lps kinase which could phosphorylate more lps postsynthetically at higher temperatures. the phosphorylation was low at a lower temperature and was also found to occur in vivo. after phosphorylation of lps in vitro, it was found that the major part of the radioactivity (> 85%) wa ... | 1994 | 8021210 |
| analysis of the streptomyces coelicolor sige gene reveals the existence of a subfamily of eubacterial rna polymerase sigma factors involved in the regulation of extracytoplasmic functions. | sigma e, an rna polymerase sigma factor of apparent m(r) 28,000, was previously identified by its ability to direct transcription from the p2 promoter of the agarose gene (daga) of streptomyces coelicolor. a degenerate oligonucleotide probe, designed from the n-terminal sequence of purified sigma e, was used to isolate the sigma e gene (sige). the predicted sequence of sigma e shows greatest similarity to sequences of seven other proteins: myxococcus xanthus carq, pseudomonas aeruginosa algu, ps ... | 1994 | 8052622 |
| characterization of ppt23b, the plasmid involved in syringolide production by pseudomonas syringae pv. tomato pt23. | avirulence gene d (avrd) in strain pt23 of pseudomonas syringae pv. tomato (pst) specifies the production of syringolides, which are elicitors of plant defense reactions. an 83-kb indigenous plasmid (ppt23b) that carries avrd has been mapped and characterized and a putative par region was identified. ppt23b contains a large amount of dna that is repeated in other native plasmids in pt23. a putative mobile insertion element that occurs on plasmid ppt23a as well as on the chromosome was also ident ... | 1994 | 8058820 |
| a disease resistance gene in arabidopsis with specificity for two different pathogen avirulence genes. | the rps3 and rpm1 disease resistance loci of arabidopsis confer resistance to pseudomonas syringae strains that carry the avirulence genes avrb and avrrpm1, respectively. we have previously shown that rps3 and rpm1 are closely linked genetically. here, we show that rps3 and rpm1 are in fact the same gene. we screened a mutagenized arabidopsis population with a p. syringae strain carrying avrb and found 12 susceptible mutants. all 12 mutants were also susceptible to an isogenic strain carrying av ... | 1994 | 8069104 |
| characterization of the hrpj and hrpu operons of pseudomonas syringae pv. syringae pss61: similarity with components of enteric bacteria involved in flagellar biogenesis and demonstration of their role in harpinpss secretion. | the hrp/hrma gene cluster of pseudomonas syringae pv. syringae pss61 has been shown to form a minimum genetic unit sufficient to enable nonpathogenic bacteria, such as escherichia coli, to elicit the hypersensitive response associated with disease resistance. the biochemical functions of most of these genes have not been established. the nucleotide sequence of a 4.3-kb ssti-bglii fragment carrying hrp apparent translational units v, vi, and vii revealed one partial open reading frame (orf) and f ... | 1994 | 8075421 |
| effect on lipopolysaccharide structure of aeration during growth of a plum isolate of pseudomonas syringae pv. morsprunorum. | the composition of lipopolysaccharide (lps) extracted with aqueous phenol from a virulent english plum isolate of pseudomonas syringae pv. morsprunorum varied according to the partial pressure of oxygen (po2) in the culture medium at the time of harvest. when po2 was low, the organism grew slowly and produced smooth lps bearing rhamnan sidechains. as po2 was raised, the rate of growth increased and smooth lps was replaced by a rough species deficient in rhamnose, which co-extracted with a d-gluc ... | 1994 | 8075800 |
| purification and characterization of copr, a transcriptional activator protein that binds to a conserved domain (cop box) in copper-inducible promoters of pseudomonas syringae. | the copper resistance (cop) operon promoter (pcop) of pseudomonas syringae is copper-inducible, and requires the regulatory genes coprs. sequence analysis revealed that copr has significant homology with other known activator proteins from bacterial two-component regulatory systems. in the present study we characterized pcop and its interaction with copr. we found that crude protein extracts from copper-resistant and -sensitive strains of p. syringae contain a pcop-specific dna-binding protein. ... | 1994 | 8078459 |
| 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 |
| molecular characterization of field isolates of pseudomonas syringae pv. glycinea differing in coronatine production. | coronatine-producing and non-producing strains of pseudomonas syringae pv. glycinea have been examined. we found a connection between copper resistance and synthesis of coronatine. published data implied that these properties may be encoded on different plasmids. production of coronatine and copper resistance were also found to be correlated for pv. glycinea in 19 field-isolates from leaf spots of plants in a soybean field and in 28 strains of a bacterial culture collection. genomic diversity wi ... | 1993 | 8105024 |
| 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 |
| changes in cultivar-specificity toward pea can result from transfer of plasmid rp4 and other incompatibility group p1 replicons to pseudomonas syringae pv. pisi. | transfer of rp4 and related replicons belonging to the escherichia coli incompatibility group p (pseudomonas aeruginosa incp1) to races 2 and 6 of p. syringae pv. pisi was associated with the creation of two types of transconjugant, one resembling the parental race and the other showing an altered cultivar-specificity towards pea. the latter, irrespective of the parental race, exhibited a novel pattern of interaction with pea that corresponded to race 4; consequently such transconjugants were te ... | 1993 | 8126435 |
| an inducible nadp(+)-dependent d-phenylserine dehydrogenase from pseudomonas syringae nk-15: purification and biochemical characterization. | an inducible nadp(+)-dependent d-phenylserine dehydrogenase [ec 1.1.1.-], which catalyzes the oxidation of the hydroxyl group of d-threo-beta-phenylserine, was purified to homogeneity from a crude extract of pseudomonas syringae nk-15 isolated from soil. the enzyme consisted of two subunits identical in molecular weight (about 31,000). in addition to d-threo-beta-phenylserine, it utilized d-threo-beta-thienylserine, d-threo-beta-hydroxynorvaline, and d-threonine as substrates but was inert towar ... | 1993 | 8138554 |
| the cloning and characterization of phage promoters, directing high expression of luciferase in pseudomonas syringae pv. phaseolicola, allowing single cell and microcolony detection. | regions of dna containing promoter sequences from a pseudomonas syringae pv. phaseolicola-specific phage (phi 11p) were identified by shotgun cloning into a broad-host-range promoter-probe vector (pqf70). when used in conjunction with the luciferase reporter genes, one of these dna fragments, 19h, directed gene expression at a level which enabled the subsequent light output (bioluminescence) of single cells of p. syringae pv. phaseolicola to be detected and visualized using a charge-coupled devi ... | 1993 | 8162227 |
| 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 |
| expression of the alpha-thionin gene from barley in tobacco confers enhanced resistance to bacterial pathogens. | thionins are cysteine-rich, 5 kda polypeptides which are toxic to plant pathogens in vitro. expression of the gene encoding alpha-thionin from barley endosperm, under the 35s promoter from cauliflower mosaic virus, conferred to transgenic tobacco enhanced resistance to the bacterial plant pathogens pseudomonas syringae pv. tabaci 153 and p. syringae pv. syringae. the barley alpha-thionin gene, which has two introns, was correctly spliced in tobacco. the alpha-thionin in transgenic plants had the ... | 1993 | 8220454 |
| arabidopsis mutants compromised for the control of cellular damage during pathogenesis and aging. | mutants of arabidopsis thaliana which exhibit accelerated cell death in response to pathogens were isolated and characterized to gain insight into how symptom severity and disease resistance are modulated. this paper describes mutants that fall into one of two complementation groups that were identified. a novel feature of these mutants is that they are unable to control the rate and extent of cell death after exposure to a variety of stimuli that induce senescence responses. thus, accelerated c ... | 1993 | 8220484 |
| characterization of the genes controlling the biosynthesis of the polyketide phytotoxin coronatine including conjugation between coronafacic and coronamic acid. | pseudomonas syringae pv. glycinea pg4180 produces a chlorosis-inducing phytotoxin, coronatine (cor), which consists of a polyketide component, coronafacic acid (cfa), which is coupled via amide bond formation to coronamic acid (cma), an ethylcyelopropyl amino acid (aa) derived from isoleucine. p. syringae pv. syringae strains ps51 and ps61, which do not synthesize coronafacoyl compounds (conjugates between cfa and aa), acquired the ability to produce cfa and cor when transformed with p4180a, a 9 ... | 1993 | 8224892 |
| kinetics of appearance and disappearance of classes of bacterial ice nuclei support an aggregation model for ice nucleus assembly. | the kinetics of appearance and disappearance of three classes of ice nuclei in pseudomonas syringae was investigated under conditions where high-level expression of the ice nucleation phenotype was obtained. the appearance of types 1, 2, and 3 ice nuclei, catalyzing nucleation at -2 to -5, -5 to -7, and -7 to -10 degrees c, respectively, was investigated during low-temperature induction in wild-type strains and in a unique, detergent-sensitive mutant that contained no type 3 ice nuclei when grow ... | 1993 | 8226668 |
| dodecylguanidine monoacetate (dodine) causes severe membrane damage in pseudomonas syringae above the critical micelle concentration. | the release of k+ from pseudomonas syringae cells treated with dodecylguanidine monoacetate (dodine) was followed with a k(+)-selective glass electrode. treatment of the cells with 5-15 mumol/l dodine resulted in low levels of k+ release, but higher surfactant concentrations caused extensive and rapid k+ efflux. dodine concentrations that caused high k+ release also induced significant leakage of inorganic phosphate. the addition of 5-10 mumol/l dodine also caused an increase in the rate of oxyg ... | 1993 | 8229668 |
| occurrence of antimicrobial activities of bacteria from soybean leaf spots. | bacteria were isolated from leaf spots of field grown soybeans during two growing seasons. the leaf spots yielded up to 4 different species and a total population size of about 10(7)-10(8) bacteria/cm2. the majority of the 192 isolates belonged to the species pseudomonas syringae pv. glycinea (55%), causing leaf spots of bacterial blight on soybeans, and erwinia herbicola (22%). the remaining isolates included bacteria from other genera, but occurred occasionally. the determination of biological ... | 1993 | 8229675 |
| syrd is required for syringomycin production by pseudomonas syringae pathovar syringae and is related to a family of atp-binding secretion proteins. | the syrd gene of pseudomonas syringae pathovar syringae strain b301d-r was characterized and sequenced. the syrd open reading frame is 1695 bp long and encodes a predicted protein, syrd, of approximately 63 kda. database searches revealed that syrd shares a high degree of similarity with the atp-binding cassette (abc) superfamily of transporter proteins which are responsible for specific nutrient uptake and for secretion of certain cellular products in prokaryotes, and for multiple drug resistan ... | 1993 | 8231810 |
| leucine aminopeptidase: an inducible component of the defense response in lycopersicon esculentum (tomato). | a leucine aminopeptidase (ec 3.4.11.1) cdna clone (dr57) that was induced in response to pseudomonas syringae pv. tomato (p.s. tomato) infection was isolated using a subtractive hybridization-enriched cdna probe. genomic dna blot analysis showed that the tomato genome had two leucine aminopeptidase genes. the levels of dr57 mrnas after p.s. tomato infection and mechanical wounding were determined in two inbred tomato lines that exhibit susceptibility and resistance to p.s. tomato. dr57 mrnas wer ... | 1993 | 8234334 |
| 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 |
| nucleotide sequence and properties of the hrma locus associated with the pseudomonas syringae pv. syringae 61 hrp gene cluster. | the hrma locus, isolated from pseudomonas syringae pv. syringae 61, is essential for phenotypic expression of the p. s. pv. syringae 61 hrp cluster in escherichia coli strains and enables bacteria carrying the hrp/hrm gene cluster to elicit the hypersensitive response (hr) associated with plant disease resistance. the phenotype of p. s. pv syringae 61 hrma mutants (pathogenicity+, delayed hr) was distinct from that of hrp mutants. the locus was localized to a 3.6-kb bamh1-ecor1 fragment whose nu ... | 1993 | 8274770 |
| recognition of the avirulence gene avrb from pseudomonas syringae pv. glycinea by arabidopsis thaliana. | the response of arabidopsis thaliana land race columbia to the bacterial pathogen pseudomonas syringae pv. maculicola 4326 harboring cloned avirulence genes avrb and avrc from p. syringae pv. glycinea and avra and avrd from p. syringae pv. tomato was examined. only avrb was recognized by columbia, as evidenced by attenuation of disease symptoms, slower bacterial multiplication in planta, and differentially greater induction of mrna for several defense-related genes. this contrasts with two a. th ... | 1993 | 8274772 |
| pathological and molecular characterizations of alfalfa interactions with compatible and incompatible bacteria, xanthomonas campestris pv. alfalfae and pseudomonas syringae pv. pisi. | we report on the interactions of alfalfa with xanthomonas campestris pv. alfalfae and pseudomonas syringae pv. pisi. a hypersensitive response was observed when leaves were infiltrated with p. s. pv. pisi, which remained strictly limited to the injected zone. the compatible interaction with x. c. pv. alfalfae was characterized by water-soaking symptoms and the spreading of the bacterium into the leaf blade. analyses of transcript accumulation were conducted with cdnas encoding enzymes involved i ... | 1993 | 8274775 |
| identification of a disease resistance locus in arabidopsis that is functionally homologous to the rpg1 locus of soybean. | a new disease resistance locus in arabidopsis, rps3, was identified using a previously cloned avirulence gene from a non-arabidopsis pathogen. the avrb avirulence gene from the soybean pathogen pseudomonas syringae pv. glycinea was transferred into a p. syringae pv. tomato strain that is virulent on arabidopsis, and conversion to avirulence was assayed on arabidopsis plants. the avrb gene had avirulence activity on most, but not all, arabidopsis ecotypes. of 53 ecotypes examined, 45 were resista ... | 1993 | 8275100 |
| purification of aspartate transcarbamoylase from pseudomonas syringae. | the aspartate transcarbamoylase (atcase) from pseudomonas syringae has been purified. the purified enzyme was shown by sds-page to give two bands. unambiguous results from n-terminal sequencing suggested that each band represented a homogeneous polypeptide. the m(r) (relative molecular mass) of the polypeptides was estimated to be 47 kda and 34 kda. the m(r) of the holoenzyme determined by gel filtration and electrophoretic migration in polyacrylamide gradient gels under non-denaturing condition ... | 1993 | 8282189 |
| molecular cloning, chromosomal mapping, and sequence analysis of copper resistance genes from xanthomonas campestris pv. juglandis: homology with small blue copper proteins and multicopper oxidase. | copper-resistant strains of xanthomonas campestris pv. juglandis occur in walnut orchards throughout northern california. the copper resistance genes from a copper-resistant strain c5 of x. campestris pv. juglandis were cloned and located on a 4.9-kb clai fragment, which hybridized only to dna of copper-resistant strains of x. campestris pv. juglandis, and was part of an approximately 20-kb region which was conserved among such strains of x. campestris pv. juglandis. hybridization analysis indic ... | 1994 | 8282694 |
| yeast genes involved in growth inhibition by pseudomonas syringae pv. syringae syringomycin family lipodepsipeptides. | saccharomyces cerevisiae genes encoding functions necessary for inhibition by the pseudomonas syringae pv. syringae cyclic lipodepsipeptide, syringomycin-e, were identified by mutant analyses. syringomycin-e-resistant mutants were isolated, shown to contain single recessive mutations, and divided into eight gene complementation groups. representative strains from five groups were resistant to nystatin, and deficient in the plasma membrane lipid, ergosterol. all of the mutant strains were resista ... | 1993 | 8288110 |
| high-level expression of ice nuclei in a pseudomonas syringae strain is induced by nutrient limitation and low temperature. | attempts were made to maximize the expression of ice nuclei in pseudomonas syringae t1 isolated from a tomato leaf. nutritional starvation for nitrogen, phosphorous, sulfur, or iron but not carbon at 32 degrees c, coupled to a shift to 14 to 18 degrees c, led to the rapid induction of type 1 ice nuclei (i.e., ice nuclei active at temperatures warmer than -5 degrees c). induction was most pronounced in stationary-phase cells that were grown with sorbitol as the carbon source and cooled rapidly, a ... | 1993 | 8320222 |
| somatic antigens of pseudomonads: structure of the o-specific polysaccharide of pseudomonas syringae pv. tomato 140(r). | | 1993 | 8324762 |
| pseudomonas syringae pv. syringae harpinpss: a protein that is secreted via the hrp pathway and elicits the hypersensitive response in plants. | the ability of p. syringae to elicit the hypersensitive response in nonhost plants or pathogenesis in hosts is controlled by hrp genes. the p. syringae pv. syringae 61 hrpz gene encodes harpinpss, a 34.7 kd extracellular protein that elicits hypersensitive necrosis in tobacco and other plants. harpinpss is heat stable, glycine rich, dissimilar in amino acid sequence to any known protein, produced only in apoplastic fluid-mimicking minimal media, and secreted in a hrph-dependent manner. the carbo ... | 1993 | 8324821 |
| multiple copies of a dna sequence from pseudomonas syringae pathovar phaseolicola abolish thermoregulation of phaseolotoxin production. | phaseolotoxin, a phytotoxin of pseudomonas syringae pv. phaseolicola, is produced at 18 degrees c but not at 28 degrees c. here we report that a fragment (24.4 kb) cloned from the wild-type strain, which does not harbour a gene(s) involved in phaseolotoxin biosynthesis, abolishes this thermoregulation in the wild type and suppresses a tox- mutant at both temperatures. a subclone harbouring a 485 bp fragment contains motifs that are characteristic of dna-binding sites. in mobility shift assays we ... | 1993 | 8326870 |
| characterization of chromosomal homologs of the plasmid-borne copper resistance operon of pseudomonas syringae. | copper-resistant and copper-sensitive strains of pseudomonas syringae, as well as many other pseudomonads, contain chromosomal dna homologous to the plasmid-borne copper resistance operon (copabcd). cop homologs were cloned from the chromosome of p. syringae pv. tomato pt12.2, which had an elevated level of resistance to copper compared with typical copper-sensitive strains of other p. syringae pathovars and showed an unusually high frequency of spontaneous mutation to high levels of copper resi ... | 1993 | 8331076 |
| molecular analysis of avirulence gene avrrpt2 and identification of a putative regulatory sequence common to all known pseudomonas syringae avirulence genes. | the avrrpt2 locus from pseudomonas syringae pv. tomato causes virulent strains of p. syringae to be avirulent on some, but not all, lines of arabidopsis thaliana and glycine max (soybean). we determined the dna sequence of the avrrpt2 locus and identified the avrrpt2 gene as a 768-bp open reading frame encoding a putative 28.2-kda protein. deletion analysis and transcription studies provided further evidence that this open reading frame encodes avrrpt2. we found that the avrrpt2 gene also has av ... | 1993 | 8335641 |
| the 73-kb piaa plasmid increases competitive fitness of pseudomonas syringae subspecies savastanoi in oleander. | pseudomonas syringae subsp. savastanoi causes tumors on olive and oleander by producing the plant growth regulators indoleacetic acid (iaa) and cytokinins following infection of the plant. the contribution of iaa production to the ability of p. syringae subsp. savastanoi to grow and survive in oleander leaf tissue was studied. bacterial strains differing only with respect to iaa production were characterized. growth and survival of wild-type and two mutant strains of p. syringae subsp. savastano ... | 1993 | 8364801 |
| characterization of the promoter of avirulence gene d from pseudomonas syringae pv. tomato. | the avirulence gene d (avrd) from pseudomonas syringae pv. tomato comprises the first open reading frame (orf) of a putative operon consisting of at least five tandem orfs. the promoter of the avrd operon was localized to a 150-bp dna fragment occurring 5' to the avrd gene by using the tn7-lux and gus reporter systems. the avrd promoter in p. syringae pv. tomato and p. syringae pv. glycinea was poorly expressed when bacteria were grown in complex culture media but was activated during bacterial ... | 1993 | 8376338 |
| nucleotide sequence analysis of a transposon (tn5393) carrying streptomycin resistance genes in erwinia amylovora and other gram-negative bacteria. | a class ii tn3-type transposable element, designated tn5393 and located on plasmid pea34 from streptomycin-resistant strain ca11 of erwinia amylovora, was identified by its ability to move from pea34 to different sites in plasmids pgem3zf(+) and pucd800. nucleotide sequence analysis reveals that tn5393 consists of 6,705 bp with 81-bp terminal inverted repeats and generates 5-bp duplications of the target dna following insertion. tn5393 contains open reading frames that encode a putative transpos ... | 1993 | 8380801 |
| characterization of an insertion sequence (is53) located within is51 on the iaa-containing plasmid of pseudomonas syringae pv. savastanoi. | a 2568-base pair (bp) insertion sequence (is53) was cloned from the iaa-containing plasmid piaa2 of pseudomonas syringae subsp. savastanoi. is53 is located downstream from the iaa operon and is inserted into is51, a previously described element on piaa2. is53 causes an 8-bp target duplication and has nearly perfect terminal inverted repeats of 27 bp. several degenerate copies of the inverted repeats are located internal, and in direct orientation to the terminal inverted repeats. a putative tran ... | 1993 | 8385786 |
| arabidopsis mutations at the rps2 locus result in loss of resistance to pseudomonas syringae strains expressing the avirulence gene avrrpt2. | we isolated and characterized two arabidopsis thaliana mutants that fail to mount a hypersensitive defense response (hr) when infiltrated with phytopathogenic pseudomonas strains carrying the avirulence (avr) gene avrrpt2 but still mount an hr when infiltrated with strains carrying other avr genes. one of these mutants was isolated using a method we developed that enriches for arabidopsis seedlings that survive vacuum-infiltration with a bacterial strain carrying an avr gene. genetic analysis sh ... | 1993 | 8400373 |
| spatial and temporal accumulation of defense gene transcripts in bean (phaseolus vulgaris) leaves in relation to bacteria-induced hypersensitive cell death. | primary leaves of 7- to 9-day-old red mexican bean plants were inoculated with virulent or avirulent isolates of pseudomonas syringae pv. phaseolicola, or saprophytic p. fluorescens either by vacuum infiltration of the whole leaf lamina, or by syringe-inoculation of selected leaf panels. in the incompatible combination, resistance was associated with a hypersensitive response (hr). syringe-inoculated leaves were sampled in three zones: zone 1, the inoculated leaf area; zone 2, the surrounding 0. ... | 1993 | 8400375 |
| characterization of the pseudomonas syringae pv. syringae 61 hrpj and hrpi genes: homology of hrpi to a superfamily of proteins associated with protein translocation. | the pseudomonas syringae pv. syringae 61 hrpj and hrpi genes were sequenced and found to encode predicted proteins of 37,710 da and 76,490 da, respectively. the products of these genes were confirmed by t7 polymerase-dependent expression and sodium dodecyl sulfate-polyacrylamide gel analysis. hrpi belongs to a superfamily of proteins represented by yersinia pestis lcrd. | 1993 | 8400380 |
| rps2, an arabidopsis disease resistance locus specifying recognition of pseudomonas syringae strains expressing the avirulence gene avrrpt2. | a molecular genetic approach was used to identify and characterize plant genes that control bacterial disease resistance in arabidopsis. a screen for mutants with altered resistance to the bacterial pathogen pseudomonas syringae pv. tomato (pst) expressing the avirulence gene avrrpt2 resulted in the isolation of four susceptible rps (resistance to p. syringae) mutants. the rps mutants lost resistance specifically to bacterial strains expressing avrrpt2 as they retained resistance to pst strains ... | 1993 | 8400869 |
| genetic organization of a cluster of genes involved in the production of phaseolotoxin, a toxin produced by pseudomonas syringae pv. phaseolicola. | phaseolotoxin [n delta(n'-sulfo-diaminophosphinyl)-ornithyl-alanyl- homoarginine] produced by pseudomonas syringae pv. phaseolicola, the bean halo blight pathogen, is a potent inhibitor of ornithine carbamoyltransferase (oct). inhibition of oct in infected plants leads to chlorosis and growth inhibition. a genomic cosmid clone, phk120, containing a 25-kb fragment of dna from a wild-type strain of p. syringae pv. phaseolicola restores toxin production in tox- mutants. tn5 mutagenesis of phk120 an ... | 1993 | 8407821 |
| erwinia stewartii wtsa, a positive regulator of pathogenicity gene expression, is similar to pseudomonas syringae pv. phaseolicola hrps. | erwinia stewartii contains a large cluster of wts genes that are required by this bacterium for pathogenicity on corn plants. three complementation groups within the right half of this cluster, wtsa, wtsc, and wtsb, were previously identified. in this study, wtsa was found to be a positive activator of wtsb::lacz expression. the wtsa locus was sequenced and a single open reading frame is present within the wtsa locus, which has the capacity to encode a 323 amino acid polypeptide. a corresponding ... | 1993 | 8412697 |
| nucleotide sequences of the trpi, trpb, and trpa genes of pseudomonas syringae: positive control unique to fluorescent pseudomonads. | a 904-bp probe from pseudomonas aeruginosa was used to identify the trpb, trpa and trpi genes of pseudomonas syringae. transcription initiation at the p. syringae trpba promoter in vitro was activated by the p. aeruginosa trpi protein in the presence of indoleglycerol phosphate. thus, trpb and trpa are regulated positively in three species of fluorescent pseudomonads, p. aeruginosa, p. putida, and p. syringae, but in no other eubacteria so far investigated [crawford, annu. rev. microbiol. 43 (19 ... | 1993 | 8423001 |
| effect of phenotypic plasticity on epiphytic survival and colonization by pseudomonas syringae. | the bacterial epiphyte pseudomonas syringae mf714r was cultured on agar or in broth or collected from colonized leaves; it was then inoculated onto greenhouse-grown bean plants incubated in a growth chamber at low relative humidity or in the field or onto field-grown bean plants. cells cultured in liquid medium survived the least well after inoculation of leaf surfaces under all conditions. cells cultured in solid medium exhibited the highest percent survival and desiccation tolerance in the gro ... | 1993 | 8434910 |
| role of copper resistance in competitive survival of pseudomonas fluorescens in soil. | a copper-resistant strain (09906) of pseudomonas fluorescens that was isolated from a citrus grove soil is being investigated as a biological control agent for phytophthora root rot. since citrus grove soils in california are often contaminated with copper from many years of copper fungicide applications, the role of copper resistance in survival of strain 09906 was investigated. three copper-sensitive tn5 mutants were obtained with insertions in different chromosomal dna regions. these insertio ... | 1993 | 8434924 |
| survival differences among freeze-dried genetically engineered and wild-type bacteria. | because the death mechanisms of freeze-dried and air-dried bacteria are thought to be similar, freeze-drying was used to investigate the survival differences between potentially airborne genetically engineered microorganisms and their wild types. to this end, engineered strains of escherichia coli and pseudomonas syringae were freeze-dried and exposed to air, visible light, or both. the death rates of all engineered strains were significantly higher than those of their parental strains. light an ... | 1993 | 8434925 |
| a two-component regulatory system required for copper-inducible expression of the copper resistance operon of pseudomonas syringae. | specific induction of the copper resistance operon (cop) promoter from pseudomonas syringae was measured by beta-galactosidase production from a cop promoter-lacz fusion. induction of the cop promoter in p. syringae pv. syringae required trans-acting factors from copper resistance plasmid ppt23d, from which cop was originally cloned. tn5 mutagenesis of ppt23d was used to localize two complementation groups immediately downstream from copabcd. cloning and sequencing of the dna in this region reve ... | 1993 | 8449873 |
| structural studies of the enveloped dsrna bacteriophage phi 6 of pseudomonas syringae by raman spectroscopy. i. the virion and its membrane envelope. | we report and interpret the first raman spectrum of a double-stranded rna virus containing a membrane envelope. spectra of the native bacteriophage phi 6 and of its isolated host-attachment (spike) protein and phospholipid-free core assembly were collected from aqueous solutions over a wide range of temperature. comparison of the vibrational spectra by digital difference methods permits the following structural conclusions regarding molecular constituents of the fully assembled virion. (1) the d ... | 1993 | 8464060 |
| structural studies of the enveloped dsrna bacteriophage phi 6 of pseudomonas syringae by raman spectroscopy. ii. nucleocapsid structure and thermostability of the virion, nucleocapsid and polymerase complex. | structures and thermostabilities of the double-stranded (ds) rna bacteriophage phi 6 and of its isolated nucleocapsid-polymerase complex (nucleocapsid core) and dsrna components have been investigated by raman spectroscopy. the spectra show that proteins of the phi 6 virion are collectively deficient in beta-sheet secondary structure. in particular, the major protein (p8) of the outer spherical shell of the phi 6 nucleocapsid exhibits a secondary structure dominated largely by alpha-helix and ir ... | 1993 | 8464061 |
| 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 |
| dynamics, spread, and persistence of a single genotype of pseudomonas syringae relative to those of its conspecifics on populations of snap bean leaflets. | a rifampin-resistant strain of pseudomonas syringae (r10) was introduced onto bean plants grown in field plots to examine the processes of growth, spread, and survival of a single genotype relative to the dynamics of its conspecifics on populations of individual leaflets. r10 was applied to four plots (400, 200, 100, and 50 m2), each of which was centered in a quadrant of a bean field (90 by 90 m). population sizes of the species p. syringae and of r10 were determined on each of 25 individual le ... | 1993 | 8476284 |
| genetic characterization of the pto locus of tomato: semi-dominance and cosegregation of resistance to pseudomonas syringae pathovar tomato and sensitivity to the insecticide fenthion. | the pto locus governs resistance to bacterial speck disease in tomato caused by race 0 strains of pseudomonas syringae pathovar tomato (pst). large populations segregating for the pto locus were generated and genetically characterized. analysis of the locus has revealed that pto acts in a semi-dominant manner and cosegegrates with sensitivity to an organophosphorous insecticide, fenthion, suggesting that pto may be a complex locus responsible for both phenotypes. we have redefined its map positi ... | 1993 | 8510645 |
| molecular characterization and hrp dependence of the avirulence gene avrpto from pseudomonas syringae pv. tomato [corrected]. | the avrpto avirulence gene from pseudomonas syringae pv. tomato (pst) race 0 governs race-specific resistance to bacterial speck disease in tomato cultivars containing the pto resistance gene. the avrpto gene encodes 0.7 and 0.75 kb mrnas whose predicted translation product is a mostly hydrophilic 164 amino acid protein of 18.3 kd a that reveals no homology to protein sequences in genbank or embl databases. highest expression of avrpto in cell culture is observed in minimal media containing suga ... | 1993 | 8510663 |
| 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 |
| characterization of genes required for pilus expression in pseudomonas syringae pathovar phaseolicola. | nonpiliated, phage phi 6-resistant mutants of pseudomonas syringae pv. phaseolicola were generated by tn5 transposon mutagenesis. a p. syringae pv. phaseolicola lr700 cosmid library was screened with tn5-containing ecori fragments cloned from nonpiliated mutants. the cosmid clone pvk253 complemented the nonpiliated mutant strain hb2.5. a 3.8-kb sequenced region spanning the tn5 insertion site contained four open reading frames. the transposon-inactivated gene, designated pilp, is 525 bp long, po ... | 1996 | 8550460 |
| 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 |
| identification of a new arabidopsis disease resistance locus, rps4, and cloning of the corresponding avirulence gene, avrrps4, from pseudomonas syringae pv. pisi. | a molecular genetic approach was used to study the interaction between arabidopsis and an avirulence gene from pseudomonas syringae pv. pisi. p. syringae pv. pisi strain 151 induces a hypersensitive response (hr) when inoculated on the arabidopsis accession po-1. a genomic cosmid library was constructed from dna from p. syringae pv. pisi strain 151 and a cosmid was identified that causes the normally virulent p. syringae pv. tomato strain dc3000 to induce an hr on po-1. the cosmid was subcloned ... | 1996 | 8589423 |
| 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 |
| flagellar genes from rhodobacter sphaeroides are homologous to genes of the flif operon of salmonella typhimurium and to the type-iii secretion system. | a flagellar region of the genome of rhodobacter sphaeroides was cloned and sequenced. three orfs were identified and arranged in the same order as flih, flii and flij of salmonella typhimurium (st). orf2 is highly similar to flii from st (49% similarity) showing walker's a and b motifs. similar scores were found with proteins of the type-iii secretion system of virulence factors. orf3 shows 16.4 and 11.1% similarity to flij from st and bacillus subtilis, respectively. this work also shows that o ... | 1996 | 8621091 |
| 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 |
| gene repression by the ferric uptake regulator in pseudomonas aeruginosa: cycle selection of iron-regulated genes. | the expression of at least 24 distinct genes of pseudomonas aeruginosa pao1 is under direct control of the "ferric uptake regulator" (fur). novel targets of the fur protein were isolated in a powerful selex (systematic evolution of ligands by exponential enrichment)-like cycle selection consisting of in vitro dna-fur interaction, binding to anti-fur antibody, purification on protein g, and pcr amplification. dna fragments obtained after at least three exponential enrichment cycles were cloned an ... | 1996 | 8633080 |
| phenotypic expression of pseudomonas syringae avr genes in e. coli is linked to the activities of the hrp-encoded secretion system. | the specific recognition of elicitors produced by plant pathogenic bacteria carrying avirulence (avr) genes is postulated to initiate cellular defense responses in plants expressing corresponding resistance genes. the biochemical functions of most avr genes, however, are not known. a heterologous system was developed to phenotypically express pseudomonas syringae avr genes in escherichia coli cells that required the p. syringae hrp cluster. e. coli mc4100 transformants carrying the plasmic-borne ... | 1996 | 8634477 |
| ozone-induced responses in arabidopsis thaliana: the role of salicylic acid in the accumulation of defense-related transcripts and induced resistance. | exposure of arabidopsis thaliana to ozone results in the expression of a number of defense-related genes that are also induced during a hypersensitive response. a potential common link between the activation of defense gene expression during a hypersensitive response and by ozone treatment is the production of active oxygen species and the accumulation of hydrogen peroxide. here we report that salicylic acid accumulation, which can be induced by hydrogen peroxide and is required for the expressi ... | 1996 | 8643534 |
| molecular cloning and functional identification of a plant ornithine decarboxylase cdna. | a cdna for a plant ornithine decarboxylase (odc), a key enzyme in putrescine and polyamine biosynthesis, has been isolated from root cultures of the solanaceous plant datura stramonium. reverse transcription-pcr employing degenerate oligonucleotide primers representing conserved motifs from other eukaryotic odcs was used to isolate the cdna. the longest open reading frame potentially encodes a peptide of 431 amino acids and exhibits similarity to other eukaryotic odcs, prokaryotic and eukaryotic ... | 1996 | 8660289 |
| nucleotide sequences of four pathogen-induced alfalfa peroxidase-encoding cdnas. | we constructed an alfalfa cdna library from mrna extracted from leaves after infection with pseudomonas syringae (incompatible interaction). screening with oligodeoxyribonucleotides designed from regions conserved in all known peroxidases allowed the isolation of four cdnas (msprx1a, 1b, 1c and 2). sequence analysis revealed the presence of open reading frames of 351, 355, 358 and 323 amino acids, respectively, with the characteristic consensus sequences of plant peroxidases. sequence comparison ... | 1996 | 8666247 |
| tomato prf is a member of the leucine-rich repeat class of plant disease resistance genes and lies embedded within the pto kinase gene cluster. | in tomato, resistance to pseudomonas syringae pv. tomato (pst) strains expressing the avirulence gene avrpto requires the presence of at least two host genes, designated pto and prf. here we report that prf encodes a protein with leucine-zipper, nucleotide-binding, and leucine-rich repeat motifs, as are found in a number of resistance gene products from other plants. prf mutant alleles (4) were found to carry alterations within the prf coding sequence. a genomic fragment containing prf complemen ... | 1996 | 8689679 |
| molecular analysis of closely related copper- and streptomycin-resistance plasmids in pseudomonas syringae pv. syringae. | the genetic relationship of a group of copper (cur) and streptomycin (smr) resistance plasmids and their pseudomonas syringae pv. syringae hosts was examined. each of these plasmids contained sequences homologous to the oriv and par sequences from posu900, a cryptic p. syringae pv. syringae plasmid. analysis of restriction digest patterns of plasmid dna indicated that the plasmids could be clustered into four groups; two of the groups contained multiple members which differed by only a few fragm ... | 1996 | 8700971 |
| properties of beta-lactamase from pseudomonas syringae. | pseudomonas syringae isolate br2r produces tabtoxin, a beta-lactam-containing antibiotic, and the causative agent of wildfire disease of green bean (phaseolus vulgaris). beta-lactamase production has been suggested as the mechanism that protects p. syringae from tabtoxin. we sought to determine whether the organism produces beta-lactamase and whether the enzyme plays a role in protection from this antibiotic. p. syringae and mutants defective in tabtoxin production and resistance produce beta-la ... | 1996 | 8704658 |
| calcium-mediated apoptosis in a plant hypersensitive disease resistance response. | avirulent pathogens elicit a battery of plant defenses, often accompanied by collapse of the challenged cells. in soybean cells, sustained accumulation of h2o2 from an oxidative burst cues localized host cell death. such hypersensitive cell death appears to be an active process, but little is known about the mechanisms underlying cellular collapse. | 1996 | 8723347 |
| isolation of arabidopsis mutants with enhanced disease susceptibility by direct screening. | to discover which components of plant defense responses make significant contributions to limiting pathogen attack, we screened a mutagenized population of arabidopsis thaliana for individuals that exhibit increased susceptibility to the moderately virulent bacterial pathogen pseudomonas syringae pv. maculicola es4326 (psm es4326). the 12 enhanced disease susceptibility (eds) mutants isolated included alleles of two genes involved in phytoalexin biosynthesis (pad2, which had been identified prev ... | 1996 | 8725243 |
| the repb gene required for production of extracellular enzymes and fluorescent siderophores in pseudomonas viridiflava is an analog of the gaca gene of pseudomonas syringae. | two genes, designated repa and repb, are involved in the regulation of the synthesis of extracellular pectate lyase, protease, and alginate in pseudomonas viridiflava. the repa gene has been shown to encode a protein highly homologous to several bacterial sensors in the two-component regulator family including the lema of pseudomonas syringae. in this study, the repb locus, initially identified in a 6.3-kb ecori genomic fragment of p. viridiflava, was further characterized. results obtained from ... | 1996 | 8742358 |
| isolation of arabidopsis genes that differentiate between resistance responses mediated by the rps2 and rpm1 disease resistance genes. | the arabidopsis disease resistance gene rps2 is involved in recognition of bacterial pathogens carrying the avirulence gene avrrpt2, and the rpm1 resistance gene is involved in recognition of pathogens carrying avrrpm1 or avrb. we identified and cloned two arabidopsis genes, aig1 and aig2 (for avrrpt2-induced gene), that exhibit rps2- and avrrpt2-dependent induction early after infection with pseudomonas syringae pv maculicola strain es4326 carrying avrrpt2. however, es4326 carrying avrrpm1 or a ... | 1996 | 8742710 |
| benzothiadiazole induces disease resistance in arabidopsis by activation of the systemic acquired resistance signal transduction pathway. | benzothiadiazole (bth) is a novel chemical activator of disease resistance in tobacco, wheat and other important agricultural plants. in this report, it is shown that bth works by activating sar in arabidopsis thaliana. bth-treated plants were resistant to infection by turnip crinkle virus, pseudomonas syringae pv 'tomato' dc3000 and peronospora parasitica. chemical treatment induced accumulation of mrnas from the sar-associated genes, pr-1, pr-2 and pr-5. bth treatment induced both pr-1 mrna ac ... | 1996 | 8758979 |
| structural and mechanistic similarities of 6-phosphogluconate and 3-hydroxyisobutyrate dehydrogenases reveal a new enzyme family, the 3-hydroxyacid dehydrogenases. | rat 3-hydroxyisobutyrate dehydrogenase exhibits significant amino acid sequence homology with 6-phosphogluconate dehydrogenase, d-phenylserine dehydrogenase from pseudomonas syringae, and a number of hypothetical proteins encoded by genes of microbial origin. key residues previously proposed to have roles in substrate binding and catalysis in sheep 6-phosphogluconate dehydrogenase are highly conserved in this entire family of enzymes. site-directed mutagenesis, chemical modification, and substra ... | 1996 | 8766712 |
| expression of the pseudomonas syringae avirulence protein avrb in plant cells alleviates its dependence on the hypersensitive response and pathogenicity (hrp) secretion system in eliciting genotype-specific hypersensitive cell death. | the nonpathogenic bacteria pseudomonas fluorescens and escherichia coli can elicit a genotype-specific hypersensitive response (hr) in plants if they express both the hr and pathogenesis (hrp) protein secretion system and the hrpz harpin from p. syringae pv syringae 61 and a p. syringae avirulence (avr) gene whose presence is recognized by a corresponding disease resistance gene in the plant. we have found that the recognition event appears to require transfer of the avr protein into the plant c ... | 1996 | 8768370 |