| 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 |
| salicylic acid is needed in hypersensitive cell death in soybean but does not act as a catalase inhibitor. | the function of salicylic acid (sa) in hypersensitive cell death was studied in a soybean (glycine max)-pseudomonas syringae pv glycinea system. the infection of cell cultures with bacteria leads to a hypersensitive reaction (hr), which is dependent on an appropriate avirulence gene and on low concentrations of sa. the requirement for sa is essential for a process shortly before the onset of the hr-caused cell death 5 to 6 h after infection with bacteria. sa given 10 to 12 h after infection or p ... | 1997 | 12223807 |
| 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 |
| a complex array of proteins related to the multimeric leucine aminopeptidase of tomato. | leucine aminopeptidase (lap) mrnas are induced in response to mechanical wounding, pathogen infection, and insect infestation (v. pautot, f.m. holzer, b. reisch, l.l. walling [1993] proc natl acad sci usa 90: 9906-9910). polyclonal antibodies to a glutathione s-transferase-lap fusion protein and affinity-purified antibodies recognizing lap antigenic determinants detected four classes of polypeptides in tomato (lycopersicon esculentum) leaves. all four classes had multiple polypeptides in two-dim ... | 1996 | 12226257 |
| differential expression of a metallothionein gene during the presymbiotic versus the symbiotic phase of an arbuscular mycorrhizal fungus. | a full-length cdna encoding a metallothionein (mt)-like polypeptide, designated gmarmt1, was identified in an expressed sequence tag collection from germinated spores of the arbuscular mycorrhizal fungus gigaspora margarita (beg34). the gmarmt1 gene is composed of two exons separated by an 81-bp intron. it codes for a 65-amino acid polypeptide comprising a plant type 1 mt-like n-terminal domain and a c-terminal domain that is most closely related to an as-yet-uncharacterized fungal mt. as reveal ... | 2002 | 12226486 |
| a strobilurin fungicide enhances the resistance of tobacco against tobacco mosaic virus and pseudomonas syringae pv tabaci. | the strobilurin class of fungicides comprises a variety of synthetic plant-protecting compounds with broad-spectrum antifungal activity. in the present study, we demonstrate that a strobilurin fungicide, f 500 (pyraclostrobin), enhances the resistance of tobacco (nicotiana tabacum cv xanthi nc) against infection by either tobacco mosaic virus (tmv) or the wildfire pathogen pseudomonas syringae pv tabaci. f 500 was also active at enhancing tmv resistance in nahg transgenic tobacco plants unable t ... | 2002 | 12226492 |
| characterization of an acyltransferase capable of synthesizing benzylbenzoate and other volatile esters in flowers and damaged leaves of clarkia breweri. | a cdna encoding a protein with 456 amino acids whose sequence shows considerable similarity to plant acyltransferases was identified among 750 clarkia breweri flower expressed sequence tags. the cdna was expressed in escherichia coli, and the protein produced was shown to encode the enzyme benzoyl-coenzyme a (coa):benzyl alcohol benzoyl transferase (bebt). bebt catalyzes the formation of benzylbenzoate, a minor constituent of the c. breweri floral aroma, but it also has activity with a number of ... | 2002 | 12226525 |
| representational difference analysis between afa/dr diffusely adhering escherichia coli and nonpathogenic e. coli k-12. | diffusely adhering escherichia coli strains harboring afa/dr adhesins (afa/dr daec) have been associated with diarrhea and urinary tract infections (utis). the present work is the first extensive molecular study of a afa/dr daec strain using the representational difference analysis technique. we have searched for dna sequences present in strain c1845, recovered from a diarrheagenic child, but absent from a nonpathogenic k-12 strain. strain c1845 harbors part of a pathogenicity island (pai(cft073 ... | 2002 | 12228276 |
| analysis of sweet cherry (prunus avium l.) leaves for plant signal molecules that activate the syrb gene required for synthesis of the phytotoxin, syringomycin, by pseudomonas syringae pv syringae. | an important aspect of the interaction of pseudomonas syringae pv syringae with plant hosts is the perception of plant signal molecules that regulate expression of genes, such as syrb, required for synthesis of the phytotoxin, syringomycin. in this study, the leaves of sweet cherry (prunus avium l.) were analyzed to determine the nature of the syrb-inducing activity associated with tissues of a susceptible host. crude leaf extracts yielded high amounts of total signal activity of more than 12,00 ... | 1995 | 12228385 |
| a noninvasive technique for monitoring peroxidative and h2o2-scavenging activities during interactions between bacterial plant pathogens and suspension cells. | stimulation of active oxygen metabolism occurs during the early stages of interactions involving bacteria and plant cell suspensions. although many cellular processes are known to affect active oxygen metabolism in plants, it is not known which of these factors affect active oxygen levels during plant-bacteria interactions. extracellular peroxidases have been shown to participate in both the production and utilization of active oxygen species such as h2o2 and superoxide. catalase and other scave ... | 1995 | 12228480 |
| hrp mutant of pseudomonas syringae pv phaseolicola induces cell wall alterations but not membrane damage leading to the hypersensitive reaction in lettuce. | both wild-type (s21-wt) and hrpd- (s21-533) strains of pseudomonas syringae pv phaseolicola induced the formation of large paramural papillae in lettuce (lactuca sativa) mesophyll cells adjacent to bacterial colonies. localized alterations to the plant cell wall included deposition of hydroxyproline-rich glycoproteins, phe-nolics, and callose, and were associated with proliferation of the endoplasmic reticulum and multivesicular bodies. tissue collapse during the hypersensitive reaction caused b ... | 1995 | 12228488 |
| salicylic acid in rice (biosynthesis, conjugation, and possible role). | salicylic acid (sa) is a natural inducer of disease resistance in some dicotyledonous plants. rice seedlings (oryza sativa l.) had the highest levels of sa among all plants tested for sa content (between 0.01 and 37.19 [mu]g/g fresh weight). the second leaf of rice seedlings had slightly lower sa levels than any younger leaves. to investigate the role of sa in rice disease resistance, we examined the levels of sa in rice (cv m-201) after inoculation with bacterial and fungal pathogens. sa levels ... | 1995 | 12228500 |
| systemic responses in arabidopsis thaliana infected and challenged with pseudomonas syringae pv syringae. | attack of plants by necrotizing pathogens leads to acquired resistance to the same or other pathogens in tissues adjacent to or remotely located from the site of initial attack. we have used arabidopsis thaliana inoculated with the incompatible pathogen pseudomonas syringae pv syringae on the lower leaves to test the induction of systemic reactions. when plants were challenged with pseudomonas syringae pv syringae in the upper leaves, bacterial titers remained stable in those preinfected on the ... | 1995 | 12228548 |
| volatile products of the lipoxygenase pathway evolved from phaseolus vulgaris (l.) leaves inoculated with pseudomonas syringae pv phaseolicola. | activation of the "lipoxygenase pathway" in plants gives rise to a series of products derived from fatty acids. analysis by gas chromatography-mass spectroscopy of volatile products produced by phaseolus vulgaris (l.) cv red mexican leaves during a hypersensitive resistance response (hr) to the plant pathogenic bacterium pseudomonas syringae pv phaseolicola showed evolution of several lipid-derived volatiles, including cis-3-hexenol and trans-2-hexenal, which arise from the 13-hydroperoxide of l ... | 1993 | 12231661 |
| water relation alterations observed during hypersensitive reaction induced by bacteria. | upon exposure to pathogenic bacteria, resistant and nonhost plants undergo a hypersensitive reaction (hr) that is expressed as rapid plant cell death. if sufficient concentrations of these bacteria are inoculated to such plant tissue, then that portion of the tissue rapidly collapses and becomes necrotic. as the tissue collapses the water relations of inoculated tissues become markedly disturbed. we measured a decline in the relative water content (rwc) in the leaf-like cotyledons of cotton (gos ... | 1993 | 12232016 |
| multidrug pump inhibitors uncover remarkable activity of plant antimicrobials. | plant antimicrobials are not used as systemic antibiotics at present. the main reason for this is their low level of activity, especially against gram-negative bacteria. the reported mic is often in the range of 100 to 1,000 micro g/ml, orders of magnitude higher than those of common broad-spectrum antibiotics from bacteria or fungi. major plant pathogens belong to the gram-negative bacteria, which makes the low level of activity of plant antimicrobials against this group of microorganisms puzzl ... | 2002 | 12234835 |
| specific binding of the syringolide elicitors to a soluble protein fraction from soybean leaves. | syringolides are glycolipid elicitors produced by gram-negative bacteria expressing pseudomonas syringae avirulence gene d. the syringolides mediate gene-for-gene complementarity, inducing the hypersensitive response only in soybean plants carrying the rpg4 disease resistance gene. a site(s) for 125i-syringolide 1 was detected in the soluble protein fraction from soybean leaves, but no evidence for ligand-specific binding to the microsomal fraction was obtained. the kd value for syringolide 1 bi ... | 1997 | 12237390 |
| interference between two specific pathogen recognition events mediated by distinct plant disease resistance genes. | we demonstrate that the interaction of the avirulence gene avrrpt2 and the cognate resistance gene rps2 interferes with the interaction of avrrpm1-rpm1 in arabidopsis. interference is mediated outside of the bacterial pathogen pseudomonas syringae, presumably at the level of recognition of avr-dependent signals, yet does not require the wild-type rps2 product. a numerical excess of p. syringae expressing avrrpm1 can overcome this interference in mixed inoculations. the interference of avrrpt2-rp ... | 1996 | 12239384 |
| expression of the tomato pto gene in tobacco enhances resistance to pseudomonas syringae pv tabaci expressing avrpto. | the pto gene encodes a serine-threonine kinase that confers resistance in tomato to pseudomonas syringae pv tomato strains expressing the avirulence gene avrpto. we examined the ability of pto to function in tobacco, a species that is sexually incompatible with tomato. evidence that a heterologous pto-like signal transduction pathway is present in tobacco was suggested by the fact that tobacco line wisconsin-38 exhibits a hypersensitive response after infection with p. syringae pv tabaci express ... | 1995 | 12242354 |
| characterization of an arabidopsis mutant that is nonresponsive to inducers of systemic acquired resistance. | systemic acquired resistance (sar) is a general defense response in plants that is characterized by the expression of pathogenesis-related (pr) genes. sar can be induced after a hypersensitive response to an avirulent pathogen or by treatment with either salicylic acid (sa) or 2,6-dichloroisonicotinic acid (ina). to dissect the signal transduction pathway of sar, we isolated an arabidopsis mutant that lacks the expression of an sa-, ina-, and pathogen-responsive chimeric reporter gene composed o ... | 1994 | 12244227 |
| function of oxidative cross-linking of cell wall structural proteins in plant disease resistance. | elicitation of soybean cells causes a rapid insolubilization of two cell wall structural proteins, p33 and p100. likewise, a short elicitation of 30 min rendered cell walls more refractory to enzyme digestion as assayed by the yield of protoplasts released. this effect could be ascribed to protein cross-linking because of its insensitivity to inhibitors of transcription (actinomycin d) and translation (cycloheximide) and its induction by exogenous h2o2. moreover, the induced loss of protoplasts ... | 1994 | 12244231 |
| arabidopsis mutants selected for resistance to the phytotoxin coronatine are male sterile, insensitive to methyl jasmonate, and resistant to a bacterial pathogen. | the phytotoxin coronatine and the plant growth regulator methyl jasmonate (meja) caused similar growth-inhibitory effects on arabidopsis seedlings. to test whether these two compounds have similar action, 14 independent coi1 (coronatine-insensitive) mutants of arabidopsis were selected. the mutants segregated as single recessive mendelian markers, and all were alleles at the coi1 locus. all coi1 mutants were also insensitive to meja and were male sterile. both coronatine and meja inhibited root ... | 1994 | 12244256 |
| generalized induction of defense responses in bean is not correlated with the induction of the hypersensitive reaction. | transcripts for phenylalanine ammonia-lyase, chalcone synthase, chalcone isomerase, and chitinase accumulated in common bean after infiltration with the pseudomonas syringae pv tabaci hrp- mutant pt11528::hrp1, even though a hypersensitive reaction did not occur. the temporal pattern of this transcript accumulation was similar to that seen after infiltration with wild-type p. s. tabaci pt11528, which resulted in a hypersensitive reaction. escherichia coli dh5[alpha], p. fluorescens pf101, heat-k ... | 1993 | 12271015 |
| suppression of bean defense responses by pseudomonas syringae. | we have developed a model system to examine suppression of defense responses in bean by the compatible bacterium pseudomonas syringae pv phaseolicola. previously, we have shown that there is a general mechanism for the induction of the bean defense genes phenylalanine ammonia-lyase (pal), chalcone synthase (chs), chalcone isomerase (chi), and chitinase (cht) by incompatible, compatible, and nonpathogenic bacteria. here, we show that bean plants infiltrated with isolates of p. s. phaseolicola fai ... | 1993 | 12271016 |
| heca, a member of a class of adhesins produced by diverse pathogenic bacteria, contributes to the attachment, aggregation, epidermal cell killing, and virulence phenotypes of erwinia chrysanthemi ec16 on nicotiana clevelandii seedlings. | erwinia chrysanthemi is representative of a broad class of bacterial pathogens that are capable of inducing necrosis in plants. the e. chrysanthemi ec16 heca gene predicts a 3,850-aa member of the bordetella pertussis filamentous hemagglutinin family of adhesins. a hecatn7 mutant was reduced in virulence on nicotiana clevelandii seedlings after inoculation without wounding. epifluorescence and confocal laser-scanning microscopy observations of heca and wild-type cells expressing the green fluore ... | 2002 | 12271135 |
| a putative lipid transfer protein involved in systemic resistance signalling in arabidopsis. | localized attack by a necrotizing pathogen induces systemic acquired resistance (sar) to subsequent attack by a broad range of normally virulent pathogens. salicylic acid accumulation is required for activation of local defenses, such as pathogenesis-related protein accumulation, at the initial site of attack, and for subsequent expression of sar upon secondary, distant challenge. although salicylic acid moves through the plant, it is apparently not an essential mobile signal. we screened agroba ... | 2002 | 12353036 |
| a pathogen-responsive cdna from potato encodes a protein with homology to a phosphate starvation-induced phosphatase. | infiltration of potato leaves with the phytopathogenic bacteria pseudomonas syringae pv. maculicola induces local and systemic defense gene expression as well as increased resistance against subsequent pathogen attacks. by cdna-aflp a gene was identified that is activated locally in potato leaves in response to bacterial infiltration and after infection with phytophthora infestans, the causal agent of late blight disease. the encoded protein has high homology to a phosphate starvation-induced ac ... | 2002 | 12354923 |
| osbimk1, a rice map kinase gene involved in disease resistance responses. | the activation of mitogen-activated protein kinases (mapks) has been previously implicated in signal transduction during plant responses to pathogen attack as well as to various environmental stresses. we have isolated from rice a new mapk cdna, osbimk1 ( o ryza s ativa l. bth-induced mapk 1), which encodes a 369-amino-acid protein with moderate to high nucleotide sequence similarity to previously reported plant mapk genes. osbimk1 contains all 11 of the mapk conserved subdomains and the phospho ... | 2002 | 12355160 |
| inhibition of hydrolytic enzyme activities and plant pathogen growth by invertase inhibitors. | the invertase inhibitory protein isolated from cyphomandra betacea sendt and solanum tuberosum inhibited the invertase activity from different species, genera and even plant family. furthermore, proteinaceous inhibitors are not invertase specific; fungal, bacterial and higher plant enzymes including polygalacturonase, pectinase, pectin lyase, alpha-l-arabinofuranosidase and beta-glucosidase are also shown to be inhibited. both inhibitors exhibited an in vitro antibacterial action against phytopa ... | 2002 | 12365459 |
| 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 |
| the abcds of periplasmic copper trafficking. | the structure of the copc protein of pseudomonas syringae pathovar tomato provides fascinating clues, not only to its role in the periplasmic space in copper resistance, but also to features important for copper trafficking and homeostasis that may be conserved in a variety of biological systems. | 2002 | 12377116 |
| genomic mining type iii secretion system effectors in pseudomonas syringae yields new picks for all ttss prospectors. | many bacterial pathogens of plants and animals use a type iii secretion system (ttss) to deliver virulence effector proteins into host cells. because effectors are heterogeneous in sequence and function, there has not been a systematic way to identify the genes encoding them in pathogen genomes, and our current inventories are probably incomplete. a pre-closure draft sequence of pseudomonas syringae pv. tomato dc3000, a pathogen of tomato and arabidopsis, has recently supported five complementar ... | 2002 | 12377556 |
| two pathways act in an additive rather than obligatorily synergistic fashion to induce systemic acquired resistance and pr gene expression. | local infection with necrotizing pathogens induces whole plant immunity to secondary challenge. pathogenesis-related genes are induced in parallel with this systemic acquired resistance response and thought to be co-regulated. the hypothesis of co-regulation has been challenged by induction of arabidopsis pr-1 but not systemic acquired resistance in npr1 mutant plants responding to pseudomonas syringae carrying the avirulence gene avrrpt2. however, experiments with ndr1 mutant plants have reveal ... | 2002 | 12381270 |
| expression of the antiapoptotic baculovirus p35 gene in tomato blocks programmed cell death and provides broad-spectrum resistance to disease. | the sphinganine analog mycotoxin, aal-toxin, induces a death process in plant and animal cells that shows apoptotic morphology. in nature, the aal-toxin is the primary determinant of the alternaria stem canker disease of tomato, thus linking apoptosis to this disease caused by alternaria alternata f. sp. lycopersici. the product of the baculovirus p35 gene is a specific inhibitor of a class of cysteine proteases termed caspases, and naturally functions in infected insects. transgenic tomato plan ... | 2002 | 12403830 |
| ethylene production by botrytis cinerea in vitro and in tomatoes. | a laser-based ethylene detector was used for on-line monitoring of ethylene released by the phytopathogenic fungus botrytis cinerea in vitro and in tomato fruit. ethylene data were combined with the results of a cytological analysis of germination of b. cinerea conidia and hyphal growth. we found that aminoethoxyvinylglycine and aminooxyacetic acid, which are competitive inhibitors of the 1-aminocyclopropane-1-carboxylic acid pathway, did not inhibit the ethylene emission by b. cinerea and that ... | 2002 | 12406723 |
| comprehensive transcript profiling of pto- and prf-mediated host defense responses to infection by pseudomonas syringae pv. tomato. | the disease resistance gene pto encodes a serine/threonine protein kinase that confers resistance in tomato to pseudomonas syringae pv. tomato strains that express the effector protein avrpto. pto-mediated resistance to bacterial speck disease also requires prf, a protein with leucine-rich repeats and a putative nucleotide-binding site, although the role of prf in the defense pathway is not known. we used genecalling, an open-architecture, mrna-profiling technology, to identify genes that are ei ... | 2002 | 12410809 |
| structures of the o-polysaccharide chains of the lipopolysaccharides of xanthomonas campestris pv phaseoli var fuscans gspb 271 and x campestris pv malvacearum gspb 1386 and gspb 2388. | o-polysaccharides of phytopathogenic bacteria xanthomonas campestris were isolated by mild acid degradation of the lipopolysaccharides and studied by sugar and methylation analysis, along with 1h and 13c nmr spectroscopy. the following structures of the repeating units of the polysaccharides of x. campestris pv. phaseoli var. fuscans gspb 271 (1). and x. campestris pv. malvacearum gspb 1386 and gspb 2388 (2). were established:the o-polysaccharides of x. campestris are structurally similar to tho ... | 2002 | 12423950 |
| effects of nutritional factors on production of tabtoxin, a phytotoxin, by pseudomonas syringae pv. tabaci. | pseudomonas syringae pv. tabaci, the causal agent of the wildfire of tobacco, produces the phytotoxin tabtoxin. the effects of carbon, nitrogen sources and amino acids on growth and tabtoxin production by pv. tabaci, were examined by varying the components of a defined basal medium, which contained the following nutrients per liter: sucrose (10 g), kno3 (5 g), mgso(4).7h2o (0.2 g), cacl(2).2h2o (0.11 g), feso(4).7h2o (20 mg), nah2po(4).2h2o (0.9 g) and h2po(4).3ho (1 g). bacterial growth was det ... | 2001 | 12425044 |
| the physiological development of the chlorotic lesion induced by coronatine. | toxins are secondary metabolites produced by several plant pathogenic microorganisms. these toxins play a major role in the development of disease symptoms. coronatine, the non specific toxin, was extracted and purified from the culture medium of pseudomonas syringae pv. glycinea. in this study, the effect of coronatine on the development of the chlorotic lesion on the phaseolus vulgaris l. leaves, indicates that coronatine induced chlorosis on treated leaves as well as or untreated leaves on th ... | 2001 | 12425045 |
| aquifex aeolicus pilt, homologue of a surface motility protein, is a thermostable oligomeric ntpase. | bacterial surface motility works by retraction of surface-attached type iv pili. this retraction requires the pilt protein, a member of a large family of putative ntpases from type ii and iv secretion systems. in this study, the pilt homologue from the thermophilic eubacterium aquifex aeolicus was cloned, overexpressed, and purified. a. aeolicus pilt was shown to be a thermostable atpase with a specific activity of 15.7 nmol of atp hydrolyzed/min/mg of protein. this activity was abolished when a ... | 2002 | 12426333 |
| low-temperature-induced changes in composition and fluidity of lipopolysaccharides in the antarctic psychrotrophic bacterium pseudomonas syringae. | the antarctic psychrotrophic bacterium pseudomonas syringae was more sensitive to polymyxin b at a lower (4 degrees c) temperature of growth than at a higher (22 degrees c) temperature. the amount of hydroxy fatty acids in the lipopolysaccharides (lps) also increased at the lower temperature. these changes correlated with the increase in fluidity of the hydrophobic phase of lipopolysaccharide aggregates in vitro. | 2002 | 12426366 |
| a simple alfalfa seedling infection model for pseudomonas aeruginosa strains associated with cystic fibrosis shows algt (sigma-22) and rhlr contribute to pathogenesis. | a sensitive plant infection model was developed to identify virulence factors in nontypeable, alginate overproducing (mucoid) pseudomonas aeruginosa strains isolated from cystic fibrosis (cf) patients with chronic pulmonary disease. nontypeable strains with defects in lipopolysaccharide o-side chains are common to cf and often exhibit low virulence in animal models of infection. however, 1,000 such bacteria were enough to show disease symptoms in the alfalfa infection. a typical mucoid cf isolat ... | 2002 | 12426404 |
| nitric oxide synthase-mediated phytoalexin accumulation in soybean cotyledons in response to the diaporthe phaseolorum f. sp. meridionalis elicitor. | phytoalexin biosynthesis is part of the defense mechanism of soybean (glycine max) plants against attack by the fungus diaporthe phaseolorum f. sp. meridionalis (dpm), the causal agent of stem canker disease. the treatment of soybean cotyledons with dpm elicitor or with sodium nitroprusside (snp), a nitric oxide (no) donor, resulted in a high accumulation of phytoalexins. this response did not occur when snp was replaced by ferricyanide, a structural analog of snp devoid of the no moiety. phytoa ... | 2002 | 12427995 |
| apoptotic cell death is a common response to pathogen attack in oats. | we have examined the characteristics of cell death induced by pathogen infection in oats with respect to following hallmark apoptotic features: dna laddering, chromatin condensation, and electron microscopic-terminal deoxynucleotidyl transferase-mediated utp end labeling positive response. a wide range of plant pathogens representing different levels of parasitism in susceptible and resistant interactions were used for the inocula, which include (i) an obligate parasite, puccinia coronata f. sp. ... | 2002 | 12437297 |
| a gene in the pseudomonas syringae pv. tomato hrp pathogenicity island conserved effector locus, hopptoa1, contributes to efficient formation of bacterial colonies in planta and is duplicated elsewhere in the genome. | the ability of pseudomonas syringae to grow in planta is thought to be dependent upon the hrp (type iii secretion) system and multiple effector proteins that this system injects into plant cells. orf5 in the conserved effector locus of the p. syringae pv. tomato dc3000 hrp pathogenicity island was shown to encode a hrp-secreted protein and to have a similarly secreted homolog encoded in an effector-rich pathogenicity island located elsewhere in the genome. these putative effector genes were desi ... | 2002 | 12437299 |
| constitutive activation of jasmonate signaling in an arabidopsis mutant correlates with enhanced resistance to erysiphe cichoracearum, pseudomonas syringae, and myzus persicae. | in arabidopsis spp., the jasmonate (ja) response pathway generally is required for defenses against necrotrophic pathogens and chewing insects, while the salicylic acid (sa) response pathway is generally required for specific, resistance (r) gene-mediated defenses against both biotrophic and necrotrophic pathogens. for example, sa-dependent defenses are required for resistance to the biotrophic fungal pathogen erysiphe cichoracearum ucsc1 and the bacterial pathogen pseudomonas syringae pv. macul ... | 2002 | 12437300 |
| isolation of pathogen-induced chinese cabbage genes by subtractive hybridization employing selective adaptor ligation. | we have developed a subtractive cloning method in which target sequences are effectively enriched by selective adaptor ligation and pcr after hybridization. in this method both tester and driver dnas are digested with rsai, ligated with the linker dna containing a kpni recognition site, and amplified by pcr. the tester dna samples are divided into two aliquots, each digested with either rsai or kpni. the two dna samples are then combined and hybridized with an excess of the driver dna retaining ... | 2002 | 12445806 |
| genetic and phenotypic analysis of acinetobacter baumannii insertion derivatives generated with a transposome system. | acinetobacter baumannii is a metabolically versatile pathogen that causes severe infections in compromised patients. however, little is known about the genes and factors involved in its basic physiology and virulence properties. insertion mutagenesis was used to initiate the identification and characterization of some of these factors and genes in the prototype strain 19606. the utilization of the plofkm suicide delivery vector, which harbors a suicide mini-tn10 derivative, proved to be unsucces ... | 2002 | 12450860 |
| copper-dependent iron assimilation pathway in the model photosynthetic eukaryote chlamydomonas reinhardtii. | the unicellular green alga chlamydomonas reinhardtii is a valuable model for studying metal metabolism in a photosynthetic background. a search of the chlamydomonas expressed sequence tag database led to the identification of several components that form a copper-dependent iron assimilation pathway related to the high-affinity iron uptake pathway defined originally for saccharomyces cerevisiae. they include a multicopper ferroxidase (encoded by fox1), an iron permease (encoded by ftr1), a copper ... | 2002 | 12455693 |
| characterization of inhibitor-resistant histone deacetylase activity in plant-pathogenic fungi. | hc-toxin, a cyclic peptide made by the filamentous fungus cochliobolus carbonum, is an inhibitor of histone deacetylase (hdac) from many organisms. it was shown earlier that the hdac activity in crude extracts of c. carbonum is relatively insensitive to hc-toxin as well as to the chemically unrelated hdac inhibitors trichostatin and d85, whereas the hdac activity of aspergillus nidulans is sensitive (g. brosch et al., biochemistry 40:12855-12863, 2001). here we report that hc-toxin-resistant hda ... | 2002 | 12456002 |
| biochemistry and comparative genomics of sxxk superfamily acyltransferases offer a clue to the mycobacterial paradox: presence of penicillin-susceptible target proteins versus lack of efficiency of penicillin as therapeutic agent. | the bacterial acyltransferases of the sxxk superfamily vary enormously in sequence and function, with conservation of particular amino acid groups and all-alpha and alpha/beta folds. they occur as independent entities (free-standing polypeptides) and as modules linked to other polypeptides (protein fusions). they can be classified into three groups. the group i sxxk d,d-acyltransferases are ubiquitous in the bacterial world. they invariably bear the motifs sxxk, sxn(d), and kt(s)g. anchored in t ... | 2002 | 12456788 |
| antimycobacterial activity of lipodepsipeptides produced by pseudomonas syringae pv syringae b359. | some lipodepsipeptides produced by pseudomonas syringae pv. syringae showed strong antimycobacterial activity towards mycobacterium smegmatis. mic values found were between 1.5-3.2 microg/ml, which is comparable to some primary drugs for tuberculosis. among the lipodepsipeptides, syringomycin e (sre) appears to be the most potent antimycobacterial agent. | 2002 | 12462348 |
| a high-throughput arabidopsis reverse genetics system. | a collection of arabidopsis lines with t-dna insertions in known sites was generated to increase the efficiency of functional genomics. a high-throughput modified thermal asymmetric interlaced (tail)-pcr protocol was developed and used to amplify dna fragments flanking the t-dna left borders from approximately 100000 transformed lines. a total of 85108 tail-pcr products from 52964 t-dna lines were sequenced and compared with the arabidopsis genome to determine the positions of t-dnas in each lin ... | 2002 | 12468722 |
| rapid cell death in xanthomonas campestris pv. glycines. | xanthomonas campestris pv. glycines strain am2 (xcgam2), the etiological agent of bacterial pustule disease of soybean, exhibited post-exponential rapid cell death (rcd) in lb medium. x. campestris pv. malvacearum ncim 2310 and x. campestris ncim 2961 also displayed rcd, though less pronouncedly than xcgam2. rcd was not observed in pseudomonas syringae pv. glycines, or escherichia coli dh5alpha. incubation of the post-exponential lb-grown xcgam2 cultures at 4 degrees c arrested the rcd. rcd was ... | 2002 | 12469302 |
| the coat protein of turnip crinkle virus suppresses posttranscriptional gene silencing at an early initiation step. | posttranscriptional gene silencing (ptgs), or rna silencing, is a sequence-specific rna degradation process that targets foreign rna, including viral and transposon rna for destruction. several rna plant viruses have been shown to encode suppressors of ptgs in order to survive this host defense. we report here that the coat protein (cp) of turnip crinkle virus (tcv) strongly suppresses ptgs. the agrobacterium infiltration system was used to demonstrate that tcv cp suppressed the local ptgs as st ... | 2003 | 12477856 |
| light-dependent death of maize lls1 cells is mediated by mature chloroplasts. | we reported previously the isolation of a novel cell death-suppressing gene from maize (zea mays) encoded by the lls1 (lethal leaf spot-1) gene. although the exact metabolic function of lls1 remains elusive, here we provide insight into mechanisms that underlie the initiation and propagation of cell death associated with lls1 lesions. our data indicate that lls1 lesions are triggered in response to a cell-damaging event caused by any biotic or abiotic agent or intrinsic metabolic imbalance--as l ... | 2002 | 12481072 |
| cloning and sequencing of cdnas for hypothetical genes from chromosome 2 of arabidopsis. | about 25% of the genes in the fully sequenced and annotated arabidopsis genome have structures that are predicted solely by computer algorithms with no support from either nucleic acid or protein homologs from other species or expressed sequence matches from arabidopsis. these are referred to as "hypothetical genes." on chromosome 2, sequenced by the institute for genomic research, there are approximately 800 hypothetical genes among a total of approximately 4,100 genes. to test their expression ... | 2002 | 12481096 |
| pseudomonas viridiflava and p. syringae--natural pathogens of arabidopsis thaliana. | we report the isolation and identification of two natural pathogens of arabidopsis thaliana, pseudomonas viridiflava and pseudomonas syringae, in the midwestern united states. p. viridiflava was found in six of seven surveyed arabidopsis thaliana populations. we confirmed the presence in the isolates of the critical pathogenicity genes hrps and hrpl. the pathogenicity of these isolates was verified by estimating in planta bacterial growth rates and by testing for disease symptoms and hypersensit ... | 2002 | 12481991 |
| modulation of defense responses of malus spp. during compatible and incompatible interactions with erwinia amylovora. | erwinia amylovora is the causal agent of fire blight, a disease affecting members of subfamily maloideae. in order to analyze mechanisms leading to compatible or incompatible interactions, early plant molecular events were investigated in two genotypes of malus with contrasting susceptibility to fire blight, after confrontation with either e. amylovora or the incompatible tobacco pathogen pseudomonas syringae pv. tabaci. many defense mechanisms, including generation of an oxidative burst and acc ... | 2002 | 12481992 |
| microbial toxins in plant-pathogen interactions: biosynthesis, resistance mechanisms, and significance. | in the history of phytopathology, microbial toxins have been the objects of extensive studies as possible pathogenicity or virulence factors for the producer pathogens. the recent development of molecular genetic techniques provided an experimental basis to thoroughly test the role of these secondary metabolites in pathogenesis. some of them did prove to be highly associated with disease initiation or enhanced virulence in certain plant-pathogen interactions. in this review, we describe recent p ... | 2001 | 12483615 |
| transcriptional organization of the pseudomonas putida tol-oprl genes. | proteins of the tol system play a key role in the maintenance of outer membrane integrity and cell morphology in gram-negative bacteria. in pseudomonas putida, the seven genes, orf1, tolq, tolr, tola, tolb, oprl, and orf2, which encode the proteins of this complex, are clustered in a 5.8-kb region of chromosomal dna. analysis of polar mutations, reverse transcriptase pcr assays, and transcriptional fusion constructs with a promoterless lacz gene revealed that the genes are arranged in two operon ... | 2003 | 12486055 |
| syringotoxin pore formation and inactivation in human red blood cell and model bilayer lipid membranes. | the effect of syringotoxin (st), a member of the cyclic lipodepsipeptides family (clps) produced by pseudomonas syringae pv. syringae on the membrane permeability of human red blood cells (rbcs) and model bilayer lipid membranes (blms) was studied and compared to that of two recently investigated clps, syringomycin e (sre) and syringopeptin 22a (sp22a) [biochim. biophys. acta 1466 (2000) 79 and bioelectrochemistry 52 (2000) 161]. the permeability-increasing effect of st on rbcs was the least amo ... | 2002 | 12488047 |
| structure of the o polysaccharides and serological classification of pseudomonas syringae pv. porri from genomospecies 4. | strains of pseudomonas syringae pv. porri are characterized by a number of pathovar-specific phenotypic and genomic characters and constitute a highly homogeneous group. using monoclonal antibodies, they all were classified in a novel p. syringae serogroup o9. the o polysaccharides (ops) isolated from the lipopolysaccharides (lps) of p. syringae pv. porri ncppb 3365 and ncppb 3364t possess multiple oligosaccharide o repeats, some of which are linear and composed of l-rhamnose (l-rha), whereas th ... | 2003 | 12492471 |
| distribution and function of new bacterial intein-like protein domains. | hint protein domains appear in inteins and in the c-terminal region of hedgehog and hedgehog-like animal developmental proteins. intein hint domains are responsible and sufficient for protein-splicing of their host-protein flanks. in hedgehog proteins the hint domain autocatalyses its cleavage from the n-terminal domain of the hedgehog protein by attaching a cholesterol molecule to it. we identified two new types of hint domains. both types have active site sequence features of hint domains but ... | 2003 | 12492854 |
| isolation of labradorins 1 and 2 from pseudomonas syringae pv. coronafaciens. | investigation of pseudomonas syringae pv. coronafaciens cancer cell growth inhibitory constituents led to the isolation of 2-isobutyl-5-(3-indolyl)oxazole (1) and 2-n-pentyl-5-(3-indolyl)oxazole (2f), designated labradorins 1 (1) and 2 (2f), related to pimprinine (2a). the structures were deduced by spectroscopic techniques and x-ray crystal structure determinations. labradorin 1 (1) afforded gi(50) microg/ml values of 9.8 and 6.2 against the human cancer cell lines nci-h 460 (lung-nsc) and bxpc ... | 2002 | 12502316 |
| a simple method for preparation of d-rhamnose. | a rapid procedure for the preparation of d-rhamnose from bacterial lipopolysaccharide (lps) has been developed. it involves purification of lps from pseudomonas syringae pv. phaseolicola by phenol extraction and hydrophobic interaction chromatography (hic), followed by mild hydrolysis and cleavage of the o-antigen into d-fucose and d-rhamnose. the monosaccharides were separated by column chromatography, and d-rhamnose recovered after filtration over sephadex-lh 20. | 2003 | 12504387 |
| pseudomonas type iii effector avrptob induces plant disease susceptibility by inhibition of host programmed cell death. | the avrptob type iii effector protein is conserved among diverse genera of plant pathogens suggesting it plays an important role in pathogenesis. here we report that pseudomonas avrptob acts inside the plant cell to inhibit programmed cell death (pcd) initiated by the pto and cf9 disease resistance proteins and, remarkably, the pro-apoptotic mouse protein bax. avrptob also suppressed pcd in yeast, demonstrating that avrptob functions as a cell death inhibitor across kingdoms. using truncated avr ... | 2003 | 12505984 |
| functional and mutational analysis of conjugative transfer region 2 (tra2) from the inchi1 plasmid r27. | the transfer 2 region (tra2) of the conjugative plasmid drr27 (derepressed r27) was analyzed by psi-blast, insertional mutagenesis, genetic complementation, and an h-pilus assay. tra2 contains 11 mating-pair formation (mpf) genes that are essential for conjugative transfer, 9 of which are essential for h-pilus production (trha, -l, -e, -k, -b, -v, -c, -p, and -w). trhk has similarity to secretin proteins, suggesting a mechanism by which dna could traverse the outer membrane of donors. the remain ... | 2003 | 12511505 |
| growth dynamics of salmonella enterica strains on alfalfa sprouts and in waste seed irrigation water. | alfalfa sprouts and other seed sprouts have been implicated in numerous outbreaks of salmonellosis. the source of these epidemics appears to have been low-level contamination of seeds by salmonella bacteria that developed into clinically significant populations during the seed germination process. to test the possibility that salmonella enterica strains carry host range determinants that allow them to grow on alfalfa, strains isolated from alfalfa or other sources were surveyed for their ability ... | 2003 | 12514040 |
| molecular characterization of natural erwinia pyrifoliae strains deficient in hypersensitive response. | from necrotic tissue of a nashi pear tree, 24 erwinia pyrifoliae strains, found to be identical by pulsed-field gel electrophoresis analysis, were isolated. thirteen strains were not virulent on immature pears and did not induce a hypersensitive response in tobacco leaves. the defective gene hrpl was complemented with intact genes from e. pyrifoliae and erwinia amylovora. | 2003 | 12514060 |
| characteristics of massilia timonae and massilia timonae-like isolates from human patients, with an emended description of the species. | the description of massilia timonae, a nonfermentative aerobic gram-negative rod, was based on a single strain. a subsequent report of a second isolate has been recently published. phenotypic descriptions of these two strains were based primarily on commercial test kit results. we have identified three additional strains as m. timonae by 16s rrna sequence analysis and have characterized them phenotypically in parallel with the type strain of m. timonae, cip 105350, by conventional test methods. ... | 2003 | 12517847 |
| cloning and characterization of kata, encoding the major monofunctional catalase from xanthomonas campestris pv. phaseoli and characterization of the encoded catalase kata. | the first cloning and characterization of the gene kata, encoding the major catalase (kata), from xanthomonas is reported. a reverse genetic approach using a synthesized kata-specific dna probe to screen a x. campestris pv. phaseoli genomic library was employed. a positively hybridizing clone designated pkat29 that contained a full-length kata was isolated. analysis of the nucleotide sequence revealed an open reading frame of 1,521 bp encoding a 507-amino acid protein with a theoretical molecula ... | 2003 | 12520360 |
| crystal structure of tabtoxin resistance protein complexed with acetyl coenzyme a reveals the mechanism for beta-lactam acetylation. | tabtoxin resistance protein (ttr) is an enzyme that renders tabtoxin-producing pathogens, such as pseudomonas syringae, tolerant to their own phytotoxins. here, we report the crystal structure of ttr complexed with its natural cofactor, acetyl coenzyme a (accoa), to 1.55a resolution. the binary complex forms a characteristic "v" shape for substrate binding and contains the four motifs conserved in the gcn5-related n-acetyltransferase (gnat) superfamily, which also includes the histone acetyltran ... | 2003 | 12527305 |
| fingerprinting of prokaryotic 16s rrna genes using oligodeoxyribonucleotide microarrays and virtual hybridization. | an oligonucleotide microarray hybridization system to differentiate microbial species was designed and tested. seven microbial species were studied, including one bacillus and six pseudomonas strains. dna sequences near the 5' end of 16s rrna genes were aligned and two contiguous regions of high variability, flanked by highly conserved sequences, were found. the conserved sequences were used to design pcr primers which efficiently amplified these polymorphic regions from all seven species. the a ... | 2003 | 12527788 |
| iscce1 and iscce2, two novel insertion sequences in clostridium cellulolyticum. | two new insertion sequences, iscce1 and iscce2, were found to be inserted into the cipc gene of spontaneous mutants of clostridium cellulolyticum. in these insertional mutants, the cipc gene was disrupted either by iscce1 alone or by both iscce1 and iscce2. iscce1 is 1,292 bp long and has one open reading frame. the open reading frame encodes a putative 348-amino-acid protein with significant levels of identity with putative proteins having unknown functions and with some transposases belonging ... | 2003 | 12533447 |
| 2,5-dialkylresorcinol biosynthesis in pseudomonas aurantiaca: novel head-to-head condensation of two fatty acid-derived precursors. | 2-hexyl-5-propylresorcinol is the predominant analog of several dialkylresorcinols produced by pseudomonas aurantiaca (pseudomonas fluorescens bl915). we isolated and characterized three biosynthetic genes that encode an acyl carrier protein, a beta-ketoacyl-acyl carrier protein synthase iii, and a protein of unknown function, all of which collectively allow heterologous production of 2-hexyl-5-propylresorcinol in escherichia coli. two regulatory genes exhibiting similarity to members of the ara ... | 2003 | 12533461 |
| requirements for cu(a) and cu-s center assembly of nitrous oxide reductase deduced from complete periplasmic enzyme maturation in the nondenitrifier pseudomonas putida. | bacterial nitrous oxide (n(2)o) reductase is the terminal oxidoreductase of a respiratory process that generates dinitrogen from n(2)o. to attain its functional state, the enzyme is subjected to a maturation process which involves the protein-driven synthesis of a unique copper-sulfur cluster and metallation of the binuclear cu(a) site in the periplasm. there are seven putative maturation factors, encoded by nosa, nosd, nosf, nosy, nosl, nosx, and sco. we wanted to determine the indispensable pr ... | 2003 | 12533464 |
| plant lectin-like bacteriocin from a rhizosphere-colonizing pseudomonas isolate. | rhizosphere isolate pseudomonas sp. strain bw11m1, which belongs to the pseudomonas putida cluster, secretes a heat- and protease-sensitive bacteriocin which kills p. putida gr12-2r3. the production of this bacteriocin is enhanced by dna-damaging treatment of producer cells. we isolated a tnmod mutant of strain bw11m1 that had lost the capacity to inhibit the growth of strain gr12-2r3. a wild-type genomic fragment encompassing the transposon insertion site was shown to confer the bacteriocin phe ... | 2003 | 12533465 |
| a glutamate mutase is involved in the biosynthesis of the lipopeptide antibiotic friulimicin in actinoplanes friuliensis. | actinoplanes friuliensis produces the lipopeptide antibiotic friulimicin. this antibiotic is active against gram-positive bacteria such as multiresistant enterococcus and staphylococcus strains. it consists of 10 amino acids that form a ring structure and 1 exocyclic amino acid to which an acyl residue is attached. by a reverse genetic approach, biosynthetic genes were identified that are required for the nonribosomal synthesis of the antibiotic. in close proximity two genes (glma and glmb) were ... | 2003 | 12543643 |
| [vascular bundle specific expression of iaal gene affects the generation frequencies of transgenic tobacco]. | a vascular bundles specific expressing vector pbal1 with a promoter aq630 from rice phenylalanine ammonialyase gene and a gene encoding indoleacetic-lysine synthytase from pseudomonas syringae subsp. savastanoi was constructed. affirmed by southern blotting and rtpcr analysis, the aq630-iaal transgenic plants show increasing shoots-regeneration frequency of young stem explants on hormone-free 1/2 ms medium and lower sensibility to iaa when roots were induced from the root explants on the media c ... | 1999 | 12548796 |
| characterization of the nodulation plasmid encoded chemoreceptor gene mcpg from rhizobium leguminosarum. | in general, chemotaxis in rhizobium has not been well characterized. methyl accepting chemotaxis proteins are sensory proteins important in chemotaxis of numerous bacteria, but their involvement in rhizobium chemotaxis is unclear and merits further investigation. | 2003 | 12553885 |
| structure of the clade 1 catalase, catf of pseudomonas syringae, at 1.8 a resolution. | catalase catf of pseudomonas syringae has been identified phylogenetically as a clade 1 catalase, closely related to plant catalases, a group from which no structure has been determined. the structure of catf has been refined at 1.8 a resolution by using x-ray synchrotron data collected from a crystal flash-cooled with liquid nitrogen. the crystallographic agreement factors r and r(free) are, respectively, 18.3% and 24.0%. the asymmetric unit of the crystal contains a whole molecule that shows a ... | 2003 | 12557185 |
| overrepresentation of a gene family encoding extracytoplasmic solute receptors in bordetella. | a family of genes that are likely to encode extracytoplasmic solute receptors is strongly overrepresented in several beta-proteobacteria, including bordetella pertussis. this gene family, of which members have been called bug genes, contains some examples that are contained within polycistronic operons coding for tripartite uptake transporters of the ttt family, while the vast majority are "orphan" genes. proteomic and functional analyses demonstrated that several of these genes are expressed in ... | 2003 | 12562821 |
| quantitative nature of arabidopsis responses during compatible and incompatible interactions with the bacterial pathogen pseudomonas syringae. | we performed large-scale mrna expression profiling using an affymetrix genechip to study arabidopsis responses to the bacterial pathogen pseudomonas syringae. the interactions were compatible (virulent bacteria) or incompatible (avirulent bacteria), including a nonhost interaction and interactions mediated by two different avirulence gene-resistance (r) gene combinations. approximately 2000 of the approximately 8000 genes monitored showed reproducible significant expression level changes in at l ... | 2003 | 12566575 |
| hlm1, an essential signaling component in the hypersensitive response, is a member of the cyclic nucleotide-gated channel ion channel family. | the hypersensitive response (hr) in plants is a programmed cell death that is commonly associated with disease resistance. a novel mutation in arabidopsis, hlm1, which causes aberrant regulation of cell death, manifested by a lesion-mimic phenotype and an altered hr, segregated as a single recessive allele. broad-spectrum defense mechanisms remained functional or were constitutive in the mutant plants, which also exhibited increased resistance to a virulent strain of pseudomonas syringae pv toma ... | 2003 | 12566578 |
| tin-carbon cleavage of organotin compounds by pyoverdine from pseudomonas chlororaphis. | the triphenyltin (tpt)-degrading bacterium pseudomonas chlororaphis cnr15 produces extracellular yellow substances to degrade tpt. three substances (f-i, f-iia, and f-iib) were purified, and their structural and catalytic properties were characterized. the primary structure of f-i was established using two-dimensional nuclear magnetic resonance techniques; the structure was identical to that of suc-pyoverdine from p. chlororaphis atcc 9446, which is a peptide siderophore produced by fluorescent ... | 2003 | 12571007 |
| arthrobacter strain vai-a utilizes acyl-homoserine lactone inactivation products and stimulates quorum signal biodegradation by variovorax paradoxus. | many proteobacteria produce acyl-homoserine lactones (acyl-hsls) and employ them as dedicated cell-to-cell signals in a process known as quorum sensing. previously, variovorax paradoxus vai-c was shown to utilize diverse acyl-hsls as sole sources of energy and nitrogen. we describe here the properties of a second isolate, arthrobacter strain vai-a, obtained from the same enrichment culture that yielded v. paradoxus vai-c. although strain vai-a grew rapidly and exponentially on a number of substr ... | 2003 | 12571011 |
| high-performance liquid chromatography analyses of pyoverdin siderophores differentiate among phytopathogenic fluorescent pseudomonas species. | the relationship of pyoverdins produced by 41 pathovars of pseudomonas syringae and by phytopathogenic pseudomonas species was investigated. a high-performance liquid chromatography method for analyzing the culture medium proved to be superior to isoelectric focusing for detecting pyoverdin production, for differentiating slightly different pyoverdins, and for differentiating atypical from typical fe(iii)-chelated pyoverdins. nonfluorescent strains were found in pseudomonas amygdali, pseudomonas ... | 2003 | 12571041 |
| use of a promoter trap to identify bacillus cereus genes regulated by tomato seed exudate and a rhizosphere resident, pseudomonas aureofaciens. | the goal of this study was to identify genes in bacillus cereus, a bacterium commonly associated with plant seeds and roots, that are affected by compounds originating from a host plant, tomato, or another rhizosphere resident, pseudomonas aureofaciens. we constructed a b. cereus chromosomal dna library in a promoter-trap plasmid, pad123, which contains a promoterless version of the green fluorescent protein (gfp) gene, gfpmut3a. the library was screened by using fluorescence-activated cell sort ... | 2003 | 12571047 |
| 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 |
| enhancement of population size of a biological control agent and efficacy in control of bacterial speck of tomato through salicylate and ammonium sulfate amendments. | sodium salicylate and ammonium sulfate were applied to leaf surfaces along with suspensions of the biological control agents pseudomonas syringae cit7(pnah7), which catabolizes salicylate, and cit7, which does not catabolize salicylate, to determine whether enhanced biological control of bacterial speck of tomato could be achieved. foliar amendment with salicylate alone significantly enhanced the population size and the efficacy of cit7(pnah7), but not of cit7, on tomato leaves. application of a ... | 2003 | 12571060 |
| a pseudomonas syringae pv. tomato dc3000 hrp (type iii secretion) deletion mutant expressing the hrp system of bean pathogen p. syringae pv. syringae 61 retains normal host specificity for tomato. | the plant pathogenic species pseudomonas syringae is divided into numerous pathovars based on host specificity. for example, p. syringae pv. tomato dc3000 is pathogenic on tomato and arabidopsis, whereas p. syringae pv. syringae 61 is pathogenic on bean. the ability of p. syringae strains to elicit the hypersensitive response (hr) in non-hosts or be pathogenic (or parasitic) in hosts is dependent on the hrp (type iii secretion) system and effector proteins this system is thought to inject into p ... | 2003 | 12580281 |
| initiation of rps2-specified disease resistance in arabidopsis is coupled to the avrrpt2-directed elimination of rin4. | plants have evolved a sophisticated innate immune system to recognize invading pathogens and to induce a set of host defense mechanisms resulting in disease resistance. pathogen recognition is often mediated by plant disease resistance (r) proteins that respond specifically to one or a few pathogen-derived molecules. this specificity has led to suggestions of a receptor-ligand mode of r protein function. delivery of the bacterial effector protein avrrpt2 by pseudomonas syringae specifically indu ... | 2003 | 12581526 |
| arabidopsis rin4 is a target of the type iii virulence effector avrrpt2 and modulates rps2-mediated resistance. | type iii pili deliver effector proteins (virulence factors) from bacterial pathogens to host cells. plants express disease resistance (r) proteins that respond specifically to a particular type iii effector by activating immune responses. we demonstrated previously that two unrelated type iii effectors from pseudomonas syringae target and modify the arabidopsis rin4 protein. here, we show that avrrpt2, a third, unrelated type iii effector, also targets rin4 and induces its posttranscriptional di ... | 2003 | 12581527 |
| powdery mildew-induced mla mrnas are alternatively spliced and contain multiple upstream open reading frames. | in barley (hordeum vulgare), the mla13 powdery mildew resistance gene confers rar1-dependent, avrmla13-specific resistance to blumeria graminis f. sp. hordei (bgh). we have identified cdna and genomic copies of mla13 and used this coiled-coil nucleotide-binding site leucine-rich repeat protein-encoding gene as a model for the regulation of host resistance to obligate biotrophic fungi in cereals. we demonstrate quantitatively that a rapid increase in the accumulation of mla transcripts and transc ... | 2003 | 12586880 |
| expression profiles of the arabidopsis wrky gene superfamily during plant defense response. | wrky proteins are a recently identified class of dna-binding proteins that recognize the ttgac(c/t) w-box elements found in the promoters of a large number of plant defense-related genes. with oligo molecules containing the w-box sequences as probes, we detected a number of wrky dna-binding activities in arabidopsis that were induced by salicylic acid (sa). search of the arabidopsis genome identifies 72 genes encoding proteins characteristic of wrky dna-binding transcription factors that can be ... | 2003 | 12602888 |
| the pair of bacteriophytochromes from agrobacterium tumefaciens are histidine kinases with opposing photobiological properties. | bacteriophytochrome photoreceptors (bphps) are a family of phytochrome-like sensor kinases that help a wide variety of bacteria respond to their light environment. in agrobacterium tumefaciens, a unique pair of bphps with potentially opposing roles in light sensing are present. both atbphps contain an n-terminal chromophore-binding domain that covalently attaches a biliverdin chromophore. whereas atbphp1 assumes a pr ground state, atbphp2 is unusual in that it assumes a pfr ground state that is ... | 2003 | 12604773 |
| brassinosteroid functions in a broad range of disease resistance in tobacco and rice. | brassinolide (bl), considered to be the most important brassinosteroid (br) and playing pivotal roles in the hormonal regulation of plant growth and development, was found to induce disease resistance in plants. to study the potentialities of bl activity on stress responding systems, we analyzed its ability to induce disease resistance in tobacco and rice plants. wild-type tobacco treated with bl exhibited enhanced resistance to the viral pathogen tobacco mosaic virus (tmv), the bacterial pathog ... | 2003 | 12609030 |
| expression profiling of the host response to bacterial infection: the transition from basal to induced defence responses in rpm1-mediated resistance. | changes in transcription in leaves of arabidopsis thaliana were characterised following challenge with strains of pseudomonas syringae pv. tomato dc3000 allowing differentiation of basal resistance (hrpa mutants), gene-specific resistance (rpm1-specified interactions) and susceptibility (wild-type pathogen). in planta avirulence gene induction, changes in host [ca2+]cyt and leaf collapse were used to delineate the transition from infection to induced resistance. the plant responds rapidly, dynam ... | 2003 | 12609040 |
| loss of non-host resistance of arabidopsis nahg to pseudomonas syringae pv. phaseolicola is due to degradation products of salicylic acid. | in plants carrying the nahg transgene, salicylate hydroxylase converts salicylic acid (sa) to catechol. arabidopsis nahg plants are defective in non-host resistance to pseudomonas syringae pv. phaseolicola strain 3121 (psp), suggesting that resistance requires sa signaling. however, several mutants with defects in sa signaling, including eds1, pad4, eds5, sid2, and npr1, remain resistant to psp, demonstrating that susceptibility of nahg plants is not due to absence of sa. sa synthesis is blocked ... | 2003 | 12609045 |