Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| physical interaction between rrs1-r, a protein conferring resistance to bacterial wilt, and popp2, a type iii effector targeted to the plant nucleus. | rrs1-r confers broad-spectrum resistance to several strains of the causal agent of bacterial wilt, ralstonia solanacearum. although genetically defined as recessive, this r gene encodes a protein whose structure combines the tir-nbs-lrr domains found in several r proteins and a wrky motif characteristic of some plant transcriptional factors and behaves as a dominant gene in transgenic susceptible plants. here we show that popp2, a r. solanacearum type iii effector, which belongs to the yopj/avrr ... | 2003 | 12788974 |
| novel exchangeable effector loci associated with the pseudomonas syringae hrp pathogenicity island: evidence for integron-like assembly from transposed gene cassettes. | pseudomonas syringae strains use a type iii secretion system (ttss) to translocate effector proteins that assist in the parasitism of host plant cells. some genes for effector proteins are clustered in the exchangeable effector locus (eel) associated with the hrp pathogenicity island. a polymerase chain reaction-based screen was developed to amplify the eel from p. syringae strains. of the 86 strains screened, the eel was successfully amplified from 30 predominately north american p. syringae pv ... | 2003 | 12795376 |
| a strategy for the nmr characterization of type ii copper(ii) proteins: the case of the copper trafficking protein copc from pseudomonas syringae. | copc from pseudomonas syringae was found to be a protein capable of binding both cu(i) and cu(ii) at two different sites. the solution structure of the apo protein is available, and structural information has been obtained on the cu(i) bound form. we attempt here to set the limits for the determination of the solution structure of a cu(ii) protein, such as the cu(ii) bound form of copc, in which the cu(ii) ion takes a type ii coordination. the electron relaxation time is estimated from nmrd meas ... | 2003 | 12797793 |
| characterization of the early response of arabidopsis to alternaria brassicicola infection using expression profiling. | all tested accessions of arabidopsis are resistant to the fungal pathogen alternaria brassicicola. resistance is compromised by pad3 or coi1 mutations, suggesting that it requires the arabidopsis phytoalexin camalexin and jasmonic acid (ja)-dependent signaling, respectively. this contrasts with most well-studied arabidopsis pathogens, which are controlled by salicylic acid-dependent responses and do not benefit from absence of camalexin or ja. here, mutants with defects in camalexin synthesis (p ... | 2003 | 12805591 |
| the pattern of systemic acquired resistance induction within the arabidopsis rosette in relation to the pattern of translocation. | local leaf infections by a necrogenic pathogen can lead to systemic acquired resistance (sar) in untreated leaves. we reasoned that, whatever the nature of the long-distance signal, if it is transported in the phloem, the pattern of sar induced within the plant by treatment of a single leaf should match the pattern of translocation out of that leaf. the source-sink relationships (orthostichies) in the arabidopsis rosette were established with [14c]suc or phloem-mobile 3-aminotriazole at herbicid ... | 2003 | 12805614 |
| systemic gene expression in arabidopsis during an incompatible interaction with alternaria brassicicola. | pathogen challenge can trigger an integrated set of signal transduction pathways, which ultimately leads to a state of "high alert," otherwise known as systemic or induced resistance in tissue remote to the initial infection. although large-scale gene expression during systemic acquired resistance, which is induced by salicylic acid or necrotizing pathogens has been previously reported using a bacterial pathogen, the nature of systemic defense responses triggered by an incompatible necrotrophic ... | 2003 | 12805628 |
| sites of interaction between the feca and fecr signal transduction proteins of ferric citrate transport in escherichia coli k-12. | transcription of the fecabcde ferric citrate transport genes of escherichia coli k-12 is initiated by a signaling cascade from the cell surface into the cytoplasm. fecr receives the signal in the periplasm from the outer membrane protein feca loaded with ferric citrate, transmits the signal across the cytoplasmic membrane, and converts feci in the cytoplasm to an active sigma factor. in this study, it was shown through the use of a bacterial two-hybrid system that, in the periplasm, the c-termin ... | 2003 | 12813067 |
| molecular analysis of the copper-transporting efflux system cuscfba of escherichia coli. | the cus determinant of escherichia coli encodes the cuscfba proteins that mediate resistance to copper and silver by cation efflux. cusa and cusb were essential for copper resistance, and cusc and cusf were required for full resistance. replacements of methionine residues 573, 623, and 672 with isoleucine in cusa resulted in loss of copper resistance, demonstrating their functional importance. substitutions for several other methionine residues of this protein did not have any effect. the small ... | 2003 | 12813074 |
| a pseudomonas syringae type iii effector suppresses cell wall-based extracellular defense in susceptible arabidopsis plants. | bacterial effector proteins secreted through the type iii secretion system (ttss) play a crucial role in causing plant and human diseases. although the ability of type iii effectors to trigger defense responses in resistant plants is well understood, the disease-promoting functions of type iii effectors in susceptible plants are largely enigmatic. previous microscopic studies suggest that in susceptible plants the ttss of plant-pathogenic bacteria transports suppressors of a cell wall-based plan ... | 2003 | 12817082 |
| functional similarities between the icm/dot pathogenesis systems of coxiella burnetii and legionella pneumophila. | coxiella burnetii, the etiological agent of q fever, is an obligate intracellular pathogen, whereas legionella pneumophila, the causative agent of legionnaires' disease, is a facultative intracellular pathogen. during infection of humans both of these pathogens multiply in alveolar macrophages inside a closed phagosome. l. pneumophila intracellular multiplication was shown to be dependent on the icm/dot system, which probably encodes a type iv-related translocation apparatus. recently, genes hom ... | 2003 | 12819052 |
| characterization of a pathogen-induced calmodulin-binding protein: mapping of four ca2+-dependent calmodulin-binding domains. | ca2+ and calmodulin (cam), a key ca2+ sensor in all eukaryotes, have been implicated in defense responses in plants. to elucidate the role of ca2+ and cam in defense signaling, we used 35s-labeled cam to screen expression libraries prepared from tissues that were either treated with an elicitor derived from phytophthora megasperma or infected with pseudomonas syringae pv. tabaci. nineteen cdnas that encode the same protein, pathogen-induced cam-binding protein (picbp), were isolated. the picbp f ... | 2003 | 12825696 |
| the pseudomonas syringae type iii-secreted protein hopptod2 possesses protein tyrosine phosphatase activity and suppresses programmed cell death in plants. | the bacterial plant pathogen pseudomonas syringae possesses a type iii protein secretion system that delivers many virulence proteins into plant cells. a subset of these proteins (called avr proteins) is recognized by the plant's innate immune system and triggers defences. one defence-associated response is the hypersensitive response (hr), a programmed cell death (pcd) of plant tissue. we have previously identified hopptod2 as a type iii secreted protein from p. s. pv. tomato dc3000. sequence a ... | 2003 | 12828636 |
| a translocated protein tyrosine phosphatase of pseudomonas syringae pv. tomato dc3000 modulates plant defence response to infection. | pseudomonas syringae strains translocate effector proteins into host cells via the hrp-encoded type iii protein secretion system (ttss) to facilitate pathogenesis in susceptible plants. however, the mechanisms by which pathogenesis is favoured by these effectors are not well understood. individual strains express multiple effectors with apparently distinct activities that are co-ordinately regulated by the alternative sigma factor hrpl. genes for several effectors were identified in the p. syrin ... | 2003 | 12828637 |
| characterization of salicylic acid-induced genes in chinese cabbage. | salicylic acid is a messenger molecule in the activation of defense responses in plants. in this study, we isolated four cdna clones representing salicylic acid-induced genes in chinese cabbage (brassica rapa subsp. pekinensis) by subtractive hybridization. of the four clones, the bc5-2 clone encodes a putative glucosyltransferase protein. the bc5-3 clone is highly similar to an arabidopsis gene encoding a putative metal-binding farnesylated protein. the bc6-1 clone is a chitinase gene with simi ... | 2003 | 12835914 |
| freshwater bacteria can methylate selenium through the thiopurine methyltransferase pathway. | involvement of the bacterial thiopurine methyltransferase (btpmt) in natural selenium methylation by freshwater was investigated. a freshwater environment that had no known selenium contamination but exhibited reproducible emission of dimethyl selenide (dmse) or dimethyl diselenide (dmdse) when it was supplemented with an organic form of selenium [(methyl)selenocysteine] or an inorganic form of selenium (sodium selenite) was used. the distribution of the btpmt gene (tpm) in the microflora was st ... | 2003 | 12839745 |
| identification of two-component regulatory systems in bifidobacterium infantis by functional complementation and degenerate pcr approaches. | two-component signal transduction systems (2css) are widely used by bacteria to sense and adapt to changing environmental conditions. with two separate approaches, three different 2css were identified on the chromosome of the probiotic bacterium bifidobacterium infantis ucc 35624. one locus was identified by means of functional complementation of an escherichia coli mutant. another two were identified by pcr with degenerate primers corresponding to conserved regions of one protein component of t ... | 2003 | 12839803 |
| detection and diversity assessment of xylella fastidiosa in field-collected plant and insect samples by using 16s rrna and gyrb sequences. | the causal agent of diseases in many economically important plants is attributed to the xylem-limited bacterium xylella fastidiosa. the detection of this plant pathogen has been hampered due to its difficult isolation and slow growth on plates. nearly complete nucleotide sequences of the 16s rrna gene and partial sequences of the gyrb gene were determined for 18 strains of x. fastidiosa isolated from different plant hosts. a phylogenetic analysis, based on gyrb, grouped strains in three clusters ... | 2003 | 12839807 |
| ethylene and jasmonic acid signaling affect the npr1-independent expression of defense genes without impacting resistance to pseudomonas syringae and peronospora parasitica in the arabidopsis ssi1 mutant. | salicylic acid (sa), ethylene, and jasmonic acid (ja) are important signaling molecules in plant defense to biotic stress. an intricate signaling network involving sa, ethylene, and ja fine tunes plant defense responses. sa-dependent defense responses in arabidopsis thaliana are mediated through npr1-dependent and -independent mechanisms. we have previously shown that activation of an npr1-independent defense mechanism confers enhanced disease resistance and constitutive expression of the pathog ... | 2003 | 12848424 |
| the lower cell density of leaf parenchyma in the arabidopsis thaliana mutant lcd1-1 is associated with increased sensitivity to ozone and virulent pseudomonas syringae. | under optimal growth conditions (120 micro mol photons m-2 sec-1 photosynthetically active radiation (par), 16-h photoperiod), the recessive ozone-sensitive arabidopsis thaliana l. heynh. mutant lcd1-1 exhibits a pale phenotype compared to the wild type. confocal and multiphoton microscopy revealed that the paleness of lcd1-1 is because of a lower cell density in the leaf palisade parenchyma, resulting in decreased chlorophyll content. when exposed to ozone, lcd1-1 leaves become paler and contai ... | 2003 | 12848826 |
| regulation of arabidopsis copine 1 gene expression in response to pathogens and abiotic stimuli. | the copines are a widely distributed class of calcium-dependent, phospholipid-binding proteins of undetermined biological function. mutation of the arabidopsis cpn1 (copine 1) gene causes a humidity-sensitive lesion mimic phenotype with increased resistance to a bacterial and an oomyceteous pathogen, constitutive pathogenesis-related gene expression, and an accelerated hypersensitive cell death defense response. here, we show that the disease resistance phenotype of the cpn1-1 mutant was also te ... | 2003 | 12857819 |
| molecular characterization and quantitative analysis of superoxide dismutases in virulent and avirulent strains of aeromonas salmonicida subsp. salmonicida. | aeromonas salmonicida subsp. salmonicida is a facultatively intracellular gram-negative bacterium that is the etiological agent of furunculosis, a bacterial septicemia of salmonids that causes significant economic loss to the salmon farming industry. the mechanisms by which a. salmonicida evades intracellular killing may be relevant in understanding virulence and the eventual design of appropriate treatment strategies for furunculosis. we have identified two open reading frames (orfs) and relate ... | 2003 | 12867441 |
| isolation and analysis of mutants of double-stranded-rna bacteriophage phi6 with altered packaging specificity. | the genomes of bacteriophage phi6 and its relatives are packaged through a mechanism that involves the recognition and translocation of the three different plus strand transcripts of the segmented double-stranded rna genomes into preformed polyhedral structures called procapsids or inner cores. this packaging requires hydrolysis of nucleoside triphosphates and takes place in the order s-m-l. packaging is dependent on unique sequences of about 200 nucleotides near the 5' ends of plus strand trans ... | 2003 | 12867467 |
| simultaneous analysis of phytohormones, phytotoxins, and volatile organic compounds in plants. | phytohormones regulate the protective responses of plants against both biotic and abiotic stresses by means of synergistic or antagonistic actions referred to as signaling crosstalk. a bottleneck in crosstalk research is the quantification of numerous interacting phytohormones and regulators. the chemical analysis of salicylic acid, jasmonic acid, indole-3-acetic acid, and abscisic acid is typically achieved by using separate and complex methodologies. moreover, pathogen-produced phytohormone mi ... | 2003 | 12874387 |
| the rapid induction of glutathione s-transferases atgstf2 and atgstf6 by avirulent pseudomonas syringae is the result of combined salicylic acid and ethylene signaling. | the expression of two members of the glutathione s-transferase (gst) multigene family was studied in arabidopsis plants inoculated with an avirulent strain of pseudomonas syringae pv. tomato (pst). accumulation of atgstf2 and atgstf6 transcripts started 4 and 2 h after inoculation, respectively, and clearly preceded the induction of the pathogenesis-related pr-1 gene. the aim of this work was to find the reason for the faster induction of the two gsts compared with classical salicylic acid (sa)- ... | 2003 | 12881503 |
| electroporation and stable maintenance of plasmid dnas in a biocontrol strain of pseudomonas syringae. | transformation efficiencies as high as 10(7) transformants microg(-1) dna have been previously reported for pseudomonads using electroporation protocols established for e. coli with plasmid dnas prepared from methylation proficient e. coli hosts. we report here a protocol for electroporation of plasmid dnas into a biocontrol strain of pseudomonas syringae which could not be electroporated by standard e. coli methods. transformation efficiencies of 10(7) or higher were obtained with dna recovered ... | 2003 | 12882571 |
| an arabidopsis mutant resistant to thaxtomin a, a cellulose synthesis inhibitor from streptomyces species. | thaxtomin a is a phytotoxin produced by streptomyces scabies and other streptomyces species, the causative agents of common scab disease in potato and other taproot crops. at nanomolar concentrations, thaxtomin causes dramatic cell swelling, reduced seedling growth, and inhibition of cellulose synthesis in arabidopsis. we identified a mutant of arabidopsis, designated txr1, that exhibits increased resistance to thaxtomin as a result of a decrease in the rate of toxin uptake. the txr1 gene was id ... | 2003 | 12897252 |
| p-coumaroylnoradrenaline, a novel plant metabolite implicated in tomato defense against pathogens. | the avr9 peptide elicitor from the fungus cladosporium fulvum, the bacterial pathogen pseudomonas syringae pathovar tomato carrying the avirulence gene avrpto (pst (avrpto)), and the organophosphorous insecticide fenitrothion induce resistance-related responses in tomato lines carrying the cf-9, pto, and fen genes, respectively. these responses were associated with synthesis of p-coumaroyloctopamine and p-coumaroylnoradrenaline, a novel compound for plants. in susceptible near isogenic tomato li ... | 2003 | 12900412 |
| colonization of arabidopsis thaliana with salmonella enterica and enterohemorrhagic escherichia coli o157:h7 and competition by enterobacter asburiae. | enteric pathogens, such as salmonella enterica and escherichia coli o157:h7, have been shown to contaminate fresh produce. under appropriate conditions, these bacteria will grow on and invade the plant tissue. we have developed arabidopsis thaliana (thale cress) as a model system with the intention of studying plant responses to human pathogens. under sterile conditions and at 100% humidity, s. enterica serovar newport and e. coli o157:h7 grew to 10(9) cfu g(-1) on a. thaliana roots and to 2 x 1 ... | 2003 | 12902287 |
| analysis of the argk-tox gene cluster in nontoxigenic strains of pseudomonas syringae pv. phaseolicola. | the analysis of 46 isolates obtained directly from different and distant common bean fields from the northwestern part of spain revealed that they do not produce phaseolotoxin. the isolates were classified as race 5, and their analysis revealed that they do not carry the argk-tox gene cluster involved in the biosynthesis of the phaseolotoxin. | 2003 | 12902295 |
| identifying the methyltransferases for m(5)u747 and m(5)u1939 in 23s rrna using maldi mass spectrometry. | there are three sites of m(5)u modification in escherichia coli stable rnas: one at the invariant trna position u54 and two in 23s rrna at the phylogenetically conserved positions u747 and u1939. each of these sites is modified by its own methyltransferase, and the trna methyltransferase, trma, is well-characterised. two open reading frames, ybjf and ygca, are approximately 30% identical to trma, and here we determine the functions of these candidate methyltransferases using maldi mass spectrome ... | 2003 | 12907714 |
| overexpression of the disease resistance gene pto in tomato induces gene expression changes similar to immune responses in human and fruitfly. | the pto gene encodes a serine/threonine protein kinase that confers resistance in tomato (lycopersicon esculentum) to pseudomonas syringae pv tomato strains that express the type iii effector protein avrpto. constitutive overexpression of pto in tomato, in the absence of avrpto, activates defense responses and confers resistance to several diverse bacterial and fungal plant pathogens. we have used a series of gene discovery and expression profiling methods to examine the effect of pto overexpres ... | 2003 | 12913147 |
| bwmk1, a rice mitogen-activated protein kinase, locates in the nucleus and mediates pathogenesis-related gene expression by activation of a transcription factor. | mitogen-activated protein kinase (mapk) cascades are known to transduce plant defense signals, but the downstream components of the mapk have as yet not been elucidated. here, we report an mapk from rice (oryza sativa), bwmk1, and a transcription factor, oserebp1, phosphorylated by the kinase. the mapk carries a tdy phosphorylation motif instead of the more common tey motif in its kinase domain and has an unusually extended c-terminal domain that is essential to its kinase activity and transloca ... | 2003 | 12913152 |
| the arabidopsis nhl3 gene encodes a plasma membrane protein and its overexpression correlates with increased resistance to pseudomonas syringae pv. tomato dc3000. | the arabidopsis genome contains a family of ndr1/hin1-like (nhl) genes that show homology to the nonrace-specific disease resistance (ndr1) and the tobacco (nicotiana tabacum) harpin-induced (hin1) genes. nhl3 is a pathogen-responsive member of this nhl gene family that is potentially involved in defense. in independent transgenic nhl3-overexpressing plant lines, a clear correlation between increased resistance to virulent pseudomonas syringae pv. tomato dc3000 and enhanced nhl3 transcript level ... | 2003 | 12913158 |
| molecular characterization of a novel lipase-like pathogen-inducible gene family of arabidopsis. | in a differential screening between arabidopsis plants pretreated with the resistance-inducer beta-aminobutyric acid and untreated control plants, we have identified a gene encoding a novel lipase-like protein, prlip1. the abundance of prlip1 mrnas in arabidopsis leaves was up-regulated by application of beta-aminobutyric acid, salicylic acid (sa), and ethylene as well as by various pathogens. induction of prlip1 depended on a functioning sa and ethylene signal transduction pathway but was indep ... | 2003 | 12913177 |
| application of comparative genomics in the identification and analysis of novel families of membrane-associated receptors in bacteria. | a great diversity of multi-pass membrane receptors, typically with 7 transmembrane (tm) helices, is observed in the eukaryote crown group. so far, they are relatively rare in the prokaryotes, and are restricted to the well-characterized sensory rhodopsins of various phototropic prokaryotes. | 2003 | 12914674 |
| polynucleotide phosphorylase-deficient mutants of pseudomonas putida. | in bacteria, polynucleotide phosphorylase (pnpase) is one of the main exonucleolytic activities involved in rna turnover and is widely conserved. in spite of this, pnpase does not seem to be essential for growth if the organisms are not subjected to special conditions, such as low temperature. we identified the pnpase-encoding gene (pnp) of pseudomonas putida and constructed deletion mutants that did not exhibit cold sensitivity. in addition, we found that the transcription pattern of pnp upon c ... | 2003 | 12923102 |
| regulation of the vitamin b12 metabolism and transport in bacteria by a conserved rna structural element. | cobalamin in the form of adenosylcobalamin (ado-cbl) is known to repress expression of genes for vitamin b(12) biosynthesis and be transported by a posttranscriptional regulatory mechanism, which involves direct binding of ado-cbl to 5'untranslated gene regions (5'utr). using comparative analysis of genes and regulatory regions, we identified a highly conserved rna structure, the b12-element, which is widely distributed in 5'utrs of vitamin b(12)-related genes in eubacteria. multiple alignment o ... | 2003 | 12923257 |
| the complete genome sequence of the arabidopsis and tomato pathogen pseudomonas syringae pv. tomato dc3000. | we report the complete genome sequence of the model bacterial pathogen pseudomonas syringae pathovar tomato dc3000 (dc3000), which is pathogenic on tomato and arabidopsis thaliana. the dc3000 genome (6.5 megabases) contains a circular chromosome and two plasmids, which collectively encode 5,763 orfs. we identified 298 established and putative virulence genes, including several clusters of genes encoding 31 confirmed and 19 predicted type iii secretion system effector proteins. many of the virule ... | 2003 | 12928499 |
| pseudomonas syringae pv. tomato dc3000 hopptom (cel orf3) is important for lesion formation but not growth in tomato and is secreted and translocated by the hrp type iii secretion system in a chaperone-dependent manner. | pseudomonas syringae pv. tomato dc3000 is a pathogen of tomato and arabidopsis that injects virulence effector proteins into host cells via a type iii secretion system (ttss). ttss-deficient mutants have a hrp- phenotype, that is, they cannot elicit the hypersensitive response (hr) in non-host plants or pathogenesis in host plants. mutations in effector genes typically have weak virulence phenotypes (apparently due to redundancy), but deletion of six open reading frames (orf) in the dc3000 conse ... | 2003 | 12940984 |
| direct delivery of bacterial avirulence proteins into resistant arabidopsis protoplasts leads to hypersensitive cell death. | many bacterial avirulence (avr) proteins, including the pseudomonas syringae proteins, avrrpt2 and avrb, appear to be recognized inside the host plant cell by resistance mechanisms mediated by the cognate resistance (r) genes. it is thought that avr proteins are either delivered directly into the host cell via the bacterial type iii secretion system (ttss) or taken up by the plant cell following secretion into the apoplast through the ttss. recently, it was shown that the xanthomonas campestris ... | 2003 | 12943547 |
| [effect of the lipopolysaccharide-protein complex of pseudomonas syringae pv. atrofaciens on the process of tumor formation caused by agrobacterium tumefaciens]. | it has been found that the agent of bacterial spotting of rye p. syringae pv. atrofaciens 8281 has no antagonistic action on the strains 9052 and 9054 of agrobacterium tumefaciens--the agent of crown gall tumor. lipopolysaccharide-protein complex of p. syringae pv. atrofaciens 8281 when added to the culture medium does not affect the growth and development of a. tumefaciens bacteria. it has been experimentally established that the lipopolysaccharide-protein complex of p. syringae pv. atrofaciens ... | 2003 | 12945188 |
| cleavage of arabidopsis pbs1 by a bacterial type iii effector. | plant disease-resistance (r) proteins are thought to function as receptors for ligands produced directly or indirectly by pathogen avirulence (avr) proteins. the biochemical functions of most avr proteins are unknown, and the mechanisms by which they activate r proteins have not been determined. in arabidopsis, resistance to pseudomonas syringae strains expressing avrpphb requires rps5, a member of the class of r proteins that have a predicted nucleotide-binding site and leucine-rich repeats, an ... | 2003 | 12947197 |
| genetic and molecular evidence that the pseudomonas syringae type iii effector protein avrrpt2 is a cysteine protease. | upon delivery to the plant cell during infection, the pseudomonas syringae effector protein avrrpt2 undergoes proteolytic processing, enhances pathogen virulence and causes the elimination of the arabidopsis rin4 protein. a structure-prediction method was employed in order to investigate possible biochemical functions of avrrpt2. results of a secondary structure prediction algorithm suggest that the functional c-terminal portion of avrrpt2 is a cysteine protease. mutation of predicted catalytic ... | 2003 | 12950919 |
| colonization of flax roots and early physiological responses of flax cells inoculated with pathogenic and nonpathogenic strains of fusarium oxysporum. | fusarium oxysporum includes nonpathogenic strains and pathogenic strains that can induce necrosis or tracheomycosis in plants. the objective of this study was to compare the abilities of a pathogenic strain (foln3) and a nonpathogenic strain (fo47) to colonize flax roots and to induce early physiological responses in flax cell culture suspensions. both strains colonized the outer cortex of the root; however, plant defense reactions, i.e., the presence of wall appositions, osmiophilic material, a ... | 2003 | 12957934 |
| local context finder (lcf) reveals multidimensional relationships among mrna expression profiles of arabidopsis responding to pathogen infection. | a major task in computational analysis of mrna expression profiles is definition of relationships among profiles on the basis of similarities among them. this is generally achieved by pattern recognition in the distribution of data points representing each profile in a high-dimensional space. some drawbacks of commonly used pattern recognition algorithms stem from their use of a globally linear space and/or limited degrees of freedom. a pattern recognition method called local context finder (lcf ... | 2003 | 12960373 |
| does lowering glutamine synthetase activity in nodules modify nitrogen metabolism and growth of lotus japonicus? | a cdna encoding cytosolic glutamine synthetase (gs) from lotus japonicus was fused in the antisense orientation relative to the nodule-specific lbc3 promoter of soybean (glycine max) and introduced into l. japonicus via transformation with agrobacterium tumefaciens. among the 12 independent transformed lines into which the construct was introduced, some of them showed diminished levels of gs1 mrna and lower levels of gs activity. three of these lines were selected and their t(1) progeny was furt ... | 2003 | 12970491 |
| a developmental response to pathogen infection in arabidopsis. | we present evidence that susceptible arabidopsis plants accelerate their reproductive development and alter their shoot architecture in response to three different pathogen species. we infected 2-week-old arabidopsis seedlings with two bacterial pathogens, pseudomonas syringae and xanthomonas campestris, and an oomycete, peronospora parasitica. infection with each of the three pathogens reduced time to flowering and the number of aerial branches on the primary inflorescence. in the absence of co ... | 2003 | 12970499 |
| genetic and physical localization of the soybean rpg1-b disease resistance gene reveals a complex locus containing several tightly linked families of nbs-lrr genes. | alleles or tightly linked genes at the soybean (glycine max l. merr.) rpg1 locus confer resistance to strains of pseudomonas syringae pv. glycinea that express the avirulence genes avrb or avrrpm1. we have previously mapped rpg1-b (the gene specific for avrb) to a cluster of resistance genes (r genes) with diverse specificities in molecular linkage group f. here, we describe the high-resolution physical and genetic mapping of rpg1-b to a 0.16-cm interval encompassed by two overlapping bac clones ... | 2003 | 12971605 |
| construction and analysis of a recombinant cyanobacterium expressing a chromosomally inserted gene for an ethylene-forming enzyme at the psbai locus. | the coding sequence of a gene for a pseudomonas syringae ethylene-forming enzyme was inserted at the psbai locus in a cyanobacterium, synechococcus elongatus pcc 7942 via rps12-mediated gene replacement. the recombinant strain photoautotrophically produced ethylene at 451 nl ml(-1) h(-1) od730(-1), but showed a depressed specific growth rate as well as a yellow-green phenotype indicating a severe metabolic stress. the rate of ethylene production in the recombinant culture decreased as a result o ... | 2003 | 16233410 |
| [investigation of the mechanism of cell membrane-active cyclic lipodepsipeptides compounds]. | the cyclic lipodepsipeptides produced by pseudomonas syringae pv. syringae possess fungicide properties. they inhibit much of the cell functions, presumably on the basis of their pore-forming activity. the syringomycin e, studied earlier by our research group, formed pores on human red blood cells (rbc), and caused also partially hemolysis. to reach selective toxicity, knowledge of the relationship between the structure and function of the clps is required. to fulfill this requirement, the pore ... | 2003 | 15279038 |
| two mapk cascades, npr1, and tga transcription factors play a role in pto-mediated disease resistance in tomato. | the tomato pto kinase confers resistance to the causative agent of bacterial speck disease, pseudomonas syringae pv. tomato, by recognizing the pathogen effector proteins avrpto or avrptob. pto-mediated resistance requires multiple signal transduction pathways and has been shown to activate many defense responses including an oxidative burst, rapid changes in the expression of over 400 genes, and localized cell death. we have tested the role in pto-mediated resistance in tomato of a set of 21 ge ... | 2003 | 14675454 |
| 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 |
| identifying type iii effectors of plant pathogens and analyzing their interaction with plant cells. | many bacterial pathogens cause disease by injecting virulence proteins (effectors) into host cells via the specialized type iii secretion system. recently, exceptional progress in identifying effectors was made in the phytopathogen pseudomonas syringae using a novel genetic screen and bioinformatic approach. these studies, along with localization experiments, suggest that most p. syringae effectors function by targeting the plasma membrane, chloroplasts or mitochondria of host cells. the type ii ... | 2003 | 12615215 |
| nicotiana benthamiana gp91phox homologs nbrboha and nbrbohb participate in h2o2 accumulation and resistance to phytophthora infestans. | active oxygen species (aos) are responsible for triggering defense responses in plants. respiratory burst oxidase homologs (rboh genes) have been implicated in aos generation. we have isolated two rboh cdnas, nbrboha and nbrbohb, from nicotiana benthamiana leaves. nbrboha was expressed constitutively at a low level and the transcripts were increased after mechanical stress of control leaf infiltration, whereas nbrbohb was induced specifically by the protein elicitor inf1 from the potato pathogen ... | 2003 | 12615943 |
| recognition specificity and rar1/sgt1 dependence in barley mla disease resistance genes to the powdery mildew fungus. | a large number of resistance specificities to the powdery mildew fungus blumeria graminis f. sp. hordei map to the barley mla locus. this complex locus harbors multiple members of three distantly related gene families that encode proteins that contain an n-terminal coiled-coil (cc) structure, a central nucleotide binding (nb) site, a leu-rich repeat (lrr) region, and a c-terminal non-lrr (ct) region. we identified mla12, which encodes a cc-nb-lrr-ct protein that shares 89 and 92% identical resid ... | 2003 | 12615945 |
| npr1 modulates cross-talk between salicylate- and jasmonate-dependent defense pathways through a novel function in the cytosol. | plant defenses against pathogens and insects are regulated differentially by cross-communicating signal transduction pathways in which salicylic acid (sa) and jasmonic acid (ja) play key roles. in this study, we investigated the molecular mechanism of the antagonistic effect of sa on ja signaling. arabidopsis plants unable to accumulate sa produced 25-fold higher levels of ja and showed enhanced expression of the ja-responsive genes lox2, pdf1.2, and vsp in response to infection by pseudomonas s ... | 2003 | 12615947 |
| natural selection for polymorphism in the disease resistance gene rps2 of arabidopsis thaliana. | pathogen resistance is an ecologically important phenotype increasingly well understood at the molecular genetic level. in this article, we examine levels of avrrpt2-dependent resistance and rps2 locus dna sequence variability in a worldwide sample of 27 accessions of arabidopsis thaliana. the rooted parsimony tree of rps2 sequences drawn from a diverse set of ecotypes includes a deep bifurcation separating major resistance and susceptibility clades of alleles. we find evidence for selection mai ... | 2003 | 12618410 |
| the competitiveness of pseudomonas chlororaphis carrying pjp4 is reduced in the arabidopsis thaliana rhizosphere. | the effect of the large catabolic incp plasmid pjp4 on the competitiveness of pseudomonas chlororaphis spr044 and on its derivatives spr244 (gacs deficient), spr344 (phenazine-1-carboxamide overproducer), and spr644 (phenazine-1-carboxamide deficient) in the arabidopsis thaliana rhizosphere was assessed. solitary rhizosphere colonization by the wild type, spr244, and spr644 was not affected by the plasmid. the size of the population of spr344 carrying pjp4, however, was significantly reduced com ... | 2003 | 12620876 |
| nucleotide sequence, functional characterization and evolution of pfkn, a virulence plasmid in pseudomonas syringae pathovar maculicola. | pseudomonas syringae pv. maculicola strain m6 (psm m6) carries the avrrpm1 gene, encoding a type iii effector, on a 40 kb plasmid, pfkn. we hypothesized that this plasmid might carry additional genes required for pathogenesis on plants. we report the sequence and features of pfkn. in addition to avrrpm1, pfkn carries an allele of another type iii effector, termed avrpphe, and a gene of unknown function (orf8), expression of which is induced in planta, suggesting a role in the plant-pathogen inte ... | 2003 | 12622811 |
| interplay of the arabidopsis nonhost resistance gene nho1 with bacterial virulence. | it is poorly understood why a particular plant species is resistant to the vast majority of potential pathogens that infect other plant species, a phenomenon referred to as "nonhost" resistance. here, we show that arabidopsis nho1, encoding a glycerol kinase, is required for resistance to and induced by pseudomonas syringae isolates from bean and tobacco. nho1 is also required for resistance to the fungal pathogen botrytis cinerea, indicating that nho1 is not limited to bacterial resistance. str ... | 2003 | 12626746 |
| pto mutants differentially activate prf-dependent, avrpto-independent resistance and gene-for-gene resistance. | pto confers disease resistance to pseudomonas syringae pv tomato carrying the cognate avrpto gene. overexpression of pto under the cauliflower mosaic virus 35s promoter activates spontaneous lesions and confers disease resistance in tomato (lycopersicon esculentum) plants in the absence of avrpto. here, we show that these avrpto-independent defenses require a functional prf gene. several pto-interacting (pti) proteins are thought to play a role in pto-mediated defense pathways. to test if intera ... | 2003 | 12644674 |
| a redox switch in copc: an intriguing copper trafficking protein that binds copper(i) and copper(ii) at different sites. | the protein copc from pseudomonas syringae has been found capable of binding copper(i) and copper(ii) at two different sites, occupied either one at a time or simultaneously. the protein, consisting of 102 amino acids, is known to bind copper(ii) in a position that is now found consistent with a coordination arrangement including his-1, glu-27, asp-89, and his-91. a full solution structure analysis is reported here for cu(i)-copc. the copper(i) site is constituted by his-48 and three of the four ... | 2003 | 12651950 |
| autodisplay: development of an efficacious system for surface display of antigenic determinants in salmonella vaccine strains. | to optimize antigen delivery by salmonella vaccine strains, a system for surface display of antigenic determinants was established by using the autotransporter secretion pathway of gram-negative bacteria. a modular system for surface display allowed effective targeting of heterologous antigens or fragments thereof to the bacterial surface by the autotransporter domain of aida-i, the escherichia coli adhesin involved in diffuse adherence. a major histocompatibility complex class ii-restricted epi ... | 2003 | 12654812 |
| post-translational modification of flagellin determines the specificity of hr induction. | flagellin, a constituent of the flagellar filament, is a potent elicitor of hypersensitive cell death in plant cells. flagellins of pseudomonas syringae pvs. glycinea and tomato induce hypersensitive cell death in their non-host tobacco plants, whereas those of p. syringae pv. tabaci do not remarkably induce it in its host tobacco plants. however, the deduced amino acid sequences of flagellins from pvs. tabaci and glycinea are identical, indicating that post-translational modification of flagell ... | 2003 | 12668781 |
| pseudomonas syringae exchangeable effector loci: sequence diversity in representative pathovars and virulence function in p. syringae pv. syringae b728a. | pseudomonas syringae is a plant pathogen whose pathogenicity and host specificity are thought to be determined by hop/avr effector proteins injected into plant cells by a type iii secretion system. p. syringae pv. syringae b728a, which causes brown spot of bean, is a particularly well-studied strain. the type iii secretion system in p. syringae is encoded by hrp (hypersensitive response and pathogenicity) and hrc (hrp conserved) genes, which are clustered in a pathogenicity island with a tripart ... | 2003 | 12670984 |
| colonization of vitis vinifera by a green fluorescence protein-labeled, gfp-marked strain of xylophilus ampelinus, the causal agent of bacterial necrosis of grapevine. | the dynamics of xylophilus ampelinus were studied in vitis vinifera cv. ugni blanc using gfp-marked bacterial strains to evaluate the relative importance of epiphytic and endophytic phases of plant colonization in disease development. currently, bacterial necrosis of grapevine is of economic importance in vineyards in three regions in france: the cognac, armagnac, and die areas. this disease is responsible for progressive destruction of vine shoots, leading to their death. we constructed gfp-mar ... | 2003 | 12676663 |
| bacteriophages of erwinia amylovora. | fifty bacteriophage isolates of erwinia amylovora, the causal agent of fire blight, were collected from sites in and around the niagara region of southern ontario and the royal botanical gardens, hamilton, ontario. forty-two phages survived the isolation, purification, and storage processes. the majority of the phages in the collection were isolated from the soil surrounding trees exhibiting fire blight symptoms. only five phages were isolated from infected aerial tissue in pear and apple orchar ... | 2003 | 12676693 |
| heavy metal resistance of biofilm and planktonic pseudomonas aeruginosa. | a study was undertaken to examine the effects of the heavy metals copper, lead, and zinc on biofilm and planktonic pseudomonas aeruginosa. a rotating-disk biofilm reactor was used to generate biofilm and free-swimming cultures to test their relative levels of resistance to heavy metals. it was determined that biofilms were anywhere from 2 to 600 times more resistant to heavy metal stress than free-swimming cells. when planktonic cells at different stages of growth were examined, it was found tha ... | 2003 | 12676715 |
| n-acylethanolamine signaling in tobacco is mediated by a membrane-associated, high-affinity binding protein. | n-acylethanolamines (naes) are fatty acid derivatives found as minor constituents of animal and plant tissues, and their levels increase 10- to 50-fold in tobacco (nicotiana tabacum) leaves treated with fungal elicitors. infiltration of tobacco leaves with submicromolar to micromolar concentrations of n-myristoylethanolamine (nae 14:0) resulted in an increase in relative phenylalanine ammonia-lyase (pal) transcript abundance within 8 h after infiltration, and this pal activation was reduced afte ... | 2003 | 12692337 |
| molecular interactions between the specialist herbivore manduca sexta (lepidoptera, sphingidae) and its natural host nicotiana attenuata: v. microarray analysis and further characterization of large-scale changes in herbivore-induced mrnas. | we extend our analysis of the transcriptional reorganization that occurs when the native tobacco, nicotiana attenuata, is attacked by manduca sexta larvae by cloning 115 transcripts by mrna differential display reverse transcription-polymerase chain reaction and subtractive hybridization using magnetic beads (shmb) from the m. sexta-responsive transcriptome. these transcripts were spotted as cdna with eight others, previously confirmed to be differentially regulated by northern analysis on glass ... | 2003 | 12692347 |
| molecular interactions between the specialist herbivore manduca sexta (lepidoptera, sphingidae) and its natural host nicotiana attenuata. vi. microarray analysis reveals that most herbivore-specific transcriptional changes are mediated by fatty acid-amino acid conjugates. | evidence is accumulating that insect-specific plant responses are mediated by constituents in the oral secretions and regurgitants (r) of herbivores, however the relative importance of the different potentially active constituents remains unclear. fatty acid-amino acid conjugates (facs) are found in the r of many insect herbivores and have been shown to be necessary and sufficient to elicit a set of herbivore-specific responses when the native tobacco plant nicotiana attenuata is attacked by the ... | 2003 | 12692348 |
| negative cross-talk between salicylate- and jasmonate-mediated pathways in the wassilewskija ecotype of arabidopsis thaliana. | plants often respond to attack by insect herbivores and necrotrophic pathogens with induction of jasmonate-dependent resistance traits, but respond to attack by biotrophic pathogens with induction of salicylate-dependent resistance traits. to assess the degree to which the jasmonate- and salicylate-dependent pathways interact, we compared pathogenesis-related protein activity and bacterial performance in four mutant arabidopsis thaliana lines relative to their wild-type backgrounds. we found tha ... | 2003 | 12694277 |
| non-conventional methods for the control of post-harvest pear diseases. | pears are highly perishable products, especially during the post-harvest phase, when considerable losses can occur. among the fungal diseases, blue mold caused by penicillium expansum, grey mould caused by botrytis cinerea, mucor rot caused by mucor piriformis are common on pear fruits. other (weak) pathogens like phialophora malorum, alternaria spp., and cladosporium herbarum tend to infect wounds and senescent fruits. a post-harvest fungicide treatment can reduce decay but effectiveness decrea ... | 2003 | 12694440 |
| use of in-biofilm expression technology to identify genes involved in pseudomonas aeruginosa biofilm development. | mature pseudomonas aeruginosa biofilms form complex three-dimensional architecture and are tolerant of antibiotics and other antimicrobial compounds. in this work, an in vivo expression technology system, originally designed to study virulence-associated genes in complex mammalian environments, was used to identify genes up-regulated in p. aeruginosa grown to a mature (5-day) biofilm. five unique cloned promoters unable to promote in vitro growth in the absence of purines after recovery from the ... | 2003 | 12700249 |
| substrate specificity of the nonribosomal peptide synthetase pvdd from pseudomonas aeruginosa. | pseudomonas aeruginosa pao1 secretes a siderophore, pyoverdine(pao), which contains a short peptide attached to a dihydroxyquinoline moiety. synthesis of this peptide is thought to be catalyzed by nonribosomal peptide synthetases, one of which is encoded by the pvdd gene. the first module of pvdd was overexpressed in escherichia coli, and the protein product was purified. l-threonine, one of the amino acid residues in pyoverdine(pao), was an effective substrate for the recombinant protein in atp ... | 2003 | 12700264 |
| bacteriocin serratine-p as a biological tool in the control of fire blight erwinia amylovora. | fire blight, caused by the bacterium erwinia amylovora (burill winslow et al.), is the most important bacterial disease in european pear growing. it can cause a lot of damage in some countries on apple and on pear trees in orchards and also in the fruit tree nurseries. in belgium, the disease is present since 1972. control of fire blight in belgian fruit orchards is made on a broad basis of measurements in and around the fruit trees. the use of an antibiotic is allowed for application only durin ... | 2002 | 12701444 |
| a novel type of conserved dna-binding domain in the transcriptional regulators of the algr/agra/lytr family. | sequence analysis of bacterial genomes revealed a novel dna-binding domain. this domain is found in several response regulators of the two-component signal transduction system, such as pseudomonas aeruginosa algr, involved in the regulation of alginate biosynthesis and in the pathogenesis of cystic fibrosis; clostridium perfringens virr, a regulator of virulence factors, and in several regulators of bacteriocin biosynthesis, previously unified in the agra/come family. most of the transcriptional ... | 2002 | 12034833 |
| arabidopsis sgt1b is required for defense signaling conferred by several downy mildew resistance genes. | we describe the identification of a mutant in the arabidopsis accession columbia (col-0) that exhibits enhanced downy mildew (edm1) susceptibility to several peronospora parasitica isolates, including the rpp7-diagnostic isolate hiks1. the mutation was mapped to chromosome iv and characterized physically as a 35-kb deletion spanning seven genes. one of these genes complemented the mutant to full wild-type resistance against all of the peronospora isolates tested. this gene (atsgt1b) encodes a pr ... | 2002 | 12034892 |
| protection of tomato seedlings against infection by pseudomonas syringae pv. tomato by using the plant growth-promoting bacterium azospirillum brasilense. | pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. the population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. when inoculated onto separate plants, the a. brasilense population in the rhizosphere of tomato plants was 2 orders o ... | 2002 | 12039714 |
| siderophore typing, a powerful tool for the identification of fluorescent and nonfluorescent pseudomonads. | a total of 301 strains of fluorescent pseudomonads previously characterized by conventional phenotypic and/or genomic taxonomic methods were analyzed through siderotyping, i.e., by the isoelectrophoretic characterization of their main siderophores and pyoverdines and determination of the pyoverdine-mediated iron uptake specificity of the strains. as a general rule, strains within a well-circumscribed taxonomic group, namely the species pseudomonas brassicacearum, pseudomonas fuscovaginae, pseudo ... | 2002 | 12039729 |
| ppi1: a novel pathogen-induced basic region-leucine zipper (bzip) transcription factor from pepper. | we have isolated a full-length cdna, ppi1 (pepper-pmmv interaction 1), encoding a novel basic region-leucine zipper (bzip) dna-binding protein, from expressed sequence tags differentially expressed in capsicum chinense p1257284 infected with pepper mild mottle virus (pmmv). ppi1 encodes a predicted protein of 170 amino acids and contains a putative dna-binding domain that shares significant amino acid identity with acgt-binding domains of members of the bzip dna-binding protein family. ppi1 was ... | 2002 | 12059102 |