Publications

suppression of pathogen-inducible no synthase (inos) activity in tomato increases susceptibility to pseudomonas syringae.	inducible no synthase (inos) activity is induced upon pathogen inoculation in resistant, but not susceptible, tobacco and arabidopsis plants. it was shown recently that a variant form of the arabidopsis p protein (atvarp) has inos activity. p protein is part of the glycine decarboxylase complex (gdc). it is unclear whether p protein also has inos activity and, if so, whether atvarp, p, or both, play a role in plant defense. here, we show that inos activity is induced in both resistant and suscep ...	2004	15146069
the pseudomonas syringae hopptov protein is secreted in culture and translocated into plant cells via the type iii protein secretion system in a manner dependent on the shcv type iii chaperone.	the bacterial plant pathogen pseudomonas syringae depends on a type iii protein secretion system and the effector proteins that it translocates into plant cells to cause disease and to elicit the defense-associated hypersensitive response on resistant plants. the availability of the p. syringae pv. tomato dc3000 genome sequence has resulted in the identification of many novel effectors. we identified the hopptov effector gene on the basis of its location next to a candidate type iii chaperone (t ...	2004	15150250
the global arginine regulator argr controls expression of argf in pseudomonas syringae pv. phaseolicola but is not required for the synthesis of phaseolotoxin or for the regulated expression of argk.	in pseudomonas syringae pv. phaseolicola the enzyme ornithine carbamoyltransferase (octase), encoded by argf, is negatively regulated by argr, similar to what has been reported for pseudomonas aeruginosa. however, production of the phaseolotoxin-resistant octase encoded by argk, synthesis of phaseolotoxin, and infectivity for bean pods occur independently of the argr protein.	2004	15150254
comparison of atpase-encoding type iii secretion system hrcn genes in biocontrol fluorescent pseudomonads and in phytopathogenic proteobacteria.	type iii protein secretion systems play a key role in the virulence of many pathogenic proteobacteria, but they also occur in nonpathogenic, plant-associated bacteria. certain type iii protein secretion genes (e.g., hrcc) have been found in pseudomonas sp. strain sbw25 (and other biocontrol pseudomonads), but other type iii protein secretion genes, such as the atpase-encoding gene hrcn, have not been found. using both colony hybridization and a pcr approach, we show here that hrcn is nevertheles ...	2004	15345390
regulation of the n-acyl homoserine lactone-dependent quorum-sensing system in rhizosphere pseudomonas putida wcs358 and cross-talk with the stationary-phase rpos sigma factor and the global regulator gaca.	quorum sensing is a cell population-density dependent regulatory system which in gram-negative bacteria often involves the production and detection of n-acyl homoserine lactones (ahls). some pseudomonas putida strains have been reported to produce ahls, and one quorum-sensing locus has been identified. however, it appears that the majority of strains do not produce ahls. in this study we report the identification and regulation of the ahl-dependent system of rhizosphere p. putida wcs358. this sy ...	2004	15345437
the pepper transcription factor capf1 confers pathogen and freezing tolerance in arabidopsis.	an erf/ap2-type transcription factor (capf1) was isolated by differential-display reverse transcription-pcr, following inoculation of the soybean pustule pathogen xanthomonas axonopodis pv glycines 8ra, which induces hypersensitive response in pepper (capsicum annuum) leaves. capf1 mrna was induced under conditions of biotic and abiotic stress. higher levels of capf1 transcripts were observed in disease-resistant tissue compared with susceptible tissue. capf1 expression was additionally induced ...	2004	15347795
genetic elucidation of nitric oxide signaling in incompatible plant-pathogen interactions.	recent experiments indicate that nitric oxide (no) plays a pivotal role in disease resistance and several other physiological processes in plants. however, most of the current information about the function of no in plants is based on pharmacological studies, and additional approaches are therefore required to ascertain the role of no as an important signaling molecule in plants. we have expressed a bacterial nitric oxide dioxygenase (nod) in arabidopsis plants and/or avirulent pseudomonas syrin ...	2004	15347797
modulation of the biological activity of a tobacco ltp1 by lipid complexation.	plant lipid transfer proteins (ltps) are small, cysteine-rich proteins secreted into the extracellular space. they belong to the pathogenesis-related proteins (pr-14) family and are believed to be involved in several physiological processes including plant disease resistance, although their precise biological function is still unknown. here, we show that a recombinant tobacco ltp1 is able to load fatty acids and jasmonic acid. this ltp1 binds to specific plasma membrane sites, previously charact ...	2004	15356262
arabidopsis rin4 negatively regulates disease resistance mediated by rps2 and rpm1 downstream or independent of the ndr1 signal modulator and is not required for the virulence functions of bacterial type iii effectors avrrpt2 or avrrpm1.	bacterial pathogens deliver type iii effector proteins into the plant cell during infection. on susceptible (r) hosts, type iii effectors can contribute to virulence. some trigger the action of specific disease resistance (r) gene products. the activation of r proteins can occur indirectly via modification of a host target. thus, at least some type iii effectors are recognized at site(s) where they may act as virulence factors. these data indicate that a type iii effector's host target might be ...	2004	15361584
arabidopsis nonsymbiotic hemoglobin ahb1 modulates nitric oxide bioactivity.	nitric oxide (no) is a widespread signaling molecule, and numerous targets of its action exist in plants. whereas the activity of no in erythrocytes, microorganisms, and invertebrates has been shown to be regulated by several hemoglobins, the function of plant hemoglobins in no detoxification has not yet been elucidated. here, we show that arabidopsis thaliana nonsymbiotic hemoglobin ahb1 scavenges no through production of s-nitrosohemoglobin and reduces no emission under hypoxic stress, indicat ...	2004	15367716
a patch of surface-exposed residues mediates negative regulation of immune signaling by tomato pto kinase.	tomato (lycopersicon esculentum) pto kinase specifically recognizes the pseudomonas effector proteins avrpto and avrptob, leading to induction of defense responses and hypersensitive cell death. structural modeling of pto combined with site-directed mutagenesis identified a patch of surface-exposed residues required for native regulation of signaling. mutations in this area resulted in constitutive gain-of-function (cgf) forms of pto that activated avrpto-independent cell death via the cognate s ...	2004	15367718
identification of mapks and their possible mapk kinase activators involved in the pto-mediated defense response of tomato.	the pto kinase mediates resistance to bacterial speck disease in tomato by activating host defenses upon recognition of pseudomonas syringae pv. tomato strains expressing the avrpto or avrptob proteins. previous gene-silencing experiments have indicated that mitogen activated protein kinase (mapk) cascades play a key role downstream of the pto kinase to activate host defense responses. here we use biochemical methods to demonstrate that two tomato mapks, lempk2 and lempk3, are activated in leave ...	2004	15371431
complete genomic sequence of bacteriophage b3, a mu-like phage of pseudomonas aeruginosa.	bacteriophage b3 is a transposable phage of pseudomonas aeruginosa. in this report, we present the complete dna sequence and annotation of the b3 genome. dna sequence analysis revealed that the b3 genome is 38,439 bp long with a g+c content of 63.3%. the genome contains 59 proposed open reading frames (orfs) organized into at least three operons. of these orfs, the predicted proteins from 41 orfs (68%) display significant similarity to other phage or bacterial proteins. many of the predicted b3 ...	2004	15375138
an energy taxis transducer promotes root colonization by azospirillum brasilense.	motility responses triggered by changes in the electron transport system are collectively known as energy taxis. in azospirillum brasilense, energy taxis was shown to be the principal form of locomotor control. in the present study, we have identified a novel chemoreceptor-like protein, named tlp1, which serves as an energy taxis transducer. the tlp1 protein is predicted to have an n-terminal periplasmic region and a cytoplasmic c-terminal signaling module homologous to those of other chemorecep ...	2004	15375141
genomic plasticity of the causative agent of melioidosis, burkholderia pseudomallei.	burkholderia pseudomallei is a recognized biothreat agent and the causative agent of melioidosis. this gram-negative bacterium exists as a soil saprophyte in melioidosis-endemic areas of the world and accounts for 20% of community-acquired septicaemias in northeastern thailand where half of those affected die. here we report the complete genome of b. pseudomallei, which is composed of two chromosomes of 4.07 megabase pairs and 3.17 megabase pairs, showing significant functional partitioning of g ...	2004	15377794
consequences of binding an s-adenosylmethionine analogue on the structure and dynamics of the thiopurine methyltransferase protein backbone.	in humans, the enzyme thiopurine methyltransferase (tpmt) metabolizes 6-thiopurine (6-tp) medications, commonly used for immune suppression and for the treatment of hematopoietic malignancies. genetic polymorphisms in the tpmt protein sequence accelerate intracellular degradation of the enzyme through an ubiquitylation and proteasomal-dependent pathway. research has led to the hypothesis that these polymorphisms destabilize the native structure of tpmt, resulting in the formation of misfolded or ...	2004	15379558
a key role for ald1 in activation of local and systemic defenses in arabidopsis.	the arabidopsis thaliana agd2-like defense response protein1 (ald1) mutant was previously found to be hypersusceptible to the virulent bacterial pathogen pseudomonas syringae and had reduced accumulation of the defense signal salicylic acid (sa). ald1 was shown to possess aminotransferase activity in vitro, suggesting it generates an amino acid-derived defense signal. we now find ald1 to be a key defense component that acts in multiple contexts and partially requires the phytoalexin deficient4 ( ...	2004	15447647
expression of rps4 in tobacco induces an avrrps4-independent hr that requires eds1, sgt1 and hsp90.	the arabidopsis rps4 gene belongs to the toll/interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (tir-nb-lrr) class of plant resistance (r) genes. it confers resistance to pseudomonas syringae carrying the avirulence gene avrrps4. transient expression of genomic rps4 driven by the 35s promoter in tobacco leaves induces an avrrps4-independent hypersensitive response (hr). the same phenotype is seen after expression of a full-length rps4 cdna. this indicates that alternative splici ...	2004	15447648
overexpression of the plasma membrane-localized ndr1 protein results in enhanced bacterial disease resistance in arabidopsis thaliana.	previous studies have established that mutations in the ndr1 gene in arabidopsis thaliana suppress the resistance response of three resistance proteins, rps2, rpm1, and rps5, to pseudomonas syringae pv. tomato (pst) strain dc3000 containing the cognate effector genes, avrrpt2, avrrpm1, and avrpphb, respectively. ndr1 is a plasma membrane (pm)-localized protein, and undergoes several post-translational modifications including carboxy-terminal processing and n-linked glycosylation. expression of n ...	2004	15447649
intragenomic heterogeneity of the 16s rrna-23s rrna internal transcribed spacer among pseudomonas syringae and pseudomonas fluorescens strains.	the 16s-23s rrna internal transcribed spacer regions (its1) from 14 strains of pseudomonas syringae and p. fluorescens were sequenced. its1 exhibited significant sequence variability among different operons within a single genome. from 1 to 4 types of its1 were found in individual genomes of the p. syringae and p. fluorescens strains. a total of eight its1 types were identified among strains studied. the its1 nucleotide sequences consisted of conserved blocks including, among others, a stem-form ...	2004	15451096
replicon-specific regulation of small heat shock genes in agrobacterium tumefaciens.	four genes coding for small heat shock proteins (shsps) were identified in the genome sequence of agrobacterium tumefaciens, one on the circular chromosome (hspc), one on the linear chromosome (hspl), and two on the pat plasmid (hspat1 and hspat2). induction of shsps at elevated temperatures was revealed by immunoblot analyses. primer extension experiments and translational lacz fusions demonstrated that expression of the pat-derived genes and hspl is controlled by temperature in a regulon-speci ...	2004	15466035
antimicrobial activity of some pentacyclic triterpenes and their synthesized 3-o-lipophilic chains.	the major metabolites of diopsyros melanoxylon viz. amyrins and ursolic acid and their lipophilic 3-o-fatty acid ester chains (c12-c18), which are synthesized now under mild esterification conditions in excellent yields (80-95%), were evaluated for their antimicrobial activity against a series of gram positive and gram negative bacteria. significantly these compounds were found to exhibit potent activity against gram negative bacteria pseudomonas syringae (atcc #13457) and fairly good activity a ...	2004	15467198
disabling surveillance: bacterial type iii secretion system effectors that suppress innate immunity.	many gram-negative bacterial pathogens of plants and animals are dependent on a type iii protein secretion system (ttss). ttsss translocate effector proteins into host cells and are capable of modifying signal transduction pathways. the innate immune system of eukaryotes detects the presence of pathogens using specific pathogen recognition receptors (prrs). plant prrs include the fls2 receptor kinase and resistance proteins. animal prrs include toll-like receptors and nucleotide-binding oligomer ...	2004	15469432
two arabidopsis srfr (suppressor of rps4-rld) mutants exhibit avrrps4-specific disease resistance independent of rps4.	rps4 specifies the arabidopsis disease resistance response to pseudomonas syringae pv. tomato expressing avrrps4 and was cloned based on the identification of rld as a naturally occurring susceptible accession. to dissect the molecular and genetic basis of disease resistance, we used a genetic approach to identify suppressor mutations that reactivate the avrrps4-triggered defense response in rld. in this report, we describe two non-allelic srfr (suppressor of rps4-rld) mutants, srfr1 and srfr3, ...	2004	15469494
hoppton is a pseudomonas syringae hrp (type iii secretion system) cysteine protease effector that suppresses pathogen-induced necrosis associated with both compatible and incompatible plant interactions.	pseudomonas syringae pv. tomato dc3000 causes bacterial speck disease in tomato, and it elicits the hypersensitive response (hr) in non-host plants such as nicotiana tabacum and nicotiana benthamiana. the compatible and incompatible interactions of dc3000 with tomato and nicotiana spp., respectively, result in plant cell death, but the hr cell death occurs more rapidly and is associated with effective plant defense. both interactions require the hrp (hr and pathogenicity) type iii secretion syst ...	2004	15469508
molecular characterization of a thij-like gene in chinese cabbage.	a cdna clone for a salicylic acid-induced gene in chinese cabbage (brassica rapa subsp. pekinensis) was isolated and characterized. the cabbage gene encoding a protein of 392 amino acids contained a tandem array of two thij-like sequences. thij is a thiamin biosynthesis enzyme that catalyzes the phosphorylation of hydroxymethylpyrimidine (hmp) to hmp monophosphate. although the cabbage gene shows a similarity to bacterial thij genes, it also shares a similarity with the human dj-1, a multifuncti ...	2004	15469717
variation suggestive of horizontal gene transfer at a lipopolysaccharide (lps) biosynthetic locus in xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen of rice.	in animal pathogenic bacteria, horizontal gene transfer events (hgt) have been frequently observed in genomic regions that encode functions involved in biosynthesis of the outer membrane located lipopolysaccharide (lps). as a result, different strains of the same pathogen can have substantially different lps biosynthetic gene clusters. since lps is highly antigenic, the variation at lps loci is attributed to be of advantage in evading the host immune system. although lps has been suggested as a ...	2004	15473911
identification of an antibacterial compound, benzylideneacetone, from xenorhabdus nematophila against major plant-pathogenic bacteria.	an entomopathogenic bacterium, xenorhabdus nematophila, is known to have potent antibiotic activities to maintain monoxenic condition in its insect host for effective pathogenesis and ultimately for optimal development of its nematode symbiont, steinernema carpocapsae. in this study we assess its antibacterial activity against plant-pathogenic bacteria and identify its unknown antibiotics. the bacterial culture broth had significant antibacterial activity that increased with development of the b ...	2004	15476972
the completely sequenced plasmid pest4011 contains a novel incp1 backbone and a catabolic transposon harboring tfd genes for 2,4-dichlorophenoxyacetic acid degradation.	the herbicide 2,4-dichlorophenoxyacetic acid (2,4-d)-degrading bacterium achromobacter xylosoxidans subsp. denitrificans strain est4002 contains plasmid pest4011. this plasmid ensures its host a stable 2,4-d(+) phenotype. we determined the complete 76,958-bp nucleotide sequence of pest4011. this plasmid is a deletion and duplication derivative of pd2m4, the 95-kb highly unstable laboratory ancestor of pest4011, and was self-generated during different laboratory manipulations performed to increas ...	2004	15489427
construction of an enterococcus faecalis tn917-mediated-gene-disruption library offers insight into tn917 insertion patterns.	sequencing the insertion sites of 8,865 tn917 insertions in enterococcus faecalis strain og1rf identified a hot spot in the replication terminus region corresponding to 6% of the genome where 65% of the transposons had inserted. in e. faecalis, tn917 preferentially inserted at a 29-bp consensus sequence centered on tataa, a 5-bp sequence that is duplicated during insertion. the regional insertion site preference at the chromosome terminus was not observed in another low-g+c gram-positive bacteri ...	2004	15489440
algx is a periplasmic protein required for alginate biosynthesis in pseudomonas aeruginosa.	alginate, an exopolysaccharide produced by pseudomonas aeruginosa, provides the bacterium with a selective advantage that makes it difficult to eradicate from the lungs of cystic fibrosis (cf) patients. previous studies identified a gene, algx, within the alginate biosynthetic gene cluster on the p. aeruginosa chromosome. by probing cell fractions with anti-algx antibodies in a western blot, algx was localized within the periplasm. consistent with these results is the presence of a 26-amino-acid ...	2004	15489449
use of in vivo expression technology to identify genes important in growth and survival of pseudomonas fluorescens pf0-1 in soil: discovery of expressed sequences with novel genetic organization.	studies were undertaken to determine the genetic needs for the survival of pseudomonas fluorescens pf0-1, a gram-negative soil bacterium potentially important for biocontrol and bioremediation, in soil. in vivo expression technology (ivet) identified 22 genes with elevated expression in soil relative to laboratory media. soil-induced sequences included genes with probable functions of nutrient acquisition and use, and of gene regulation. ten sequences, lacking similarity to known genes, overlapp ...	2004	15489453
impact of temperature on in planta expression of genes involved in synthesis of the pseudomonas syringae phytotoxin coronatine.	coronatine (cor) is a chlorosis-inducing phytotoxin produced by the plant-pathogenic bacterium pseudomonas syringae. confocal laser scanning microscopy was used to investigate in vitro and in planta expression of cor genes by two model organisms, p. syringae pv. glycinea pg4180, a pathogen of soybean, and p syringae pv. tomato dc3000, a pathogen of tomato and crucifers. previously, it was shown in vitro that the cma operon involved in cor synthesis in pg4180 is expressed in a temperature-depende ...	2004	15497402
overexpression of nterf5, a new member of the tobacco ethylene response transcription factor family enhances resistance to tobacco mosaic virus.	a new member of the tobacco (nicotiana tabacum) ap2/erf (ethylene response factor) transcription factor family, designated nterf5, has been isolated by yeast one-hybrid screening. in vitro, recombinant nterf5 protein weakly binds gcc box cis-elements, which mediate pathogen-regulated transcription of several pr (pathogenesis related) genes. nterf5 transcription is transiently activated by wounding, by infection with the bacterial pathogen pseudomonas syringae, as well as by inoculation with toba ...	2004	15497409
innate immunity in arabidopsis thaliana: lipopolysaccharides activate nitric oxide synthase (nos) and induce defense genes.	lipopolysaccharides (lps) are cell-surface components of gram-negative bacteria and are microbe-/pathogen-associated molecular patterns in animal pathosystems. as for plants, the molecular mechanisms of signal transduction in response to lps are not known. here, we show that arabidopsis thaliana reacts to lps with a rapid burst of no, a hallmark of innate immunity in animals. fifteen lps preparations (among them burkholderia cepacia, pseudomonas aeruginosa, and erwinia carotovora) as well as lip ...	2004	15498873
the bos loci of arabidopsis are required for resistance to botrytis cinerea infection.	three botrytis-susceptible mutants bos2, bos3, and bos4 which define independent and novel genetic loci required for arabidopsis resistance to botrytis cinerea were isolated. the bos2 mutant is susceptible to b. cinerea but retains wild-type levels of resistance to other pathogens tested, indicative of a defect in a response pathway more specific to b. cinerea. the bos3 and bos4 mutants also show increased susceptibility to alternaria brassicicola, another necrotrophic pathogen, suggesting a bro ...	2004	15500471
unique features revealed by the genome sequence of acinetobacter sp. adp1, a versatile and naturally transformation competent bacterium.	acinetobacter sp. strain adp1 is a nutritionally versatile soil bacterium closely related to representatives of the well-characterized pseudomonas aeruginosa and pseudomonas putida. unlike these bacteria, the acinetobacter adp1 is highly competent for natural transformation which affords extraordinary convenience for genetic manipulation. the circular chromosome of the acinetobacter adp1, presented here, encodes 3325 predicted coding sequences, of which 60% have been classified based on sequence ...	2004	15514110
suppression of pathogen-inducible no synthase (inos) activity in tomato increases susceptibility to pseudomonas syringae.		2004	15516371
downstream divergence of the ethylene signaling pathway for harpin-stimulated arabidopsis growth and insect defense.	ethylene (et) signal transduction may regulate plant growth and defense, depending on which components are recruited into the pathway in response to different stimuli. we report here that the et pathway controls both insect resistance (ir) and plant growth enhancement (pge) in arabidopsis (arabidopsis thaliana) plants responding to harpin, a protein produced by a plant pathogenic bacterium. pge may result from spraying plant tops with harpin or by soaking seeds in harpin solution; the latter esp ...	2004	15516507
analysis of the cytoplasmic domains of salmonella flha and interactions with components of the flagellar export machinery.	most flagellar proteins are exported via a type iii export apparatus which, in part, consists of the membrane proteins flha, flhb, flio, flip, fliq, and flir and is housed within the membrane-supramembrane ring formed by flif subunits. salmonella flha is a 692-residue integral membrane protein with eight predicted transmembrane spans. its function is not understood, but it is necessary for flagellar export. we have created mutants in which potentially important sequences were deleted. flha lacki ...	2004	15516571
long-term effect of mutagenic dna repair on accumulation of mutations in pseudomonas syringae b86-17.	forty replicate lineages of pseudomonas syringae b86-17 cells expressing the rulab mutagenic dna repair (mdr) determinant or the rulb::km mdr-deficient mutant gws242 were passaged through single-cell bottlenecks (60 cycles), with a uv radiation (uvr) exposure given to half of the lineages at the beginning of each cycle. after every 10th bottleneck cycle, single-colony isolates from all 80 lineages were subjected to 39 phenotypic screens, with newly arising mutations detected in 60 and 0% of uvr- ...	2004	15516596
inactivation of an abc transporter gene, mcyh, results in loss of microcystin production in the cyanobacterium microcystis aeruginosa pcc 7806.	the cyanobacterium microcystis aeruginosa is widely known for its production of the potent hepatotoxin microcystin. microcystin is synthesized nonribosomally by the thiotemplate function of a large, modular enzyme complex encoded within the 55-kb microcystin synthetase (mcy) gene cluster. also encoded within the mcy gene cluster is a putative atp binding cassette (abc) transporter, mcyh. this study details the bioinformatic and mutational analyses of mcyh and offers functional predictions for th ...	2004	15528494
survival of shewanella oneidensis mr-1 after uv radiation exposure.	we systematically investigated the physiological response as well as dna damage repair and damage tolerance in shewanella oneidensis mr-1 following uvc, uvb, uva, and solar light exposure. mr-1 showed the highest uvc sensitivity among shewanella strains examined, with d37 and d10 values of 5.6 and 16.5% of escherichia coli k-12 values. stationary cells did not show an increased uva resistance compared to exponential-phase cells; instead, they were more sensitive at high uva dose. uva-irradiated ...	2004	15528503
vpegamma exhibits a caspase-like activity that contributes to defense against pathogens.	caspases are a family of aspartate-specific cysteine proteases that play an essential role in initiating and executing programmed cell death (pcd) in metazoans. caspase-like activities have been shown to be required for the initiation of pcd in plants, but the genes encoding those activities have not been identified. vpegamma, a cysteine protease, is induced during senescence, a form of pcd in plants, and is localized in precursor protease vesicles and vacuoles, compartments associated with pcd ...	2004	15530390
the pyoverdins of pseudomonas syringae and pseudomonas cichorii.	the structure elucidation of the cyclic (lactonic) forms of the pyoverdins with a succinamide side chain originally produced by the closely related species pseudomonas syringae and p. cichorii is reported. mass spectrometry and nuclear magnetic resonance analyses as well as the determination of the configuration of the amino acids after degradation indicate that these two pyoverdins differ only by the replacement of the first in-chain serine by glycine. the pyoverdins of p. syringae and p. cicho ...	2004	15540590
a genetic screen to isolate type iii effectors translocated into pepper cells during xanthomonas infection.	the bacterial pathogen xanthomonas campestris pv. vesicatoria (xcv) uses a type iii secretion system (ttss) to translocate effector proteins into host plant cells. the ttss is required for xcv colonization, yet the identity of many proteins translocated through this apparatus is not known. we used a genetic screen to functionally identify xcv ttss effectors. a transposon 5 (tn5)-based transposon construct including the coding sequence for the xcv avrbs2 effector devoid of its ttss signal was ran ...	2004	15545602
the pseudomonas syringae type iii effector avrrpt2 promotes virulence independently of rin4, a predicted virulence target in arabidopsis thaliana.	avrrpt2, an effector protein from pseudomonas syringae pv. tomato (pst), behaves as an avirulence factor that activates resistance in arabidopsis thaliana lines expressing the resistance gene rps2. avrrpt2 can also enhance pathogen fitness by promoting the ability of the bacteria to grow and to cause disease on susceptible lines of a. thaliana that lack functional rps2. the activation of rps2 is coupled to the avrrpt2-induced disappearance of the a. thaliana rin4 protein. however, the significan ...	2004	15546361
ralstonia solanacearum iron scavenging by the siderophore staphyloferrin b is controlled by phca, the global virulence regulator.	phca is a transcriptional regulator that activates expression of multiple virulence genes in the plant pathogen ralstonia solanacearum. relative to their wild-type parents, phca mutants overproduced iron-scavenging activity detected with chrome azurol s siderophore detection medium. transposon mutagenesis of strain aw1-pc (phca1) generated strain gb6, which was siderophore negative but retained weak iron-scavenging activity. the ssd gene inactivated in gb6 encodes a protein similar to group iv a ...	2004	15547261
bacteriophage and phenotypic variation in pseudomonas aeruginosa biofilm development.	a current question in biofilm research is whether biofilm-specific genetic processes can lead to differentiation in physiology and function among biofilm cells. in pseudomonas aeruginosa, phenotypic variants which exhibit a small-colony phenotype on agar media and a markedly accelerated pattern of biofilm development compared to that of the parental strain are often isolated from biofilms. we grew p. aeruginosa biofilms in glass flow cell reactors and observed that the emergence of small-colony ...	2004	15547279
transferable antibiotic resistance elements in haemophilus influenzae share a common evolutionary origin with a diverse family of syntenic genomic islands.	transferable antibiotic resistance in haemophilus influenzae was first detected in the early 1970s. after this, resistance spread rapidly worldwide and was shown to be transferred by a large 40- to 60-kb conjugative element. bioinformatics analysis of the complete sequence of a typical h. influenzae conjugative resistance element, icehin1056, revealed the shared evolutionary origin of this element. icehin1056 has homology to 20 contiguous sequences in the national center for biotechnology inform ...	2004	15547285
the n terminus of bacterial elongation factor tu elicits innate immunity in arabidopsis plants.	innate immunity is based on the recognition of pathogen-associated molecular patterns (pamps). here, we show that elongation factor tu (ef-tu), the most abundant bacterial protein, acts as a pamp in arabidopsis thaliana and other brassicaceae. ef-tu is highly conserved in all bacteria and is known to be n-acetylated in escherichia coli. arabidopsis plants specifically recognize the n terminus of the protein, and an n-acetylated peptide comprising the first 18 amino acids, termed elf18, is fully ...	2004	15548740
rar1 positively controls steady state levels of barley mla resistance proteins and enables sufficient mla6 accumulation for effective resistance.	the polymorphic barley (hordeum vulgare) mla locus harbors allelic race-specific resistance (r) genes to the powdery mildew fungus blumeria graminis f sp hordei. the highly sequence-related mla proteins contain an n-terminal coiled-coil structure, a central nucleotide binding (nb) site, a leu-rich repeat (lrr) region, and a c-terminal non-lrr region. using transgenic barley lines expressing epitope-tagged mla1 and mla6 derivatives driven by native regulatory sequences, we show a reversible and s ...	2004	15548741
antagonistic interaction between abscisic acid and jasmonate-ethylene signaling pathways modulates defense gene expression and disease resistance in arabidopsis.	the plant hormones abscisic acid (aba), jasmonic acid (ja), and ethylene are involved in diverse plant processes, including the regulation of gene expression during adaptive responses to abiotic and biotic stresses. previously, aba has been implicated in enhancing disease susceptibility in various plant species, but currently very little is known about the molecular mechanisms underlying this phenomenon. in this study, we obtained evidence that a complex interplay between aba and ja-ethylene sig ...	2004	15548743
identification and expression profiling of tomato genes differentially regulated during a resistance response to xanthomonas campestris pv. vesicatoria.	the gram-negative bacterium xanthomonas campestris pv. vesicatoria is the causal agent of spot disease in tomato and pepper. plants of the tomato line hawaii 7981 are resistant to race t3 of x. campestris pv. vesicatoria expressing the type iii effector protein avrxv3 and develop a typical hypersensitive response upon bacterial challenge. a combination of suppression subtractive hybridization and microarray analysis identified a large set of cdnas that are induced or repressed during the resista ...	2004	15553246
transcriptional regulation of components of the type iii secretion system and effectors in pseudomonas syringae pv. phaseolicola.	quantitative real-time polymerase chain reaction was used with specific taqman probes to examine transcription of selected hrp and effector genes in pseudomonas syringae pv. phaseolicola strains 1448a (race 6) and 1449b (race 7). transcripts examined were from genes encoding the regulators hrpr and hrpl, core structural components of the type iii secretion system (ttss) hrcc, hrcj, hrcn, hrcu, and hrpa; the first open-reading frame of each hrp operon, including hrpf, hrpj, hrpp, and hrpy, and al ...	2004	15553250
adaptation of the endogenous salmonella enterica serovar typhi clya-encoded hemolysin for antigen export enhances the immunogenicity of anthrax protective antigen domain 4 expressed by the attenuated live-vector vaccine strain cvd 908-htra.	bacterial live-vector vaccines aim to deliver foreign antigens to the immune system and induce protective immune responses, and surface-expressed or secreted antigens are generally more immunogenic than cytoplasmic constructs. we hypothesize that an optimum expression system will use an endogenous export system to avoid the need for large amounts of heterologous dna encoding additional proteins. here we describe the cryptic chromosomally encoded 34-kda cytolysin a hemolysin of salmonella enteric ...	2004	15557633
regulators encoded in the escherichia coli type iii secretion system 2 gene cluster influence expression of genes within the locus for enterocyte effacement in enterohemorrhagic e. coli o157:h7.	enterohemorrhagic escherichia coli (ehec) o157:h7 subverts host cells through a type iii secretion system encoded by the locus for enterocyte effacement (lee). genome sequencing of this pathotype revealed the existence of a gene cluster encoding components of a second cryptic type iii secretion system, e. coli type iii secretion system 2 (ett2). recently, we showed that the ett2 gene cluster is present in whole or in part in the majority of e. coli strains but is unable to encode a functional se ...	2004	15557654
pnuc and the utilization of the nicotinamide riboside analog 3-aminopyridine in haemophilus influenzae.	the utilization pathway for the uptake of nad and nicotinamide riboside was previously characterized for haemophilus influenzae. we now report on the cellular location, topology, and substrate specificity of pnuc. pnuc of h. influenzae is only distantly related to pnuc of escherichia coli and salmonella enterica serovar typhimurium. when e. coli pnuc was expressed in an h. influenzae pnuc mutant, it was able to take up only nicotinamide riboside and not nicotinamide mononucleotide. therefore, we ...	2004	15561822
inhibition of phosphoinositide-specific phospholipase c results in the induction of pathogenesis-related genes in soybean.	the inositol 1,4,5-trisphosphate (ip3) content is decreased in soybean cells following infection with pseudomonas syringae pv. glycinea (psg). in this investigation, a differential display approach was applied to isolate soybean genes that are transcriptionally up-regulated by the inhibition of phosphoinositide-specific phospholipase c (pi-plc) activity and to study if the transcription of those genes is altered following psg infection. four genes, transcriptionally activated following treatment ...	2004	15570470
use of pseudomonas putida esta as an anchoring motif for display of a periplasmic enzyme on the surface of escherichia coli.	the functional expression of proteins on the surface of bacteria has proven important for numerous biotechnological applications. in this report, we investigated the n-terminal fusion display of the periplasmic enzyme beta-lactamase (bla) on the surface of escherichia coli by using the translocator domain of the pseudomonas putida outer membrane esterase (esta), which is a member of the lipolytic autotransporter enzymes. to find out the transport function of a c-terminal domain of esta, we gener ...	2004	15574889
complete nucleotide sequence of the conjugative tetracycline resistance plasmid pfbaot6, a member of a group of incu plasmids with global ubiquity.	this study presents the first complete sequence of an incu plasmid, pfbaot6. this plasmid was originally isolated from a strain of aeromonas caviae from hospital effluent (westmorland general hospital, kendal, united kingdom) in september 1997 (g. rhodes, g. huys, j. swings, p. mcgann, m. hiney, p. smith, and r. w. pickup, appl. environ. microbiol. 66:3883-3890, 2000) and belongs to a group of related plasmids with global ubiquity. pfbaot6 is 84,748 bp long and has 94 predicted coding sequences, ...	2004	15574953
nucleotide sequences, genetic organization, and distribution of peu30 and pel60 from erwinia amylovora.	the nucleotide sequences, genetic organization, and distribution of plasmids peu30 (30,314 bp) and pel60 (60,145 bp) from the plant pathogen erwinia amylovora are described. the newly characterized peu30 and pel60 plasmids inhabited strains isolated in the western united states and lebanon, respectively. the gene content of peu30 resembled plasmids found in plant-associated bacteria, while that of pel60 was most similar to incl/m plasmids inhabiting enteric bacteria.	2004	15574957
role of chloroplast trienoic fatty acids in plant disease defense responses.	trienoic fatty acids (tas) are the major polyunsaturated fatty acid species in the membrane lipids in plant cells. tas are crucial for the adaptation to abiotic stresses, especially low- or high-temperature stress. we show that tas in chloroplast membrane lipids are involved in defense responses against avirulent bacterial pathogens. avirulent pathogen invasion of plants induces a transient production of reactive oxygen intermediates (roi), programmed cell death and subsequent disease resistance ...	2004	15584958
mutations in pmr5 result in powdery mildew resistance and altered cell wall composition.	powdery mildews and other obligate biotrophic pathogens are highly adapted to their hosts and often show limited host ranges. one facet of such host specialization is likely to be penetration of the host cell wall, a major barrier to infection. a mutation in the pmr5 gene rendered arabidopsis resistant to the powdery mildew species erysiphe cichoracearum and erysiphe orontii, but not to the unrelated pathogens pseudomonas syringae or peronospora parasitica. pmr5 belongs to a large family of plan ...	2004	15584961
pseudomonas type iii effector avrpto suppresses the programmed cell death induced by two nonhost pathogens in nicotiana benthamiana and tomato.	many gram-negative bacterial pathogens rely on a type iii secretion system to deliver a number of effector proteins into the host cell. though a number of these effectors have been shown to contribute to bacterial pathogenicity, their functions remain elusive. here we report that avrpto, an effector known for its ability to interact with pto and induce pto-mediated disease resistance, inhibited the hypersensitive response (hr) induced by nonhost pathogen interactions. pseudomonas syringae pv. to ...	2004	15597738
functional analysis of avr9/cf-9 rapidly elicited genes identifies a protein kinase, acik1, that is essential for full cf-9-dependent disease resistance in tomato.	tomato (lycopersicon esculentum) cf genes confer resistance to the fungal pathogen cladosporium fulvum through recognition of secreted avirulence (avr) peptides. plant defense responses, including rapid alterations in gene expression, are immediately activated upon perception of the pathogen. previously, we identified a collection of avr9/cf-9 rapidly (15 to 30 min) elicited (acre) genes from tobacco (nicotiana tabacum). many of the acre genes encode putative signaling components and thus may pl ...	2004	15598806
the abi2-dependent abscisic acid signalling controls hrpn-induced drought tolerance in arabidopsis.	hrpn, a protein produced by the plant pathogenic bacterium erwinia amylovora, has been shown to stimulate plant growth and resistance to pathogens and insects. here we report that hrpn activates abscisic acid (aba) signalling to induce drought tolerance (dt) in arabidopsis thaliana l. plants grown with water stress. spraying wild-type plants with hrpn-promoted stomatal closure decreased leaf transpiration rate, increased moisture and proline levels in leaves, and alleviated extents of damage to ...	2004	15599761
the pcr amplification and characterization of entire pseudomonas syringae hrp/hrc clusters.	summary we describe the use of degenerate primers to amplify the core hrp/hrc region of p. syringae pv. phaseolicola nps3121. 18 826 bp were amplified using long-range pcr, digested and shotgun sequenced. sequence analysis finds a hypervariable region between the hrpu and hrpc operons, and indications of positive selection on the hrpe locus. the primers were also shown to work on four other, widely divergent p. syringae strains. these primers should be of great utility for the characterization o ...	2004	20565590
the jasmonate-insensitive mutant jin1 shows increased resistance to biotrophic as well as necrotrophic pathogens.	summary jasmonic acid and related oxylipin compounds are plant signalling molecules that are involved in the response to pathogens, insects, wounding and ozone. to explore further the role of jasmonates in stress signal transduction, the response of two jasmonate-signalling mutants, jin1 and jin4, to pathogens and ozone was analysed in this study. upon treatment with the biotrophic bacterial pathogen pseudomonas syringae, endogenous jasmonate levels increased in jin1 and jin4 similar to wild-typ ...	2004	20565618
an arabidopsis mutant with altered hypersensitive response to xanthomonas campestris pv. campestris, hxc1, displays a complex pathophenotype.	summary the hxc1 mutant was identified by screening an ems (ethylmethane sulphonate) mutagenized population of arabidopsis col-0 plants for an altered hypersensitive response (hr), after spray inoculation with an hr-inducing isolate of xanthomonas campestris pv. campestris (xcc) (strain 147). the hxc1 mutant shows a susceptible phenotype several days after initiation of the interaction with the avirulent strain. this macroscopically observed phenotype was confirmed by measurement of in planta ba ...	2004	20565620
knot formation caused by pseudomonas syringae subsp. savastanoi on olive plants is hrp-dependent.	abstract the virulence of pseudomonas syringae subsp. savastanoi, which causes hyperplastic symptoms (knots) on olive plants, is associated with secreted phytohormones. we identified a tn5-induced mutant of p. syringae subsp. savastanoi that did not cause disease symptoms on olive plants although it was still able to produce phytohormones. in addition, the mutant failed to elicit a hypersensitive response in a nonhost plant. molecular characterization of the mutant revealed that a single tn5 ins ...	2004	18943767
a promoter from pea gene drr206 is suitable to regulate an elicitor-coding gene and develop disease resistance.	abstract plant nonhost disease resistance is characterized by the induction of multiple defense genes. the pea drr206 gene is induced following inoculation with pathogens and treatment with abiotic agents, and moderately induced by wounding. a deletion series of drr206 promoter segments was fused with the beta-glucuronidase (gus) reporter gene and transiently transferred to tobacco, potato, and pea. gus activity revealed that two upstream regions of the drr206 promoter were particularly importan ...	2004	18943490
nontoxigenic strains of pseudomonas syringae pv. phaseolicola are a main cause of halo blight of beans in spain and escape current detection methods.	abstract from a collection of 152 pseudomonads isolated from diseased beans in spain, 138 (91%) of the strains were identified as pseudomonas syringae pv. phaseolicola and the rest as p. syringae pv. syringae. the p. syringae pv. phaseolicola strains produced typical water-soaked lesions on bean pods, although 95 of them did not produce phaseolotoxin in vitro. ninety-four of these isolates did not produce the expected 0.5-kb product after polymerase chain reaction (pcr) amplification using prime ...	2003	18943619
pseudomonas syringae responds to the environment on leaves by cell size reduction.	abstract the length and volume of cells of the plant-pathogenic bacterium pseudomonas syringae strain b728a were measured in vitro and with time after inoculation on bean leaf surfaces to assess both the effect of nutrient availability on the cell size of p. syringae and, by inference, the variability in nutrient availability in the leaf surface habitat. cells of p. syringae harboring a green fluorescent protein marker gene were visualized by epifluorescence microscopy after recovery from leaves ...	2003	18944318
factors that affect spread of pseudomonas syringae in the phyllosphere.	abstract successful spread of an organism to a new habitat requires both immigration to and growth on that habitat. field experiments were conducted to determine the relative roles of dispersal (i.e., immigration) and bacterial multiplication in spread of pseudomonas syringae pv. syringae in the phyllosphere. to study spread, individual plots consisted of three nested concentric squares with the inner 6 m(2) planted to snap beans serving as the sink. each sink, in turn, was surrounded by a barri ...	2003	18944091
deciphering host resistance and pathogen virulence: the arabidopsis/pseudomonas interaction as a model.	summary the last decade has witnessed steady progress in deciphering the molecular basis of plant disease resistance and pathogen virulence. although contributions have been made using many different plant and pathogen species, studies of the interactions between arabidopsis thaliana and pseudomonas syringae have yielded a particularly significant body of information. the present review focuses on recent findings regarding r gene products and the guard hypothesis, rar1/sgt1 and other examples wh ...	2003	20569411
biohazards and ecotoxicological considerations of landspreading of spent compost wastes.	spent mushroom compost (smc) is a major waste of the mushroom industry with low economic value. smc arises after mushroom production in phase ii compost (piic), predominantly comprising straw and chicken litter as principal raw ingredients. the majority of smc waste is disposed off by application to agricultural land. it is an attractive proposition for utilising smc as soil inorganic fertiliser supplementation. however, there is limited data available as to the consequences of this method of di ...	2003	15151327
[serological heterogeneity of pseudomonas syringae pv. atrofaciens strains and their ecological niches].	the paper deals with a comparative analysis of the serological and ecological properties of pseudomonas syringae pv. atrofaciens strains from the collections of microbial cultures at the malkov institute for plant genetic resources and zabolotny institute of microbiology and virology. all of the strains from the bulgarian collection, except for one, fall into five serogroups (ii through vi) of the classification system of pastushenko and simonovich. the p. syringae pv. atrofaciens strains isolat ...	2003	14768551
the insecticidal toxin makes caterpillars floppy 2 (mcf2) shows similarity to hrma, an avirulence protein from a plant pathogen.	the photorhabdus luminescens w14 toxin encoding gene makes caterpillars floppy (mcf) was discovered due to its ability to kill caterpillars when expressed in escherichia coli. here we describe a homologue of mcf (renamed as mcf1), termed mcf2, discovered in the same genome. the mcf2 gene predicts another large toxin whose central domain, like mcf1, also shows limited homology to clostridium cytotoxin b. however, the n-terminus of mcf2 shows significant similarity to the type-iii secreted effecto ...	2003	14680709
photosynthetic acclimation is reflected in specific patterns of gene expression in drought-stressed loblolly pine.	because the product of a single gene can influence many aspects of plant growth and development, it is necessary to understand how gene products act in concert and upon each other to effect adaptive changes to stressful conditions. we conducted experiments to improve our understanding of the responses of loblolly pine (pinus taeda) to drought stress. water was withheld from rooted plantlets of to a measured water potential of -1 mpa for mild stress and -1.5 mpa for severe stress. net photosynthe ...	2003	14681533
sensitization of defense responses and activation of programmed cell death by a pathogen-induced receptor-like protein kinase in arabidopsis.	during the search for potential target genes of wrky dna-binding transcription factors, we have previously identified four pathogen-induced arabidopsis genes (crk5, crk6, crk10 and crk11) encoding receptor-like protein kinases (rlks) containing novel cysteine-rich repeats in their extracellular domains. in the present study, we transformed arabidopsis plants with the rlk genes under control of the constitutive camv 35s promoter or a steroid-inducible ga14 promoter. expression of crk5, but not th ...	2003	14756307
efficiency of procedures for induction and cultivation of pseudomonas syringae pv. pisi l-form.	the l-form of pseudomonas syringae pv. phaseolicola has been proved to induce resistance to bean halo blight. various procedures were tested to induce the l-form of pseudomonas syringae pv. pisi for its potential use as biocontrol agent of pea bacterial blight. cell-wall deficient cells were induced in a liquid medium with penicillin following a protocol described for p. s. pv. phaseolicola. cell growth on solid induction medium developed as typical granular and vacuolated structures, and charac ...	2003	14717447
a dna element recognised by the molybdenum-responsive transcription factor mode is conserved in proteobacteria, green sulphur bacteria and archaea.	the transition metal molybdenum is essential for life. escherichia coli imports this metal into the cell in the form of molybdate ions, which are taken up via an abc transport system. in e. coli and other proteobacteria molybdenum metabolism and homeostasis are regulated by the molybdate-responsive transcription factor mode.	2003	14641908
xopc and xopj, two novel type iii effector proteins from xanthomonas campestris pv. vesicatoria.	pathogenicity of the gram-negative plant pathogen xanthomonas campestris pv. vesicatoria depends on a type iii secretion (tts) system which translocates bacterial effector proteins into the plant cell. previous transcriptome analysis identified a genome-wide regulon of putative virulence genes that are coexpressed with the tts system. in this study, we characterized two of these genes, xopc and xopj. both genes encode xanthomonas outer proteins (xops) that were shown to be secreted by the tts sy ...	2003	14645268
pathways leading from bara/sira to motility and virulence gene expression in salmonella.	the bara and sira genes of salmonella enterica serovar typhimurium encode a two-component sensor kinase and a response regulator, respectively. this system increases the expression of virulence genes and decreases the expression of motility genes. in this study, we examined the pathways by which sira affects these genes. we found that the master regulator of flagellar genes, flhdc, had a positive regulatory effect on the primary regulator of intestinal virulence determinants, hila, but that hila ...	2003	14645287
gaca, the response regulator of a two-component system, acts as a master regulator in pseudomonas syringae pv. tomato dc3000 by controlling regulatory rna, transcriptional activators, and alternate sigma factors.	concerted investigations of factors affecting host-pathogen interactions are now possible with the model plant arabidopsis thaliana and its model pathogen pseudomonas syringae pv. tomato dc3000, as their whole genome sequences have become available. as a prelude to analysis of the regulatory genes and their targets, we have focused on gaca, the response regulator of a two-component system. the dc3000 gene was cloned by testing for the reversal of phenotypes of an erwinia gaca- mutant. a gaca- mu ...	2003	14651344
new connections in the prokaryotic toxin-antitoxin network: relationship with the eukaryotic nonsense-mediated rna decay system.	several prokaryotic plasmids maintain themselves in their hosts by means of diverse post-segregational cell killing systems. recent findings suggest that chromosomally encoded copies of toxins and antitoxins of post-segregational cell killing systems - such as the rele system - might function as regulatory switches under stress conditions. the rele toxin cleaves ribosome-associated transcripts, whereas another post-segregational cell killing toxin, pare, functions as a gyrase inhibitor.	2003	14659018
efficient degradation of 2,4,6-trichlorophenol requires a set of catabolic genes related to tcp genes from ralstonia eutropha jmp134(pjp4).	2,4,6-trichlorophenol (2,4,6-tcp) is a hazardous pollutant. several aerobic bacteria are known to degrade this compound. one of these, ralstonia eutropha jmp134(pjp4), a well-known, versatile chloroaromatic compound degrader, is able to grow in 2,4,6-tcp by converting it to 2,6-dichlorohydroquinone, 6-chlorohydroxyquinol, 2-chloromaleylacetate, maleylacetate, and beta-ketoadipate. three enzyme activities encoded by tcp genes, 2,4,6-tcp monooxygenase (tcpa), 6-chlorohydroxyquinol 1,2-dioxygenase ...	2003	14660355
biochemical, genetic, and zoosporicidal properties of cyclic lipopeptide surfactants produced by pseudomonas fluorescens.	zoospores play an important role in the infection of plant and animal hosts by oomycetes and other zoosporic fungi. in this study, six fluorescent pseudomonas isolates with zoosporicidal activities were obtained from the wheat rhizosphere. zoospores of multiple oomycetes, including pythium species, albugo candida, and phytophthora infestans, were rendered immotile within 30 s of exposure to cell suspensions or cell culture supernatants of the six isolates, and subsequent lysis occurred within 60 ...	2003	14660362
characterization of the arga gene required for arginine biosynthesis and syringomycin production by pseudomonas syringae pv. syringae.	two types of necrosis-inducing lipodepsipeptide toxins, called syringomycin and syringopeptin, are major virulence factors of pseudomonas syringae pv. syringae strain b301d. a previous study showed that a locus, called syra, was required for both syringomycin production and plant pathogenicity, and the syra locus was speculated to encode a regulator of toxin production. in this study, sequence analysis of the 8-kb genomic dna fragment that complements the syra phenotype revealed high conservatio ...	2003	14660376
metagenome survey of biofilms in drinking-water networks.	most naturally occurring biofilms contain a vast majority of microorganisms which have not yet been cultured, and therefore we have little information on the genetic information content of these communities. therefore, we initiated work to characterize the complex metagenome of model drinking water biofilms grown on rubber-coated valves by employing three different strategies. first, a sequence analysis of 650 16s rrna clones indicated a high diversity within the biofilm communities, with the ma ...	2003	14660379
concomitant induction of systemic resistance to pseudomonas syringae pv. lachrymans in cucumber by trichoderma asperellum (t-203) and accumulation of phytoalexins.	most studies on the reduction of disease incidence in soil treated with trichoderma asperellum have focused on microbial interactions rather than on plant responses. this study presents conclusive evidence for the induction of a systemic response against angular leaf spot of cucumber (pseudomonas syringae pv. lachrymans) following application of t. asperellum to the root system. to ascertain that t. asperellum was the only microorganism present in the root milieu, plants were grown in an aseptic ...	2003	14660384
differential survival of solitary and aggregated bacterial cells promotes aggregate formation on leaf surfaces.	the survival of individual pseudomonas syringae cells was determined on bean leaf surfaces maintained under humid conditions or periodically exposed to desiccation stress. cells of p. syringae strain b728a harboring a gfp marker gene were visualized by epifluorescence microscopy, either directly in situ or after recovery from leaves, and dead cells were identified as those that were stained with propidium iodide in such populations. under moist, conducive conditions on plants, the proportion of ...	2003	14665692
virulence systems of pseudomonas syringae pv. tomato promote bacterial speck disease in tomato by targeting the jasmonate signaling pathway.	pseudomonas syringae pv. tomato strain dc3000 (pst dc3000) causes bacterial speck disease on tomato. the pathogenicity of pst dc3000 depends on both the type iii secretion system that delivers virulence effector proteins into host cells and the phytotoxin coronatine (cor), which is thought to mimic the action of the plant hormone jasmonic acid (ja). we found that a ja-insensitive mutant (jai1) of tomato was unresponsive to cor and highly resistant to pst dc3000, whereas host genotypes that are d ...	2003	14617079
genetic evidence that expression of nahg modifies defence pathways independent of salicylic acid biosynthesis in the arabidopsis-pseudomonas syringae pv. tomato interaction.	the salicylic acid (sa)-induction deficient (sid) mutants of arabidopsis, eds5 and sid2 accumulate normal amounts of camalexin after inoculation with pseudomonas syringae pv. tomato (pst), while transgenic nahg plants expressing an sa hydroxylase that degrades sa have reduced levels of camalexin and exhibit a higher susceptibility to different pathogens compared to the sid mutants. sid2 encodes an isochorismate synthase necessary for the synthesis of sa. nahg was shown to act epistatically to th ...	2003	14617091
translocated intimin receptor and its chaperone interact with atpase of the type iii secretion apparatus of enteropathogenic escherichia coli.	few interactions have been reported between effectors and components of the type iii secretion apparatus, although many interactions have been demonstrated between type iii effectors and their cognate chaperones. it is thought that chaperones may play a role in directing effectors to the type iii secretion apparatus. the atpase flii in the flagellar assembly apparatus plays a pivotal role in interacting with other components of the apparatus and with substrates of the flagellar system. we perfor ...	2003	14617638
purification and characterization of a phytase from pseudomonas syringae mok1.	a phytase (ec 3.1.3.8) from pseudomonas syringae mok1 was purified to apparent homogeneity in two steps employing cation and an anion exchange chromatography. the molecular weight of the purified enzyme was estimated to be 45 kda by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. the optimal activity occurred at ph 5.5 and 40 degrees c. the michaelis constant (km) and maximum reaction rate (vmax) for sodium phytate were 0.38 mm and 769 u/mg of protein, respectively. the enzym ...	2003	14629009
structure and expression of phosphoenolpyruvate carboxylase kinase genes in solanaceae. a novel gene exhibits alternative splicing.	phosphorylation of phosphoenolpyruvate carboxylase (pepc; ec 4.1.1.31) plays an important role in the control of central metabolism in higher plants. two ppck (pepc kinase) genes have been identified in tomato (lycopersicon esculentum cv alicante), hereafter termed leppck1 and leppck2. the function of the gene products has been confirmed by transcription of full-length cdnas, translation, and in vitro assay of kinase activity. previously studied ppck genes contain a single intron. leppck2 also c ...	2003	14630963
the tomato transcription factor pti4 regulates defense-related gene expression via gcc box and non-gcc box cis elements.	the tomato transcription factor pti4, an ethylene-responsive factor (erf), interacts physically with the disease resistance protein pto and binds the gcc box cis element that is present in the promoters of many pathogenesis-related (pr) genes. we reported previously that arabidopsis plants expressing pti4 constitutively express several gcc box-containing pr genes and show reduced disease symptoms compared with wild-type plants after inoculation with pseudomonas syringae pv tomato or erysiphe oro ...	2003	14630974
cytosolic hsp90 associates with and modulates the arabidopsis rpm1 disease resistance protein.	the arabidopsis protein rpm1 activates disease resistance in response to pseudomonas syringae proteins targeted to the inside of the host cell via the bacterial type iii delivery system. we demonstrate that specific mutations in the atp-binding domain of a single arabidopsis cytosolic hsp90 isoform compromise rpm1 function. these mutations do not affect the function of related disease resistance proteins. rpm1 associates with hsp90 in plant cells. the arabidopsis proteins rar1 and sgt1 are requi ...	2003	14592967