Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| 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 |
| pathogenicity islands in bacterial pathogenesis. | in this review, we focus on a group of mobile genetic elements designated pathogenicity islands (pai). these elements play a pivotal role in the virulence of bacterial pathogens of humans and are also essential for virulence in pathogens of animals and plants. characteristic molecular features of pai of important human pathogens and their role in pathogenesis are described. the availability of a large number of genome sequences of pathogenic bacteria and their benign relatives currently offers a ... | 2004 | 14726454 |
| the nifl-nifa system: a multidomain transcriptional regulatory complex that integrates environmental signals. | 2004 | 14729684 | |
| direct glutaminyl-trna biosynthesis and indirect asparaginyl-trna biosynthesis in pseudomonas aeruginosa pao1. | the genomic sequence of pseudomonas aeruginosa pao1 was searched for the presence of open reading frames (orfs) encoding enzymes potentially involved in the formation of gln-trna and of asn-trna. we found orfs similar to known glutamyl-trna synthetases (glurs), glutaminyl-trna synthetases (glnrs), aspartyl-trna synthetases (asprs), and trimeric trna-dependent amidotransferases (adt) but none similar to known asparaginyl-trna synthetases (asnrs). the absence of asnrs was confirmed by biochemical ... | 2004 | 14729703 |
| the arabidopsis thaliana dihydroxyacetone phosphate reductase gene suppresssor of fatty acid desaturase deficiency1 is required for glycerolipid metabolism and for the activation of systemic acquired resistance. | systemic acquired resistance (sar) is a broad-spectrum resistance mechanism in plants that is activated in naive organs after exposure of another organ to a necrotizing pathogen. the organs manifesting sar exhibit an increase in levels of salicylic acid (sa) and expression of the pathogenesis-related1 (pr1) gene. sa signaling is required for the manifestation of sar. we demonstrate here that the arabidopsis thaliana suppressor of fatty acid desaturase deficiency1 (sfd1) mutation compromises the ... | 2004 | 14729910 |
| divergent roles in arabidopsis thaliana development and defense of two homologous genes, aberrant growth and death2 and agd2-like defense response protein1, encoding novel aminotransferases. | the disease-resistant arabidopsis thaliana aberrant growth and death2 (agd2-1) mutant has elevated levels of the defense signal salicylic acid (sa), altered leaf morphology, and mild dwarfism. agd2 and its close homolog ald1 (for agd2-like defense response protein1) encode aminotransferases that act on an overlapping set of amino acids in vitro. however, kinetic parameters indicate that agd2 and ald1 may drive the aminotransferase reaction in opposite directions. ald1-deficient mutants have the ... | 2004 | 14729919 |
| characterization and functional identification of a novel plant 4,5-extradiol dioxygenase involved in betalain pigment biosynthesis in portulaca grandiflora. | betalains are pigments that replace anthocyanins in the majority of families of the plant order caryophyllales. betalamic acid is the common chromophore of betalains. the key enzyme of the betalain biosynthetic pathway is an extradiol dioxygenase that opens the cyclic ring of dihydroxy-phenylalanine (dopa) between carbons 4 and 5, thus producing an unstable seco-dopa that rearranges nonenzymatically to betalamic acid. a gene for a 4,5-dopa-dioxygenase has already been isolated from the fungus am ... | 2004 | 14730069 |
| lempk3 is a mitogen-activated protein kinase with dual specificity induced during tomato defense and wounding responses. | mitogen-activated protein (map) kinase cascades are readily activated during the response of plants to avirulent pathogens or to pathogen-derived elicitors. here we show that the tomato map kinase lempk3 is specifically induced at the mrna level during elicitation of the hypersensitive response in resistant plants infected by avirulent strains of the phytopathogenic bacteria xanthomonas campestris pv. vesicatoria and pseudomonas syringae pv. tomato, as well as upon treatment with the fungal elic ... | 2004 | 14742423 |
| molecular characterization of a glucose-inhibited division gene, gida, that regulates cytotoxic enterotoxin of aeromonas hydrophila. | by using a mini-transposon, we obtained two mutated strains of a diarrheal isolate, ssu, of aeromonas hydrophila that exhibited a 50 to 53% reduction in the hemolytic activity and 83 to 87% less cytotoxic activity associated with the cytotoxic enterotoxin (act). act is a potent virulence factor of a. hydrophila and has been shown to contribute significantly to the development of both diarrhea and septicemia in animal models. subsequent cloning and dna sequence analysis revealed that transposon i ... | 2004 | 14742556 |
| identification of five outer membrane-associated proteins among cross-protective factor proteins of pasteurella multocida. | fowl cholera is caused by pasteurella multocida serovars a:1, a:3, and a:4. the 39-kda cross-protective factor protein and four other membrane proteins of the membrane proteome of p. multocida were identified. we determined that the 39-kda cross-protective protein was pasteurella lipoprotein b, or plpb. | 2004 | 14742575 |
| convergent evolution of disease resistance gene specificity in two flowering plant families. | plant disease resistance (r) genes that mediate recognition of the same pathogen determinant sometimes can be found in distantly related plant families. this observation implies that some r gene alleles may have been conserved throughout the diversification of land plants. to address this question, we have compared r genes from glycine max (soybean), rpg1-b, and arabidopsis thaliana, rpm1, that mediate recognition of the same type iii effector protein from pseudomonas syringae, avrb. rpm1 has be ... | 2004 | 14742871 |
| the wrky70 transcription factor: a node of convergence for jasmonate-mediated and salicylate-mediated signals in plant defense. | cross talk between salicylic acid (sa)- and jasmonic acid (ja)-dependent defense signaling has been well documented in plants, but how this cross talk is executed and the components involved remain to be elucidated. we demonstrate that the plant-specific transcription factor wrky70 is a common component in sa- and ja-mediated signal pathways. expression of wrky70 is activated by sa and repressed by ja. the early induction of wrky70 by sa is npr1-independent, but functional npr1 is required for f ... | 2004 | 14742872 |
| cassette-like variation of restriction enzyme genes in escherichia coli c and relatives. | a surprising result of comparative bacterial genomics has been the large amount of dna found to be present in one strain but not in another of the same species. we examine in detail one location where gene content varies extensively, the restriction cluster in escherichia coli. this region is designated the immigration control region (icr) for the density and variability of restriction functions found there. to better define the boundaries of this variable locus, we determined the sequence of th ... | 2004 | 14744977 |
| automated correction of genome sequence errors. | by using information from an assembly of a genome, a new program called autoeditor significantly improves base calling accuracy over that achieved by previous algorithms. this in turn improves the overall accuracy of genome sequences and facilitates the use of these sequences for polymorphism discovery. we describe the algorithm and its application in a large set of recent genome sequencing projects. the number of erroneous base calls in these projects was reduced by 80%. in an analysis of over ... | 2004 | 14744981 |
| functional reclassification of the putative cinnamyl alcohol dehydrogenase multigene family in arabidopsis. | of 17 genes annotated in the arabidopsis genome database as cinnamyl alcohol dehydrogenase (cad) homologues, an in silico analysis revealed that 8 genes were misannotated. of the remaining nine, six were catalytically competent for nadph-dependent reduction of p-coumaryl, caffeyl, coniferyl, 5-hydroxyconiferyl, and sinapyl aldehydes, whereas three displayed very low activity and only at very high substrate concentrations. of the nine putative cads, two (atcad5 and atcad4) had the highest activit ... | 2004 | 14745009 |
| evolutionary potential of an rna virus. | rna viruses are remarkably adaptable to changing environments. this is medically important because it enables pathogenic viruses to escape the immune response and chemotherapy and is of considerable theoretical interest since it allows the investigation of evolutionary processes within convenient time scales. a number of earlier studies have addressed the dynamics of adapting rna virus populations. however, it has been difficult to monitor the trajectory of molecular changes in rna genomes in re ... | 2004 | 14747576 |
| 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 |
| the pseudomonas syringae type iii effector avrrpt2 functions downstream or independently of sa to promote virulence on arabidopsis thaliana. | avrrpt2, a pseudomonas syringae type iii effector protein, functions from inside plant cells to promote the virulence of p. syringae pv. tomato strain dc3000 (pstdc3000) on arabidopsis thaliana plants lacking a functional copy of the corresponding rps2 resistance gene. in this study, we extended our understanding of avrrpt2 virulence activity by exploring the hypothesis that avrrpt2 promotes pstdc3000 virulence by suppressing plant defenses. when delivered by pstdc3000, avrrpt2 suppresses pathog ... | 2004 | 14756766 |
| identification of pseudomonas syringae type iii effectors that can suppress programmed cell death in plants and yeast. | the pseudomonas syringae pv. tomato dc3000 type iii secretion system (ttss) is required for bacterial pathogenicity on plants and elicitation of the hypersensitive response (hr), a programmed cell death (pcd) that occurs on resistant plants. cosmid phir11 enables non-pathogens to elicit an hr dependent upon the ttss and the effector hoppsya. we used phir11 to determine that effectors hopptoe, avirulence avrpphepto, avrppib1pto, avrptob, and hopptof could suppress a hoppsya-dependent hr on tobacc ... | 2004 | 14756767 |
| activation of a coi1-dependent pathway in arabidopsis by pseudomonas syringae type iii effectors and coronatine. | gram-negative bacteria use a variety of virulence factors including phytotoxins, exopolysaccharides, effectors secreted by the type iii secretion system, and cell-wall-degrading enzymes to promote parasitism in plants. however, little is known about how these virulence factors alter plant cellular responses to promote disease. in this study, we show that virulent pseudomonas syringae strains activate the transcription of an arabidopsis ethylene response factor (erf) gene, rap2.6, in a coronatine ... | 2004 | 14756769 |
| constitutive and inducible trypsin proteinase inhibitor production incurs large fitness costs in nicotiana attenuata. | plant trypsin proteinase inhibitors (tpis) are potent herbivore- and jasmonate (ja)-induced defenses, but support for the commonly invoked explanation for their inducible expression, namely their associated fitness costs, has been elusive. to determine whether the expression of tpis incurs fitness costs, we expressed 175 bp of the seven-domain pi from nicotiana attenuata in an antisense orientation in a tpi-producing genotype (wt) of n. attenuata to reduce tpi expression. moreover, we expressed ... | 2004 | 14757829 |
| coordinated regulation of genes for secretion in tobacco at late developmental stages: association with resistance against oomycetes. | besides the systemic acquired resistance (sar) induced in response to microbial stimulation, host plants may also acquire resistance to pathogens in response to endogenous stimuli associated with their own development. in tobacco (nicotiana tabacum), the vegetative-to-flowering transition comes along with a susceptibility-to-resistance transition to the causal agent of black shank disease, the oomycete phytophthora parasitica. this resistance affects infection effectiveness and hyphal expansion ... | 2004 | 14764907 |
| an extracellular aspartic protease functions in arabidopsis disease resistance signaling. | we have used activation tagging with t-dna carrying cauliflower mosaic virus 35s enhancers to investigate the complex signaling networks underlying disease resistance in arabidopsis. from a screen of approximately 5000 lines, we identified constitutive disease resistance (cdr1) encoding an apoplastic aspartic protease, the overexpression of which causes dwarfing and resistance to virulent pseudomonas syringae. these phenotypes reflect salicylic-acid-dependent activation of micro-oxidative bursts ... | 2004 | 14765119 |
| pseudomonas syringae pv. phaseolicola can be separated into two genetic lineages distinguished by the possession of the phaseolotoxin biosynthetic cluster. | the bean (phaseolus spp.) plant pathogen pseudomonas syringae pv. phaseolicola is characterized by the ability to produce phaseolotoxin (tox(+)). we recently reported that the majority of the spanish p. syringae pv. phaseolicola population is unable to synthesize this toxin (tox(-)). these tox(-) isolates appear to lack the entire dna region for the biosynthesis of phaseolotoxin (argk-tox gene cluster), as shown by pcr amplification and dna hybridization using dna sequences specific for separate ... | 2004 | 14766926 |
| [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 |
| harpin inactivates mitochondria in arabidopsis suspension cells. | harpin is a well-known proteinaceous bacterial elicitor that can induce an oxidative burst and programmed cell death in various host plants. given the demonstrated roles of mitochondria in animal apoptosis, we investigated the effect of harpin from pseudomonas syringae on mitochondrial functions in arabidopsis suspension cells in detail. fluorescence microscopy in conjunction with double-staining for reactive oxygen species (ros) and mitochondria suggested co-localization of mitochondria and ros ... | 2004 | 14964527 |
| importance of opghxcv of xanthomonas campestris pv. vesicatoria in host-parasite interactions. | tn5 insertion mutants of xanthomonas campestris pv. vesicatoria were inoculated into tomato and screened for reduced virulence. one mutant exhibited reduced aggressiveness and attenuated growth in planta. southern blot analyses indicated that the mutant carried a single tn5 insertion not associated with previously cloned pathogenicity-related genes of x. campestris pv. vesicatoria. the wild-type phenotype of this mutant was restored by one recombinant plasmid (popg361) selected from a genomic li ... | 2004 | 14964529 |
| identification and characterization of a well-defined series of coronatine biosynthetic mutants of pseudomonas syringae pv. tomato dc3000. | to identify pseudomonas syringae pv. tomato genes involved in pathogenesis, we carried out a screen for tn5 mutants of p. syringae pv. tomato dc3000 with reduced virulence on arabidopsis thaliana. several mutants defining both known and novel virulence loci were identified. six mutants contained insertions in biosynthetic genes for the phytotoxin coronatine (cor). the p. syringae pv. tomato dc3000 cor genes are chromosomally encoded and are arranged in two separate clusters, which encode enzymes ... | 2004 | 14964530 |
| nopl, an effector protein of rhizobium sp. ngr234, thwarts activation of plant defense reactions. | bacterial effector proteins delivered into eukaryotic cells via bacterial type iii secretion systems are important virulence factors in plant-pathogen interactions. type iii secretion systems have been found in rhizobium species that form symbiotic, nitrogen-fixing associations with legumes. one such bacterium, rhizobium sp. ngr234, secretes a number of type iii effectors, including nodulation outer protein l (nopl, formerly y4xl). here, we show that expression of nopl in tobacco (nicotiana taba ... | 2004 | 14966249 |
| genomic and genetic analysis of bordetella bacteriophages encoding reverse transcriptase-mediated tropism-switching cassettes. | liu et al. recently described a group of related temperate bacteriophages that infect bordetella subspecies and undergo a unique template-dependent, reverse transcriptase-mediated tropism switching phenomenon (liu et al., science 295: 2091-2094, 2002). tropism switching results from the introduction of single nucleotide substitutions at defined locations in the vr1 (variable region 1) segment of the mtd (major tropism determinant) gene, which determines specificity for receptors on host bacteria ... | 2004 | 14973019 |
| evidence for a symbiosis island involved in horizontal acquisition of pederin biosynthetic capabilities by the bacterial symbiont of paederus fuscipes beetles. | pederin belongs to a group of antitumor compounds found in terrestrial beetles and marine sponges. it is used by apparently all members of the rove beetle genera paederus and paederidus as a chemical defense against predators. however, a recent analysis of the putative pederin biosynthesis (ped) gene cluster strongly suggests that pederin is produced by bacterial symbionts. we have sequenced an extended region of the symbiont genome to gain further insight into the biology of this as-yet-uncultu ... | 2004 | 14973122 |
| the melampsora lini avrl567 avirulence genes are expressed in haustoria and their products are recognized inside plant cells. | the linum usitatissimum (flax) l gene alleles, which encode nucleotide binding site-leu rich repeat class intracellular receptor proteins, confer resistance against the melampsora lini (flax rust) fungus. at least 11 different l resistance specificities are known, and the corresponding avirulence genes in m. lini map to eight independent loci, some of which are complex and encode multiple specificities. we identified an m. lini cdna marker that cosegregates in an f2 rust family with a complex lo ... | 2004 | 14973158 |
| the arabidopsis cytosolic thioredoxin h5 gene induction by oxidative stress and its w-box-mediated response to pathogen elicitor. | the attrxh5 protein belongs to the cytosolic thioredoxins h family that, in arabidopsis, contains eight members showing very distinct patterns and levels of expression. here, we show that the attrxh5 gene is up-regulated during wounding, abscission, and senescence, as well as during incompatible interactions with the bacterial pathogen pseudomonas syringae. by electrophoretic mobility shift assays, a binding activity on a w-box in the attrxh5 promoter region was found induced by treatments with ... | 2004 | 14976236 |
| evidence for a hybrid genomic island in verocytotoxin-producing escherichia coli cl3 (serotype o113:h21) containing segments of edl933 (serotype o157:h7) o islands 122 and 48. | genomic o island 122 (oi-122) of the verocytotoxin-producing escherichia coli (vtec) strain edl933 contains four putative virulence genes, z4321, z4326, z4332, and z4333. however, strain cl3 (serotype o113:h21) contains only z4321, not the other three genes. to determine whether z4321 is part of a different genomic island in cl3, a region of 27,293 bp up- and downstream of z4321 was sequenced and found to contain elements of two different edl933 genomic islands (oi-48 and oi-122) and a yersinia ... | 2004 | 14977955 |
| pseudomonas syringae pv. tomato cells encounter inhibitory levels of water stress during the hypersensitive response of arabidopsis thaliana. | during plant defense against bacterial pathogens, the hypersensitive response (hr) functions to restrict pathogen growth and spread. the mechanisms driving this growth restriction are poorly understood. we used a water stress-responsive transcriptional fusion to quantify the water potential sensed by individual pseudomonas syringae pv. tomato dc3000 cells during infection of arabidopsis thaliana leaves. a nonpathogenic dc3000 hrcc mutant defective in type iii secretion, as well as the saprophyte ... | 2004 | 14981249 |
| the broad host range pathogen pseudomonas aeruginosa strain pa14 carries two pathogenicity islands harboring plant and animal virulence genes. | the ubiquitous bacterium pseudomonas aeruginosa is the quintessential opportunistic pathogen. certain isolates infect a broad range of host organisms, from plants to humans. the pathogenic promiscuity of particular variants may reflect an increased virulence gene repertoire beyond the core p. aeruginosa genome. we have identified and characterized two p. aeruginosa pathogenicity islands (papi-1 and papi-2) in the genome of pa14, a highly virulent clinical isolate. the 108-kb papi-1 and 11-kb pap ... | 2004 | 14983043 |
| dissecting virulence: systematic and functional analyses of a pathogenicity island. | bacterial pathogenicity islands (pai) often encode both effector molecules responsible for disease and secretion systems that deliver these effectors to host cells. human enterohemorrhagic escherichia coli (ehec), enteropathogenic e. coli, and the mouse pathogen citrobacter rodentium (cr) possess the locus of enterocyte effacement (lee) pai. we systematically mutagenized all 41 cr lee genes and functionally characterized these mutants in vitro and in a murine infection model. we identified 33 vi ... | 2004 | 14988506 |
| phosphatidylethanolamine is not essential for growth of sinorhizobium meliloti on complex culture media. | in addition to phosphatidylglycerol (pg), cardiolipin (cl), and phosphatidylethanolamine (pe), sinorhizobium meliloti also possesses phosphatidylcholine (pc) as a major membrane lipid. the biosynthesis of pc in s. meliloti can occur via two different routes, either via the phospholipid n-methylation pathway, in which pe is methylated three times in order to obtain pc, or via the phosphatidylcholine synthase (pcs) pathway, in which choline is condensed with cdp-diacylglycerol to obtain pc directl ... | 2004 | 14996797 |
| identification of a novel pseudomonas syringae psy61 effector with virulence and avirulence functions by a hrpl-dependent promoter-trap assay. | the hrp pathogenicity island of pseudomonas syringae encodes a type iii secretion system (ttss) that translocates effectors into plant cells. most genes encoding effectors are dispersed in the p. syringae genome. regardless of location, all are regulated coordinately by the alternative sigma factor hrpl. an hrpl-dependent promoter-trap assay was developed to screen genomic libraries of p. syringae strains for promoters whose activity in escherichia coli is dependent on an inducible hrpl construc ... | 2004 | 15000392 |
| mutations in the pseudomonas syringae avrrpt2 gene that dissociate its virulence and avirulence activities lead to decreased efficiency in avrrpt2-induced disappearance of rin4. | the avrrpt2 gene from pseudomonas syringae pv. tomato exhibits avirulence activity on arabidopsis expressing the resistance gene rps2 but promotes bacterial virulence on susceptible rps2 arabidopsis. to understand the functional relationship between the avirulence and virulence activities of avrrpt2, we analyzed a series of six avrrpt2 mutants deficient in eliciting the rps2-dependent hypersensitive response. we show that the mutants are also severely impaired in triggering rsp2-dependent resist ... | 2004 | 15000398 |
| pathogens: the plight of plants. | 2004 | 15003115 | |
| myrbase: analysis of genome-wide glycine myristoylation enlarges the functional spectrum of eukaryotic myristoylated proteins. | we evaluated the evolutionary conservation of glycine myristoylation within eukaryotic sequences. our large-scale cross-genome analyses, available as myrbase, show that the functional spectrum of myristoylated proteins is currently largely underestimated. we give experimental evidence for in vitro myristoylation of selected predictions. furthermore, we classify five membrane-attachment factors that occur most frequently in combination with, or even replacing, myristoyl anchors, as some protein f ... | 2004 | 15003124 |
| impact of agricultural practices on the zea mays l. endophytic community. | agricultural practices are known to alter bulk soil microbial communities, but little is known about the effect of such practices on the plant endophytic community. we assessed the influence of long-term applications (20 years) of herbicides and different fertilizer types on the endophytic community of maize plants grown in different field experiments. nested pcr-denaturing gradient gel electrophoresis (dgge) analyses targeting general bacteria, type i or ii methanotrophs, actinomycetes, and gen ... | 2004 | 15006768 |
| molecular evidence for the evolution of metal homeostasis genes by lateral gene transfer in bacteria from the deep terrestrial subsurface. | lateral gene transfer (lgt) plays a vital role in increasing the genetic diversity of microorganisms and promoting the spread of fitness-enhancing phenotypes throughout microbial communities. to date, lgt has been investigated in surface soils, natural waters, and biofilm communities but not in the deep terrestrial subsurface. here we used a combination of molecular analyses to investigate the role of lgt in the evolution of metal homeostasis in lead-resistant subsurface bacteria. a nested pcr a ... | 2004 | 15006795 |
| bacterial avirulence genes. | although more than 30 bacterial avirulence genes have been cloned and characterized, the function of the gene products in the elictitation of resistance is unknown in all cases but one. the product of avrd from pseudomonas syringae pv. glycinea likely functions indirectly to elicit resistance in soybean, that is, evidence suggests the gene product is an enzyme involved in elicitor production. in most if not all cases, bacterial avirulence gene function is dependent on interactions with the hyper ... | 1996 | 15012539 |
| the o-polysaccharide of pseudomonas syringae pv. mori ncppb 1656 is a beta-(1-->2)-linked homopolymer of l-rhamnose. | the o-polysaccharide from the lipopolysaccharide of the phytopathogenic bacterium pseudomonas syringae pv. mori ncppb 1656 was studied by sugar analysis along with 1h and 13c nmr spectroscopy and found to be a new beta-(1-->2)-linked homopolymer of l-rhamnose. | 2004 | 15013414 |
| fusicoccin activates pathogen-responsive gene expression independently of common resistance signalling pathways, but increases disease symptoms in pseudomonas syringae-infected tomato plants. | fusicoccin (fc), an activator of the plant plasma membrane h+-atpase, induces several components of plant pathogen resistance responses, including defence hormone biosynthesis and pathogenesis-related (pr) gene expression. the mechanism by which these responses occur, and the effect they have on plant-pathogen interactions is unknown. here, we show that pr gene expression in response to fc in tomato (lycopersicon esculentum mill.) plants does not strictly require the common defence hormones, sal ... | 2004 | 15014997 |
| crystal structure of the type iii effector avrb from pseudomonas syringae. | avrb is a pseudomonas syringae type iii effector protein that is translocated into host plant cells during attempted pathogenesis. arabidopsis harboring the corresponding resistance protein rpm1 can detect avrb and mount a rapid host defense response, thus avoiding active infection. in the plant cell, avrb induces phosphorylation of rin4, a key component in avrb/rpm1 recognition. although the avrb/rpm1 system is among the best characterized of the numerous bacterial effector/plant resistance pro ... | 2004 | 15016364 |
| universally occurring phenylpropanoid and species-specific indolic metabolites in infected and uninfected arabidopsis thaliana roots and leaves. | a total of eleven alkali-released, aromatic compounds were identified by hplc, ms and nmr analyses in cell wall extracts from arabidopsis thaliana roots. nine of them together constituted the three complete series of 4-hydroxy-, 4-hydroxy-3-methoxy, and 4-hydroxy-3,5-dimethoxy-substituted benzaldehydes, benzoic acids and cinnamic acids. the other two were indolic metabolites: indole-3-carboxylic acid and indole-3-carbaldehyde. qualitatively similar, but quantitatively distinct profiles were obta ... | 2004 | 15016565 |
| bacterial biota in the human distal esophagus. | the esophagus, like other luminal organs of the digestive system, provides a potential environment for bacterial colonization, but little is known about the presence of a bacterial biota or its nature. by using broad-range 16s rdna pcr, biopsies were examined from the normal esophagus of four human adults. the 900 pcr products cloned represented 833 unique sequences belonging to 41 genera, or 95 species-level operational taxonomic units (slotu); 59 slotu were homologous with culture-defined bact ... | 2004 | 15016918 |
| silencing of the mitogen-activated protein kinase mpk6 compromises disease resistance in arabidopsis. | here, we use a loss-of-function approach to demonstrate that the arabidopsis (arabidopsis thaliana) mitogen-activated protein kinase (mapk) mpk6 plays a role in resistance to certain pathogens. mpk6-silenced arabidopsis showed no apparent morphological phenotype or reduced fertility, indicating mpk6 is not required for development. however, resistances to an avirulent strain of peronospora parasitica and avirulent and virulent strains of pseudomonas syringae were compromised, suggesting that mpk ... | 2004 | 15020743 |
| identification of a novel steroid inducible gene associated with the beta hsd locus of comamonas testosteroni. | comamonas testosteroni is a soil bacterium, which can use a variety of steroids as carbon and energy source. even if it can be estimated that the complete degradation of the steroid nucleus requires more than 20 enzymatic reactions, the complete molecular characterization of the genes encoding these steroid degradative enzymes as well as the genetic organization of them remain to be elucidated. we have previously reported the cloning and nucleotide sequence of two steroid-inducible genes, beta h ... | 2004 | 15026087 |
| arabidopsis peptide methionine sulfoxide reductase2 prevents cellular oxidative damage in long nights. | peptide methionine sulfoxide reductase (pmsr) is a ubiquitous enzyme that repairs oxidatively damaged proteins. in arabidopsis (arabidopsis thaliana), a null mutation in pmsr2 (pmsr2-1), encoding a cytosolic isoform of the enzyme, exhibited reduced growth in short-day conditions. in wild-type plants, a diurnally regulated peak of total pmsr activity occurred at the end of the 16-h dark period that was absent in pmsr2-1 plants. this pmsr activity peak in the wild-type plant coincided with increas ... | 2004 | 15031406 |
| specific and common alterations in host gene transcript accumulation following infection of the chestnut blight fungus by mild and severe hypoviruses. | we report the use of a cdna microarray to monitor global transcriptional responses of the chestnut blight fungus, cryphonectria parasitica, to infection by mild and severe isolates of virulence-attenuating hypoviruses that share 87 to 93% and 90 to 98% identity at the nucleotide and amino acid levels, respectively. infection by the mild hypovirus isolate chv1-euro7 resulted in differential expression of 166 of the ca. 2,200 genes represented on the microarray (90 upregulated and 76 downregulated ... | 2004 | 15047830 |
| hetr homodimer is a dna-binding protein required for heterocyst differentiation, and the dna-binding activity is inhibited by pats. | hetr plays a key role in regulation of heterocyst differentiation. when the cys-48 residue of the hetr from anabaena sp. pcc 7120 was replaced with an ala residue, the mutant hetr (hetr(c48a)) could not dimerize, indicating that hetr forms a homodimer through a disulfide bond. the anabaena strain c48, containing the hetrc48a gene, could not produce hetr homodimer and failed to form heterocyst. we show that hetr is a dna-binding protein and that its homodimerization is required for the dna bindin ... | 2004 | 15051891 |
| mutagenic dna repair potential in pseudomonas spp., and characterization of the rulabpc operon from the highly mutable strain pseudomonas cichorii 302959. | we assessed the tolerance to ultraviolet b (uvb; 290-320 nm) radiation and uvb-induced mutability in 28 pseudomonas spp. and four burkholderia cepacia strains. the uvb survival of 23 (72%) of the strains was elevated (>46% survival following irradiation with a 2250 j m-2 dose), and 17 (53%) strains were defined as mutable by uvb. a mutagenic dna repair determinant was cloned and characterized from the highly mutable strain p. cichorii 302959 and shown by sequence analysis to be an allele of rula ... | 2004 | 15052319 |
| a dynamic mathematical model to clarify signaling circuitry underlying programmed cell death control in arabidopsis disease resistance. | plant cells undergo programmed cell death in response to invading pathogens. this cell death limits the spread of the infection and triggers whole plant antimicrobial and immune responses. the signaling network connecting molecular recognition of pathogens to these responses is a prime target for manipulation in genetic engineering strategies designed to improve crop plant disease resistance. moreover, as alterations to metabolism can be misinterpreted as pathogen infection, successful plant met ... | 2004 | 15058987 |
| comparative genomics of gene-family size in closely related bacteria. | the wealth of genomic data in bacteria is helping microbiologists understand the factors involved in gene innovation. among these, the expansion and reduction of gene families appears to have a fundamental role in this, but the factors influencing gene family size are unclear. | 2004 | 15059260 |
| gldi is a lipoprotein that is required for flavobacterium johnsoniae gliding motility and chitin utilization. | cells of flavobacterium johnsoniae glide rapidly over surfaces by an unknown mechanism. seven genes (glda, gldb, gldd, gldf, gldg, gldh, and ftsx) that are required for gliding motility have been described. complementation of the nonmotile mutants uw102-41, uw102-85, and uw102-92 identified another gene, gldi, that is required for gliding motility. gldi mutants formed nonspreading colonies, and individual cells were completely nonmotile. they were also resistant to bacteriophages that infect wil ... | 2004 | 15060031 |
| characterization of the cis-acting regulatory element controlling hrpb-mediated activation of the type iii secretion system and effector genes in ralstonia solanacearum. | the ability of ralstonia solanacearum to cause disease on plants depends on its type iii secretion system (ttss) encoded by hrp genes. the expression of hrp genes and known ttss substrates is coordinately regulated by hrpb, a member of the arac family of transcriptional regulators. two hrpb-regulated promoters (hrpy and popabc) were characterized by deletion analysis, and the hrpb-dependent activation of these promoters was found to be conferred by a 25-nucleotide dna element, the hrp(ii) box (t ... | 2004 | 15060033 |
| genetic analysis of the salmonella enterica type iii secretion-associated atpase invc defines discrete functional domains. | an essential component of all type iii secretion systems is a highly conserved atpase that shares significant amino acid sequence similarity to the beta subunit of the f(0)f(1) atpases and is thought to provide the energy for the secretion process. we have performed a genetic and functional analysis of invc, the atpase associated with the salmonella enterica type iii secretion system encoded within its pathogenicity island 1. through a mutagenesis analysis, we have identified amino acid residues ... | 2004 | 15060043 |
| characterization of cfa1, a monofunctional acyl carrier protein involved in the biosynthesis of the phytotoxin coronatine. | cfa1 was overproduced in escherichia coli and pseudomonas syringae, and the degree of 4'-phosphopantetheinylation was determined. the malonyl-coenzyme a:acyl carrier protein transacylase (fabd) of p. syringae was overproduced and shown to catalyze malonylation of cfa1, suggesting that fabd plays a role in coronatine biosynthesis. highly purified cfa1 did not exhibit self-malonylation activity. | 2004 | 15060056 |
| the timing of senescence and response to pathogens is altered in the ascorbate-deficient arabidopsis mutant vitamin c-1. | the ozone-sensitive arabidopsis mutant vitamin c-1 (vtc1) is deficient in l-ascorbic acid (asa) due to a mutation in gdp-man pyrophosphorylase (conklin et al., 1999), an enzyme involved in the asa biosynthetic pathway (smirnoff et al., 2001). in this study, the physiology of this asa deficiency was initially investigated in response to biotic (virulent pathogens) stress and subsequently with regards to the onset of senescence. infection with either virulent pseudomonas syringae or peronospora pa ... | 2004 | 15064386 |
| evolution of the core genome of pseudomonas syringae, a highly clonal, endemic plant pathogen. | pseudomonas syringae is a common foliar bacterium responsible for many important plant diseases. we studied the population structure and dynamics of the core genome of p. syringae via multilocus sequencing typing (mlst) of 60 strains, representing 21 pathovars and 2 nonpathogens, isolated from a variety of plant hosts. seven housekeeping genes, dispersed around the p. syringae genome, were sequenced to obtain 400 to 500 nucleotides per gene. forty unique sequence types were identified, with most ... | 2004 | 15066790 |
| identification of the bacterial community of maple sap by using amplified ribosomal dna (rdna) restriction analysis and rdna sequencing. | the bacterial community of maple sap was characterized by analysis of samples obtained at the taphole of maple trees for the 2001 and 2002 seasons. among the 190 bacterial isolates, 32 groups were formed according to the similarity of the banding patterns obtained by amplified ribosomal dna restriction analysis (ardra). a subset of representative isolates for each ardra group was identified by 16s rrna gene fragment sequencing. results showed a wide variety of organisms, with 22 different genera ... | 2004 | 15066796 |
| urease-encoding genes in ammonia-oxidizing bacteria. | many but not all ammonia-oxidizing bacteria (aob) produce urease (urea amidohydrolase, ec 3.5.1.5) and are capable of using urea for chemolithotrophic growth. we sequenced the urease operons from two aob, the beta-proteobacterium nitrosospira sp. strain npav and the gamma-proteobacterium nitrosococcus oceani. in both organisms, all seven urease genes were contiguous: the three structural urease genes ureabc were preceded and succeeded by the accessory genes ured and ureefg, respectively. green f ... | 2004 | 15066830 |
| proline accumulation and atp5cs2 gene activation are induced by plant-pathogen incompatible interactions in arabidopsis. | accumulation of free l-proline (pro) is a typical stress response incited by osmotic injuries in plants and microorganisms. although the protective role of pro in osmotic stress is not well understood, it is thought to function as compatible osmolyte or as a scavenger of reactive oxygen species (ros). here we show that, in arabidopsis thaliana, pro biosynthesis can be activated by incompatible plant-pathogen interactions triggering a hypersensitive response (hr). pro accumulates in leaf tissues ... | 2004 | 15077666 |
| feedback control of the arabidopsis hypersensitive response. | the plant hypersensitive response (hr) to avirulent bacterial pathogens results from programmed cell death of plant cells in the infected region. ion leakage and changes in signaling components associated with hr progression were measured. these studies compared arabidopsis mutants affecting feedback loops with wild-type plants, with timepoints taken hourly. in response to pseudomonas syringae pv. tomato dc3000 x avrb, npr1-2 mutant plants showed increased ion leakage relative to wild-type plant ... | 2004 | 15077668 |
| bacterial disease resistance in arabidopsis through flagellin perception. | plants and animals recognize microbial invaders by detecting pathogen-associated molecular patterns (pamps) such as flagellin. however, the importance of flagellin perception for disease resistance has, until now, not been demonstrated. here we show that treatment of plants with flg22, a peptide representing the elicitor-active epitope of flagellin, induces the expression of numerous defence-related genes and triggers resistance to pathogenic bacteria in wild-type plants, but not in plants carry ... | 2004 | 15085136 |
| structural and genetic characterization of glycosylation of type a flagellin in pseudomonas aeruginosa. | type a flagellins from two strains of pseudomonas aeruginosa, strains pak and jj692, were found to be glycosylated with unique glycan structures. in both cases, two sites of o-linked glycosylation were identified on each monomer, and these sites were localized to the central, surface-exposed domain of the monomer in the assembled filament. the pak flagellin was modified with a heterogeneous glycan comprising up to 11 monosaccharide units that were o linked through a rhamnose residue to the prote ... | 2004 | 15090491 |
| enzymatic characterization of a prokaryotic urea carboxylase. | we identified the first prokaryotic urea carboxylase (uca) from a member of the alpha subclass of the class proteobacteria, oleomonas sagaranensis. this enzyme (o. sagaranensis uca) was composed of 1,171 amino acids, and its n-terminal region resembled the biotin carboxylase domains of various biotin-dependent carboxylases. the c-terminal region of the enzyme harbored the met-lys-met motif found in biotin carboxyl carrier proteins. the primary structure of the enzyme was 45% identical to that of ... | 2004 | 15090492 |
| divergence and redundancy of 16s rrna sequences in genomes with multiple rrn operons. | the level of sequence heterogeneity among rrn operons within genomes determines the accuracy of diversity estimation by 16s rrna-based methods. furthermore, the occurrence of widespread horizontal gene transfer (hgt) between distantly related rrn operons casts doubt on reconstructions of phylogenetic relationships. for this study, patterns of distribution of rrn copy numbers, interoperonic divergence, and redundancy of 16s rrna sequences were evaluated. bacterial genomes display up to 15 operons ... | 2004 | 15090503 |
| origin and diversity of alginate lyases of families pl-5 and -7 in sphingomonas sp. strain a1. | sphingomonas sp. strain a1 has three endotype alginate lyases (a1-i, a1-ii [family pl-7], and a1-iii [family pl-5]), each of which is encoded by a single gene. in addition to those of these lyases, a gene (the a1-ii' gene) showing significant identity with the a1-ii gene was present in the bacterial genome and coded for an alginate lyase with broad substrate specificity. since no expression of a1-ii' was observed even in bacterial cells grown on alginate, the a1-ii' gene was thought to be a sile ... | 2004 | 15090531 |
| segmentally variable genes: a new perspective on adaptation. | genomic sequence variation is the hallmark of life and is key to understanding diversity and adaptation among the numerous microorganisms on earth. analysis of the sequenced microbial genomes suggests that genes are evolving at many different rates. we have attempted to derive a new classification of genes into three broad categories: lineage-specific genes that evolve rapidly and appear unique to individual species or strains; highly conserved genes that frequently perform housekeeping function ... | 2004 | 15094797 |
| light conditions influence specific defence responses in incompatible plant-pathogen interactions: uncoupling systemic resistance from salicylic acid and pr-1 accumulation. | in incompatible plant-pathogen interactions, disease resistance is generated by rapid activation of a multitude of plant defence reactions. little is known about the dependency of these resistance responses on external factors. the plasticity of plant defence mechanisms in terms of light conditions is studied here. interaction of arabidopsis thaliana (l.) heynh. with an avirulent strain of pseudomonas syringae pv. maculicola in the dark resulted in increased apoplastic bacterial growth and there ... | 2004 | 15098125 |
| functional transfer of salmonella pathogenicity island 2 to salmonella bongori and escherichia coli. | the type iii secretion system (t3ss) encoded by the salmonella pathogenicity island 2 (spi2) has a central role in systemic infections by salmonella enterica and for the intracellular phenotype. intracellular s. enterica uses the spi2-encoded t3ss to translocate a set of effector proteins into the host cell, which modify host cell functions, enabling intracellular survival and replication of the bacteria. we sought to determine whether specific functions of the spi2-encoded t3ss can be transferr ... | 2004 | 15102800 |
| the defh9-iaam auxin-synthesizing gene increases plant fecundity and fruit production in strawberry and raspberry. | the defh9-iaam gene fusion which is expressed specifically in placenta/ovules and promotes auxin-synthesis confers parthenocarpic fruit development to eggplant, tomato and tobacco. transgenic defh9-iaam eggplants and tomatoes show increased fruit production due mainly to an improved fruit set. however, the weight of the fruits is also frequently increased. | 2004 | 15113427 |
| analysis of nitric oxide signaling functions in tobacco cells challenged by the elicitor cryptogein. | nitric oxide (no) has recently emerged as an important cellular mediator in plant defense responses. however, elucidation of the biochemical mechanisms by which no participates in this signaling pathway is still in its infancy. we previously demonstrated that cryptogein, an elicitor of tobacco defense responses, triggers a no burst within minutes in epidermal sections from tobacco leaves (nicotiana tabacum cv xanthi). here, we investigate the signaling events that mediate no production, and anal ... | 2004 | 15122020 |
| a novel cost of r gene resistance in the presence of disease. | resistance responses can impose fitness costs when pests are absent. here, we test whether the induction of resistance can decrease fitness even in plants under attack; we call this potential outcome a net cost with attack. using lines in which genetic background was controlled, we investigated whether susceptible arabidopsis thaliana plants can outperform r gene resistant plants when infected with pathogens. for the r gene rps2, there was a fitness benefit of resistance in the presence of intra ... | 2004 | 15122498 |
| the pseudomonas syringae genome encodes a combined mannuronan c-5-epimerase and o-acetylhydrolase, which strongly enhances the predicted gel-forming properties of alginates. | alginates are industrially important, linear copolymers of beta-d-mannuronic acid (m) and its c-5-epimer alpha-l-guluronic acid (g). the g residues originate from a postpolymerization reaction catalyzed by mannuronan c-5-epimerases (mes), leading to extensive variability in m/g ratios and distribution patterns. alginates containing long continuous stretches of g residues (g blocks) can form strong gels, a polymer type not found in alginate-producing bacteria belonging to the genus pseudomonas. h ... | 2004 | 15123694 |
| silencing of subfamily i of protein phosphatase 2a catalytic subunits results in activation of plant defense responses and localized cell death. | the central importance of protein phosphorylation in plant defense responses has been demonstrated by the isolation of several disease-resistance genes that encode protein kinases. in addition, there are many reports of changes in protein phosphorylation accompanying plant responses to pathogens. in contrast, little is known about the role of protein dephosphorylation in regulating plant defenses. we report that expression of the lepp2ac1 gene, which encodes a catalytic subunit of the heterotrim ... | 2004 | 15125764 |
| a novel family of p-loop ntpases with an unusual phyletic distribution and transmembrane segments inserted within the ntpase domain. | recent sequence-structure studies on p-loop-fold ntpases have substantially advanced the existing understanding of their evolution and functional diversity. these studies provide a framework for characterization of novel lineages within this fold and prediction of their functional properties. | 2004 | 15128444 |
| negative cross-communication among wheat rhizosphere bacteria: effect on antibiotic production by the biological control bacterium pseudomonas aureofaciens 30-84. | phenazine antibiotic production in the biological control bacterium pseudomonas aureofaciens 30-84 is regulated in part via the phzr/phzi n-acyl homoserine lactone (ahl) system. previous work showed that a subpopulation of the wheat rhizosphere community positively affected phenazine gene expression in strain 30-84 via ahl signals (e. a. pierson, d. w. wood, j. a. cannon, f. m. blachere, and l. s. pierson iii, mol. plant-microbe interact. 11:1078-1084, 1998). in the present work, a second subpop ... | 2004 | 15128573 |
| citrx thioredoxin interacts with the tomato cf-9 resistance protein and negatively regulates defence. | to identify proteins involved in tomato cf-9 resistance protein function, a yeast two-hybrid screen was undertaken using the cytoplasmic c-terminus of cf-9 as bait. a thioredoxin-homologous clone, interacting specifically with cf-9, was identified and called citrx (cf-9-interacting thioredoxin). virus-induced gene silencing (vigs) of citrx resulted in an accelerated cf-9/avr9-triggered hypersensitive response in both tomato and nicotiana benthamiana, accompanied by enhanced accumulation of react ... | 2004 | 15131698 |
| the role of the jasmonate response in plant susceptibility to diverse pathogens with a range of lifestyles. | plants defend themselves against attack from insects and pathogens with various resistance strategies. the jasmonate and salicylate signaling pathways are two induced responses that protect plants against these attackers. knowledge of the range of organisms that are affected by each response is important for understanding how plants coordinate their defenses against multiple attackers and the generality of effect of different resistance mechanisms. the jasmonate response is known to protect plan ... | 2004 | 15133157 |
| proton-transfer-reaction mass spectrometry as a new tool for real time analysis of root-secreted volatile organic compounds in arabidopsis. | plant roots release about 5% to 20% of all photosynthetically-fixed carbon, and as a result create a carbon-rich environment for numerous rhizosphere organisms, including plant pathogens and symbiotic microbes. although some characterization of root exudates has been achieved, especially of secondary metabolites and proteins, much less is known about volatile organic compounds (vocs) released by roots. in this communication, we describe a novel approach to exploring these rhizosphere vocs and th ... | 2004 | 15141066 |
| the hopptof locus of pseudomonas syringae pv. tomato dc3000 encodes a type iii chaperone and a cognate effector. | type iii secretion systems are highly conserved among gram-negative plant and animal pathogenic bacteria. through the type iii secretion system, bacteria inject a number of virulence proteins into the host cells. analysis of the whole genome sequence of pseudomonas syringae pv. tomato dc3000 strain identified a locus, named hopptof, that is homologous to the avirulence gene locus avrpphf in p. syringae pv. phaseolicola. the hopptof locus harbors two genes, shcf(pto) and hopf(pto), that are prece ... | 2004 | 15141948 |
| arabidopsis dnd2, a second cyclic nucleotide-gated ion channel gene for which mutation causes the "defense, no death" phenotype. | a previous mutant screen identified arabidopsis dnd1 and dnd2 "defense, no death" mutants, which exhibit loss of hypersensitive response (hr) cell death without loss of gene-for-gene resistance. the dnd1 phenotype is caused by mutation of the gene encoding cyclic nucleotide-gated (cng) ion channel atcngc2. this study characterizes dnd2 plants. even in the presence of high titers of pseudomonas syringae expressing avrrpt2, most leaf mesophyll cells in the dnd2 mutant exhibited no hr. these plants ... | 2004 | 15141955 |
| regulation of ahl production and its contribution to epiphytic fitness in pseudomonas syringae. | pseudomonas syringae forms large cell aggregates that are more stress tolerant than solitary cells during epiphytic growth on plants. the differential survival of aggregates on leaves suggests that epiphytic fitness traits may be controlled in a density-dependent manner via cell-cell signaling. we investigated this hypothesis in p. syringae b728a. synthesis of n-acyl-homoserine lactone (ahl), 3-oxo-hexanoyl homoserine lactone, and the expression of the gene encoding ahl synthase ahli were maxima ... | 2004 | 15141956 |
| phenylpropanoids, phenylalanine ammonia lyase and peroxidases in elicitor-challenged cassava (manihot esculenta) suspension cells and leaves. | control of diseases in the key tropical staple, cassava, is dependent on resistant genotypes, but the innate mechanisms are unknown. the aim was to study phenylpropanoids and associated enzymes as possible defence components. | 2004 | 15145789 |
| 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 |
| camalexin is synthesized from indole-3-acetaldoxime, a key branching point between primary and secondary metabolism in arabidopsis. | characteristic for cruciferous plants is their production of n- and s-containing indole phytoalexins with disease resistance and cancer-preventive properties, previously proposed to be synthesized from indole independently of tryptophan. we show that camalexin, the indole phytoalexin of arabidopsis thaliana, is synthesized from tryptophan via indole-3-acetaldoxime (iaox) in a reaction catalyzed by cyp79b2 and cyp79b3. cyp79b2/cyp79b3 double knockout mutant is devoid of camalexin, as it is also d ... | 2004 | 15148388 |
| 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 |
| 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 |
| arabidopsis downy mildew resistance gene rpp27 encodes a receptor-like protein similar to clavata2 and tomato cf-9. | the arabidopsis ler-rpp27 gene confers atsgt1b-independent resistance to downy mildew (peronospora parasitica) isolate hiks1. the rpp27 locus was mapped to a four-bacterial artificial chromosome interval on chromosome 1 from genetic analysis of a cross between the enhanced susceptibility mutant col-edm1 (col-sgt1) and landsberg erecta (ler-0). a cf-like candidate gene in this interval was pcr amplified from ler-0 and transformed into mutant col-rpp7.1 plants. homozygous transgenic lines conferre ... | 2004 | 15155873 |
| the receptor for the fungal elicitor ethylene-inducing xylanase is a member of a resistance-like gene family in tomato. | an ethylene-inducing xylanase (eix) is a potent elicitor of plant defense responses in specific cultivars of tobacco (nicotiana tabacum) and tomato (lycopersicon esculentum). the leeix locus in tomatoes was characterized by map-based cloning, which led to the identification of a novel gene cluster from which two members (leeix1 and leeix2) were isolated. similar to the tomato ve resistance genes in tomato plants, the deduced amino acid sequences encoded by leeix1 and leeix2 contain a leu zipper, ... | 2004 | 15155877 |
| salicylate accumulation inhibits growth at chilling temperature in arabidopsis. | the growth of arabidopsis plants in chilling conditions could be related to their levels of salicylic acid (sa). plants with the sa hydroxylase nahg transgene grew at similar rates to col-0 wild types at 23 degrees c, and growth of both genotypes was slowed by transfer to 5 degrees c. however, at 5 degrees c, nahg plants displayed relative growth rates about one-third greater than col-0, so that by 2 months nahg plants were typically 2.7-fold larger. this resulted primarily from greater cell exp ... | 2004 | 15173571 |
| identification of mdod, an mdog paralog which encodes a twin-arginine-dependent periplasmic protein that controls osmoregulated periplasmic glucan backbone structures. | osmoregulated periplasmic glucans (opgs) of escherichia coli are anionic and highly branched oligosaccharides that accumulate in the periplasmic space in response to low osmolarity of the medium. the glucan length, ranging from 5 to 12 glucose residues, is under strict control. two genes that form an operon, mdogh, govern glucose backbone synthesis. the new gene mdod, which appears to be a paralog of mdog, was characterized in this study. cassette inactivation of mdod resulted in production of o ... | 2004 | 15175282 |
| genomic diversity of burkholderia pseudomallei clinical isolates: subtractive hybridization reveals a burkholderia mallei-specific prophage in b. pseudomallei 1026b. | burkholderia pseudomallei is the etiologic agent of the disease melioidosis and is a category b biological threat agent. the genomic sequence of b. pseudomallei k96243 was recently determined, but little is known about the overall genetic diversity of this species. suppression subtractive hybridization was employed to assess the genetic variability between two distinct clinical isolates of b. pseudomallei, 1026b and k96243. numerous mobile genetic elements, including a temperate bacteriophage de ... | 2004 | 15175308 |