Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| high throughput virus-induced gene silencing implicates heat shock protein 90 in plant disease resistance. | virus-induced gene silencing was used to assess the function of random nicotiana benthamiana cdnas in disease resistance. out of 4992 cdnas tested from a normalized library, there were 79 that suppressed a hypersensitive response (hr) associated with pto-mediated resistance against pseudomonas syringae. however, only six of these clones blocked the pto-mediated suppression of p.syringae growth. the three clones giving the strongest loss of pto resistance had inserts corresponding to hsp90 and al ... | 2003 | 14592968 |
| flagellin glycosylation island in pseudomonas syringae pv. glycinea and its role in host specificity. | the deduced amino acid sequences of the flagellins of pseudomonas syringae pv. tabaci and p. syringae pv. glycinea are identical; however, their abilities to induce a hypersensitive reaction are clearly different. the reason for the difference seems to depend on the posttranslational modification of the flagellins. to investigate the role of this posttranslational modification in the interactions between plants and bacterial pathogens, we isolated genes that are potentially involved in the postt ... | 2003 | 14594840 |
| nitric oxide does not trigger early programmed cell death events but may contribute to cell-to-cell signaling governing progression of the arabidopsis hypersensitive response. | nitric oxide (no) has been suggested to play a role in the hypersensitive response (hr). single- and double-label fluorescence microscopy experiments were conducted using arabidopsis leaves infected with pseudomonas syringae pv. tomato dc3000 carrying either avrb or avrrpt2. kinetics of no production were followed by measurement of green 4-amino-5-methylamino-2',7'-difluorofluorescein (daf-fm) triazole fluorescence in leaves coinfiltrated with daf-fm diacetate. kinetics of hypersensitive cell de ... | 2003 | 14601664 |
| population structure of alexandrium (dinophyceae) cyst formation-promoting bacteria in hiroshima bay, japan. | a total of 31 bacterial isolates that have potential alexandrium cyst formation-promoting activity (alex-cfpb) were isolated from hiroshima bay (japan), which is characterized by seasonal blooms of the toxic dinoflagellate alexandrium tamarense. the population structure of alex-cfpb was analyzed by means of restriction fragment length polymorphism analysis of the 16s rrna genes (16s rdna). fourteen ribotypes, a to n, were observed among the 31 isolates of alex-cfpb by using four restriction enzy ... | 2003 | 14602614 |
| development and application of a dapb-based in vivo expression technology system to study colonization of rice by the endophytic nitrogen-fixing bacterium pseudomonas stutzeri a15. | pseudomonas stutzeri a15 is a nitrogen-fixing bacterium isolated from paddy rice. strain a15 is able to colonize and infect rice roots. this strain may provide rice plants with fixed nitrogen and hence promote plant growth. in this article, we describe the use of dapb-based in vivo expression technology to identify p. stutzeri a15 genes that are specifically induced during colonization and infection (cii). we focused on the identification of p. stutzeri a15 genes that are switched on during rice ... | 2003 | 14602651 |
| complete sequence of virulence plasmid pjm1 from the marine fish pathogen vibrio anguillarum strain 775. | the virulence plasmid pjm1 enables the fish pathogen vibrio anguillarum, a gram-negative polarly flagellated comma-shaped rod bacterium, to cause a highly fatal hemorrhagic septicemic disease in salmonids and other fishes, leading to epizootics throughout the world. the pjm1 plasmid 65,009-nucleotide sequence, with an overall g+c content of 42.6%, revealed genes and open reading frames (orfs) encoding iron transporters, nonribosomal peptide enzymes, and other proteins essential for the biosynthe ... | 2003 | 13129954 |
| transcriptional organization of the pseudomonas putida tol-oprl genes. | proteins of the tol system play a key role in the maintenance of outer membrane integrity and cell morphology in gram-negative bacteria. in pseudomonas putida, the seven genes, orf1, tolq, tolr, tola, tolb, oprl, and orf2, which encode the proteins of this complex, are clustered in a 5.8-kb region of chromosomal dna. analysis of polar mutations, reverse transcriptase pcr assays, and transcriptional fusion constructs with a promoterless lacz gene revealed that the genes are arranged in two operon ... | 2003 | 12486055 |
| structure of the o polysaccharides and serological classification of pseudomonas syringae pv. porri from genomospecies 4. | strains of pseudomonas syringae pv. porri are characterized by a number of pathovar-specific phenotypic and genomic characters and constitute a highly homogeneous group. using monoclonal antibodies, they all were classified in a novel p. syringae serogroup o9. the o polysaccharides (ops) isolated from the lipopolysaccharides (lps) of p. syringae pv. porri ncppb 3365 and ncppb 3364t possess multiple oligosaccharide o repeats, some of which are linear and composed of l-rhamnose (l-rha), whereas th ... | 2003 | 12492471 |
| distribution and function of new bacterial intein-like protein domains. | hint protein domains appear in inteins and in the c-terminal region of hedgehog and hedgehog-like animal developmental proteins. intein hint domains are responsible and sufficient for protein-splicing of their host-protein flanks. in hedgehog proteins the hint domain autocatalyses its cleavage from the n-terminal domain of the hedgehog protein by attaching a cholesterol molecule to it. we identified two new types of hint domains. both types have active site sequence features of hint domains but ... | 2003 | 12492854 |
| a simple method for preparation of d-rhamnose. | a rapid procedure for the preparation of d-rhamnose from bacterial lipopolysaccharide (lps) has been developed. it involves purification of lps from pseudomonas syringae pv. phaseolicola by phenol extraction and hydrophobic interaction chromatography (hic), followed by mild hydrolysis and cleavage of the o-antigen into d-fucose and d-rhamnose. the monosaccharides were separated by column chromatography, and d-rhamnose recovered after filtration over sephadex-lh 20. | 2003 | 12504387 |
| pseudomonas type iii effector avrptob induces plant disease susceptibility by inhibition of host programmed cell death. | the avrptob type iii effector protein is conserved among diverse genera of plant pathogens suggesting it plays an important role in pathogenesis. here we report that pseudomonas avrptob acts inside the plant cell to inhibit programmed cell death (pcd) initiated by the pto and cf9 disease resistance proteins and, remarkably, the pro-apoptotic mouse protein bax. avrptob also suppressed pcd in yeast, demonstrating that avrptob functions as a cell death inhibitor across kingdoms. using truncated avr ... | 2003 | 12505984 |
| functional and mutational analysis of conjugative transfer region 2 (tra2) from the inchi1 plasmid r27. | the transfer 2 region (tra2) of the conjugative plasmid drr27 (derepressed r27) was analyzed by psi-blast, insertional mutagenesis, genetic complementation, and an h-pilus assay. tra2 contains 11 mating-pair formation (mpf) genes that are essential for conjugative transfer, 9 of which are essential for h-pilus production (trha, -l, -e, -k, -b, -v, -c, -p, and -w). trhk has similarity to secretin proteins, suggesting a mechanism by which dna could traverse the outer membrane of donors. the remain ... | 2003 | 12511505 |
| growth dynamics of salmonella enterica strains on alfalfa sprouts and in waste seed irrigation water. | alfalfa sprouts and other seed sprouts have been implicated in numerous outbreaks of salmonellosis. the source of these epidemics appears to have been low-level contamination of seeds by salmonella bacteria that developed into clinically significant populations during the seed germination process. to test the possibility that salmonella enterica strains carry host range determinants that allow them to grow on alfalfa, strains isolated from alfalfa or other sources were surveyed for their ability ... | 2003 | 12514040 |
| molecular characterization of natural erwinia pyrifoliae strains deficient in hypersensitive response. | from necrotic tissue of a nashi pear tree, 24 erwinia pyrifoliae strains, found to be identical by pulsed-field gel electrophoresis analysis, were isolated. thirteen strains were not virulent on immature pears and did not induce a hypersensitive response in tobacco leaves. the defective gene hrpl was complemented with intact genes from e. pyrifoliae and erwinia amylovora. | 2003 | 12514060 |
| characteristics of massilia timonae and massilia timonae-like isolates from human patients, with an emended description of the species. | the description of massilia timonae, a nonfermentative aerobic gram-negative rod, was based on a single strain. a subsequent report of a second isolate has been recently published. phenotypic descriptions of these two strains were based primarily on commercial test kit results. we have identified three additional strains as m. timonae by 16s rrna sequence analysis and have characterized them phenotypically in parallel with the type strain of m. timonae, cip 105350, by conventional test methods. ... | 2003 | 12517847 |
| cloning and characterization of kata, encoding the major monofunctional catalase from xanthomonas campestris pv. phaseoli and characterization of the encoded catalase kata. | the first cloning and characterization of the gene kata, encoding the major catalase (kata), from xanthomonas is reported. a reverse genetic approach using a synthesized kata-specific dna probe to screen a x. campestris pv. phaseoli genomic library was employed. a positively hybridizing clone designated pkat29 that contained a full-length kata was isolated. analysis of the nucleotide sequence revealed an open reading frame of 1,521 bp encoding a 507-amino acid protein with a theoretical molecula ... | 2003 | 12520360 |
| crystal structure of tabtoxin resistance protein complexed with acetyl coenzyme a reveals the mechanism for beta-lactam acetylation. | tabtoxin resistance protein (ttr) is an enzyme that renders tabtoxin-producing pathogens, such as pseudomonas syringae, tolerant to their own phytotoxins. here, we report the crystal structure of ttr complexed with its natural cofactor, acetyl coenzyme a (accoa), to 1.55a resolution. the binary complex forms a characteristic "v" shape for substrate binding and contains the four motifs conserved in the gcn5-related n-acetyltransferase (gnat) superfamily, which also includes the histone acetyltran ... | 2003 | 12527305 |
| fingerprinting of prokaryotic 16s rrna genes using oligodeoxyribonucleotide microarrays and virtual hybridization. | an oligonucleotide microarray hybridization system to differentiate microbial species was designed and tested. seven microbial species were studied, including one bacillus and six pseudomonas strains. dna sequences near the 5' end of 16s rrna genes were aligned and two contiguous regions of high variability, flanked by highly conserved sequences, were found. the conserved sequences were used to design pcr primers which efficiently amplified these polymorphic regions from all seven species. the a ... | 2003 | 12527788 |
| iscce1 and iscce2, two novel insertion sequences in clostridium cellulolyticum. | two new insertion sequences, iscce1 and iscce2, were found to be inserted into the cipc gene of spontaneous mutants of clostridium cellulolyticum. in these insertional mutants, the cipc gene was disrupted either by iscce1 alone or by both iscce1 and iscce2. iscce1 is 1,292 bp long and has one open reading frame. the open reading frame encodes a putative 348-amino-acid protein with significant levels of identity with putative proteins having unknown functions and with some transposases belonging ... | 2003 | 12533447 |
| 2,5-dialkylresorcinol biosynthesis in pseudomonas aurantiaca: novel head-to-head condensation of two fatty acid-derived precursors. | 2-hexyl-5-propylresorcinol is the predominant analog of several dialkylresorcinols produced by pseudomonas aurantiaca (pseudomonas fluorescens bl915). we isolated and characterized three biosynthetic genes that encode an acyl carrier protein, a beta-ketoacyl-acyl carrier protein synthase iii, and a protein of unknown function, all of which collectively allow heterologous production of 2-hexyl-5-propylresorcinol in escherichia coli. two regulatory genes exhibiting similarity to members of the ara ... | 2003 | 12533461 |
| requirements for cu(a) and cu-s center assembly of nitrous oxide reductase deduced from complete periplasmic enzyme maturation in the nondenitrifier pseudomonas putida. | bacterial nitrous oxide (n(2)o) reductase is the terminal oxidoreductase of a respiratory process that generates dinitrogen from n(2)o. to attain its functional state, the enzyme is subjected to a maturation process which involves the protein-driven synthesis of a unique copper-sulfur cluster and metallation of the binuclear cu(a) site in the periplasm. there are seven putative maturation factors, encoded by nosa, nosd, nosf, nosy, nosl, nosx, and sco. we wanted to determine the indispensable pr ... | 2003 | 12533464 |
| plant lectin-like bacteriocin from a rhizosphere-colonizing pseudomonas isolate. | rhizosphere isolate pseudomonas sp. strain bw11m1, which belongs to the pseudomonas putida cluster, secretes a heat- and protease-sensitive bacteriocin which kills p. putida gr12-2r3. the production of this bacteriocin is enhanced by dna-damaging treatment of producer cells. we isolated a tnmod mutant of strain bw11m1 that had lost the capacity to inhibit the growth of strain gr12-2r3. a wild-type genomic fragment encompassing the transposon insertion site was shown to confer the bacteriocin phe ... | 2003 | 12533465 |
| a glutamate mutase is involved in the biosynthesis of the lipopeptide antibiotic friulimicin in actinoplanes friuliensis. | actinoplanes friuliensis produces the lipopeptide antibiotic friulimicin. this antibiotic is active against gram-positive bacteria such as multiresistant enterococcus and staphylococcus strains. it consists of 10 amino acids that form a ring structure and 1 exocyclic amino acid to which an acyl residue is attached. by a reverse genetic approach, biosynthetic genes were identified that are required for the nonribosomal synthesis of the antibiotic. in close proximity two genes (glma and glmb) were ... | 2003 | 12543643 |
| hsp90 interacts with rar1 and sgt1 and is essential for rps2-mediated disease resistance in arabidopsis. | rar1 and its interacting partner sgt1 play a central role in plant disease resistance triggered by a number of resistance (r) proteins. we identified cytosolic heat shock protein 90 (hsp90), a molecular chaperone, as another rar1 interacting protein by yeast two-hybrid screening. rar1 interacts with the n-terminal half of hsp90 that contains the atpase domain. hsp90 also specifically interacts with sgt1 that contains a tetratricopeptide repeat motif and a domain with similarity to the cochaperon ... | 2003 | 14504384 |
| arabidopsis sfd mutants affect plastidic lipid composition and suppress dwarfing, cell death, and the enhanced disease resistance phenotypes resulting from the deficiency of a fatty acid desaturase. | a loss-of-function mutation in the arabidopsis ssi2/fab2 gene, which encodes a plastidic stearoyl-acyl-carrier protein desaturase, has pleiotropic effects. the ssi2 mutant plant is dwarf, spontaneously develops lesions containing dead cells, accumulates increased salicylic acid (sa) levels, and constitutively expresses sa-mediated, npr1-dependent and -independent defense responses. in parallel, jasmonic acid-regulated signaling is compromised in the ssi2 mutant. in an effort to discern the invol ... | 2003 | 14507997 |
| acd6, a novel ankyrin protein, is a regulator and an effector of salicylic acid signaling in the arabidopsis defense response. | the previously reported arabidopsis dominant gain-of-function mutant accelerated cell death6-1 (acd6-1) shows spontaneous cell death and increased disease resistance. acd6-1 also confers increased responsiveness to the major defense signal salicylic acid (sa). to further explore the role of acd6 in the defense response, we cloned and characterized the gene. acd6 encodes a novel protein with putative ankyrin and transmembrane regions. it is a member of one of the largest uncharacterized gene fami ... | 2003 | 14507999 |
| antibacterial and proteolytic activity in venom from the endoparasitic wasp pimpla hypochondriaca (hymenoptera: ichneumonidae). | venom from the endoparasitic wasp, pimpla hypochondriaca, is composed of a mixture of high and low molecular weight proteins, possesses phenoloxidase activity, has immunosuppressive properties, and induces paralysis in several insect species. in the present study we demonstrate that p. hypochondriaca venom also contains antibacterial and proteolytic activity. antibacterial activity was detected against the gram-negative bacteria escherichia coli and xanthamonas campestris but not against pseudom ... | 2003 | 14511827 |
| properties of a novel extracellular cell-free ice nuclei from ice-nucleating pseudomonas antarctica in-74. | some ice-nucleating bacterial strains, including pantoea ananatis (erwinia uredovora), pseudomonas fluorescens, and pseudomonas syringae isolates, were examined for the ability to shed ice nuclei into the growth medium. a novel ice-nucleating bacterium, pseudomonas antarctica in-74, was isolated from ross island, antarctica. cell-free ice nuclei from p. antarctica in-74 were different from the conventional cell-free ice nuclei and showed a unique characterization. cell-free ice nuclei were purif ... | 2003 | 14519981 |
| activation of the fatty acid alpha-dioxygenase pathway during bacterial infection of tobacco leaves. formation of oxylipins protecting against cell death. | a pathogen-induced oxygenase showing homology to prostaglandin endoperoxide synthases-1 and -2 was recently characterized by in vitro experiments as a fatty acid alpha-dioxygenase catalyzing formation of unstable 2(r)-hydroperoxy fatty acids. to study the activity of this enzyme under in vivo conditions and to elucidate the fate of enzymatically produced 2-hydroperoxides, leaves of tobacco were analyzed for the presence of alpha-dioxygenase-generated compounds as well as for lipoxygenase (lox) p ... | 2003 | 14522973 |
| clonal population structure of pseudomonas avellanae strains of different origin based on multilocus enzyme electrophoresis. | to assess the genetic diversity and genetic relationships of pseudomonas avellanae, the causative agent of hazelnut decline, a total of 102 strains, obtained from central italy (provinces of viterbo and rome) and northern greece, were studied using multilocus enzyme electrophoresis (mlee). their allelic variation in 10 loci was determined. all loci were polymorphic and 53 electrophoretic types (ets) were identified from the total sample. the mean genetic diversity (h) was 0.65 and this value ran ... | 2003 | 14523121 |
| rps4-mediated disease resistance requires the combined presence of rps4 transcripts with full-length and truncated open reading frames. | arabidopsis rps4 belongs to the toll/interleukin-1 receptor (tir)-nucleotide binding site (nbs)-leu-rich repeat (lrr) class of disease resistance (r) genes. like other family members in different plant species, rps4 produces alternative transcripts with truncated open reading frames. the dominant alternative rps4 transcripts are generated by retention of intron 3 or introns 2 and 3, which contain in-frame stop codons and lie downstream of the nbs-encoding exon. we analyzed the biological signifi ... | 2003 | 14523247 |
| cleavage of the pseudomonas syringae type iii effector avrrpt2 requires a host factor(s) common among eukaryotes and is important for avrrpt2 localization in the host cell. | many phytopathogenic bacteria use a type iii secretion system to deliver type iii effector proteins into the host plant cell. the pseudomonas syringae type iii effector avrrpt2 is cleaved at a specific site when translocated into the host cell. in this study, we first demonstrate that the factor(s) required for avrrpt2 cleavage is present in extracts from animal and yeast cells, as well as plant cells. the cleavage factor in animal and plant cell extracts was heat labile but relatively insensiti ... | 2003 | 14526114 |
| molecular basis of pto-mediated resistance to bacterial speck disease in tomato. | the pto gene in tomato confers gene-for-gene resistance to pseudomonas syringae pv. tomato, the causative agent of bacterial speck disease. pto was first introgressed from a wild species of tomato into cultivated tomato varieties over 60 years ago and is now widely used to control speck disease. cloning of the pto gene revealed that it encodes a cytoplasmically localized serine-threonine protein kinase. the molecular basis of gene-for-gene recognition in this pathosystem is the direct physical i ... | 2003 | 14527329 |
| conditional survival as a selection strategy to identify plant-inducible genes of pseudomonas syringae. | a novel strategy termed habitat-inducible rescue of survival (hirs) was developed to identify genes of pseudomonas syringae that are induced during growth on bean leaves. this strategy is based on the complementation of metxw, two cotranscribed genes that are necessary for methionine biosynthesis and required for survival of p. syringae on bean leaves exposed to conditions of low humidity. we constructed a promoter trap vector, ptrap, containing a promoterless version of the wild-type p. syringa ... | 2003 | 14532027 |
| characterization of a salicylic acid- and pathogen-induced lipase-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, designated br-sil1 (for brassica rapa salicylate-induced lipase-like 1 gene), encodes a putative lipase that has the family ii lipase motif gdsxxdxg around the active site serine. a database search showed that plant genomes have a large number of genes that contain the family ii lipase motif. the lipase-like proteins include a myrosinase-associated ... | 2003 | 14536025 |
| multiple hormones act sequentially to mediate a susceptible tomato pathogen defense response. | phytohormones regulate plant responses to a wide range of biotic and abiotic stresses. how a limited number of hormones differentially mediate individual stress responses is not understood. we have used one such response, the compatible interaction of tomato (lycopersicon esculentum) and xanthomonas campestris pv vesicatoria (xcv), to examine the interactions of jasmonic acid (ja), ethylene, and salicylic acid (sa). the role of ja was assessed using an antisense allene oxide cyclase transgenic l ... | 2003 | 14551324 |
| bacterial cell surface display for epitope mapping of hepatitis c virus core antigen. | cell surface expression of protein has been widely used to display enzymes and antigens. here we show that pseudomonas syringae ice nucleation protein with a deletion of internal repeating domain (inc) can be used in escherichia coli to display peptide in a conformationally active form on the outside of the folded protein by fusing to the c-terminus of inc. diagnostic potential of this technology was demonstrated by effective mapping of antigenic epitopes derived from hepatitis c virus (hcv) cor ... | 2003 | 14553932 |
| the botrytis susceptible1 gene encodes an r2r3myb transcription factor protein that is required for biotic and abiotic stress responses in arabidopsis. | the molecular and cellular mechanisms involved in plant resistance to the necrotrophic fungal pathogen botrytis cinerea and their genetic control are poorly understood. botrytis causes severe disease in a wide range of plant species, both in the field and in postharvest situations, resulting in significant economic losses. we have isolated the bos1 (botrytis-susceptible1) gene of arabidopsis based on a t-dna insertion allele that resulted in increased susceptibility to botrytis infection. the bo ... | 2003 | 14555693 |
| tertiary structure of thiopurine methyltransferase from pseudomonas syringae, a bacterial orthologue of a polymorphic, drug-metabolizing enzyme. | in humans, the enzyme thiopurine methyltransferase (tpmt) metabolizes 6-thiopurine (6-tp) medications, including 6-thioguanine, 6-mercaptopurine and azathioprine, commonly used for immune suppression and for the treatment of hematopoietic malignancies. s-methylation by tpmt prevents the intracellular conversion of these drugs into active 6-thioguanine nucleotides (6-tgns). genetic polymorphisms in the tpmt protein sequence have been associated with decreased tissue enzymatic activities and an in ... | 2003 | 14556746 |
| the is1111 family members is4321 and is5075 have subterminal inverted repeats and target the terminal inverted repeats of tn21 family transposons. | is5075 and is4321 are closely related (93.1% identical) members of the is1111 family that target a specific position in the 38-bp terminal inverted repeats of tn21 family transposons and that are inserted in only one orientation. they are 1,327 bp long and have identical ends consisting of short inverted repeats of 12 bp with an additional 7 bp (taatgag) or 6 bp (aatgag) to the left of the left inverted repeats and 3 bp (aga) or 4 bp (agat) to the right of the right inverted repeat. circular for ... | 2003 | 14563872 |
| analysis of specific binding involved in genomic packaging of the double-stranded-rna bacteriophage phi6. | the genomes of bacteriophage phi6 and its relatives are packaged through a mechanism that involves the recognition and translocation of the three different plus-strand transcripts of the segmented double-stranded-rna genomes into preformed polyhedral structures called procapsids or inner cores. the packaging requires the hydrolysis of nucleoside triphosphates and takes place in the order segment s-segment m, segment l. packaging is dependent upon unique sequences of about 200 nucleotides near th ... | 2003 | 14563876 |
| the effect of antifreeze proteins and poly(vinyl alcohol) on the nucleation of ice: a preliminary study. | three substances have been tested for ice nucleation inhibition. these were an antifreeze protein afp iii from the fish macrozoarces americanus, an antifreeze glycoprotein afgp from the fish dissostichus mawsoni, and an 80% hydrolysed poly(vinyl alcohol) with a molecular weight of 9 to 10 kd. a nucleation spectrometer was used to test nucleation inhibition at a range of concentrations against two types of ice nuclei: those present in tap water and a bacterial nucleator from pseudomonas syringae. ... | 2003 | 14566392 |
| knockout analysis of arabidopsis transcription factors tga2, tga5, and tga6 reveals their redundant and essential roles in systemic acquired resistance. | arabidopsis nonexpresser of pathogenesis-related (pr) genes (npr1) is the sole positive regulator that has been shown to be essential for the induction of systemic acquired resistance. in npr1 mutant plants, salicylic acid (sa)-mediated pr gene expression and pathogen resistance are abolished completely. npr1 has been shown to interact with three closely related tga transcription factors-tga2, tga5, and tga6-in yeast two-hybrid assays. to elucidate the biological functions of these three tga tra ... | 2003 | 14576289 |
| a gain-of-function mutation in a plant disease resistance gene leads to constitutive activation of downstream signal transduction pathways in suppressor of npr1-1, constitutive 1. | plants have evolved sophisticated defense mechanisms against pathogen infections, during which resistance (r) genes play central roles in recognizing pathogens and initiating defense cascades. most of the cloned r genes share two common domains: the central domain, which encodes a nucleotide binding adaptor shared by apaf-1, certain r proteins, and ced-4 (nb-arc), plus a c-terminal region that encodes leu-rich repeats (lrr). in arabidopsis, a dominant mutant, suppressor of npr1-1, constitutive 1 ... | 2003 | 14576290 |
| the coat protein of turnip crinkle virus suppresses posttranscriptional gene silencing at an early initiation step. | posttranscriptional gene silencing (ptgs), or rna silencing, is a sequence-specific rna degradation process that targets foreign rna, including viral and transposon rna for destruction. several rna plant viruses have been shown to encode suppressors of ptgs in order to survive this host defense. we report here that the coat protein (cp) of turnip crinkle virus (tcv) strongly suppresses ptgs. the agrobacterium infiltration system was used to demonstrate that tcv cp suppressed the local ptgs as st ... | 2003 | 12477856 |
| differential expression of the leps2 phosphatase gene family in response to phosphate availability, pathogen infection and during development. | in this study, we report the cloning of the three-member leps2 gene family of acid phosphatases via subtractive screening of a cdna library of pi-starved cultivated tomato cells (lycopersicon esculentum mill. cv. lukullus). as members of the plant pi-starvation response, leps2 genes were tightly regulated in cultivated cells and tomato seedlings by pi availability. the leps2 enzymes which are most likely expressed in the cytoplasma could be involved in processes that are accompanied by degradati ... | 2003 | 12702022 |
| use of the galleria mellonella caterpillar as a model host to study the role of the type iii secretion system in pseudomonas aeruginosa pathogenesis. | nonvertebrate model hosts represent valuable tools for the study of host-pathogen interactions because they facilitate the identification of bacterial virulence factors and allow the discovery of novel components involved in host innate immune responses. in this report, we determined that the greater wax moth caterpillar galleria mellonella is a convenient nonmammalian model host for study of the role of the type iii secretion system (ttss) in pseudomonas aeruginosa pathogenesis. based on the ob ... | 2003 | 12704110 |
| overexpression of barley bax inhibitor 1 induces breakdown of mlo-mediated penetration resistance to blumeria graminis. | cell death regulation is linked to pathogen defense in plants and animals. execution of apoptosis as one type of programmed cell death in animals is irreversibly triggered by cytochrome c release from mitochondria via pores formed by bax proteins. this type of programmed cell death can be prevented by expression of bax inhibitor 1 (bi-1), a membrane protein that protects cells from the effects of bax by an unknown mechanism. in barley, a homologue of the mammalian bi-1 is expressed in response t ... | 2003 | 12704231 |
| type iii protein secretion in pseudomonas syringae. | the type iii secretion system is an essential virulence system used by many gram-negative bacterial pathogens to deliver effector proteins into host cells. this review summarizes recent advancements in the understanding of the type iii secretion system of pseudomonas syringae, including regulation of the type iii secretion genes, assembly of the hrp pilus, secretion signals, the putative type iii effectors identified to date, and their virulence action after translocation into plant cells. | 2003 | 12706443 |
| differential volatile emissions and salicylic acid levels from tobacco plants in response to different strains of pseudomonas syringae. | pathogen-induced plant responses include changes in both volatile and non-volatile secondary metabolites. to characterize the role of bacterial pathogenesis in plant volatile emissions, tobacco plants, nicotiana tabacum l. k326, were inoculated with virulent, avirulent, and mutant strains of pseudomonas syringae. volatile compounds released by pathogen-inoculated tobacco plants were collected, identified, and quantified. tobacco plants infected with the avirulent strains p. syringae pv. maculico ... | 2003 | 12712338 |
| the deltaflid mutant of pseudomonas syringae pv. tabaci, which secretes flagellin monomers, induces a strong hypersensitive reaction (hr) in non-host tomato cells. | to investigate the role of flagella and monomer flagellin in the interaction between pseudomonas syringae pv. tabaci and plants, non-polar flic and flid mutants were produced. the orfs for flic and flid are deleted in the deltaflic and deltaflid mutants, respectively. both mutants lost all flagella and were non-motile. the deltaflic mutant did not produce flagellin, whereas the deltaflid mutant, which lacks the hap2 protein, secreted large amounts of monomer flagellin into the culture medium. in ... | 2003 | 12715150 |
| activation of defense-related gene expression and systemic acquired resistance in cucumber mosaic virus-infected tobacco plants expressing the mammalian 2'5'oligoadenylate system. | tobacco plants expressing the mammalian 2'5'oligoadenylate system (2-5a system) exhibit resistance to cucumber mosaic virus (cmv). here, to characterize the molecular aspect of the resistance to cmv in 2-5a system-expressing tobaccos, the activation of defense-related genes and systemic acquired resistance (sar) as the markers for the hypersensitive resistance (hr), were elucidated. northern hybridization analysis indicated that the expression of four pathogenesis-related (pr) protein genes and ... | 2003 | 12721807 |
| alginate gene expression by pseudomonas syringae pv. tomato dc3000 in host and non-host plants. | pseudomonas syringae produces the exopolysaccharide alginate, a copolymer of mannuronic and guluronic acid. although alginate has been isolated from plants infected by p. syringae, the signals and timing of alginate gene expression in planta have not been described. in this study, an algd : : uida transcriptional fusion, designated pdcalgdp, was constructed and used to monitor alginate gene expression in host and non-host plants inoculated with p. syringae pv. tomato dc3000. when leaves of susce ... | 2003 | 12724374 |
| rpon (sigma(54)) is required for plasmid-encoded coronatine biosynthesis in pseudomonas syringae. | the plant pathogen pseudomonas syringae pv. glycinea pg4180 produces coronatine (cor), a phytotoxin which functions as a virulence factor in bacterial blight of soybeans. the cor biosynthetic gene cluster in pg4180 is borne on a 90-kb plasmid named p4180a. although pathway-specific regulatory genes for cor have been identified, global regulatory genes for cor production in pg4180 remain undefined. in the present study, we evaluated the role of rpon, which encodes sigma(54), in the virulence of s ... | 2003 | 12726764 |
| n-cyanomethyl-2-chloroisonicotinamide induces systemic acquired resistance in arabidopsis without salicylic acid accumulation. | systemic acquired resistance (sar) is a potent innate immunity system in plants that is induced through the salicylic acid-mediated pathway. n-cyanomethyl-2-chloroisonicotinamide (nci) is able to induce a broad range of disease resistance in tobacco and rice and induces sar marker gene expression without sa accumulation in tobacco. to clarify the detailed mode of action of nci, we analyzed its ability to induce defense gene expression and resistance in arabidopsis mutants that are defective in v ... | 2003 | 12728993 |
| characterization of the xanthomonas axonopodis pv. glycines hrp pathogenicity island. | we sequenced an approximately 29-kb region from xanthomonas axonopodis pv. glycines that contained the hrp type iii secretion system, and we characterized the genes in this region by tn3-gus mutagenesis and gene expression analyses. from the region, hrp (hypersensitive response and pathogenicity) and hrc (hrp and conserved) genes, which encode type iii secretion systems, and hpa (hrp-associated) genes were identified. the characteristics of the region, such as the presence of many virulence gene ... | 2003 | 12730176 |
| quorum sensing in plant-pathogenic bacteria. | quorum sensing (qs) allows bacteria to assess their local population density and/or physical confinement via the secretion and detection of small, diffusible signal molecules. this review describes how phytopathogenic bacteria have incorporated qs mechanisms into complex regulatory cascades that control genes for pathogenicity and colonization of host surfaces. traits regulated by qs include the production of extracellular polysaccharides, degradative enzymes, antibiotics, siderophores, and pigm ... | 2003 | 12730390 |
| global expression profiling and physiological characterization of corynebacterium glutamicum grown in the presence of l-valine. | addition of l-valine (50 to 200 mm) to glucose minimal medium had no effect on the growth of wild-type corynebacterium glutamicum atcc 13032 but inhibited the growth of the derived valine production strain val1 [13032 deltailva deltapanbc(pjc1ilvbncd)] in a concentration-dependent manner. in order to explore this strain-specific valine effect, genomewide expression profiling was performed using dna microarrays, which showed that valine caused an increased ilvbn mrna level in val1 but not in the ... | 2003 | 12732517 |
| purification and characterization of an inverting stereo- and enantioselective sec-alkylsulfatase from the gram-positive bacterium rhodococcus ruber dsm 44541. | whole cells of rhodococcus ruber dsm 44541 were found to hydrolyze (+/-)-2-octyl sulfate in a stereo- and enantiospecific fashion. when growing on a complex medium, the cells produced two sec-alkylsulfatases and (at least) one prim-alkylsulfatase in the absence of an inducer, such as a sec-alkyl sulfate or a sec-alcohol. from the crude cell-free lysate, two proteins responsible for sulfate ester hydrolysis (designated rs1 and rs2) were separated from each other based on their different hydrophob ... | 2003 | 12732552 |
| identification of an emergent and atypical pseudomonas viridiflava lineage causing bacteriosis in plants of agronomic importance in a spanish region. | pseudomonas strains with an atypical lopat profile (where lopat is a series of determinative tests: l, levan production; o, oxidase production; p, pectinolitic activity; a, arginine dihydrolase production; and t, tobacco hypersensibility) can be regarded as emergent pathogens in the principality of asturias (spain), where they have been causing, since 1999, severe damage in at least three taxonomically unrelated orchard plants of agronomic importance: common bean (phaseolus vulgaris), kiwifruit ... | 2003 | 12732569 |
| type iii protein translocase: hrcn is a peripheral atpase that is activated by oligomerization. | type iii protein secretion (tts) is catalyzed by translocases that span both membranes of gram-negative bacteria. a hydrophilic tts component homologous to f1/v1-atpases is ubiquitous and essential for secretion. we show that hrcn encodes the putative tts atpase of pseudomonas syringae pathovar phaseolicola and that hrcn is a peripheral protein that assembles in clusters at the membrane. a decahistidinyl hrcn derivative was overexpressed in escherichia coli and purified to homogeneity in a folde ... | 2003 | 12734178 |
| the sypa, syps, and sypc synthetase genes encode twenty-two modules involved in the nonribosomal peptide synthesis of syringopeptin by pseudomonas syringae pv. syringae b301d. | syringopeptin is a necrosis-inducing phytotoxin, composed of 22 amino acids attached to a 3-hydroxy fatty acid tail. syringopeptin, produced by pseudomonas syringae pv. syringae, functions as a virulence determinant in the plant-pathogen interaction. a 73,800-bp dna region was sequenced, and analysis identified three large open reading frames, sypa, sypb, and sypc, that are 16.1, 16.3, and 40.6 kb in size. sequence analysis of the putative sypa, sypb, and sypc sequences determined that they are ... | 2003 | 12744455 |
| ethylene insensitivity modulates ozone-induced cell death in birch. | we have used genotypic variation in birch (betula pendula roth) to investigate the roles of ozone (o(3))-induced ethylene (et), jasmonic acid, and salicylic acid in the regulation of tissue tolerance to o(3). of these hormones, et evolution correlated best with o(3)-induced cell death. disruption of et perception by transformation of birch with the dominant negative mutant allele etr1-1 of the arabidopsis et receptor gene etr1 or blocking of et perception with 1-methylcyclopropene reduced but di ... | 2003 | 12746524 |
| isolation and characterization of the neutral leucine aminopeptidase (lapn) of tomato. | tomatoes (lycopersicon esculentum) express two forms of leucine aminopeptidase (lap-a and lap-n) and two lap-like proteins. the relatedness of lap-n and lap-a was determined using affinity-purified antibodies to four lap-a protein domains. antibodies to epitopes in the most n-terminal region were able to discriminate between lap-a and lap-n, whereas antibodies recognizing central and cooh-terminal regions recognized both lap polypeptides. two-dimensional immunoblots showed that lap-n and the lap ... | 2003 | 12746529 |
| the expression of the t-snare atsnap33 is induced by pathogens and mechanical stimulation. | the fusion of vesicles in the secretory pathway involves the interaction of t-soluble n-ethylmaleimide-sensitive factor attachment protein receptors (t-snares) on the target membrane and v-snares on the vesicle membrane. atsnap33 is an arabidopsis homolog of the neuronal t-snare snap-25 involved in exocytosis and is localized at the cell plate and at the plasma membrane. in this paper, the expression of atsnap33 was analyzed after different biotic and abiotic stresses. the expression of atsnap33 ... | 2003 | 12746539 |
| secretin of the enteropathogenic escherichia coli type iii secretion system requires components of the type iii apparatus for assembly and localization. | at least 16 proteins are thought to be involved in forming the enteropathogenic escherichia coli (epec) type iii translocation apparatus which delivers virulence factors into host cells, yet their function and location have not been determined. a biochemical analysis was performed on three components: escn, a predicted cytoplasmic atpase; escv, a predicted inner membrane protein; and escc, a predicted outer membrane secretin. wild-type epec and mutants constructed in these genes were fractionate ... | 2003 | 12761113 |
| oxygen-evolving enhancer protein 2 is phosphorylated by glycine-rich protein 3/wall-associated kinase 1 in arabidopsis. | the arabidopsis wall-associated receptor kinase, wak1, is a member of wak family that links the plasma membrane to the extracellular matrix. a glycine-rich secreted protein, atgrp-3, was previously shown to regulate wak1 functions through binding to the extracellular domain of wak1. in this study, we sought to determine the downstream molecules of the atgrp-3/wak1 signaling pathway, by using two-dimensional gel electrophoresis combined with edman sequencing and matrix-assisted laser desorption/i ... | 2003 | 12767910 |
| the pseudomonas fluorescens algg protein, but not its mannuronan c-5-epimerase activity, is needed for alginate polymer formation. | bacterial alginates are produced as 1-4-linked beta-d-mannuronan, followed by epimerization of some of the mannuronic acid residues to alpha-l-guluronic acid. here we report the isolation of four different epimerization-defective point mutants of the periplasmic pseudomonas fluorescens mannuronan c-5-epimerase algg. all mutations affected amino acids conserved among algg-epimerases and were clustered in a part of the enzyme also sharing some sequence similarity to a group of secreted epimerases ... | 2003 | 12775688 |
| ferredoxin from sweet pepper (capsicum annuum l.) intensifying harpin(pss)-mediated hypersensitive response shows an enhanced production of active oxygen species (aos). | the hypersensitive response (hr) is a form of cell death associated with plant resistance to pathogen infection. harpin(pss), an elicitor from the bacterium pseudomonas syringae pv. syringae, induces a hr in non-host plants. previously, we reported an amphipathic protein from sweet pepper interfering with harpin(pss)-mediated hr. in this report, we isolated and characterized a cdna clone encoded that amphipathic protein from sweet pepper. this protein is designated as pflp (plant ferredoxin-like ... | 2003 | 12777051 |
| nutritional similarity between leaf-associated nonpathogenic bacteria and the pathogen is not predictive of efficacy in biological control of bacterial spot of tomato. | it has been demonstrated that for a nonpathogenic, leaf-associated bacterium, effectiveness in the control of bacterial speck of tomato is correlated with the similarity in the nutritional needs of the nonpathogenic bacterium and the pathogen pseudomonas syringae pv. tomato. this relationship was investigated further in this study by using the pathogen xanthomonas campestris pv. vesicatoria, the causal agent of bacterial spot of tomato, and a collection of nonpathogenic bacteria isolated from to ... | 2003 | 12788754 |
| physical interaction between rrs1-r, a protein conferring resistance to bacterial wilt, and popp2, a type iii effector targeted to the plant nucleus. | rrs1-r confers broad-spectrum resistance to several strains of the causal agent of bacterial wilt, ralstonia solanacearum. although genetically defined as recessive, this r gene encodes a protein whose structure combines the tir-nbs-lrr domains found in several r proteins and a wrky motif characteristic of some plant transcriptional factors and behaves as a dominant gene in transgenic susceptible plants. here we show that popp2, a r. solanacearum type iii effector, which belongs to the yopj/avrr ... | 2003 | 12788974 |
| novel exchangeable effector loci associated with the pseudomonas syringae hrp pathogenicity island: evidence for integron-like assembly from transposed gene cassettes. | pseudomonas syringae strains use a type iii secretion system (ttss) to translocate effector proteins that assist in the parasitism of host plant cells. some genes for effector proteins are clustered in the exchangeable effector locus (eel) associated with the hrp pathogenicity island. a polymerase chain reaction-based screen was developed to amplify the eel from p. syringae strains. of the 86 strains screened, the eel was successfully amplified from 30 predominately north american p. syringae pv ... | 2003 | 12795376 |
| a strategy for the nmr characterization of type ii copper(ii) proteins: the case of the copper trafficking protein copc from pseudomonas syringae. | copc from pseudomonas syringae was found to be a protein capable of binding both cu(i) and cu(ii) at two different sites. the solution structure of the apo protein is available, and structural information has been obtained on the cu(i) bound form. we attempt here to set the limits for the determination of the solution structure of a cu(ii) protein, such as the cu(ii) bound form of copc, in which the cu(ii) ion takes a type ii coordination. the electron relaxation time is estimated from nmrd meas ... | 2003 | 12797793 |
| characterization of the early response of arabidopsis to alternaria brassicicola infection using expression profiling. | all tested accessions of arabidopsis are resistant to the fungal pathogen alternaria brassicicola. resistance is compromised by pad3 or coi1 mutations, suggesting that it requires the arabidopsis phytoalexin camalexin and jasmonic acid (ja)-dependent signaling, respectively. this contrasts with most well-studied arabidopsis pathogens, which are controlled by salicylic acid-dependent responses and do not benefit from absence of camalexin or ja. here, mutants with defects in camalexin synthesis (p ... | 2003 | 12805591 |
| the pattern of systemic acquired resistance induction within the arabidopsis rosette in relation to the pattern of translocation. | local leaf infections by a necrogenic pathogen can lead to systemic acquired resistance (sar) in untreated leaves. we reasoned that, whatever the nature of the long-distance signal, if it is transported in the phloem, the pattern of sar induced within the plant by treatment of a single leaf should match the pattern of translocation out of that leaf. the source-sink relationships (orthostichies) in the arabidopsis rosette were established with [14c]suc or phloem-mobile 3-aminotriazole at herbicid ... | 2003 | 12805614 |
| systemic gene expression in arabidopsis during an incompatible interaction with alternaria brassicicola. | pathogen challenge can trigger an integrated set of signal transduction pathways, which ultimately leads to a state of "high alert," otherwise known as systemic or induced resistance in tissue remote to the initial infection. although large-scale gene expression during systemic acquired resistance, which is induced by salicylic acid or necrotizing pathogens has been previously reported using a bacterial pathogen, the nature of systemic defense responses triggered by an incompatible necrotrophic ... | 2003 | 12805628 |
| sites of interaction between the feca and fecr signal transduction proteins of ferric citrate transport in escherichia coli k-12. | transcription of the fecabcde ferric citrate transport genes of escherichia coli k-12 is initiated by a signaling cascade from the cell surface into the cytoplasm. fecr receives the signal in the periplasm from the outer membrane protein feca loaded with ferric citrate, transmits the signal across the cytoplasmic membrane, and converts feci in the cytoplasm to an active sigma factor. in this study, it was shown through the use of a bacterial two-hybrid system that, in the periplasm, the c-termin ... | 2003 | 12813067 |
| molecular analysis of the copper-transporting efflux system cuscfba of escherichia coli. | the cus determinant of escherichia coli encodes the cuscfba proteins that mediate resistance to copper and silver by cation efflux. cusa and cusb were essential for copper resistance, and cusc and cusf were required for full resistance. replacements of methionine residues 573, 623, and 672 with isoleucine in cusa resulted in loss of copper resistance, demonstrating their functional importance. substitutions for several other methionine residues of this protein did not have any effect. the small ... | 2003 | 12813074 |
| a pseudomonas syringae type iii effector suppresses cell wall-based extracellular defense in susceptible arabidopsis plants. | bacterial effector proteins secreted through the type iii secretion system (ttss) play a crucial role in causing plant and human diseases. although the ability of type iii effectors to trigger defense responses in resistant plants is well understood, the disease-promoting functions of type iii effectors in susceptible plants are largely enigmatic. previous microscopic studies suggest that in susceptible plants the ttss of plant-pathogenic bacteria transports suppressors of a cell wall-based plan ... | 2003 | 12817082 |
| functional similarities between the icm/dot pathogenesis systems of coxiella burnetii and legionella pneumophila. | coxiella burnetii, the etiological agent of q fever, is an obligate intracellular pathogen, whereas legionella pneumophila, the causative agent of legionnaires' disease, is a facultative intracellular pathogen. during infection of humans both of these pathogens multiply in alveolar macrophages inside a closed phagosome. l. pneumophila intracellular multiplication was shown to be dependent on the icm/dot system, which probably encodes a type iv-related translocation apparatus. recently, genes hom ... | 2003 | 12819052 |
| characterization of a pathogen-induced calmodulin-binding protein: mapping of four ca2+-dependent calmodulin-binding domains. | ca2+ and calmodulin (cam), a key ca2+ sensor in all eukaryotes, have been implicated in defense responses in plants. to elucidate the role of ca2+ and cam in defense signaling, we used 35s-labeled cam to screen expression libraries prepared from tissues that were either treated with an elicitor derived from phytophthora megasperma or infected with pseudomonas syringae pv. tabaci. nineteen cdnas that encode the same protein, pathogen-induced cam-binding protein (picbp), were isolated. the picbp f ... | 2003 | 12825696 |
| the pseudomonas syringae type iii-secreted protein hopptod2 possesses protein tyrosine phosphatase activity and suppresses programmed cell death in plants. | the bacterial plant pathogen pseudomonas syringae possesses a type iii protein secretion system that delivers many virulence proteins into plant cells. a subset of these proteins (called avr proteins) is recognized by the plant's innate immune system and triggers defences. one defence-associated response is the hypersensitive response (hr), a programmed cell death (pcd) of plant tissue. we have previously identified hopptod2 as a type iii secreted protein from p. s. pv. tomato dc3000. sequence a ... | 2003 | 12828636 |
| a translocated protein tyrosine phosphatase of pseudomonas syringae pv. tomato dc3000 modulates plant defence response to infection. | pseudomonas syringae strains translocate effector proteins into host cells via the hrp-encoded type iii protein secretion system (ttss) to facilitate pathogenesis in susceptible plants. however, the mechanisms by which pathogenesis is favoured by these effectors are not well understood. individual strains express multiple effectors with apparently distinct activities that are co-ordinately regulated by the alternative sigma factor hrpl. genes for several effectors were identified in the p. syrin ... | 2003 | 12828637 |
| characterization of salicylic acid-induced genes in chinese cabbage. | salicylic acid is a messenger molecule in the activation of defense responses in plants. in this study, we isolated four cdna clones representing salicylic acid-induced genes in chinese cabbage (brassica rapa subsp. pekinensis) by subtractive hybridization. of the four clones, the bc5-2 clone encodes a putative glucosyltransferase protein. the bc5-3 clone is highly similar to an arabidopsis gene encoding a putative metal-binding farnesylated protein. the bc6-1 clone is a chitinase gene with simi ... | 2003 | 12835914 |
| freshwater bacteria can methylate selenium through the thiopurine methyltransferase pathway. | involvement of the bacterial thiopurine methyltransferase (btpmt) in natural selenium methylation by freshwater was investigated. a freshwater environment that had no known selenium contamination but exhibited reproducible emission of dimethyl selenide (dmse) or dimethyl diselenide (dmdse) when it was supplemented with an organic form of selenium [(methyl)selenocysteine] or an inorganic form of selenium (sodium selenite) was used. the distribution of the btpmt gene (tpm) in the microflora was st ... | 2003 | 12839745 |
| identification of two-component regulatory systems in bifidobacterium infantis by functional complementation and degenerate pcr approaches. | two-component signal transduction systems (2css) are widely used by bacteria to sense and adapt to changing environmental conditions. with two separate approaches, three different 2css were identified on the chromosome of the probiotic bacterium bifidobacterium infantis ucc 35624. one locus was identified by means of functional complementation of an escherichia coli mutant. another two were identified by pcr with degenerate primers corresponding to conserved regions of one protein component of t ... | 2003 | 12839803 |
| detection and diversity assessment of xylella fastidiosa in field-collected plant and insect samples by using 16s rrna and gyrb sequences. | the causal agent of diseases in many economically important plants is attributed to the xylem-limited bacterium xylella fastidiosa. the detection of this plant pathogen has been hampered due to its difficult isolation and slow growth on plates. nearly complete nucleotide sequences of the 16s rrna gene and partial sequences of the gyrb gene were determined for 18 strains of x. fastidiosa isolated from different plant hosts. a phylogenetic analysis, based on gyrb, grouped strains in three clusters ... | 2003 | 12839807 |
| ethylene and jasmonic acid signaling affect the npr1-independent expression of defense genes without impacting resistance to pseudomonas syringae and peronospora parasitica in the arabidopsis ssi1 mutant. | salicylic acid (sa), ethylene, and jasmonic acid (ja) are important signaling molecules in plant defense to biotic stress. an intricate signaling network involving sa, ethylene, and ja fine tunes plant defense responses. sa-dependent defense responses in arabidopsis thaliana are mediated through npr1-dependent and -independent mechanisms. we have previously shown that activation of an npr1-independent defense mechanism confers enhanced disease resistance and constitutive expression of the pathog ... | 2003 | 12848424 |
| the lower cell density of leaf parenchyma in the arabidopsis thaliana mutant lcd1-1 is associated with increased sensitivity to ozone and virulent pseudomonas syringae. | under optimal growth conditions (120 micro mol photons m-2 sec-1 photosynthetically active radiation (par), 16-h photoperiod), the recessive ozone-sensitive arabidopsis thaliana l. heynh. mutant lcd1-1 exhibits a pale phenotype compared to the wild type. confocal and multiphoton microscopy revealed that the paleness of lcd1-1 is because of a lower cell density in the leaf palisade parenchyma, resulting in decreased chlorophyll content. when exposed to ozone, lcd1-1 leaves become paler and contai ... | 2003 | 12848826 |
| regulation of arabidopsis copine 1 gene expression in response to pathogens and abiotic stimuli. | the copines are a widely distributed class of calcium-dependent, phospholipid-binding proteins of undetermined biological function. mutation of the arabidopsis cpn1 (copine 1) gene causes a humidity-sensitive lesion mimic phenotype with increased resistance to a bacterial and an oomyceteous pathogen, constitutive pathogenesis-related gene expression, and an accelerated hypersensitive cell death defense response. here, we show that the disease resistance phenotype of the cpn1-1 mutant was also te ... | 2003 | 12857819 |
| molecular characterization and quantitative analysis of superoxide dismutases in virulent and avirulent strains of aeromonas salmonicida subsp. salmonicida. | aeromonas salmonicida subsp. salmonicida is a facultatively intracellular gram-negative bacterium that is the etiological agent of furunculosis, a bacterial septicemia of salmonids that causes significant economic loss to the salmon farming industry. the mechanisms by which a. salmonicida evades intracellular killing may be relevant in understanding virulence and the eventual design of appropriate treatment strategies for furunculosis. we have identified two open reading frames (orfs) and relate ... | 2003 | 12867441 |
| isolation and analysis of mutants of double-stranded-rna bacteriophage phi6 with altered packaging specificity. | the genomes of bacteriophage phi6 and its relatives are packaged through a mechanism that involves the recognition and translocation of the three different plus strand transcripts of the segmented double-stranded rna genomes into preformed polyhedral structures called procapsids or inner cores. this packaging requires hydrolysis of nucleoside triphosphates and takes place in the order s-m-l. packaging is dependent on unique sequences of about 200 nucleotides near the 5' ends of plus strand trans ... | 2003 | 12867467 |
| simultaneous analysis of phytohormones, phytotoxins, and volatile organic compounds in plants. | phytohormones regulate the protective responses of plants against both biotic and abiotic stresses by means of synergistic or antagonistic actions referred to as signaling crosstalk. a bottleneck in crosstalk research is the quantification of numerous interacting phytohormones and regulators. the chemical analysis of salicylic acid, jasmonic acid, indole-3-acetic acid, and abscisic acid is typically achieved by using separate and complex methodologies. moreover, pathogen-produced phytohormone mi ... | 2003 | 12874387 |
| the rapid induction of glutathione s-transferases atgstf2 and atgstf6 by avirulent pseudomonas syringae is the result of combined salicylic acid and ethylene signaling. | the expression of two members of the glutathione s-transferase (gst) multigene family was studied in arabidopsis plants inoculated with an avirulent strain of pseudomonas syringae pv. tomato (pst). accumulation of atgstf2 and atgstf6 transcripts started 4 and 2 h after inoculation, respectively, and clearly preceded the induction of the pathogenesis-related pr-1 gene. the aim of this work was to find the reason for the faster induction of the two gsts compared with classical salicylic acid (sa)- ... | 2003 | 12881503 |
| electroporation and stable maintenance of plasmid dnas in a biocontrol strain of pseudomonas syringae. | transformation efficiencies as high as 10(7) transformants microg(-1) dna have been previously reported for pseudomonads using electroporation protocols established for e. coli with plasmid dnas prepared from methylation proficient e. coli hosts. we report here a protocol for electroporation of plasmid dnas into a biocontrol strain of pseudomonas syringae which could not be electroporated by standard e. coli methods. transformation efficiencies of 10(7) or higher were obtained with dna recovered ... | 2003 | 12882571 |
| an arabidopsis mutant resistant to thaxtomin a, a cellulose synthesis inhibitor from streptomyces species. | thaxtomin a is a phytotoxin produced by streptomyces scabies and other streptomyces species, the causative agents of common scab disease in potato and other taproot crops. at nanomolar concentrations, thaxtomin causes dramatic cell swelling, reduced seedling growth, and inhibition of cellulose synthesis in arabidopsis. we identified a mutant of arabidopsis, designated txr1, that exhibits increased resistance to thaxtomin as a result of a decrease in the rate of toxin uptake. the txr1 gene was id ... | 2003 | 12897252 |
| p-coumaroylnoradrenaline, a novel plant metabolite implicated in tomato defense against pathogens. | the avr9 peptide elicitor from the fungus cladosporium fulvum, the bacterial pathogen pseudomonas syringae pathovar tomato carrying the avirulence gene avrpto (pst (avrpto)), and the organophosphorous insecticide fenitrothion induce resistance-related responses in tomato lines carrying the cf-9, pto, and fen genes, respectively. these responses were associated with synthesis of p-coumaroyloctopamine and p-coumaroylnoradrenaline, a novel compound for plants. in susceptible near isogenic tomato li ... | 2003 | 12900412 |
| colonization of arabidopsis thaliana with salmonella enterica and enterohemorrhagic escherichia coli o157:h7 and competition by enterobacter asburiae. | enteric pathogens, such as salmonella enterica and escherichia coli o157:h7, have been shown to contaminate fresh produce. under appropriate conditions, these bacteria will grow on and invade the plant tissue. we have developed arabidopsis thaliana (thale cress) as a model system with the intention of studying plant responses to human pathogens. under sterile conditions and at 100% humidity, s. enterica serovar newport and e. coli o157:h7 grew to 10(9) cfu g(-1) on a. thaliana roots and to 2 x 1 ... | 2003 | 12902287 |
| analysis of the argk-tox gene cluster in nontoxigenic strains of pseudomonas syringae pv. phaseolicola. | the analysis of 46 isolates obtained directly from different and distant common bean fields from the northwestern part of spain revealed that they do not produce phaseolotoxin. the isolates were classified as race 5, and their analysis revealed that they do not carry the argk-tox gene cluster involved in the biosynthesis of the phaseolotoxin. | 2003 | 12902295 |
| identifying the methyltransferases for m(5)u747 and m(5)u1939 in 23s rrna using maldi mass spectrometry. | there are three sites of m(5)u modification in escherichia coli stable rnas: one at the invariant trna position u54 and two in 23s rrna at the phylogenetically conserved positions u747 and u1939. each of these sites is modified by its own methyltransferase, and the trna methyltransferase, trma, is well-characterised. two open reading frames, ybjf and ygca, are approximately 30% identical to trma, and here we determine the functions of these candidate methyltransferases using maldi mass spectrome ... | 2003 | 12907714 |