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characterization of a cryptic plasmid psm429 and its application for heterologous expression in psychrophilic pseudoalteromonas.abstract: background: pseudoalteromonas is an important genus widespread in marine environment, and a lot of psychrophilic pseudoalteromonas strains thrive in deep sea and polar sea. by now, there are only a few genetic systems for pseudoalteromonas reported and no commercial pseudoalteromonas genetic system is available, which impedes the study of pseudoalteromonas, especially for psychrophilic strains. the aim of this study is to develop a heterologous expression system for psychrophilic pseud ...201121542941
multiple roles of win3 in regulating disease resistance, cell death, and flowering time in arabidopsis.the salicylic acid (sa) regulatory gene hopw1-1-interacting 3 (win3) was previously shown to confer resistance to the biotrophic pathogen pseudomonas syringae. here we report that win3 controls broad-spectrum disease resistance to the necrotrophic pathogen botrytis cinerae and contributes to basal defense induced by flg22, a 22-amino acid peptide derived from the conserved region of bacterial flagellin proteins. genetic analysis indicates that win3 acts additively with several known sa regulator ...201121543726
arabidopsis argonaute 2 regulates innate immunity via mirna393(∗)-mediated silencing of a golgi-localized snare gene, memb12.argonaute (ago) proteins are critical components of rna silencing pathways that bind small rnas and mediate gene silencing at their target sites. we found that arabidopsis ago2 is highly induced by the bacterial pathogen pseudomonas syringae pv. tomato (pst). further genetic analysis demonstrated that ago2 functions in antibacterial immunity. one abundant species of ago2-bound small rna is mir393b(∗), which targets a golgi-localized snare gene, memb12. pst infection downregulates memb12 in a mir ...201121549312
pseudomonas syringae colonizes distant tissues in nicotiana benthamiana through xylem vessels.the ability to move from the primary infection site and colonize distant tissue in the leaf is an important property of bacterial plant pathogens, yet hardly investigated for model pathogens. here we show that gfp-expressing pseudomonas syringae pv. syringae dc3000 lacking the hopq1-1 effector (ptodc3000δhq) has a strong capacity to colonize distant leaf tissue from wound-inoculated sites in n. benthamiana. distant colonization occurs within one week after toothpick inoculation and is characteri ...201121554458
vibrio cholerae requires the type vi secretion system virulence factor vasx to kill dictyostelium discoideum.the type vi secretion system (t6ss) is recognized as an important virulence mechanism in several gram-negative pathogens. in vibrio cholerae, the causative agent of the diarrheal disease cholera, a minimum of three gene clusters-one main cluster and two auxiliary clusters-are required to form a functional t6ss apparatus capable of conferring virulence towards eukaryotic and prokaryotic hosts. despite an increasing understanding of the components that make up the t6ss apparatus, little is known a ...201121555399
the main virulence determinant of yersinia entomophaga mh96 is a broad-host-range toxin complex active against insects.through transposon mutagenesis and dna sequence analysis, the main disease determinant of the entomopathogenic bacterium yersinia entomophaga mh96 was localized to an ~32-kb pathogenicity island (pai) designated pai(ye96). residing within pai(ye96) are seven open reading frames that encode an insecticidal toxin complex (tc), comprising not only the readily recognized toxin complex a (tca), tcb, and tcc components but also two chitinase proteins that form a composite tc molecule. the central tc g ...201121278295
myb46 modulates disease susceptibility to botrytis cinerea in arabidopsis.in this study, we show that the arabidopsis (arabidopsis thaliana) transcription factor myb46, previously described to regulate secondary cell wall biosynthesis in the vascular tissue of the stem, is pivotal for mediating disease susceptibility to the fungal pathogen botrytis cinerea. we identified myb46 by its ability to bind to a new cis-element located in the 5' promoter region of the pathogen-induced ep5c gene, which encodes a type iii cell wall-bound peroxidase. we present genetic and molec ...201121282403
genetic disassembly and combinatorial reassembly identify a minimal functional repertoire of type iii effectors in pseudomonas syringae.the virulence of pseudomonas syringae and many other proteobacterial pathogens is dependent on complex repertoires of effector proteins injected into host cells by type iii secretion systems. the 28 well-expressed effector genes in the repertoire of the model pathogen p. syringae pv. tomato dc3000 were deleted to produce polymutant dc3000d28e. growth of dc3000d28e in nicotiana benthamiana was symptomless and 4 logs lower than that of dc3000?hopq1-1, which causes disease in this model plant. dc30 ...201121282655
a high throughput amenable arabidopsis-p. aeruginosa system reveals a rewired regulatory module and the utility to identify potent anti-infectives.we previously demonstrated that in a metasystem consisting of arabidopsis seedlings growing in liquid medium (in 96 well plates) even microbes considered to be innocuous such as laboratory strains of e. coli and b. subtilis can cause potent damage to the host. we further posited that such environment-induced adaptations are brought about by 'system status changes' (rewiring of pre-existing cellular signaling networks and components) of the host and the microbe, and that prolongation of such a si ...201121283656
regulation of the co-evolved hrpr and hrps aaa+ proteins required for pseudomonas syringae pathogenicity.the bacterial aaa+ enhancer-binding proteins (ebps) hrpr and hrps (hrprs) of pseudomonas syringae (ps) activate s(54)-dependent transcription at the hrpl promoter; triggering type-three secretion system-mediated pathogenicity. in contrast with singly acting ebps, the evolution of the strictly co-operative hrprs pair raises questions of potential benefits and mechanistic differences this transcription control system offers. here, we show distinct properties of hrpr and hrps variants, indicating f ...201121285955
the elicitation of a systemic resistance by pseudomonas putida btp1 in tomato involves the stimulation of two lipoxygenase isoforms.some non-pathogenic rhizobacteria called plant growth promoting rhizobacteria (pgpr) possess the capacity to induce in plant defense mechanisms effective against pathogens. precedent studies showed the ability of pseudomonas putida btp1 to induce pgpr-mediated resistance, termed isr (induced systemic resistance), in different plant species. despite extensive works, molecular defense mechanisms involved in isr are less well understood that in the case of pathogen induced systemic acquired resista ...201121294872
detection of peroxynitrite accumulation in arabidopsis thaliana during the hypersensitive defense response.nitric oxide (no) is synthesized in plants in response to stress, and its role in signaling is well-documented. in contrast, very little is known about the physiological role of its derivate peroxynitrite (onoo(-)), which forms when no reacts with o(2)(-) and induces protein modification by tyrosine nitration. infection with an avirulent pathogen triggers the simultaneous production of no and reactive oxygen species, as well as an increase in tyrosine nitration, so peroxynitrite could be physiol ...201121296177
the pepper receptor-like cytoplasmic protein kinase capik1 is involved in plant signaling of defense and cell-death responses.certain protein kinases have been shown to be crucial for plant cell signaling pathways associated with plant immune responses. here we identified a pepper (capsicum annuum) receptor-like cytoplasmic protein kinase (rlck) gene (capik1) that is transcriptionally activated by infection with xanthomonas campestris pv. vesicatoria (xcv). silencing of capik1 in pepper plants confers enhanced susceptibility to xcv infection. salicylic acid-dependent defense responses are attenuated in the capik1-silen ...201121299658
transcription reprogramming during root nodule development in medicago truncatula.many genes which are associated with root nodule development and activity in the model legume medicago truncatula have been described. however information on precise stages of activation of these genes and their corresponding transcriptional regulators is often lacking. whether these regulators are shared with other plant developmental programs also remains an open question. here detailed microarray analyses have been used to study the transcriptome of root nodules induced by either wild type or ...201121304580
genome sequence analyses of pseudomonas savastanoi pv. glycinea and subtractive hybridization-based comparative genomics with nine pseudomonads.bacterial blight, caused by pseudomonas savastanoi pv. glycinea (psg), is a common disease of soybean. in an effort to compare a current field isolate with one isolated in the early 1960s, the genomes of two psg strains, race 4 and b076, were sequenced using 454 pyrosequencing. the genomes of both psg strains share more than 4,900 highly conserved genes, indicating very low genetic diversity between psg genomes. though conserved, genome rearrangements and recombination events occur commonly with ...201121304594
new detection systems of bacteria using highly selective media designed by smart: selective medium-design algorithm restricted by two constraints.culturing is an indispensable technique in microbiological research, and culturing with selective media has played a crucial role in the detection of pathogenic microorganisms and the isolation of commercially useful microorganisms from environmental samples. although numerous selective media have been developed in empirical studies, unintended microorganisms often grow on such media probably due to the enormous numbers of microorganisms in the environment. here, we present a novel strategy for ...201121304596
algw regulates multiple pseudomonas syringae virulence strategies.gram-negative bacterial pathogens have evolved a number of virulence-promoting strategies including the production of extracellular polysaccharides such as alginate and the injection of effector proteins into host cells. the induction of these virulence mechanisms can be associated with concomitant downregulation of the abundance of proteins that trigger the host immune system, such as bacterial flagellin. in pseudomonas syringae, we observed that bacterial motility and the abundance of flagelli ...201121306444
a novel immunity system for bacterial nucleic acid degrading toxins and its recruitment in various eukaryotic and dna viral systems.the use of nucleases as toxins for defense, offense or addiction of selfish elements is widely encountered across all life forms. using sensitive sequence profile analysis methods, we characterize a novel superfamily (the sukh superfamily) that unites a diverse group of proteins including smi1/knr4, pgs2, fbxo3, skip16, syd, herpesviral us22, irs1 and trs1, and their bacterial homologs. using contextual analysis we present evidence that the bacterial members of this superfamily are potential imm ...201121306995
proline dehydrogenase contributes to pathogen defense in arabidopsis.l-proline (pro) catabolism is activated in plants recovering from abiotic stresses associated with water deprivation. in this catabolic pathway, pro is converted to glutamate by two reactions catalyzed by proline dehydrogenase (prodh) and ?(1)-pyrroline-5-carboxylate dehydrogenase (p5cdh), with ?(1)-pyrroline-5-carboxylate (p5c) as the intermediate. alternatively, under certain conditions, the p5c derived from pro is converted back to pro by p5c reductase, thus stimulating the pro-p5c cycle, whi ...201121311034
interconnection between methyl salicylate and lipid-based long-distance signaling during the development of systemic acquired resistance in arabidopsis and tobacco. 201121311035
the genetic basis of resistance to downy mildew in cucumis spp.--latest developments and prospects.downy mildew, caused by the oomycete pathogen pseudoperonospora cubensis, is one of the most destructive diseases of cucumber (cucumis sativus l.) and muskmelon (c. melo l.). although the process of pathogenesis is well understood, there are few disease control options available. the development and deployment of resistant cultivars is generally considered to be the best approach to control downy mildew. the recently completed sequencing of the cucumber genome provides a great opportunity for re ...201121318301
specific threonine phosphorylation of a host target by two unrelated type iii effectors activates a host innate immune receptor in plants.the arabidopsis nb-lrr immune receptor rpm1 recognizes the pseudomonas syringae type iii effectors avrb or avrrpm1 to mount an immune response. although neither effector is itself a kinase, avrrpm1 and avrb are known to target arabidopsis rin4, a negative regulator of basal plant defense, for phosphorylation. we show that rin4 phosphorylation activates rpm1. rin4(142-176) is necessary and, with appropriate localization sequences, sufficient to support effector-triggered rpm1 activation, with the ...201121320695
a receptor-like cytoplasmic kinase phosphorylates the host target rin4, leading to the activation of a plant innate immune receptor.plants have evolved sophisticated surveillance systems to recognize pathogen effectors delivered into host cells. rpm1 is an nb-lrr immune receptor that recognizes the pseudomonas syringae effectors avrb and avrrpm1. both effectors associate with and affect the phosphorylation of rin4, an immune regulator. although the kinase and the specific mechanisms involved are unclear, it has been hypothesized that rpm1 recognizes phosphorylated rin4. here, we identify ripk as a rin4-interacting receptor-l ...201121320696
multilocus sequence typing of pseudomonas syringae sensu lato confirms previously described genomospecies and permits rapid identification of p. syringae pv. coriandricola and p. syringae pv. apii causing bacterial leaf spot on parsley.since 2002, severe leaf spotting on parsley (petroselinum crispum) has occurred in monterey county, ca. either of two different pathovars of pseudomonas syringae sensu lato were isolated from diseased leaves from eight distinct outbreaks and once from the same outbreak. fragment analysis of dna amplified between repetitive sequence polymerase chain reaction; 16s rdna sequence analysis; and biochemical, physiological, and host range tests identified the pathogens as pseudomonas syringae pv. apii ...201121323469
zmpep1, an ortholog of arabidopsis elicitor peptide 1, regulates maize innate immunity and enhances disease resistance.zmpep1 is a bioactive peptide encoded by a previously uncharacterized maize (zea mays) gene, zmpropep1. zmpropep1 was identified by sequence similarity as an ortholog of the arabidopsis (arabidopsis thaliana) atpropep1 gene, which encodes the precursor protein of elicitor peptide 1 (atpep1). together with its receptors, atpepr1 and atpepr2, atpep1 functions to activate and amplify innate immune responses in arabidopsis and enhances resistance to both pythium irregulare and pseudomonas syringae. ...201121205619
the pepper mannose-binding lectin gene cambl1 is required to regulate cell death and defense responses to microbial pathogens.plant mannose-binding lectins (mbls) are crucial for plant defense signaling during pathogen attack by recognizing specific carbohydrates on pathogen surfaces. in this study, we isolated and functionally characterized a novel pepper (capsicum annuum) mbl gene, cambl1, from pepper leaves infected with xanthomonas campestris pv vesicatoria (xcv). the cambl1 gene contains a predicted galanthus nivalis agglutinin-related lectin domain responsible for the recognition of high-mannose n-glycans but lac ...201121205632
the transport mechanism of bacterial cu+-atpases: distinct efflux rates adapted to different function.cu(+)-atpases play a key role in bacterial cu(+) homeostasis by participating in cu(+) detoxification and cuproprotein assembly. characterization of archaeoglobus fulgidus copa, a model protein within the subfamily of p(1b-1) type atpases, has provided structural and mechanistic details on this group of transporters. atomic resolution structures of cytoplasmic regulatory metal binding domains (mbds) and catalytic actuator, phosphorylation, and nucleotide binding domains are available. these, in ...201121210186
comparative analysis of the biosynthetic gene clusters and pathways for three structurally related antitumor antibiotics: bleomycin, tallysomycin, and zorbamycin.the biosynthetic gene clusters for the glycopeptide antitumor antibiotics bleomycin (blm), tallysomycin (tlm), and zorbamycin (zbm) have been recently cloned and characterized from streptomyces verticillus atcc15003, streptoalloteichus hindustanus e465-94 atcc31158, and streptomyces flavoviridis atcc21892, respectively. the striking similarities and differences among the biosynthetic gene clusters for the three structurally related glycopeptide antitumor antibiotics prompted us to compare and co ...201121210656
loss-of-function mutation of reduced wall acetylation2 in arabidopsis leads to reduced cell wall acetylation and increased resistance to botrytis cinerea.nearly all polysaccharides in plant cell walls are o-acetylated, including the various pectic polysaccharides and the hemicelluloses xylan, mannan, and xyloglucan. however, the enzymes involved in the polysaccharide acetylation have not been identified. while the role of polysaccharide acetylation in vivo is unclear, it is known to reduce biofuel yield from lignocellulosic biomass by the inhibition of microorganisms used for fermentation. we have analyzed four arabidopsis (arabidopsis thaliana) ...201121212300
new insights into the signaling mechanism of the ph-responsive, membrane-integrated transcriptional activator cadc of escherichia coli.the membrane-integrated transcriptional regulator cadc of escherichia coli activates expression of the cadba operon at low external ph with concomitantly available lysine, providing adaptation to mild acidic stress. cadc is a representative of the toxr-like proteins that combine sensory, signal transduction, and dna-binding activities within a single polypeptide. although several toxr-like regulators such as cadc, as well as the main regulator of vibrio cholerae virulence, toxr itself, which act ...201121216950
identification of genes differentially expressed in a resistant reaction to mycosphaerella pinodes in pea using microarray technology.ascochyta blight, caused by mycosphaerella pinodes is one of the most important pea pathogens. however, little is known about the genes and mechanisms of resistance acting against m. pinodes in pea. resistance identified so far to this pathogen is incomplete, polygenic and scarce in pea, being most common in pisum relatives. the identification of the genes underlying resistance would increase our knowledge about m. pinodes-pea interaction and would facilitate the introgression of resistance into ...201121226971
plant targets for pseudomonas syringae type iii effectors: virulence targets or guarded decoys?the phytopathogenic bacterium pseudomonas syringae can suppress both pathogen-associated molecular pattern (pamp)-triggered immunity (pti) and effector-triggered immunity (eti) by the injection of type iii effector (t3e) proteins into host cells. t3es achieve immune suppression using a variety of strategies including interference with immune receptor signaling, blocking rna pathways and vesicle trafficking, and altering organelle function. t3es can be recognized indirectly by resistance proteins ...201121227738
genetic characterization indicates that a specific subpopulation of pseudomonas aeruginosa is associated with keratitis infections.pseudomonas aeruginosa is a common opportunistic bacterial pathogen that causes a variety of infections in humans. populations of p. aeruginosa are dominated by common clones that can be isolated from diverse clinical and environmental sources. to determine whether specific clones are associated with corneal infection, we used a portable genotyping microarray system to analyze a set of 63 p. aeruginosa isolates from patients with corneal ulcers (keratitis). we then used population analysis to co ...201121227987
next-generation genomics of pseudomonas syringae.the first wave of pseudomonas syringae next-generation genomic studies has revealed insights into host-specific virulence and immunity, genome dynamics and evolution, and genetic and metabolic specialization. these studies have further enhanced our understanding of type iii effector diversity, identified an atypical type iii secretion system (t3ss) in a new clade of nonpathogenic p. syringae, identified metabolic pathways common to pathogens of woody hosts and revealed extensive genomic diversit ...201121233007
nicotiana tabacum overexpressing γ-ecs exhibits biotic stress tolerance likely through npr1-dependent salicylic acid-mediated pathway.the elaborate networks and the crosstalk of established signaling molecules like salicylic acid (sa), jasmonic acid (ja), ethylene (et), abscisic acid (aba), reactive oxygen species (ros) and glutathione (gsh) play key role in plant defense response. to obtain further insight into the mechanism through which gsh is involved in this crosstalk to mitigate biotic stress, transgenic nicotiana tabacum overexpressing lycopersicon esculentum gamma-glutamylcysteine synthetase (leecs) gene (ntgb lines) w ...201121234598
the metabolic interface between pseudomonas syringae and plant cells.the bacterial plant pathogen pseudomonas syringae causes economically important diseases of a wide variety of plant species and is used as a model organism to understand the molecular basis of plant disease. much existing research into p. syringae-plant interactions has focused on the molecular basis of plant disease resistance and the role of secreted effector proteins in the suppression of plant defences. however, researchers have speculated that the diverse array of effectors, toxins and horm ...201121236723
potential application of northern argentine propolis to control some phytopathogenic bacteria.the antimicrobial activity of samples of northern argentine propolis (tucumán, santiago del estero and chaco) against phytopathogenic bacteria was assessed and the most active samples were identified. minimal inhibitory concentration (mic) values were determined by agar macrodilution and broth microdilution assays. strong antibacterial activity was detected against erwinia carotovora spp carotovora cect 225, pseudomonas syringae pvar tomato cect 126, pseudomonas corrugata cect 124 and xanthomona ...201121237629
autoregulation of nodulation interferes with impacts of nitrogen fertilization levels on the leaf-associated bacterial community in soybeans.the diversities leaf-associated bacteria on nonnodulated (nod(-)), wild-type nodulated (nod(+)), and hypernodulated (nod(++)) soybeans were evaluated by clone library analyses of the 16s rrna gene. to analyze the impact of nitrogen fertilization on the bacterial leaf community, soybeans were treated with standard nitrogen (sn) (15 kg n ha(-1)) or heavy nitrogen (hn) (615 kg n ha(-1)) fertilization. under sn fertilization, the relative abundance of alphaproteobacteria was significantly higher in ...201121239540
glutathione-indole-3-acetonitrile is required for camalexin biosynthesis in arabidopsis thaliana.camalexin, a major phytoalexin in arabidopsis thaliana, consists of an indole ring and a thiazole ring. the indole ring is produced from trp, which is converted to indole-3-acetonitrile (ian) by cyp79b2/cyp79b3 and cyp71a13. conversion of cys(ian) to dihydrocamalexic acid and subsequently to camalexin is catalyzed by cyp71b15. recent studies proposed that cys derivative, not cys itself, is the precursor of the thiazole ring that conjugates with ian. the nature of the cys derivative and how it co ...201121239642
characterization of a non-ribosomal peptide synthetase-associated diiron arylamine n-oxygenase from pseudomonas syringae pv. phaseolicola.the regiospecific oxidation of aromatic amines to aryl nitro compounds is critical to the synthesis of several natural products having pharmacological importance. the arylamine n-oxygenase (aao) from streptomyces thioluteus (aurf) selectively oxidizes p-aminobenzoic acid to p-nitrobenzoic acid and has been the subject of investigation for its unique chemistry and substrate preferences. little, however, is known about the biochemistry and substrate specificities of aurf homologues, which are ofte ...201121241656
performance and long-term stability of the barley hordothionin gene in multiple transgenic apple lines.introduction of sustainable scab resistance in elite apple cultivars is of high importance for apple cultivation when aiming at reducing the use of chemical crop protectants. genetic modification (gm) allows the rapid introduction of resistance genes directly into high quality apple cultivars. resistance genes can be derived from apple itself but genetic modification also opens up the possibility to use other, non-host resistance genes. a prerequisite for application is the long-term performance ...201121243525
bsctv c2 attenuates the degradation of samdc1 to suppress dna methylation-mediated gene silencing in arabidopsis.plant viruses are excellent tools for studying microbial-plant interactions as well as the complexities of host activities. our study focuses on the role of c2 encoded by beet severe curly top virus (bsctv) in the virus-plant interaction. using bsctv c2 as bait in a yeast two-hybrid screen, a c2-interacting protein, s-adenosyl-methionine decarboxylase 1 (samdc1), was identified from an arabidopsis thaliana cdna library. the interaction was confirmed by an in vitro pull-down assay and a firefly l ...201121245466
cross-talk of calcium-dependent protein kinase and map kinase signaling.plants use different signalling pathways to acclimate to changing environmental conditions. fast changes in the concentration of free ca(2+) ions - so called ca(2+) signals - are among the first responses to many stress situations. these signals are decoded by different types of calcium-dependent protein kinases, which - together with mitogen-activated protein kinases (mapk) - present two major pathways that are widely used to adapt the cellular metabolism to a changing environment. ca(2+)-depen ...201121248475
the slmkk2 and slmpk2 genes play a role in tomato disease resistance to xanthomonas campestris pv. vesicatoria.xanthomonas campestris pv. vesicatoria (xcv) is the causal agent of bacterial spot disease in tomato (solanum lycopersicum) plants. we recently identified a mapkkk gene, slmapkkkε, which is required for tomato resistance to xcv strains and encodes a positive regulator of cell death. we also provided evidence that the mek2 mapkk, and the wipk and sipk mapks act downstream to mapkkkε in nicotiana benthamiana plants. here, we used the virus-induced gene silencing technique to assess whether tomato ...201121248478
ralstonia solanacearum extracellular polysaccharide is a specific elicitor of defense responses in wilt-resistant tomato plants.ralstonia solanacearum, which causes bacterial wilt of diverse plants, produces copious extracellular polysaccharide (eps), a major virulence factor. the function of eps in wilt disease is uncertain. leading hypotheses are that eps physically obstructs plant water transport, or that eps cloaks the bacterium from host plant recognition and subsequent defense. tomato plants infected with r. solanacearum race 3 biovar 2 strain uw551 and tropical strain gmi1000 upregulated genes in both the ethylene ...201121253019
bacterial effector hopf2 suppresses arabidopsis innate immunity at the plasma membrane.many bacterial pathogens inject a cocktail of effector proteins into host cells through type iii secretion systems. these effectors act in concert to modulate host physiology and immune signaling, thereby promoting pathogenicity. in a search for additional pseudomonas syringae effectors in suppressing plant innate immunity triggered by pathogen or microbe-associated molecular patterns (pamps or mamps), we identified p. syringae tomato dc3000 effector hopf2 as a potent suppressor of early immune- ...201121198360
the plant growth-promoting rhizobacterium bacillus cereus ar156 induces systemic resistance in arabidopsis thaliana by simultaneously activating salicylate- and jasmonate/ethylene-dependent signaling pathways.bacillus cereus ar156 is a plant growth-promoting rhizobacterium that induces resistance against a broad spectrum of pathogens including pseudomonas syringae pv. tomato dc3000. this study analyzed ar156-induced systemic resistance (isr) to dc3000 in arabidopsis ecotype col-0 plants. compared with mock-treated plants, ar156-treated ones showed an increase in biomass and reductions in disease severity and pathogen density in the leaves. the defense-related genes pr1, pr2, pr5, and pdf1.2 were conc ...201121198361
HPR1, a component of the THO/TREX complex, plays an important role in disease resistance and senescence in Arabidopsis.ENHANCED DISEASE RESISTANCE 1 (EDR1) is a negative regulator of powdery mildew resistance, cell death and ethylene-induced senescence. To identify components involved in EDR1 signaling, we performed a forward genetic screen for edr1 suppressors. In this screen, we identified the hpr1-4 mutation, which partially suppresses edr1-mediated resistance to the powdery mildew pathogen Golovinomyces cichoracearum and mildew-induced cell death. However, the hpr1-4 mutation enhanced the ethylene-induced se ...201122035198
Localization of DIR1 at the tissue, cellular and subcellular levels during Systemic Acquired Resistance in Arabidopsis using DIR1:GUS and DIR1:EGFP reporters.Systemic Acquired Resistance (SAR) is an induced resistance response to pathogens, characterized by the translocation of a long-distance signal from induced leaves to distant tissues to prime them for increased resistance to future infection. DEFECTIVE in INDUCED RESISTANCE 1 (DIR1) has been hypothesized to chaperone a small signaling molecule to distant tissues during SAR in Arabidopsis.201121896186
a novel antimicrobial protein for plant protection consisting of a xanthomonas oryzae harpin and active domains of cecropin a and melittin.discoveries about antimicrobial peptides and plant defence activators have made possible the de novo and rational design of novel peptides for use in crop protection. here we report a novel chimeric protein, hcm1, which was made by linking the active domains of cecropin a and melittin to the hypersensitive response (hr)-elicitor hpa1 of xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak. the resulting chimeric protein maintained not only the hr-inducing property of ...201121895994
use of low-coverage, large-insert, short-read data for rapid and accurate generation of enhanced-quality draft pseudomonas genome sequences.next-generation genomic technology has both greatly accelerated the pace of genome research as well as increased our reliance on draft genome sequences. while groups such as the genomics standards consortium have made strong efforts to promote genome standards there is a still a general lack of uniformity among published draft genomes, leading to challenges for downstream comparative analyses. this lack of uniformity is a particular problem when using standard draft genomes that frequently have ...201122073286
RNA-Seq Analysis of a Soybean Near-Isogenic Line Carrying Bacterial Leaf Pustule-Resistant and -Susceptible Alleles.Bacterial leaf pustule (BLP) disease is caused by Xanthomonas axonopodis pv. glycines (Xag). To investigate the plant basal defence mechanisms induced in response to Xag, differential gene expression in near-isogenic lines (NILs) of BLP-susceptible and BLP-resistant soybean was analysed by RNA-Seq. Of a total of 46 367 genes that were mapped to soybean genome reference sequences, 1978 and 783 genes were found to be up- and down-regulated, respectively, in the BLP-resistant NIL relative to the BL ...201121987089
Increasing Nitric Oxide Content in Arabidopsis thaliana by Expressing Rat Neuronal Nitric Oxide Synthase Resulted in Enhanced Stress Tolerance.Nitric oxide (NO) plays essential roles in many physiological and developmental processes in plants, including biotic and abiotic stresses, which cause adverse effect on agricultural production. However, for the lack of findings for nitric oxide synthase (NOS), it raises many difficulties to investigate the physiological roles of NO in vivo and thus its utilization for genetic engineering. Here, to explore the possibility of manipulating the endogenous NO level, the rat neuronal NOS (nNOS) was e ...201122186181
Extensive Genomic Variation within Clonal Complexes of Neisseria meningitidis.Meningococcal disease is a widely distributed complex disease affecting all age categories. It can cause severe meningitis and septicemia, especially in unvaccinated infants and young children. The causative agent, Neisseria meningitidis (Nm), can be phenotypically and genetically differentiated into serogroups and sequence types (STs) and has a highly dynamic population structure. To obtain a deeper understanding of the epidemiology of Nm, we sequenced seven Nm genomes. Large-scale genomic anal ...201122084315
Defence responses of Arabidopsis thaliana to infection by Pseudomonas syringae are regulated by the circadian clock.The circadian clock allows plants to anticipate predictable daily changes in abiotic stimuli, such as light; however, whether the clock similarly allows plants to anticipate interactions with other organisms is unknown. Here we show that Arabidopsis thaliana (Arabidopsis) has circadian clock-mediated variation in resistance to the virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), with plants being least susceptible to infection in the subjective morning. We suggest ...201122066021
Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa.Pseudomonas aeruginosa synthesizes phosphorylcholine phosphatase (PchP) when grown on choline, betaine, dimethylglycine or carnitine. In the presence of Mg(2+) or Zn(2+), PchP catalyzes the hydrolysis of p-nitrophenylphosphate (p-NPP) or phosphorylcholine (Pcho). The regulation of pchP gene expression is under the control of GbdR and NtrC; dimethylglycine is likely the metabolite directly involved in the induction of PchP. Therefore, the regulation of choline metabolism and consequently PchP syn ...201121915373
Genomes and Virulence Factors of Novel Bacterial Pathogens Causing Bleaching Disease in the Marine Red Alga Delisea pulchra.Nautella sp. R11, a member of the marine Roseobacter clade, causes a bleaching disease in the temperate-marine red macroalga, Delisea pulchra. To begin to elucidate the molecular mechanisms underpinning the ability of Nautella sp. R11 to colonize, invade and induce bleaching of D. pulchra, we sequenced and analyzed its genome. The genome encodes several factors such as adhesion mechanisms, systems for the transport of algal metabolites, enzymes that confer resistance to oxidative stress, cytolys ...201122162749
attenuation of virulence in pathogenic bacteria using synthetic quorum-sensing modulators under native conditions on plant hosts.quorum sensing (qs) is often critical in both pathogenic and mutualistic relationships between bacteria and their eukaryotic hosts. gram-negative bacteria typically use n-acylated l-homoserine lactone (ahl) signals for qs. we have identified a number of synthetic ahl analogues that are able to strongly modulate qs in culture-based, reporter gene assays. while informative, these assays represent idealized systems, and their relevance to qs under native conditions is often unclear. as one of our g ...201121932837
Diverting the flux of the JA pathway in Nicotiana attenuata compromises the plant's defense metabolism and fitness in nature and glasshouse.A plant's inducible defenses against herbivores as well as certain developmental processes are known to be controlled by the jasmonic acid (JA) pathway. We have previously shown that ectopically expressing Arabidopsis thaliana JA O-methyltransferase in Nicotiana attenuata (35S-jmt) strongly reduces the herbivory-elicited jasmonate bursts by acting as metabolic sink that redirects free JA towards methylation; here we examine the consequences of this metabolic sink on N. attenuata's secondary meta ...201122022469
effect of glutaraldehyde fixation on bacterial cells observed by atomic force microscopy.atomic force microscopy (afm) is a promising microscopy technique that can provide high-resolution images of bacterial cells without fixation. three species of bacteria, xanthomonas campestris, pseudomonas syringae, and bacillus subtilis, were used in this study. afm images were obtained from unfixed and glutaraldehyde-fixed cells, and cell height was measured. the mean height of bacterial cells prepared by fixation was higher than that of those prepared by nonfixation. however, the height chang ...201121898456
Direct Infusion Mass Spectrometry of Oxylipin-Containing Arabidopsis thaliana Membrane Lipids Reveals Varied Patterns in Different Stress Responses.Direct infusion electrospray ionization triple quadrupole precursor scanning for three oxidized fatty acyl anions revealed 86 mass spectral peaks representing polar membrane lipids in extracts from Arabidopsis thaliana infected with Pseudomonas syringae pv tomato DC3000 expressing AvrRpt2 (PstAvr). Quadrupole time-of-flight and Fourier transform ion cyclotron resonance mass spectrometry provided evidence for the presence of membrane lipids containing one or more oxidized acyl chains. The membra ...201122086419
Direct Infusion Mass Spectrometry of Oxylipin-Containing Arabidopsis thaliana Membrane Lipids Reveals Varied Patterns in Different Stress Responses.Direct infusion electrospray ionization triple quadrupole precursor scanning for three oxidized fatty acyl anions revealed 86 mass spectral peaks representing polar membrane lipids in extracts from Arabidopsis thaliana infected with Pseudomonas syringae pv tomato DC3000 expressing AvrRpt2 (PstAvr). Quadrupole time-of-flight and Fourier transform ion cyclotron resonance mass spectrometry provided evidence for the presence of membrane lipids containing one or more oxidized acyl chains. The membra ...201122086419
Role of 9-Lipoxygenase and a-Dioxygenase Oxylipin Pathways as Modulators of Local and Systemic Defense.Plant 9-lipoxygenases (9-LOX) and a-dioxygenases (a-DOX) initiate the synthesis of oxylipins after bacterial infection. Here, the role of these enzymes in plants' defense was investigated using individual Arabidopsis thaliana lox1 and dox1 mutants and a double lox1 dox1 mutant. Studies with Pseudomonas syringae pv. tomato (Pst) revealed the enhanced susceptibility of lox1 to the virulent strain Pst DC3000 and the partial impairment of lox1 and dox1 mutants to activate systemic acquired resistanc ...201122199234
Biosynthesis and defensive function of Nd-acetylornithine, a jasmonate-induced Arabidopsis metabolite.Since research on plant interactions with herbivores and pathogens is often constrained by the analysis of already known compounds, there is a need to identify new defense-related plant metabolites. The uncommon nonprotein amino acid N(d)-acetylornithine was discovered in a targeted search for Arabidopsis thaliana metabolites that are strongly induced by the phytohormone methyl jasmonate (MeJA). Stable isotope labeling experiments show that, after MeJA elicitation, Arg, Pro, and Glu are converte ...201121917546
biochemical and genetic requirements for function of the immune response regulator botrytis-induced kinase1 in plant growth, ethylene signaling, and pamp-triggered immunity in arabidopsis.arabidopsis thaliana botrytis-induced kinase1 (bik1) regulates immune responses to a distinct class of pathogens. here, mechanisms underlying bik1 function and its interactions with other immune response regulators were determined. we describe bik1 function as a component of ethylene (et) signaling and pamp-triggered immunity (pti) to fungal pathogens. bik1 in vivo kinase activity increases in response to flagellin peptide (flg22) and the et precursor 1-aminocyclopropane-1-carboxylic acid (acc) ...201121862710
basic peptide-morpholino oligomer conjugate that is very effective in killing bacteria by gene-specific and nonspecific modes.basic peptides covalently linked to nucleic acids, or chemically modified nucleic acids, enable the insertion of such a conjugate into bacteria grown in liquid medium and mammalian cells in tissue culture. a unique peptide, derived from human t cells, has been employed in a chemical synthesis to make a conjugate with a morpholino oligonucleotide. this new conjugate is at least 10- to 100-fold more effective than previous peptides used in altering the phenotype of host bacteria if the external gu ...201121949365
excision of an unstable pathogenicity island in salmonella enterica serovar enteritidis is induced during infection of phagocytic cells.the availability of the complete genome sequence of several salmonella enterica serovars has revealed the presence of unstable genetic elements in these bacteria, such as pathogenicity islands and prophages. this is the case of salmonella enterica serovar enteritidis (s. enteritidis), a bacterium that causes gastroenteritis in humans and systemic infection in mice. the whole genome sequence analysis for s. enteritidis unveiled the presence of several genetic regions that are absent in other salm ...201122039432
Genome-wide transcriptome analysis of the plant pathogen Xanthomonas identifies sRNAs with putative virulence functions.The Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is an important model to elucidate the mechanisms involved in the interaction with the host. To gain insight into the transcriptome of the Xcv strain 85-10, we took a differential RNA sequencing (dRNA-seq) approach. Using a novel method to automatically generate comprehensive transcription start site (TSS) maps we report 1421 putative TSSs in the Xcv genome. Genes in Xcv exhibit a poorly conserved -10 promo ...201122080557
Genome-wide transcriptome analysis of the plant pathogen Xanthomonas identifies sRNAs with putative virulence functions.The Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is an important model to elucidate the mechanisms involved in the interaction with the host. To gain insight into the transcriptome of the Xcv strain 85-10, we took a differential RNA sequencing (dRNA-seq) approach. Using a novel method to automatically generate comprehensive transcription start site (TSS) maps we report 1421 putative TSSs in the Xcv genome. Genes in Xcv exhibit a poorly conserved -10 promo ...201122080557
crystal structures of multicopper oxidase cueo bound to copper(i) and silver(i): functional role of a methionine-rich sequence.the multicopper oxidase cueo oxidizes toxic cu(i) and is required for copper homeostasis in escherichia coli. like many proteins involved in copper homeostasis, cueo has a methionine-rich segment that is thought to be critical for copper handling. how such segments function is poorly understood. here, we report the crystal structure of cueo at 1.1 å with the 45-residue methionine-rich segment fully resolved, revealing an n-terminal helical segment with methionine residues juxtaposed for cu(i) li ...201121903583
Peptidotriazoles with antimicrobial activity against bacterial and fungal plant pathogens.We designed and prepared peptidotriazoles based on the antimicrobial peptide BP100 (LysLysLeuPheLysLysIleLeuLysTyrLeu-NH(2)) by introducing a triazole ring in the peptide backbone or onto the side chain of a selected residue. These compounds were screened for their in vitro growth inhibition of bacterial and fungal phytopathogens, and for their cytotoxic effects on eukaryotic cells and tobacco leaves. Their proteolytic susceptibility was also analyzed. The antibacterial activity and the hemolysi ...201122198367
The major volatile organic compound emitted from Arabidopsis thaliana flowers, the sesquiterpene (E)-ß-caryophyllene, is a defense against a bacterial pathogen.• Flowers have a high risk of pathogen attack because of their rich nutrient and moisture content, and high frequency of insect visitors. We investigated the role of (E)-ß-caryophyllene in floral defense against a microbial pathogen. This sesquiterpene is a common volatile compound emitted from flowers, and is a major volatile released from the stigma of Arabidopsis thaliana flowers. • Arabidopsis thaliana lines lacking a functional (E)-ß-caryophyllene synthase or constitutively overexpressing t ...201122187939
n-acyl-homoserine lactone confers resistance toward biotrophic and hemibiotrophic pathogens via altered activation of atmpk6.pathogenic and symbiotic bacteria rely on quorum sensing to coordinate the collective behavior during the interactions with their eukaryotic hosts. many gram-negative bacteria use n-acyl-homoserine lactones (ahls) as signals in such communication. here we show that plants have evolved means to perceive ahls and that the length of acyl moiety and the functional group at the γ position specify the plant's response. root treatment with the n-3-oxo-tetradecanoyl-l-homoserine lactone (oxo-c14-hsl) re ...201121940998
sulfate supply influences compartment specific glutathione metabolism and confers enhanced resistance to tobacco mosaic virus during a hypersensitive response.sufficient sulfate supply has been linked to the development of sulfur induced resistance or sulfur enhanced defense (sir/sed) in plants. in this study we investigated the effects of sulfate (s) supply on the response of genetically resistant tobacco (nicotiana tabacum cv. samsun nn) to tobacco mosaic virus (tmv). plants grown with sufficient sulfate (+s plants) developed significantly less necrotic lesions during a hypersensitive response (hr) when compared to plants grown without sulfate (-s p ...201122122784
degradation of a benzene-toluene mixture by hydrocarbon-adapted bacterial communities.we examined the rate of degradation of a benzene-toluene mixture in aerobic microcosms prepared with samples of an aquifer that lies below a petrochemical plant (siren, uk). five samples exposed to different concentrations of benzene (from 0.6 to 317 mg l(-1)) were used. fast degradation (approx. 1-6 mg l(-1) day(-1)) of both contaminants was observed in all groundwater samples and complete degradation was recorded by the seventh day except for one sample. we also identified the microbial commun ...201121949494
degradation of a benzene-toluene mixture by hydrocarbon-adapted bacterial communities.we examined the rate of degradation of a benzene-toluene mixture in aerobic microcosms prepared with samples of an aquifer that lies below a petrochemical plant (siren, uk). five samples exposed to different concentrations of benzene (from 0.6 to 317 mg l(-1)) were used. fast degradation (approx. 1-6 mg l(-1) day(-1)) of both contaminants was observed in all groundwater samples and complete degradation was recorded by the seventh day except for one sample. we also identified the microbial commun ...201121949494
AtRbohF is a crucial modulator of defence-associated metabolism and a key actor in the interplay between intracellular oxidative stress and pathogenesis responses in Arabidopsis.This work investigated the contribution of AtRbohD and AtRbohF to regulating defence-associated metabolism during three types of interaction: (i) incompatible and (ii) compatible interaction with Pseudomonas syringae; and (iii) intracellular oxidative stress in the catalase-deficient cat2 background. In all three cases, loss of function of either gene modulated the response of defence compounds. AtRbohF gene function was necessary for rapid and full induction of salicylic acid (SA) during compat ...201121985584
agc kinases in plant development and defense.more than 100,000 publications demonstrate that agc kinases are important regulators of growth, metabolism, proliferation, cell divison, survival and apoptosis in mammalian systems. mutation and/or dysregulation of these kinases contribute to the pathogenesis of many human diseases, including cancer and diabetes. although agc kinases are also present in plants, little is known about their functions. we demonstrated that the agc kinase oxidative signal-inducible 1 (oxi1/agc2-1) regulate important ...201122005000
transportin-sr is required for proper splicing of resistance genes and plant immunity.transportin-sr (trn-sr) is a member of the importin-+¦ super-family that functions as the nuclear import receptor for serine-arginine rich (sr) proteins, which play diverse roles in rna metabolism. here we report the identification and cloning of mos14 (modifier of snc1-1, 14), a mutation that suppresses the immune responses conditioned by the auto-activated resistance (r) protein snc1 (suppressor of npr1-1, constitutive 1). mos14 encodes a nuclear protein with high similarity to previously char ...201121738492
pseudomonas syringae pv. phaseolicola: from 'has bean' to supermodel.pseudomonas syringae pv. phaseolicola causes halo blight of the common bean, phaseolus vulgaris, worldwide and remains difficult to control. races of the pathogen cause either disease symptoms or a resistant hypersensitive response on a series of differentially reacting bean cultivars. the molecular genetics of the interaction between p. syringae pv. phaseolicola and bean, and the evolution of bacterial virulence, have been investigated in depth and this research has led to important discoveries ...201121726364
molecular characterization of a catalase-negative staphylococcus aureus subsp. aureus strain collected from a patient with mitral valve endocarditis and pericarditis revealed a novel nonsense mutation in the kata gene.we report a case of endocarditis and pericarditis caused by catalase-negative staphylococcus aureus. molecular characterization revealed a novel nonsense mutation in the kata gene, leading to a loss of 238 amino acids (47% of the wild-type catalase protein), including the heme-binding site, nadph-binding region, and tyr-337, essential for catalysis.201121715584
regulation of stomatal tropism and infection by light in cercospora zeae-maydis: evidence for coordinated host/pathogen responses to photoperiod?cercospora zeae-maydis causes gray leaf spot of maize, which has become one of the most widespread and destructive diseases of maize in the world. c. zeae-maydis infects leaves through stomata, which is predicated on the ability of the pathogen to perceive stomata and reorient growth accordingly. in this study, the discovery that light was required for c. zeae-maydis to perceive stomata and infect leaves led to the identification of crp1, a gene encoding a putative blue-light photoreceptor homol ...201121829344
resolving the phylogenetic and taxonomic relationship of xanthomonas and stenotrophomonas strains using complete rpob gene sequence. 201121686310
comparative analysis of the xopd type iii secretion (t3s) effector family in plant pathogenic bacteria.xopd is a type iii effector protein that is required for xanthomonas campestris pathovar vesicatoria (xcv) growth in tomato. it is a modular protein consisting of an n-terminal dna-binding domain, two ethylene-responsive element binding factor-associated amphiphilic repression (ear) transcriptional repressor motifs and a c-terminal small ubiquitin-related modifier (sumo) protease. in tomato, xopd functions as a transcriptional repressor, resulting in the suppression of defence responses at late ...201121726373
a novel function for a redox-related lea protein (sag21/atlea5) in root development and biotic stress responses.sag21/atlea5 belongs to the late embryogenesis-associated (lea) protein family. although it has been implicated in growth and redox responses, its precise roles remain obscure. to address this problem, we characterized root and shoot development and response to biotic stress in sag21/atlea5 over-expressor (oex) and antisense (as) lines. as lines exhibited earlier flowering and senescence and reduced shoot biomass. primary root length was reduced in as lines, as was the number of laterals relativ ...201121736589
quantitative and qualitative stem rust resistance factors in barley are associated with transcriptional suppression of defense regulons.stem rust (puccinia graminis f. sp. tritici; pgt) is a devastating fungal disease of wheat and barley. pgt race ttksk (isolate ug99) is a serious threat to these triticeae grain crops because resistance is rare. in barley, the complex rpg-ttksk locus on chromosome 5h is presently the only known source of qualitative resistance to this aggressive pgt race. segregation for resistance observed on seedlings of the q21861 +ù sm89010 (qsm) doubled-haploid (dh) population was found to be predominantly ...201121829384
arabidopsis cell death in compatible and incompatible interactions with alternaria brassicicola.two strains of necrotrophic alternaria brassicicola, ab40857 and ab42464, are virulent on korean cabbage and several wild types of arabidopsis thaliana. interaction between ab42464 and col-0 was compatible, whereas interaction between ab40857 and col-0 was incompatible. the loss of defense, no death (dnd) 1 function abrogated the compatibility between ab42464 and col-0, and the accelerated cell death (acd) 2 mutation attenuated the col-0's resistance against ab40857. these two fungal strains ind ...201121688205
priming by rhizobacterium protects tomato plants from biotrophic and necrotrophic pathogen infections through multiple defense mechanisms.a selected strain of rhizobacterium, pseudomonas putida strain lsw17s (lsw17s), protects tomato plants (lycopersicon esculentum l. cv. seokwang) from bacterial speck by biotrophic pseudomonas syringae pv. tomato strain dc3000 (dc3000) and bacterial wilt by necrotrophic ralstonia solanacearum kacc 10703 (rs10703). to investigate defense mechanisms induced by lsw17s in tomato plants, transcription patterns of pathogenesis-related (pr) genes and h(2)o(2) production were analyzed in plants treated w ...201121710203
blue and red light modulates sigb-dependent gene transcription, swimming motility and invasiveness in listeria monocytogenes.in a number of gram-positive bacteria, including listeria, the general stress response is regulated by the alternative sigma factor b (sigb). common stressors which lead to the activation of sigb and the sigb-dependent regulon are high osmolarity, acid and several more. recently is has been shown that also blue and red light activates sigb in bacillus subtilis.201121264304
the jasmonate pathway is a key player in systemically induced defense against root knot nematodes in rice.complex defense signaling pathways, controlled by different hormones, are involved in the reaction of plants to a wide range of biotic and abiotic stress factors. we studied the ability of salicylic acid, jasmonate (ja), and ethylene (et) to induce systemic defense in rice (oryza sativa) against the root knot nematode meloidogyne graminicola. exogenous et (ethephon) and ja (methyl jasmonate) supply on the shoots induced a strong systemic defense response in the roots, exemplified by a major up-r ...201121715672
phylogenetic identification of fungi isolated from the marine sponge tethya aurantium and identification of their secondary metabolites.fungi associated with the marine sponge tethya aurantium were isolated and identified by morphological criteria and phylogenetic analyses based on internal transcribed spacer (its) regions. they were evaluated with regard to their secondary metabolite profiles. among the 81 isolates which were characterized, members of 21 genera were identified. some genera like acremonium, aspergillus, fusarium, penicillium, phoma, and trichoderma are quite common, but we also isolated strains belonging to gene ...201121731550
the yopj superfamily in plant-associated bacteria.bacterial pathogens employ the type iii secretion system to secrete and translocate effector proteins into their hosts. the primary function of these effector proteins is believed to be the suppression of host defence responses or innate immunity. however, some effector proteins may be recognized by the host and consequently trigger a targeted immune response. the yopj/hopz/avrrxv family of bacterial effector proteins is a widely distributed and evolutionarily diverse family, found in both anima ...201121726386
degeneration of hrpz gene in pseudomonas syringae pv. tabaci to evade tobacco defence: an arms race between tobacco and its bacterial pathogen.the hrpz harpin of pseudomonas syringae is known to induce a hypersensitive response (hr) in some plants. in p. syringae pv. tabaci (pta), the harpin gene hrpz has been spontaneously disrupted by an internal deletion in its open reading frame and a frame shift. the loss of the ability of the recombinant harpin polypeptide of pta to induce hr despite the high sensitivity of tobacco plants to harpin led us to investigate the meaning of the disrupted hrpz gene in the virulence of pta 6605. the hrpz ...201121726372
cell surface display of carbonic anhydrase on escherichia coli using ice nucleation protein for co(2) sequestration.carbonic anhydrase (ca) has recently gained renewed interests for its potential as a mass-transfer facilitator for co(2) sequestration. however, the low stability and high price severely limit its applications. in this work, the expression of +¦-ca from helicobacter pylori on the outer membrane of escherichia coli using a surface-anchoring system derived from ice nucleation protein (inp) from pseudomonas syringae was developed. to find the best surface anchoring motif, full-length inp (114ôçëkda ...201121732326
effects of botrytis cinerea and pseudomonas syringae infection on the antioxidant profile of mesembryanthemum crystallinum c3/cam intermediate plant.mesembryathemum crystallinum plants performing c(3) or cam (crassulacean acid metabolism) appear to be highly resistant to botrytis cinerea as well as to pseudomonas syringae. fungal hyphae growth was restricted to 48h post-inoculation (hpi) in both metabolic types and morphology of hyphae differed between those growing in c(3) and cam plants. growth of bacteria was inhibited significantly 24 hpi in both c(3) and cam plants. b. cinerea and p. syringae infection led to an increase in the concentr ...201121342714
construction of pseudomonas syringae pv. tomato dc3000 mutant and polymutant strains.redundancy between pseudomonas syringae pv. tomato dc3000 virulence factors has made their characterization difficult. one method to circumvent redundancy for phenotypic characterization is to simultaneously delete all redundant factors through the generation of polymutant strains. described here are methods by which single and polymutant strains of dc3000 can be generated through the use of the small mobilizable sucrose counter-selection vector pk18mobsacb, frt-flanked antibiotic marker cassett ...201121359804
pseudomonas genomes: diverse and adaptable.members of the genus pseudomonas inhabit a wide variety of environments, which is reflected in their versatile metabolic capacity and broad potential for adaptation to fluctuating environmental conditions. here, we examine and compare the genomes of a range of pseudomonas spp. encompassing plant, insect and human pathogens, and environmental saprophytes. in addition to a large number of allelic differences of common genes that confer regulatory and metabolic flexibility, genome analysis suggests ...201121361996
substrate specificity and ion coupling in the na+/betaine symporter betp.betp is an na(+)-coupled betaine-specific transporter of the betaine-choline-carnitine (bcc) transporter family involved in the response to hyperosmotic stress. the crystal structure of betp revealed an overall fold of two inverted structurally related repeats (leut-fold) that betp shares with other sequence-unrelated na(+)-coupled symporters. numerous structures of leut-fold transporters in distinct conformational states have contributed substantially to our understanding of the alternating acc ...201121364531
using genomic sequencing for classical genetics in e. coli k12.we here develop computational methods to facilitate use of 454 whole genome shotgun sequencing to identify mutations in escherichia coli k12. we had roche sequence eight related strains derived as spontaneous mutants in a background without a whole genome sequence. they provided difference tables based on assembling each genome to reference strain e. coli mg1655 (nc_000913). due to the evolutionary distance to mg1655, these contained a large number of both false negatives and positives. by manua ...201121364914
structural and biochemical characterization of nare, an iron-containing adp-ribosyltransferase from neisseria meningitidis.nare is a 16 kda protein identified from neisseria meningitidis, one of the bacterial pathogens responsible for meningitis. nare belongs to the family of adp-ribosyltransferases (adprt) and catalyzes the transfer of adp-ribose moieties to arginine residues in target protein acceptors. many pathogenic bacteria utilize adp-ribosylating toxins to modify and alter essential functions of eukaryotic cells. nare is further the first adprt which could be shown to bind iron through a fe-s center, which i ...201121367854
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