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Sample records for pseudomonas syringae erwinia

  1. Conductimetric detection of Pseudomonas syringae pathover pisi in pea seeds and soft rot Erwinia spp. on potato tubers

    NARCIS (Netherlands)

    Fraaije, B.

    1996-01-01


    Pea bacterial blight and potato blackleg are diseases caused by Pseudomonas syringae pv. pisi ( Psp ) and soft rot Erwinia spp., respectively. The primary source of inoculum for these bacteria is

  2. Extracytoplasmic function sigma factors in Pseudomonas syringae

    DEFF Research Database (Denmark)

    Kiil, Kristoffer; Oguiza, J.A.; Ussery, D.W.

    2005-01-01

    Genome analyses of the plant pathogens Pseudomonas syringae pv. tomato DC3000, pv. syringae B728a and pv. phaseolicola 1448A reveal fewer extracytoplasmic function (ECF) sigma factors than in related Pseudomonads with different lifestyles. We highlight the presence of a P. syringae-specific ECF s...... sigma factor that is an interesting target for future studies because of its potential role in the adaptation of P. syringae to its specialized phytopathogenic lifestyle....

  3. New strategies for genetic engineering Pseudomonas syringae using recombination

    Science.gov (United States)

    Here we report that DNA oligonucleotides (oligos) introduced directly into bacteria by electroporation can recombine with the bacterial chromosome. This phenomenon was identified in Pseudomonas syringae and we subsequently found that Escherichia coli, Salmonella typhimurium and Shigella flexneri are...

  4. Regulation of phytotoxin production in Pseudomonas syringae pv. tabaci

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, L.M.; Ghosh, S.; Knight, T.J.; Unkefer, P.J. (Los Alamos National Lab., NM (United States))

    1991-05-01

    Pseudomonas syringae pv. tabaci, a pathogen of tobacco, is capable of colonizing the rhizosphere of many plants. This pathogen excretes tabtoxinine-{beta}-lactam (T{beta}L), an active site directed, irreversible inhibitor of glutamine synthetase. T{beta}L is produced in planta, in the rhizosphere, and under certain culture conditions. However, the factors which regulated T{beta}L production in these environments are unknown. As a first step in characterizing T{beta}L synthesis by P. syringae pv. tabaci, the authors have determined the effects of root exudates and various nutrients on production of T{beta}L by P. syringae pv. tabaci PT113.

  5. Genomic Distribution and Divergence of Levansucrase-Coding Genes in Pseudomonas syringae

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    Matthias S. Ullrich

    2012-02-01

    Full Text Available In the plant pathogenic bacterium, Pseudomonas syringae, the exopolysaccharide levan is synthesized by extracellular levansucrase (Lsc, which is encoded by two conserved 1,296-bp genes termed lscB and lscC in P. syringae strain PG4180. A third gene, lscA, is homologous to the 1,248-bp lsc gene of the bacterium Erwinia amylovora, causing fire blight. However, lscA is not expressed in P. syringae strain PG4180. Herein, PG4180 lscA was shown to be expressed from its native promoter in the Lsc-deficient E. amylovora mutant, Ea7/74-LS6, suggesting that lscA might be closely related to the E. amylovora lsc gene. Nucleotide sequence analysis revealed that lscB and lscC homologs in several P. syringae strains are part of a highly conserved 1.8-kb region containing the ORF, flanked by 450-452-bp and 49-51-bp up- and downstream sequences, respectively. Interestingly, the 450-452-bp upstream sequence, along with the initial 48-bp ORF sequence encoding for the N-terminal 16 amino acid residues of Lsc, were found to be highly similar to the respective sequence of a putatively prophage-borne glycosyl hydrolase-encoding gene in several P. syringae genomes. Minimal promoter regions of lscB and lscC were mapped in PG4180 by deletion analysis and were found to be located in similar positions upstream of lsc genes in three P. syringae genomes. Thus, a putative 498-500-bp promoter element was identified, which possesses the prophage-associated com gene and DNA encoding common N-terminal sequences of all 1,296-bp Lsc and two glycosyl hydrolases. Since the gene product of the non-expressed 1,248-bp lscA is lacking this conserved N-terminal region but is otherwise highly homologous to those of lscB and lscC, it was concluded that lscA might have been the ancestral lsc gene in E. amylovora and P. syringae. Our data indicated that its highly expressed paralogs in P. syringae are probably derived from subsequent recombination events initiated by insertion of the 498

  6. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Science.gov (United States)

    2010-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato. ...

  7. Differentiation of Pseudomonas syringae Pathovars Originating from Stone Fruits

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    Katarina Gašić

    2012-01-01

    Full Text Available Due to an overlapping host range, similar symptomatology and many common characteristics,Pseudomonas syringae pathovars originating from stone fruits can easily be misidentified.In order to select tests for rapid and efficient differentiation of P. s. pvs. syringae,morsprunorum and persicae, we studied the suitability and differentiating potential ofsome standard bacteriological and molecular methods. Differentiation of the strains wasperformed using LOPAT, GATTa and ice nucleation tests, nutrient sucrose broth growthand utilization of various carbon sources. PCR method enabled the detection of toxin-producinggenes: syrB and syrD in P. s. pv. syringae, and cfl gene in P. s. pv. morsprunorum race1. Syringomycin production by pv. syringae was confirmed in bioassay using Geotrichumcandidum, Saccharomyces cerevisiae and Rhodotorula pilimanae as indicator organisms.Pathogenicity test on lemon and immature nectarine fruits, as well as on string bean pods,showed different intensity of reaction of the inoculated material which could separate pv.syringae from the other two pathovars. PCR-based repetitive sequences, Rep-PCR withREP, ERIC and BOX primers revealed different genetic profiles within P. syringae pathovars.

  8. Resistant and susceptible responses in alfalfa (Medicago sativa) to bacterial stem blight caused by Pseudomonas syringae pv. syringae

    Science.gov (United States)

    Bacterial stem blight caused by Pseudomonas syringae pv. syringae is a common disease of alfalfa (Medicago sativa L.) in the central and western U.S. and has been reported in Australia and Europe. The disease is not always recognized because symptoms are often associated with frost damage. Two culti...

  9. HOPM1 mediated disease resistance to Pseudomonas syringae in Arabidopsis

    Science.gov (United States)

    He, Sheng Yang [Okemos, MI; Nomura, Kinya [East Lansing, MI

    2011-11-15

    The present invention relates to compositions and methods for enhancing plant defenses against pathogens. More particularly, the invention relates to enhancing plant immunity against bacterial pathogens, wherein HopM1.sub.1-300 mediated protection is enhanced, such as increased protection to Pseudomonas syringae pv. tomato DC3000 HopM1 and/or there is an increase in activity of an ATMIN associated plant protection protein, such as ATMIN7. Reagents of the present invention further provide a means of studying cellular trafficking while formulations of the present inventions provide increased pathogen resistance in plants.

  10. Induction of Callose Deposition in Tobacco (Nicotiana tabacum by Bacterial Lipopolysaccharide Pseudomonas syringae pv. tabaci and Pseudomonas syringae pv. glycinea

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    Pipit Marianingsih

    2014-12-01

    Full Text Available Lipopolysaccharide (LPS is a major component of outer-membrane gram-negative bacteria, and it can act as a Pathogen-Associated Molecular Pattern (PAMP for perception of pathogens by plants. LPS can be recognized by plants, triggering certain plant defense-related responses, including callose deposition. This study investigated induction of callose deposition by bacterial LPS in tobacco. Tobacco leaves were infiltrated with 400 μg/mL and 800 μg/mL LPS extracted from Pseudomonas syringae pv. tabaci (Pta and Pseudomonas syringae pv. glycinea (Pgl and incubated for 24 h or 48 h. To detect callose deposition, tobacco leaves were cleared in lactophenol solution, stained with aniline blue, and visualized by fluorescence microscopy. Results showed that LPS from Pgl induced more callose deposition in tobacco leaves than did that from Pta. In addition, a Pearson correlation test revealed that incubation period was the most significant factor in callose deposition, followed by the type of LPS bacteria. However, LPS concentration was not significantly corelated to callose deposition in tobacco leaves.

  11. Pseudomonas syringae pv. tabaci in papaya seedlings Pseudomonas syringae pv. tabaci em plântulas de mamoeiro

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    Luís Otávio S. Beriam

    2006-03-01

    Full Text Available The natural occurrence of Pseudomonas syringae pv. tabaci causing leaf spot symptoms in papaya seedlings is reported. The pathogen was identified through biochemical, physiological, serological, and molecular assays and artificial inoculations in papaya plants. It was also shown that the strains were pathogenic to bean and tobacco plants. The restriction patterns obtained with Afa I, Alu I, Dde I, Hae III, Hpa II, Hinf I, Sau 3A I and Taq I of the PCR-RFLP of 16S-23S DNAr were identical to the P. s. pv. tabaci patterns. Primers corresponding to hrpL gene of P. syringae were also tested and the results grouped the papaya strains with P s. pv. tabaci. Bacterial strains were deposited at Coleção de Culturas IBSBF, Instituto Biológico, Campinas, Brazil, under access numbers 1687 and 1822.É relatada a ocorrência natural de Pseudomonas syringae pv. tabaci causando sintomas de lesões foliares em plântulas de mamoeiro. O patógeno foi identificado por meio de testes bioquímicos, fisiológicos, serológicos e moleculares, além de ensaios de patogenicidade em plantas de mamoeiro, feijoeiro e fumo. Os padrões de restrição obtidos com as enzimas Afa I, Alu I, Dde I, Hae III, Hpa II, Hinf I, Sal 3A I e Taq I, utilizando-se a técnica de PCR-RLFP da região espaçadora 16S-23S do DNA ribossômico, foram idênticos àqueles apresentados para P. s. pv. tabaci. Primers correspondentes ao gene hrpL de P. syringae foram também testados e os resultados obtidos permitiram agrupar as linhagens isoladas de mamão com P. s. pv. tabaci. Linhagens bacterianas estão depositadas na coleção de culturas IBSBF, Instituto Biológico, Campinas, sob n. 1687 e 1822.

  12. Characterization of the phytopathogen Pseudomonas syringae pathovar ribicola NCPPB 963.

    Science.gov (United States)

    Charnock, C

    1998-01-01

    In 1939, a bacterial spot caused severe defoliation of Ribes aureum (Golden Currant) The causal agent is now recognized as Pseudomonas syringae pathovar ribicola. This communication extends the phenotype of the only identified strain of P. syringae pv. ribicola, which is reminiscent of those of other pathovars, and provides a molecular biological characterization. A minimum size of 5.55 Mb for the bacterial genome was obtained using pulsed-field electrophoresis. The SDS-PAGE outer-membrane profile contained seven major bands, and has obvious similarities to that of P. aeruginosa. SDS-PAGE of concentrated mid-log phase culture supernatants revealed large amounts of a single, cryptic 24.0 kD protein. The amino acid composition and 57 residues in the N-terminus of this protein. were determined. The protein sequence was nearly identical to the translation of a region of unknown function in the P. aeruginosa genome. Extensive similarity in N-terminal sequence, composition and subunit size to a secreted hydrophilic Vibrio cholerae protein of unknown function was also found. Neither protein has been directly associated with disease development.

  13. Contribution of nitrate assimilation to the fitness of Pseudomonas syringae pv. syringae B728a on plants.

    Science.gov (United States)

    Parangan-Smith, Audrey; Lindow, Steven

    2013-01-01

    The ability of Pseudomonas syringae pv. syringae to use nitrate as a nitrogen source in culture and on leaves was assessed. Substantial amounts of leaf surface nitrate were detected directly and by use of a bioreporter of nitrate on bean plants grown with a variety of nitrogen sources. While a nitrate reductase mutant, P. syringae ΔnasB, exhibited greatly reduced growth in culture with nitrate as the sole nitrogen source, it exhibited population sizes similar to those of the wild-type strain on leaves. However, the growth of the ΔnasB mutant was much less than that of the wild-type strain when cultured in bean leaf washings supplemented with glucose, suggesting that P. syringae experiences primarily carbon-limited and only secondarily nitrogen-limited growth on bean leaves. Only a small proportion of the cells of a green fluorescent protein (GFP)-based P. syringae nitrate reductase bioreporter, LK2(pOTNas4), exhibited fluorescence on leaves. This suggests that only a subset of cells experience high nitrate levels or that nitrate assimilation is repressed by the presence of ammonium or other nitrogenous compounds in many leaf locations. While only a subpopulation of P. syringae consumes nitrate at a given time on the leaves, the ability of those cells to consume this resource would be strongly beneficial to those cells, especially in environments in which nitrate is the most abundant form of nitrogen.

  14. Homeopathic Treatment of Arabidopsis thaliana Plants Infected with Pseudomonas syringae

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    Devika Shah-Rossi

    2009-01-01

    Full Text Available Homeopathic basic research is still in the screening phase to identify promising model systems that are adapted to the needs and peculiarities of homeopathic medicine and pharmacy. We investigated the potential of a common plant-pathogen system, Arabidopsis thaliana infected with the virulent bacteria Pseudomonas syringae, regarding its response towards a homeopathic treatment. A. thaliana plants were treated with homeopathic preparations before and after infection. Outcome measure was the number of P. syringae bacteria in the leaves of A. thaliana, assessed in randomized and blinded experiments. After a screening of 30 homeopathic preparations, we investigated the effect of Carbo vegetabilis 30x, Magnesium phosphoricum 30x, Nosode 30x, Biplantol (a homeopathic complex remedy, and Biplantol 30x on the infection rate in five or six independent experiments in total. The screening yielded significant effects for four out of 30 tested preparations. In the repeated experimental series, only the homeopathic complex remedy Biplantol induced a significant reduction of the infection rate (p = 0.01; effect size, d = 0.38. None of the other four repeatedly tested preparations (Carbo vegetabilis 30x, Magnesium phosphoricum 30x, Nosode 30x, Biplantol 30x yielded significant effects in the overall evaluation. This phytopathological model yielded a small to medium effect size and thus might be of interest for homeopathic basic research after further improvement. Compared to Bion (a common SAR inducer used as positive control, the magnitude of the treatment effect of Biplantol was about 50%. Thus, homeopathic formulations might have a potential for the treatment of plant diseases after further optimization. However, the ecological impact should be investigated more closely before widespread application.

  15. Pseudomonas syringae pv. syringae uses proteasome inhibitor syringolin A to colonize from wound infection sites.

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    Johana C Misas-Villamil

    2013-03-01

    Full Text Available Infection of plants by bacterial leaf pathogens at wound sites is common in nature. Plants defend wound sites to prevent pathogen invasion, but several pathogens can overcome spatial restriction and enter leaf tissues. The molecular mechanisms used by pathogens to suppress containment at wound infection sites are poorly understood. Here, we studied Pseudomonas syringae strains causing brown spot on bean and blossom blight on pear. These strains exist as epiphytes that can cause disease upon wounding caused by hail, sand storms and frost. We demonstrate that these strains overcome spatial restriction at wound sites by producing syringolin A (SylA, a small molecule proteasome inhibitor. Consequently, SylA-producing strains are able to escape from primary infection sites and colonize adjacent tissues along the vasculature. We found that SylA diffuses from the primary infection site and suppresses acquired resistance in adjacent tissues by blocking signaling by the stress hormone salicylic acid (SA. Thus, SylA diffusion creates a zone of SA-insensitive tissue that is prepared for subsequent colonization. In addition, SylA promotes bacterial motility and suppresses immune responses at the primary infection site. These local immune responses do not affect bacterial growth and were weak compared to effector-triggered immunity. Thus, SylA facilitates colonization from wounding sites by increasing bacterial motility and suppressing SA signaling in adjacent tissues.

  16. A Mathematical model to investigate quorum sensing regulation and its heterogenecity in pseudomonas syringae on leaves

    Science.gov (United States)

    The bacterium Pseudomonas syringae is a plant-pathogen, which through quorum sensing (QS), controls virulence. In this paper, by means of mathematical modeling, we investigate QS of this bacterium when living on leaf surfaces. We extend an existing stochastic model for the formation of Pseudomonas s...

  17. Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis

    Science.gov (United States)

    Guo, Ming; Block, Anna; Bryan, Crystal D.; Becker, Donald F.

    2012-01-01

    The bacterial pathogen Pseudomonas syringae pv. tomato DC3000 must detoxify plant-produced hydrogen peroxide (H2O2) in order to survive in its host plant. Candidate enzymes for this detoxification include the monofunctional catalases KatB and KatE and the bifunctional catalase-peroxidase KatG of DC3000. This study shows that KatG is the major housekeeping catalase of DC3000 and provides protection against menadione-generated endogenous H2O2. In contrast, KatB rapidly and substantially accumulates in response to exogenous H2O2. Furthermore, KatB and KatG have nonredundant roles in detoxifying exogenous H2O2 and are required for full virulence of DC3000 in Arabidopsis thaliana. Therefore, the nonredundant ability of KatB and KatG to detoxify plant-produced H2O2 is essential for the bacteria to survive in plants. Indeed, a DC3000 catalase triple mutant is severely compromised in its ability to grow in planta, and its growth can be partially rescued by the expression of katB, katE, or katG. Interestingly, our data demonstrate that although KatB and KatG are the major catalases involved in the virulence of DC3000, KatE can also provide some protection in planta. Thus, our results indicate that these catalases are virulence factors for DC3000 and are collectively required for pathogenesis. PMID:22797762

  18. Soil water flow is a source of the plant pathogen Pseudomonas syringae in subalpine headwaters.

    OpenAIRE

    Monteil, Caroline; LAFOLIE, Francois; Laurent, Jimmy; Clement, Jean-Christophe; Simler, Roland; Travi, Yves

    2014-01-01

    The air-borne plant pathogenic bacterium Pseudomonas syringae is ubiquitous in headwaters, snowpack and precipitation where its populations are genetically and phenotypically diverse. Here, we assessed its population dynamics during snowmelt in headwaters of the French Alps. We revealed a continuous and significant transport of P. syringae by these waters in which the population density is correlated with water chemistry. Via in situ observations and laboratory experiments, we validated that ...

  19. Housekeeping Gene Sequencing and Multilocus Variable-Number Tandem-Repeat Analysis To Identify Subpopulations within Pseudomonas syringae pv. maculicola and Pseudomonas syringae pv. tomato That Correlate with Host Specificity

    Science.gov (United States)

    Gironde, S.

    2012-01-01

    Pseudomonas syringae pv. maculicola causes bacterial spot on Brassicaceae worldwide, and for the last 10 years severe outbreaks have been reported in the Loire Valley, France. P. syringae pv. maculicola resembles P. syringae pv. tomato in that it is also pathogenic for tomato and causes the same types of symptoms. We used a collection of 106 strains of P. syringae to characterize the relationships between P. syringae pv. maculicola and related pathovars, paying special attention to P. syringae pv. tomato. Phylogenetic analysis of gyrB and rpoD gene sequences showed that P. syringae pv. maculicola, which causes diseases in Brassicaceae, forms six genetic lineages within genomospecies 3 of P. syringae strains as defined by L. Gardan et al. (Int. J. Syst. Bacteriol. 49[Pt 2]:469–478, 1999), whereas P. syringae pv. tomato forms two distinct genetic lineages. A multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) conducted with eight minisatellite loci confirmed the genetic structure obtained with rpoD and gyrB sequence analyses. These results provide promising tools for fine-scale epidemiological studies on diseases caused by P. syringae pv. maculicola and P. syringae pv. tomato. The two pathovars had distinct host ranges; only P. syringae pv. maculicola strains were pathogenic for Brassicaceae. A subpopulation of P. syringae pv. maculicola strains that are pathogenic for Pto-expressing tomato plants were shown to lack avrPto1 and avrPtoB or to contain a disrupted avrPtoB homolog. Taking phylogenetic and pathological features into account, our data suggest that the DC3000 strain belongs to P. syringae pv. maculicola. This study shows that P. syringae pv. maculicola and P. syringae pv. tomato appear multiclonal, as they did not diverge from a single common ancestral group within the ancestral P. syringae genomospecies 3, and suggests that pathovar specificity within P. syringae may be due to independent genetic events. PMID:22389364

  20. First report of mixed infection by Pseudomonas syringae pathovars garcae and tabaci on coffee plantations

    OpenAIRE

    Lucas Mateus Rivero Rodrigues; Gustavo Hiroshi Sera; Oliveiro Guerreiro Filho; Luis Otavio Saggion Beriam; Irene Maria Gatti de Almeida

    2017-01-01

    ABSTRACT The bacterial-halo-blight (Pseudomonas syringae pv. garcae) is disseminated by the main coffee areas in the producing states of Brazil. On the other hand, the disease bacterial-leaf-spot (Pseudomonas syringae pv. tabaci) was reported only once in coffee seedlings in a sample collected in the State of São Paulo. In mid-2015, samples of coffee leaves with symptoms of foliar lesions surrounded by yellow halo, were collected in coffee plantations in the State of Paraná and fluorescent ba...

  1. First report of mixed infection by Pseudomonas syringae pathovars garcae and tabaci on coffee plantations

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    Lucas Mateus Rivero Rodrigues

    2017-08-01

    Full Text Available ABSTRACT The bacterial-halo-blight (Pseudomonas syringae pv. garcae is disseminated by the main coffee areas in the producing states of Brazil. On the other hand, the disease bacterial-leaf-spot (Pseudomonas syringae pv. tabaci was reported only once in coffee seedlings in a sample collected in the State of São Paulo. In mid-2015, samples of coffee leaves with symptoms of foliar lesions surrounded by yellow halo, were collected in coffee plantations in the State of Paraná and fluorescent bacteria producing or not brown pigment in culture medium were isolated and determined as belonging to the Group I of P. syringae. Through biochemical, serological and pathogenicity tests, the pathogens were identified as P. syringae pv. garcae and P. syringae pv. tabaci, with prevalence of isolates belonging to pathovar tabaci and, as well as in certain samples, it was identified simultaneous infection by both etiological agents. Then, this is the first report of associated occurrence of garcae and tabaci pathovars of P. syringae and of the incidence of “bacterial-leaf-spot” under field conditions and in the State of Paraná.

  2. Plant signal molecules activate the syrB gene, which is required for syringomycin production by Pseudomonas syringae pv. syringae.

    Science.gov (United States)

    Mo, Y Y; Gross, D C

    1991-01-01

    The syrB gene is required for syringomycin production by Pseudomonas syringae pv. syringae and full virulence during plant pathogenesis. Strain B3AR132 containing a syrB::lacZ fusion was used to detect transcriptional activation of the syrB gene in syringomycin minimal medium by plant metabolites with signal activity. Among 34 plant phenolic compounds tested, arbutin, phenyl-beta-D-glucopyranoside, and salicin were shown to be strong inducers of syrB, giving rise to approximately 1,200 U of beta-galactosidase activity at 100 microM; esculin and helicin were moderate inducers, with about 250 to 400 U of beta-galactosidase activity at 100 microM. Acetosyringone and flavonoids that serve as signal molecules in Agrobacterium and Rhizobium species, respectively, did not induce the syrB::lacZ fusion. All syrB inducers were phenolic glucosides and none of the aglucone derivatives were active, suggesting that the beta-glycosidic linkage was necessary for signal activity. Phenyl-beta-D-galactopyranoside containing galactose substituted for glucose in the beta-glycosidic linkage also lacked inducer activity. Phenolic signal activity was enhanced two- to fivefold by specific sugars common to plant tissues, including D-fructose, D-mannose, and sucrose. The effect of sugars on syrB induction was most noticeable at low concentrations of phenolic glucoside (i.e., 1 to 10 microM), indicating that sugars such as D-fructose increase the sensitivity of P. syringae pv. syringae to the phenolic plant signal. Besides induction of syrB, syringomycin biosynthesis by parental strain B3A-R was induced to yield over 250 U of toxin by the additions of arbutin and D-fructose to syringomycin minimal medium. These data indicate that syringomycin production by most strains of P. syringae pv. syringae is modulated by the perception of two classes of plant signal molecules and transduced to the transcriptional apparatus of syringomycin (syr) genes such as syrB. PMID:1885550

  3. Inhibition of apoptic cell death induced by Pseudomonas syringae pv. Tabaci and mycotoxin fumonisin B1

    NARCIS (Netherlands)

    Iakimova, E.T.; Batchvorova, R.; Kapchina, V.; Popov, T.; Atanassov, A.; Woltering, E.J.

    2004-01-01

    The impact of programmed cell death (PCD) inhibitors on lesion formation and biochemical events in transgenic (ttr line) and non-transgenic (Nevrokop 1164) tobacco infected with Pseudomonas syringae pv. tabaci was tested. Programmed cell death in tomato cell culture was induced by Fumonisin B1 (FUM)

  4. Contribution of alginate and levan production to biofilm formation by Pseudomonas syringae

    DEFF Research Database (Denmark)

    Laue, H.; Schenk, A.; Li, H.

    2006-01-01

    formation, biofilms of Pseudomonas syringae strains with different EPS patterns were compared. The mucoid strain PG4180.muc, which produces levan and alginate, and its levan- and/or alginate-deficient derivatives all formed biofilms in the wells of microtitre plates and in flow chambers. Confocal laser...

  5. Occurrence of Pseudomonas syringae pv. actinidiae in Jin Tao kiwi plants in Italy

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    G.M. Balestra

    2009-09-01

    Full Text Available During 2007–2008 bacterial canker caused damage in Jin Tao cv. kiwi (Actinidia chinensis plants grown in northern and central Italy. A bacterial population was repeatedly isolated from these plants. Based on morphological, physiological, biochemical and molecular tests, the causal agent was identified as Pseudomonas syringae pv. actinidiae (epidemiology and control strategies are discussed.

  6. Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

    Energy Technology Data Exchange (ETDEWEB)

    Feil, H; Feil, W S; Chain, P; Larimer, F; DiBartolo, G; Copeland, A; Lykidis, A; Trong, S; Nolan, M; Goltsman, E; Thiel, J; Malfatti, S; Loper, J E; Lapidus, A; Detter, J C; Land, M; Richardson, P M; Kyrpides, N C; Ivanova, N; Lindow, S E

    2005-07-14

    The complete genomic sequence of Pseudomonas syringae pathovar syringae B728a (Pss B728a), has been determined and is compared with that of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with Pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and Pst DC3000 having a more pronounced apoplastic growth habitat. The Pss B728a genome (6.1 megabases) contains a circular chromosome and no plasmid, whereas the Pst DC3000 genome is 6.5 mbp in size, composed of a circular chromosome and two plasmids. While a high degree of similarity exists between the two sequenced Pseudomonads, 976 protein-encoding genes are unique to Pss B728a when compared to Pst DC3000, including large genomic islands likely to contribute to virulence and host specificity. Over 375 repetitive extragenic palindromic sequences (REPs) unique to Pss B728a when compared to Pst DC3000 are widely distributed throughout the chromosome except in 14 genomic islands, which generally had lower GC content than the genome as a whole. Content of the genomic islands vary, with one containing a prophage and another the plasmid pKLC102 of P. aeruginosa PAO1. Among the 976 genes of Pss B728a with no counterpart in Pst DC3000 are those encoding for syringopeptin (SP), syringomycin (SR), indole acetic acid biosynthesis, arginine degradation, and production of ice nuclei. The genomic comparison suggests that several unique genes for Pss B728a such as ectoine synthase, DNA repair, and antibiotic production may contribute to epiphytic fitness and stress tolerance of this organism.

  7. Pseudomonas syringae enhances herbivory by suppressing the reactive oxygen burst in Arabidopsis.

    Science.gov (United States)

    Groen, Simon C; Humphrey, Parris T; Chevasco, Daniela; Ausubel, Frederick M; Pierce, Naomi E; Whiteman, Noah K

    2016-01-01

    Plant-herbivore interactions have evolved in the presence of plant-colonizing microbes. These microbes can have important third-party effects on herbivore ecology, as exemplified by drosophilid flies that evolved from ancestors feeding on plant-associated microbes. Leaf-mining flies in the genus Scaptomyza, which is nested within the paraphyletic genus Drosophila, show strong associations with bacteria in the genus Pseudomonas, including Pseudomonas syringae. Adult females are capable of vectoring these bacteria between plants and larvae show a preference for feeding on P. syringae-infected leaves. Here we show that Scaptomyza flava larvae can also vector P. syringae to and from feeding sites, and that they not only feed more, but also develop faster on plants previously infected with P. syringae. Our genetic and physiological data show that P. syringae enhances S. flava feeding on infected plants at least in part by suppressing anti-herbivore defenses mediated by reactive oxygen species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Information Management of Genome Enabled Data Streams for Pseudomonas syringae on the Pseudomonas-Plant Interaction (PPI Website

    Directory of Open Access Journals (Sweden)

    Magdalen Lindeberg

    2011-11-01

    Full Text Available Genome enabled research has led to a large and ever-growing body of data on Pseudomonas syringae genome variation and characteristics, though systematic capture of this information to maximize access by the research community remains a significant challenge. Major P. syringae data streams include genome sequence data, newly identified type III effectors, biological characterization data for type III effectors, and regulatory feature characterization. To maximize data access, the Pseudomonas-Plant Interaction (PPI website [1] is primarily focused on categorization of type III effectors and curation of effector functional data represented in the Hop database and Pseudomonas-Plant Interaction Resource, respectively. The PPI website further serves as a conduit for incorporation of new genome characterization data into the annotation records at NCBI and other data repositories, and clearinghouse for additional data sets and updates in response to the evolving needs of the research community.

  9. Genome Sequences of Two Pseudomonas syringae pv. tomato Race 1 Strains, Isolated from Tomato Fields in California

    OpenAIRE

    Thapa, Shree P.; Coaker, Gitta

    2016-01-01

    Pseudomonas syringae pv. tomato race 1 strains have evolved to overcome genetic resistance in tomato. Here, we present the draft genome sequences of two race 1 P.?syringae pv. tomato strains, A9 and 407, isolated from diseased tomato plants in California.

  10. Bacterial canker of plum caused by Pseudomonas syringae pathovars, as a serious threat for plum production in the Netherlands

    NARCIS (Netherlands)

    Wenneker, M.; Janse, J.D.; Bruine, de A.; Vink, P.; Pham, K.T.K.

    2012-01-01

    In the Netherlands, bacterial canker of plum trees (Prunus domestica) caused by Pseudomonas syringae pathovars syringae and morsprunorum is a recent and serious problem. The trunks of the affected plum trees are girdled by cankers resulting in relatively sudden death of the trees 1 to 4 years after

  11. Characterization of five ECF sigma factors in the genome of Pseudomonas syringae pv. syringae B728a.

    Directory of Open Access Journals (Sweden)

    Poulami Basu Thakur

    Full Text Available Pseudomonas syringae pv. syringae B728a, a bacterial pathogen of bean, utilizes large surface populations and extracellular signaling to initiate a fundamental change from an epiphytic to a pathogenic lifestyle. Extracytoplasmic function (ECF sigma (σ factors serve as important regulatory factors in responding to various environmental signals. Bioinformatic analysis of the B728a genome revealed 10 ECF sigma factors. This study analyzed deletion mutants of five previously uncharacterized ECF sigma factor genes in B728a, including three FecI-type ECF sigma factors (ECF5, ECF6, and ECF7 and two ECF sigma factors placed in groups ECF11 and ECF18. Transcriptional profiling by qRT-PCR analysis of ECF sigma factor mutants was used to measure expression of their associated anti-sigma and outer membrane receptor proteins, and expression of genes associated with production of extracellular polysaccharides, fimbriae, glycine betaine and syringomycin. Notably, the B728aΔecf7 mutant displayed reduced swarming and had decreased expression of CupC fimbrial genes. Growth and pathogenicity assays, using a susceptible bean host, revealed that none of the tested sigma factor genes are required for in planta growth and lesion formation.

  12. Spatial and temporal dynamics of primary and secondary metabolism in Phaseolus vulgaris challenged by Pseudomonas syringae.

    Science.gov (United States)

    Pérez-Bueno, María Luisa; Pineda, Mónica; Díaz-Casado, Elena; Barón, Matilde

    2015-01-01

    Many defense mechanisms contribute to the plant immune system against pathogens, involving the regulation of different processes of the primary and secondary metabolism. At the same time, pathogens have evolved mechanisms to hijack the plant defense in order to establish the infection and proliferate. Localization and timing of the host response are essential to understand defense mechanisms and resistance to pathogens (Rico et al. 2011). Imaging techniques, such as fluorescence imaging and thermography, are a very valuable tool providing spatial and temporal information about a series of plant processes. In this study, bean plants challenged with two pathovars of Pseudomonas syringae have been investigated. Pseudomonas syringae pv. phaseolicola 1448A and P. syringae pv. tomato DC3000 elicit a compatible and incompatible interaction in bean, respectively. Both types of host-pathogen interaction triggered different changes in the activity of photosynthesis and the secondary metabolism. We conclude that the combined analysis of leaf temperature, chlorophyll fluorescence and green fluorescence emitted by phenolics allows to discriminate compatible from incompatible P. syringae-Phaseolus vulgaris interactions in very early times of the infection, prior to the development of symptoms. These can constitute disease signatures that would allow an early identification of emerging plagues in crops. © 2014 Scandinavian Plant Physiology Society.

  13. Bacteriocin Typing of Some Turkish Isolates of Pseudomonas syringae pv. phaseolicola

    OpenAIRE

    Güven, Kıymet

    2000-01-01

    Eighty-six Pseudomonas syringae pv. phaseolicola isolates collected from different bean growing areas in Eskişehir were typed for the production of bacteriocin.All the isolates tested produced bacteriocin and 24 bacteriosin groups were determined. No correlation was found between the bacteriocin groups and geographical origin. Authentic isolates of the bacterium representing 3 different races were also tested for bacteriocin production and bacteriocin types did not correlate with the races.

  14. Thermo-regulation of genes mediating motility and plant interactions in Pseudomonas syringae.

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    Kevin L Hockett

    Full Text Available Pseudomonas syringae is an important phyllosphere colonist that utilizes flagellum-mediated motility both as a means to explore leaf surfaces, as well as to invade into leaf interiors, where it survives as a pathogen. We found that multiple forms of flagellum-mediated motility are thermo-suppressed, including swarming and swimming motility. Suppression of swarming motility occurs between 28° and 30 °C, which coincides with the optimal growth temperature of P. syringae. Both fliC (encoding flagellin and syfA (encoding a non-ribosomal peptide synthetase involved in syringafactin biosynthesis were suppressed with increasing temperature. RNA-seq revealed 1440 genes of the P. syringae genome are temperature sensitive in expression. Genes involved in polysaccharide synthesis and regulation, phage and IS elements, type VI secretion, chemosensing and chemotaxis, translation, flagellar synthesis and motility, and phytotoxin synthesis and transport were generally repressed at 30 °C, while genes involved in transcriptional regulation, quaternary ammonium compound metabolism and transport, chaperone/heat shock proteins, and hypothetical genes were generally induced at 30 °C. Deletion of flgM, a key regulator in the transition from class III to class IV gene expression, led to elevated and constitutive expression of fliC regardless of temperature, but did not affect thermo-regulation of syfA. This work highlights the importance of temperature in the biology of P. syringae, as many genes encoding traits important for plant-microbe interactions were thermo-regulated.

  15. Comparative genomics reveals genes significantly associated with woody hosts in the plant pathogen Pseudomonas syringae.

    Science.gov (United States)

    Nowell, Reuben W; Laue, Bridget E; Sharp, Paul M; Green, Sarah

    2016-12-01

    The diversification of lineages within Pseudomonas syringae has involved a number of adaptive shifts from herbaceous hosts onto various species of tree, resulting in the emergence of highly destructive diseases such as bacterial canker of kiwi and bleeding canker of horse chestnut. This diversification has involved a high level of gene gain and loss, and these processes are likely to play major roles in the adaptation of individual lineages onto their host plants. In order to better understand the evolution of P. syringae onto woody plants, we have generated de novo genome sequences for 26 strains from the P. syringae species complex that are pathogenic on a range of woody species, and have looked for statistically significant associations between gene presence and host type (i.e. woody or herbaceous) across a phylogeny of 64 strains. We have found evidence for a common set of genes associated with strains that are able to colonize woody plants, suggesting that divergent lineages have acquired similarities in genome composition that may form the genetic basis of their adaptation to woody hosts. We also describe in detail the gain, loss and rearrangement of specific loci that may be functionally important in facilitating this adaptive shift. Overall, our analyses allow for a greater understanding of how gene gain and loss may contribute to adaptation in P. syringae. © 2016 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.

  16. BOX-PCR-based identification of bacterial species belonging to Pseudomonas syringae: P. viridiflava group

    Directory of Open Access Journals (Sweden)

    Abi S.A. Marques

    2008-01-01

    Full Text Available The phenotypic characteristics and genetic fingerprints of a collection of 120 bacterial strains, belonging to Pseudomonas syringae sensu lato group, P. viridiflava and reference bacteria were evaluated, with the aim of species identification. The numerical analysis of 119 nutritional characteristics did not show patterns that would help with identification. Regarding the genetic fingerprinting, the results of the present study supported the observation that BOX-PCR seems to be able to identify bacterial strains at species level. After numerical analyses of the bar-codes, all pathovars belonging to each one of the nine described genomospecies were clustered together at a distance of 0.72, and could be separated at genomic species level. Two P. syringae strains of unknown pathovars (CFBP 3650 and CFBP 3662 and the three P. syringae pv. actinidiae strains were grouped in two extra clusters and might eventually constitute two new species. This genomic species clustering was particularly evident for genomospecies 4, which gathered P. syringae pvs. atropurpurea, coronafaciens, garçae, oryzae, porri, striafaciens, and zizaniae at a noticeably low distance.

  17. Fungicidal activities and mechanisms of action of Pseudomonas syringae pv. syringae lipodepsipeptide syringopeptins 22A and 25A

    Directory of Open Access Journals (Sweden)

    Mekki F. Bensaci

    2011-10-01

    Full Text Available The plant-associated bacterium Pseudomonas syringae pv. syringae simultaneously produces two classes of metabolites: the small cyclic lipodepsinonapeptides such as the syringomycins and the larger cyclic lipodepsipeptide syringopeptins SP22 or SP25. The syringomycins inhibit a broad spectrum of fungi (but particularly yeasts by lipid-dependent membrane interaction. The syringopeptins are phytotoxic and inhibitory to Gram positive bacteria. In this study, the fungicidal activities of two major syringopeptins, SP22A and SP25A, and their mechanisms of action were investigated and compared to those of syringomycin E. SP22A and SP25A were observed to inhibit the fungal yeasts Saccharomyces cerevisiae and Candida albicans although less effectively than syringomycin E. S. cerevisiae mutants defective in ergosterol and sphingolipid biosyntheses were less susceptible to SP22A and SP25A but the relative inhibitory capabilities of SRE vs. SP22A and SP25A were maintained. Similar differences were observed for capabilities to cause cellular K+ and Ca2+ fluxes in S. cerevisiae. Interestingly, in phospholipid bilayers the syringopeptins are found to induce larger macroscopic ionic conductances than syringomycin E but form single channels with similar properties. These findings suggest that the syringopeptins target the yeast plasma membrane, and, like syringomycin E, employ a lipid-dependent channel forming mechanism of action. The differing degrees of growth inhibition by these lipodepsipeptides may be explained by differences in their hydrophobicity. The more hydrophobic SP22A and SP25A might interact more strongly with the yeast cell wall that would create a selective barrier for their incorporation into the plasma membrane.

  18. Resistant and susceptible responses in alfalfa (Medicago sativa) to bacterial stem blight caused by Pseudomonas syringae pv. syringae.

    Science.gov (United States)

    Nemchinov, Lev G; Shao, Jonathan; Lee, Maya N; Postnikova, Olga A; Samac, Deborah A

    2017-01-01

    Bacterial stem blight caused by Pseudomonas syringae pv. syringae is a common disease of alfalfa (Medicago sativa L). Little is known about host-pathogen interactions and host defense mechanisms. Here, individual resistant and susceptible plants were selected from cultivars Maverick and ZG9830 and used for transcript profiling at 24 and 72 hours after inoculation (hai) with the isolate PssALF3. Bioinformatic analysis revealed a number of differentially expressed genes (DEGs) in resistant and susceptible genotypes. Although resistant plants from each cultivar produced a hypersensitive response, transcriptome analyses indicated that they respond differently at the molecular level. The number of DEGs was higher in resistant plants of ZG9830 at 24 hai than in Maverick, suggesting that ZG9830 plants had a more rapid effector triggered immune response. Unique up-regulated genes in resistant ZG9830 plants included genes encoding putative nematode resistance HSPRO2-like proteins, orthologs for the rice Xa21 and soybean Rpg1-b resistance genes, and TIR-containing R genes lacking both NBS and LRR domains. The suite of R genes up-regulated in resistant Maverick plants had an over-representation of R genes in the CC-NBS-LRR family including two genes for atypical CCR domains and a putative ortholog of the Arabidopsis RPM1 gene. Resistance in both cultivars appears to be mediated primarily by WRKY family transcription factors and expression of genes involved in protein phosphorylation, regulation of transcription, defense response including synthesis of isoflavonoids, and oxidation-reduction processes. These results will further the identification of mechanisms involved in resistance to facilitate selection of parent populations and development of commercial varieties.

  19. Resistant and susceptible responses in alfalfa (Medicago sativa to bacterial stem blight caused by Pseudomonas syringae pv. syringae.

    Directory of Open Access Journals (Sweden)

    Lev G Nemchinov

    Full Text Available Bacterial stem blight caused by Pseudomonas syringae pv. syringae is a common disease of alfalfa (Medicago sativa L. Little is known about host-pathogen interactions and host defense mechanisms. Here, individual resistant and susceptible plants were selected from cultivars Maverick and ZG9830 and used for transcript profiling at 24 and 72 hours after inoculation (hai with the isolate PssALF3. Bioinformatic analysis revealed a number of differentially expressed genes (DEGs in resistant and susceptible genotypes. Although resistant plants from each cultivar produced a hypersensitive response, transcriptome analyses indicated that they respond differently at the molecular level. The number of DEGs was higher in resistant plants of ZG9830 at 24 hai than in Maverick, suggesting that ZG9830 plants had a more rapid effector triggered immune response. Unique up-regulated genes in resistant ZG9830 plants included genes encoding putative nematode resistance HSPRO2-like proteins, orthologs for the rice Xa21 and soybean Rpg1-b resistance genes, and TIR-containing R genes lacking both NBS and LRR domains. The suite of R genes up-regulated in resistant Maverick plants had an over-representation of R genes in the CC-NBS-LRR family including two genes for atypical CCR domains and a putative ortholog of the Arabidopsis RPM1 gene. Resistance in both cultivars appears to be mediated primarily by WRKY family transcription factors and expression of genes involved in protein phosphorylation, regulation of transcription, defense response including synthesis of isoflavonoids, and oxidation-reduction processes. These results will further the identification of mechanisms involved in resistance to facilitate selection of parent populations and development of commercial varieties.

  20. Survival and electrotransformation of Pseudomonas syringae strains under simulated cloud-like conditions.

    Science.gov (United States)

    Blanchard, Laurine S; Monin, Anaïs; Ouertani, Hounaïda; Touaibia, Lamia; Michel, Elisa; Buret, François; Simonet, Pascal; Morris, Cindy E; Demanèche, Sandrine

    2017-05-01

    To diversify their genetic material, and thereby allow adaptation to environmental disturbances and colonization of new ecological niches, bacteria use various evolutionary processes, including the acquisition of new genetic material by horizontal transfer mechanisms such as conjugation, transduction and transformation. Electrotransformation mediated by lightning-related electrical phenomena may constitute an additional gene-transfer mechanism occurring in nature. The presence in clouds of bacteria such as Pseudomonas syringae capable of forming ice nuclei that lead to precipitation, and that are likely to be involved in triggering lightning, led us to postulate that natural electrotransformation in clouds may contribute to the adaptive potential of these bacteria. Here, we quantify the survival rate of 10 P. syringae strains in liquid and icy media under such electrical pulses and their capacity to acquire exogenous DNA. In comparison to two other bacteria (Pseudomonas sp. N3 and Escherichia coli TOP10), P. syringae CC0094 appears to be best adapted for survival and for genetic electrotransformation under these conditions, which suggests that this bacterium would be able to survive and to get a boost in its adaptive potential while being transported in clouds and falling back to Earth with precipitation from storms. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Exopolysaccharides Produced by Phytopathogenic Pseudomonas syringae Pathovars in Infected Leaves of Susceptible Hosts

    Science.gov (United States)

    Fett, William F.; Dunn, Michael F.

    1989-01-01

    Bacterial exopolysaccharide (EPS) was extracted from infected leaves of several host plants inoculated with phytopathogenic strains of Pseudomonas syringae pathovars. Extraction was by a facilitated diffusion procedure or by collection of intercellular fluid using a centrifugation method. The extracted EPS was purified and characterized. All bacterial pathogens which induced watersoaked lesions on their host leaves, a characteristic of most members of this bacterial group, were found to produce alginic acid (a polymer consisting of varying ratios of mannuronic and guluronic acids). Only trace amounts of bacterial EPS could be isolated from leaves inoculated with a pathovar (pv. syringae) which does not induce the formation of lesions with a watersoaked appearance. Guluronic acid was either present in very low amounts or absent in the alginic acid preparations. All bacterial alginates were acetylated (7-11%). Levan (a fructan) was apparently not produced as an EPS in vivo by any of the pathogens tested. PMID:16666545

  2. The life history of Pseudomonas syringae: linking agriculture to earth system processes.

    Science.gov (United States)

    Morris, Cindy E; Monteil, Caroline L; Berge, Odile

    2013-01-01

    The description of the ecology of Pseudomonas syringae is moving away from that of a ubiquitous epiphytic plant pathogen to one of a multifaceted bacterium sans frontières in fresh water and other ecosystems linked to the water cycle. Discovery of the aquatic facet of its ecology has led to a vision of its life history that integrates spatial and temporal scales spanning billions of years and traversing catchment basins, continents, and the planet and that confronts the implication of roles that are potentially conflicting for agriculture (as a plant pathogen and as an actor in processes leading to rain and snowfall). This new ecological perspective has also yielded insight into epidemiological phenomena linked to disease emergence. Overall, it sets the stage for the integration of more comprehensive contexts of ecology and evolutionary history into comparative genomic analyses to elucidate how P. syringae subverts the attack and defense responses of the cohabitants of the diverse environments it occupies.

  3. Suppression of plant defense responses by extracellular metabolites from Pseudomonas syringae pv. tabaci in Nicotiana benthamiana.

    Science.gov (United States)

    Lee, Seonghee; Yang, Dong Sik; Uppalapati, Srinivasa Rao; Sumner, Lloyd W; Mysore, Kirankumar S

    2013-04-18

    Pseudomonas syringae pv. tabaci (Pstab) is the causal agent of wildfire disease in tobacco plants. Several pathovars of Pseudomonas syringae produce a phytotoxic extracellular metabolite called coronatine (COR). COR has been shown to suppress plant defense responses. Interestingly, Pstab does not produce COR but still actively suppresses early plant defense responses. It is not clear if Pstab produces any extracellular metabolites that actively suppress early defense during bacterial pathogenesis. We found that the Pstab extracellular metabolite extracts (Pstab extracts) remarkably suppressed stomatal closure and nonhost hypersensitive response (HR) cell death induced by a nonhost pathogen, P. syringae pv. tomato T1 (Pst T1), in Nicotiana benthamiana. We also found that the accumulation of nonhost pathogens, Pst T1 and P. syringae pv. glycinea (Psgly), was increased in N. benthamiana plants upon treatment with Pstab extracts . The HR cell death induced by Pathogen-Associated Molecular Pattern (INF1), gene-for-gene interaction (Pto/AvrPto and Cf-9/AvrCf-9) and ethanol was not delayed or suppressed by Pstab extracts. We performed metabolite profiling to investigate the extracellular metabolites from Pstab using UPLC-qTOF-MS and identified 49 extracellular metabolites from the Pstab supernatant culture. The results from gene expression profiling of PR-1, PR-2, PR-5, PDF1.2, ABA1, COI1, and HSR203J suggest that Pstab extracellular metabolites may interfere with SA-mediated defense pathways. In this study, we found that Pstab extracts suppress plant defense responses such as stomatal closure and nonhost HR cell death induced by the nonhost bacterial pathogen Pst T1 in N. benthamiana.

  4. AtMIN7 mediated disease resistance to Pseudomonas syringae in Arabidopsis

    Science.gov (United States)

    He, Sheng Yang [Okemos, MI; Nomura, Kinya [East Lansing, MI

    2011-07-26

    The present invention relates to compositions and methods for enhancing plant defenses against pathogens. More particularly, the invention relates to enhancing plant immunity against bacterial pathogens, wherein AtMIN7 mediated protection is enhanced and/or there is a decrease in activity of an AtMIN7 associated virulence protein such as a Pseudomonas syringae pv. tomato DC3000 HopM1. Reagents of the present invention provide a means of studying cellular trafficking while formulations of the present inventions provide increased pathogen resistance in plants.

  5. Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA

    OpenAIRE

    Pel, M.J.C.; Dijken, A.J.H. van; Bardoel, B.W.; Seidl, M.F.; Ent, S. van der; van Strijp, J. A. G.

    2014-01-01

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant athogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantl...

  6. Yersiniabactin production by Pseudomonas syringae and Escherichia coli, and description of a second yersiniabactin locus evolutionary group.

    Science.gov (United States)

    Bultreys, Alain; Gheysen, Isabelle; de Hoffmann, Edmond

    2006-06-01

    The siderophore and virulence factor yersiniabactin is produced by Pseudomonas syringae. Yersiniabactin was originally detected by high-pressure liquid chromatography (HPLC); commonly used PCR tests proved ineffective. Yersiniabactin production in P. syringae correlated with the possession of irp1 located in a predicted yersiniabactin locus. Three similarly divergent yersiniabactin locus groups were determined: the Yersinia pestis group, the P. syringae group, and the Photorhabdus luminescens group; yersiniabactin locus organization is similar in P. syringae and P. luminescens. In P. syringae pv. tomato DC3000, the locus has a high GC content (63.4% compared with 58.4% for the chromosome and 60.1% and 60.7% for adjacent regions) but it lacks high-pathogenicity-island features, such as the insertion in a tRNA locus, the integrase, and insertion sequence elements. In P. syringae pv. tomato DC3000 and pv. phaseolicola 1448A, the locus lies between homologues of Psyr_2284 and Psyr_2285 of P. syringae pv. syringae B728a, which lacks the locus. Among tested pseudomonads, a PCR test specific to two yersiniabactin locus groups detected a locus in genospecies 3, 7, and 8 of P. syringae, and DNA hybridization within P. syringae also detected a locus in the pathovars phaseolicola and glycinea. The PCR and HPLC methods enabled analysis of nonpathogenic Escherichia coli. HPLC-proven yersiniabactin-producing E. coli lacked modifications found in irp1 and irp2 in the human pathogen CFT073, and it is not clear whether CFT073 produces yersiniabactin. The study provides clues about the evolution and dispersion of yersiniabactin genes. It describes methods to detect and study yersiniabactin producers, even where genes have evolved.

  7. Arabidopsis cysteine-rich receptor-like kinase 45 positively regulates disease resistance to Pseudomonas syringae.

    Science.gov (United States)

    Zhang, Xiujuan; Han, Xiaomin; Shi, Rui; Yang, Guanyu; Qi, Liwang; Wang, Ruigang; Li, Guojing

    2013-12-01

    Arabidopsis cysteine-rich receptor-like protein kinase 45 (CRK45) was found to be involved in ABA signaling in Arabidopsis thaliana previously. Here, we reported that it also positively regulates disease resistance. The CRK45 overexpression plants increased expression of the defense genes, and enhanced resistance to Pseudomonas syringae whereas the crk45 mutant were more sensitive to P. syringae and weakened expression of the defense genes, compared to the wild type. We also found that treatment with P. syringae leads to a declined expression of CRK45 in the npr1 mutant and the NahG transgenic plants. At the same time, significantly decreased expression of CRK45 transcript in the wrky70 mutant than that in the wild type was also detected. Our results suggested that CRK45 acted as a positive regulator in Arabidopsis disease resistance, and was regulated downstream of NPR1 and WRKY70 at the transcriptional level. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  8. HopW1 from Pseudomonas syringae disrupts the actin cytoskeleton to promote virulence in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Yongsung Kang

    2014-06-01

    Full Text Available A central mechanism of virulence of extracellular bacterial pathogens is the injection into host cells of effector proteins that modify host cellular functions. HopW1 is an effector injected by the type III secretion system that increases the growth of the plant pathogen Pseudomonas syringae on the Columbia accession of Arabidopsis. When delivered by P. syringae into plant cells, HopW1 causes a reduction in the filamentous actin (F-actin network and the inhibition of endocytosis, a known actin-dependent process. When directly produced in plants, HopW1 forms complexes with actin, disrupts the actin cytoskeleton and inhibits endocytosis as well as the trafficking of certain proteins to vacuoles. The C-terminal region of HopW1 can reduce the length of actin filaments and therefore solubilize F-actin in vitro. Thus, HopW1 acts by disrupting the actin cytoskeleton and the cell biological processes that depend on actin, which in turn are needed for restricting P. syringae growth in Arabidopsis.

  9. Immunomodulation by the Pseudomonas syringae HopZ type III effector family in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Jennifer D Lewis

    Full Text Available Pseudomonas syringae employs a type III secretion system to inject 20-30 different type III effector (T3SE proteins into plant host cells. A major role of T3SEs is to suppress plant immune responses and promote bacterial infection. The YopJ/HopZ acetyltransferases are a superfamily of T3SEs found in both plant and animal pathogenic bacteria. In P. syringae, this superfamily includes the evolutionarily diverse HopZ1, HopZ2 and HopZ3 alleles. To investigate the roles of the HopZ family in immunomodulation, we generated dexamethasone-inducible T3SE transgenic lines of Arabidopsis for HopZ family members and characterized them for immune suppression phenotypes. We show that all of the HopZ family members can actively suppress various facets of Arabidopsis immunity in a catalytic residue-dependent manner. HopZ family members can differentially suppress the activation of mitogen-activated protein (MAP kinase cascades or the production of reactive oxygen species, whereas all members can promote the growth of non-virulent P. syringae. Localization studies show that four of the HopZ family members containing predicted myristoylation sites are localized to the vicinity of the plasma membrane while HopZ3 which lacks the myristoylation site is at least partially nuclear localized, suggesting diversification of immunosuppressive mechanisms. Overall, we demonstrate that despite significant evolutionary diversification, all HopZ family members can suppress immunity in Arabidopsis.

  10. Biocontrol activity of Paenibacillus polymyxa AC-1 against Pseudomonas syringae and its interaction with Arabidopsis thaliana.

    Science.gov (United States)

    Hong, Chi Eun; Kwon, Suk Yoon; Park, Jeong Mee

    2016-04-01

    Paenibacillus polymyxa AC-1 (AC-1) is a plant growth-promoting rhizobacterium (PGPR) that has been used as a soil inoculant for biocontrol of plant pathogenic fungi and to promote plant growth. In this study, we examine the effects of AC-1 on the bacterial phytopathogen Pseudomonas syringae and internal colonization of AC-1 by counting bacterial populations that colonize plants. AC-1 inhibited the growth of both P. syringae pv. tomato DC3000 (Pst) and P. syringae pv. tabaci (Pta) in a concentration-dependent manner in in vitro assays. Upon treatment of AC-1 dropping at root tip of axenically grown Arabidopsis, we found that most of the AC-1 was detected in interior of leaves of Arabidiopsis plants rather than roots after 5 days post infection, indicating systemic spreading of AC-1 occur. We examined further AC-1 colonization patterns in Arabidopsis mutants deficient in phytohormone signaling pathways. These results indicated that abscisic acid (ABA) and jasmonic acid (JA) signaling pathways positively and negatively contributed, respectively, to AC-1 colonization of leaves, whereas epiphytic accumulation of AC-1 around root tissues was not affected. This study shows that AC-1 is an effective biocontrol agent to suppress P. syringae growth, possibly owing to its colonization patterns as a leaf-inhabiting endophyte. The results showed in this work will help to expand our understanding of the mode of action of AC-1 as a biological control agent and consequently, its application in agriculture. Copyright © 2016 Elsevier GmbH. All rights reserved.

  11. Functional analysis of Arabidopsis WRKY25 transcription factor in plant defense against Pseudomonas syringae.

    Science.gov (United States)

    Zheng, Zuyu; Mosher, Stephen L; Fan, Baofang; Klessig, Daniel F; Chen, Zhixiang

    2007-01-10

    A common feature of plant defense responses is the transcriptional regulation of a large number of genes upon pathogen infection or treatment with pathogen elicitors. A large body of evidence suggests that plant WRKY transcription factors are involved in plant defense including transcriptional regulation of plant host genes in response to pathogen infection. However, there is only limited information about the roles of specific WRKY DNA-binding transcription factors in plant defense. We analyzed the role of the WRKY25 transcription factor from Arabidopsis in plant defense against the bacterial pathogen Pseudomonas syringae. WRKY25 protein recognizes the TTGACC W-box sequences and its translational fusion with green fluorescent protein is localized to the nucleus. WRKY25 expression is responsive to general environmental stress. Analysis of stress-induced WRKY25 in the defense signaling mutants npr1, sid2, ein2 and coi1 further indicated that this gene is positively regulated by the salicylic acid (SA) signaling pathway and negatively regulated by the jasmonic acid signaling pathway. Two independent T-DNA insertion mutants for WRKY25 supported normal growth of a virulent strain of P. syringae but developed reduced disease symptoms after infection. By contrast, Arabidopsis constitutively overexpressing WRKY25 supported enhanced growth of P. syringae and displayed increased disease symptom severity as compared to wild-type plants. These WRKY25-overexpressing plants also displayed reduced expression of the SA-regulated PR1 gene after the pathogen infection, despite normal levels of free SA. The nuclear localization and sequence-specific DNA-binding activity support that WRKY25 functions as a transcription factor. Based on analysis of both T-DNA insertion mutants and transgenic overexpression lines, stress-induced WRKY25 functions as a negative regulator of SA-mediated defense responses to P. syringae. This proposed role is consistent with the recent finding that WRKY25

  12. Dynamic evolution of pathogenicity revealed by sequencing and comparative genomics of 19 Pseudomonas syringae isolates.

    Directory of Open Access Journals (Sweden)

    David A Baltrus

    2011-07-01

    Full Text Available Closely related pathogens may differ dramatically in host range, but the molecular, genetic, and evolutionary basis for these differences remains unclear. In many Gram- negative bacteria, including the phytopathogen Pseudomonas syringae, type III effectors (TTEs are essential for pathogenicity, instrumental in structuring host range, and exhibit wide diversity between strains. To capture the dynamic nature of virulence gene repertoires across P. syringae, we screened 11 diverse strains for novel TTE families and coupled this nearly saturating screen with the sequencing and assembly of 14 phylogenetically diverse isolates from a broad collection of diseased host plants. TTE repertoires vary dramatically in size and content across all P. syringae clades; surprisingly few TTEs are conserved and present in all strains. Those that are likely provide basal requirements for pathogenicity. We demonstrate that functional divergence within one conserved locus, hopM1, leads to dramatic differences in pathogenicity, and we demonstrate that phylogenetics-informed mutagenesis can be used to identify functionally critical residues of TTEs. The dynamism of the TTE repertoire is mirrored by diversity in pathways affecting the synthesis of secreted phytotoxins, highlighting the likely role of both types of virulence factors in determination of host range. We used these 14 draft genome sequences, plus five additional genome sequences previously reported, to identify the core genome for P. syringae and we compared this core to that of two closely related non-pathogenic pseudomonad species. These data revealed the recent acquisition of a 1 Mb megaplasmid by a sub-clade of cucumber pathogens. This megaplasmid encodes a type IV secretion system and a diverse set of unknown proteins, which dramatically increases both the genomic content of these strains and the pan-genome of the species.

  13. Dynamic evolution of pathogenicity revealed by sequencing and comparative genomics of 19 Pseudomonas syringae isolates.

    Science.gov (United States)

    Baltrus, David A; Nishimura, Marc T; Romanchuk, Artur; Chang, Jeff H; Mukhtar, M Shahid; Cherkis, Karen; Roach, Jeff; Grant, Sarah R; Jones, Corbin D; Dangl, Jeffery L

    2011-07-01

    Closely related pathogens may differ dramatically in host range, but the molecular, genetic, and evolutionary basis for these differences remains unclear. In many Gram- negative bacteria, including the phytopathogen Pseudomonas syringae, type III effectors (TTEs) are essential for pathogenicity, instrumental in structuring host range, and exhibit wide diversity between strains. To capture the dynamic nature of virulence gene repertoires across P. syringae, we screened 11 diverse strains for novel TTE families and coupled this nearly saturating screen with the sequencing and assembly of 14 phylogenetically diverse isolates from a broad collection of diseased host plants. TTE repertoires vary dramatically in size and content across all P. syringae clades; surprisingly few TTEs are conserved and present in all strains. Those that are likely provide basal requirements for pathogenicity. We demonstrate that functional divergence within one conserved locus, hopM1, leads to dramatic differences in pathogenicity, and we demonstrate that phylogenetics-informed mutagenesis can be used to identify functionally critical residues of TTEs. The dynamism of the TTE repertoire is mirrored by diversity in pathways affecting the synthesis of secreted phytotoxins, highlighting the likely role of both types of virulence factors in determination of host range. We used these 14 draft genome sequences, plus five additional genome sequences previously reported, to identify the core genome for P. syringae and we compared this core to that of two closely related non-pathogenic pseudomonad species. These data revealed the recent acquisition of a 1 Mb megaplasmid by a sub-clade of cucumber pathogens. This megaplasmid encodes a type IV secretion system and a diverse set of unknown proteins, which dramatically increases both the genomic content of these strains and the pan-genome of the species. © 2011 Baltrus et al.

  14. Differential inactivation of alfalfa nodule glutamine synthetases by tabtoxinine-. beta. -lactam. [Pseudomonas syringae

    Energy Technology Data Exchange (ETDEWEB)

    Knight, T.J.; Unkefer, P.J.

    1987-04-01

    The presence of the pathogen Pseudomonas syringae pv. tabaci within the rhizosphere of nodulated alfalfa plants results in an increase in N/sub 2/-fixation potential and growth, but a 40-50% decrease in nodule glutamine synthetase (GS) activity, as compared to nodulated control plants. Tabtoxinine-..beta..-Lactam an exocellular toxin produced by Pseudomonas syringae pv tabaci irreversibly inhibits glutamine synthetase. Partial purification of nodule GS by DEAE-cellulose chromatography reveals two enzyme forms are present (GS/sub n1/ and GS/sub n2/). In vitro inactivation of the two glutamine synthetases associated with the nodule indicates a differential sensitivity to T-..beta..-L. The nodule specific GS/sub n1/ is much less sensitive to T-..beta..-L than the GS/sub n2/ enzyme, which was found to coelute with the root enzyme (GS/sub r/). However, both GS/sub n1/ and GS/sub n2/ are rapidly inactivated by methionine sulfoximine, another irreversible inhibitor of GS.

  15. A Boolean model of the Pseudomonas syringae hrp regulon predicts a tightly regulated system.

    Directory of Open Access Journals (Sweden)

    Daniel MacLean

    Full Text Available The Type III secretion system (TTSS is a protein secretion machinery used by certain gram-negative bacterial pathogens of plants and animals to deliver effector molecules to the host and is at the core of the ability to cause disease. Extensive molecular and biochemical study has revealed the components and their interactions within this system but reductive approaches do not consider the dynamical properties of the system as a whole. In order to gain a better understanding of these dynamical behaviours and to create a basis for the refinement of the experimentally derived knowledge we created a Boolean model of the regulatory interactions within the hrp regulon of Pseudomonas syringae pathovar tomato strain DC3000 Pseudomonas syringae. We compared simulations of the model with experimental data and found them to be largely in accordance, though the hrpV node shows some differences in state changes to that expected. Our simulations also revealed interesting dynamical properties not previously predicted. The model predicts that the hrp regulon is a biologically stable two-state system, with each of the stable states being strongly attractive, a feature indicative of selection for a tightly regulated and responsive system. The model predicts that the state of the GacS/GacA node confers control, a prediction that is consistent with experimental observations that the protein has a role as master regulator. Simulated gene "knock out" experiments with the model predict that HrpL is a central information processing point within the network.

  16. WHOP, a Genomic Region Associated With Woody Hosts in the Pseudomonas syringae Complex Contributes to the Virulence and Fitness of Pseudomonas savastanoi pv. savastanoi in Olive Plants.

    Science.gov (United States)

    Caballo-Ponce, Eloy; van Dillewijn, Pieter; Wittich, Regina Michaela; Ramos, Cayo

    2017-02-01

    Bacteria from the Pseudomonas syringae complex belonging to phylogroups 1 and 3 (PG1 and PG3, respectively) isolated from woody hosts share a genomic region herein referred to as WHOP (from woody host and Pseudomonas spp.), which is absent in strains infecting herbaceous organs. In this work, we show that this region is also encoded in P. syringae pv. actinidifoliorum (PG1) and six additional members of PG3, namely, Pseudomonas savastanoi pv. retacarpa, three P. syringae pathovars, Pseudomonas meliae, and Pseudomonas amygdali. Partial conservation of the WHOP occurs in only a few PG2 strains. In P. savastanoi pv. savastanoi NCPPB 3335, the WHOP region is organized into four operons and three independently transcribed genes. While the antABC and catBCA operons mediate the catabolism of anthranilate and catechol, respectively, the ipoABC operon confers oxygenase activity to aromatic compounds. The deletion of antABC, catBCA, or ipoABC in NCPPB 3335 caused reduced virulence in woody olive plants without affecting knot formation in nonwoody plants; catBCA, dhoAB, and PSA3335_3206 (encoding a putative aerotaxis receptor) were also required for the full fitness of this strain exclusively in woody olive plants. Overall, this study sheds light on the evolution and adaptation of bacteria from the P. syringae complex to woody hosts and highlights the enzymatic activities encoded within the WHOP region that are essential for this process.

  17. The conserved hypothetical protein PSPTO_3957 is essential for virulence in the plant pathogen Pseudomonas syringae pv. tomato DC3000

    Science.gov (United States)

    The plant pathogen Pseudomonas syringae accounts for substantial crop losses and is considered an important agricultural issue. Although many genes involved in interactions of this pathogen with hosts have been identified and characterized, little is known about processes involving bacterial metabol...

  18. Atmospheric CO2 alters resistance of arabidopsis to Pseudomonas syringae by affecting abscisic acid accumulation and stomatal responsiveness to coronatine

    NARCIS (Netherlands)

    Zhou, Yeling; Vroegop-Vos, Irene; Schuurink, Robert C; Pieterse, Corné M.J.; Van Wees, Saskia C.M.

    2017-01-01

    Atmospheric CO2 influences plant growth and stomatal aperture. Effects of high or low CO2 levels on plant disease resistance are less well understood. Here, resistance of Arabidopsis thaliana against the foliar pathogen Pseudomonas syringae pv. tomato DC3000 (Pst) was investigated at three different

  19. The role of crop waste and soil in Pseudomonas syringae pathovar porri infection of leek (Allium porrum)

    NARCIS (Netherlands)

    Overbeek, van L.S.; Nijhuis, E.H.; Koenraadt, H.; Visser, J.H.M.

    2010-01-01

    Pseudomonas syringae pv. porri, the causal agent of bacterial blight of leek, is a current threat for leek (Allium porrum) production in the Netherlands. The roles of post-harvest crop waste and plant invasion from soil in leek plant infection was investigated with the purpose to gain better

  20. Self-protection of Pseudomonas syringae pv. tabaci from its toxin, tabtoxinine-. beta. -lactam

    Energy Technology Data Exchange (ETDEWEB)

    Knight, T.J.; Durbin, R.D.; Langston-Unkefer, P.J.

    1987-05-01

    An extracellular toxin, tabtoxinine-..beta..-lactam (T..beta..L), is produced by Pseudomonas syringae pv. tabaci. This toxin irreversibly inhibits its target, glutamine synthetase; yet P. syringae pv. tabaci retains significant amounts of glutamine synthetase activity during toxin production in culture. As part of our investigation of the self-protection of P. syringae pv. tabaci, the authors compared the effects of T..beta..L on Tox/sup +/ (T..beta..L-producing, insensitive to T..beta..L) and Tox/sup -/ (T..beta..L nonproducing, sensitive to T..lambda..) strains. The extent of protection afforded to the Tox/sup -/ strain when induced to adenylylate glutamine synthetase was tested. It was concluded that an additional protection mechanism was required. A detoxification activity was found in the Tox/sup +/ strain which opens the epsilon-lactam ring to T..beta..L to produce the inactive, open-chain form, tabtoxinine. Whole cells of the Tox/sup +/ strain incubated for 24 h with (/sup 14/C)T..beta..L (0.276 ..mu..mol/3 x 10/sup 10/ cells) contained (/sup 14/C)tabtoxinine (0.056 ..mu..mol), and the medium contained T..beta..L (0.226 ..mu..mol). Extracts of spheroplasts of the Tox/sup +/ stain also converted T..beta..L to tabtoxinine, whereas extracts of the Tox/sup -/ strain did not alter T..beta..L. The conversion was time dependent and stoichiometric and was destroyed by boiling for 30 min or by the addition of 5mM EDTA. Penicillin, a possible substrate and competitive inhibitor of this lactamase activity, inhibited the conversion of T..lambda.. to tabtoxinine. Periplasmic fluid did not catalyze the conversion of T..beta..L.

  1. Early events in the pathogenicity of Pseudomonas syringae on Nicotiana benthamiana.

    Science.gov (United States)

    Hann, Dagmar R; Rathjen, John P

    2007-02-01

    Conserved microbial molecules known as PAMPs (pathogen-associated molecular patterns) elicit defence responses in plants through extracellular receptor proteins. One important PAMP is the flagellin protein derived from motile bacteria. We show here that the solanaceous species Nicotiana benthamiana perceives the flagellin proteins of both pathogenic and non-host species of Pseudomonas syringae. The response to flagellin required a gene closely related to that encoding the Arabidopsis thaliana flagellin receptor that we designated NbFls2. In addition, silencing of NbFls2 led to increased growth of compatible, non-host and non-pathogenic strains of P. syringae. Thus, flagellin perception restricts growth of P. syringae strains on N. benthamiana. Pathogenic bacteria secrete effector proteins into the plant cell to enhance virulence. We tested the ability of several unrelated effectors to suppress PAMP-mediated defences. The effector proteins AvrPto and AvrPtoB, but not AvrRps4, suppressed all responses tested including the hypersensitive response induced by non-host flagellins and the oomycete elicitor INF1. Strikingly, transient expression of avrPto or avrPtoB stimulated the growth of non-pathogenic Agrobacterium tumefaciensin planta, suggesting that multiplication of this species is also restricted by PAMP perception. Unexpectedly, AvrPtoB but not AvrPto required the defence-associated genes Rar1, Sgt1 and Eds1 for suppression. This observation separates the respective mechanisms of the two effectors, and suggests that AvrPtoB may target the defence machinery directly for its suppressive effect.

  2. Bacteria in the leaf ecosystem with emphasis on Pseudomonas syringae-a pathogen, ice nucleus, and epiphyte.

    Science.gov (United States)

    Hirano, S S; Upper, C D

    2000-09-01

    The extremely large number of leaves produced by terrestrial and aquatic plants provide habitats for colonization by a diversity of microorganisms. This review focuses on the bacterial component of leaf microbial communities, with emphasis on Pseudomonas syringae-a species that participates in leaf ecosystems as a pathogen, ice nucleus, and epiphyte. Among the diversity of bacteria that colonize leaves, none has received wider attention than P. syringae, as it gained notoriety for being the first recombinant organism (Ice(-) P. syringae) to be deliberately introduced into the environment. We focus on P. syringae to illustrate the attractiveness and somewhat unique opportunities provided by leaf ecosystems for addressing fundamental questions of microbial population dynamics and mechanisms of plant-bacterium interactions. Leaf ecosystems are dynamic and ephemeral. The physical environment surrounding phyllosphere microbes changes continuously with daily cycles in temperature, radiation, relative humidity, wind velocity, and leaf wetness. Slightly longer-term changes occur as weather systems pass. Seasonal climatic changes impose still a longer cycle. The physical and physiological characteristics of leaves change as they expand, mature, and senesce and as host phenology changes. Many of these factors influence the development of populations of P. syringae upon populations of leaves. P. syringae was first studied for its ability to cause disease on plants. However, disease causation is but one aspect of its life strategy. The bacterium can be found in association with healthy leaves, growing and surviving for many generations on the surfaces of leaves as an epiphyte. A number of genes and traits have been identified that contribute to the fitness of P. syringae in the phyllosphere. While still in their infancy, such research efforts demonstrate that the P. syringae-leaf ecosystem is a particularly attractive system with which to bridge the gap between what is known

  3. Comprehensive analysis of draft genomes of two closely related Pseudomonas syringae phylogroup 2b strains infecting mono and dicotyledon host plants

    Science.gov (United States)

    In recent years, the damage caused by bacterial pathogens to major crops has been increasing worldwide. Pseudomonas syringae is a widespread bacterial species that infects almost all major crops. Different P. syringae strains use a wide range of biochemical mechanisms, including phytotoxins and effe...

  4. Clarification of Taxonomic Status within the Pseudomonas syringae Species Group Based on a Phylogenomic Analysis

    Directory of Open Access Journals (Sweden)

    Margarita Gomila

    2017-12-01

    Full Text Available The Pseudomonas syringae phylogenetic group comprises 15 recognized bacterial species and more than 60 pathovars. The classification and identification of strains is relevant for practical reasons but also for understanding the epidemiology and ecology of this group of plant pathogenic bacteria. Genome-based taxonomic analyses have been introduced recently to clarify the taxonomy of the whole genus. A set of 139 draft and complete genome sequences of strains belonging to all species of the P. syringae group available in public databases were analyzed, together with the genomes of closely related species used as outgroups. Comparative genomics based on the genome sequences of the species type strains in the group allowed the delineation of phylogenomic species and demonstrated that a high proportion of strains included in the study are misclassified. Furthermore, representatives of at least 7 putative novel species were detected. It was also confirmed that P. ficuserectae, P. meliae, and P. savastanoi are later synonyms of P. amygdali and that “P. coronafaciens” should be revived as a nomenspecies.

  5. The hygroscopic biosurfactant syringafactin produced by Pseudomonas syringae enhances fitness on leaf surfaces during fluctuating humidity.

    Science.gov (United States)

    Burch, Adrien Y; Zeisler, Viktoria; Yokota, Kenji; Schreiber, Lukas; Lindow, Steven E

    2014-07-01

    Biosurfactant production by bacteria on leaf surfaces is poorly documented, and its role in this habitat has not been explored. Therefore, we investigated the production and fitness benefits of syringafactin by Pseudomonas syringae pv. syringae B728a on leaves. Syringafactin largely adsorbed to the waxy leaf cuticle both when topically applied and when produced by cells on plants. Syringafactin increased the rate of diffusion of water across isolated cuticles and attracted water to hydrophobic surfaces exposed to high relative humidity due to its hygroscopic properties. While a wild-type and syringafactin mutant exhibited similar fitness on bean leaves incubated in static conditions, the fitness of the wild-type strain was higher under fluctuating humidity conditions typical of field conditions. When co-inoculated onto either the host plant bean or the non-host plant romaine lettuce, the proportion of viable wild-type cells recovered from plants relative to that of a mutant unable to produce syringafactin increased 10% over 10 days. The number of disease lesions incited by the wild-type strain on bean was also significantly higher than that of the syringafactin mutant. The production of hygroscopic biosurfactants on waxy leaf surfaces apparently benefits bacteria by both attracting moisture and facilitating access to nutrients. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Transcriptome Analysis of Kiwifruit in Response to Pseudomonas syringae pv. actinidiae Infection

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2018-01-01

    Full Text Available Kiwifruit bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa has brought about a severe threat to the kiwifruit industry worldwide since its first outbreak in 2008. Studies on other pathovars of P. syringae are revealing the pathogenesis of these pathogens, but little about the mechanism of kiwifruit bacterial canker is known. In order to explore the species-specific interaction between Psa and kiwifruit, we analyzed the transcriptomic profile of kiwifruit infected by Psa. After 48 h, 8255 differentially expressed genes were identified, including those involved in metabolic process, secondary metabolites metabolism and plant response to stress. Genes related to biosynthesis of terpens were obviously regulated, indicating terpens may play roles in suppressing the growth of Psa. We identified 283 differentially expressed resistant genes, of which most U-box domain containing genes were obviously up regulated. Expression of genes involved in plant immunity was detected and some key genes showed differential expression. Our results suggest that Psa induced defense response of kiwifruit, including PAMP (pathogen/microbe-associated molecular patterns-triggered immunity, effector-triggered immunity and hypersensitive response. Metabolic process was adjusted to adapt to these responses and production of secondary metabolites may be altered to suppress the growth of Psa.

  7. Evading plant immunity: feedback control of the T3SS in Pseudomonas syringae

    Science.gov (United States)

    Waite, Christopher; Schumacher, Jörg; Jovanovic, Milija; Bennett, Mark; Buck, Martin

    2017-01-01

    Microbes are responsible for over 10% of the global yield losses in staple crops such as wheat, rice, and maize. Understanding the decision-making strategies that enable bacterial plant pathogens to evade the host immune system and cause disease is essential for managing their ever growing threat to food security. Many utilise the needle-like type III secretion system (T3SS) to suppress plant immunity, by injecting effector proteins that inhibit eukaryotic signalling pathways into the host cell cytoplasm. Plants can in turn evolve resistance to specific pathogens via recognition and blocking of the T3SS effectors, so leading to an ongoing co-evolutionary ‘arms race’ between pathogen and host pairs. The extracytoplasmic function sigma factor HrpL co-ordinates the expression of the T3SS regulon in the leaf-dwelling Pseudomonas syringae and similar pathogens. Recently, we showed that association of HrpL with a target promoter directly adjacent to the hrpL gene imposes negative autogenous control on its own expression level due to overlapping regulatory elements. Our results suggest that by down-regulating T3SS function, this fine-tuning mechanism enables P. syringae to minimise effector-mediated elicitation of plant immunity. PMID:28435841

  8. Abscisic acid-cytokinin antagonism modulates resistance against pseudomonas syringae in Tobacco

    DEFF Research Database (Denmark)

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2014-01-01

    Phytohormones are known as essential regulators of plant defenses, with ethylene, jasmonic acid, and salicylic acid as the central immunity backbone, while other phytohormones have been demonstrated to interact with this. Only recently, a function of the classic phytohormone cytokinin in plant...... immunity has been described in Arabidopsis, rice, and tobacco. Although interactions of cytokinins with salicylic acid and auxin have been indicated, the complete network of cytokinin interactions with other immunity-relevant phytohormones is not yet understood. Therefore, we studied the interaction...... of kinetin and abscisic acid as a negative regulator of plant immunity to modulate resistance in tobacco against Pseudomonas syringae. By analyzing infection symptoms, pathogen proliferation, and accumulation of the phytoalexin scopoletin as a key mediator of kinetin-induced resistance in tobacco...

  9. Assessment of strains of Pseudomonas syringae pv. tomato from Tanzania for resistance to copper and streptomycin

    DEFF Research Database (Denmark)

    Shenge, K.C.; Wydra, K.; Mabagala, M.B.

    2008-01-01

    different ecological conditions in the country. After isolation and identification, the P. s. pv. tomato strains were grown on King's medium B (KB) amended with 20% copper sulphate (w/v). The strains were also assessed for resistance to antibiotics. Results indicated that there was widespread resistance......Fifty-six strains of Pseudomonas syringae pv. tomato (P.s. pv. tomato) were collected from tomato-producing areas in Tanzania and assessed for resistance to copper and antibiotics. The collection was done from three tomato-producing regions (Morogoro, Arusha and Iringa), representing three...... of the P. s. pv. tomato strains to copper sulphate. The highest level of resistance was recorded from the Arusha region (Northern Tanzania), 83.3% of the P. s. pv. tomato strains from that region showed resistance to copper sulphate. This was followed by Iringa region (Southern Tanzania), from where...

  10. Functional analysis of Arabidopsis WRKY25 transcription factor in plant defense against Pseudomonas syringae

    Directory of Open Access Journals (Sweden)

    Klessig Daniel F

    2007-01-01

    Full Text Available Abstract Background A common feature of plant defense responses is the transcriptional regulation of a large number of genes upon pathogen infection or treatment with pathogen elicitors. A large body of evidence suggests that plant WRKY transcription factors are involved in plant defense including transcriptional regulation of plant host genes in response to pathogen infection. However, there is only limited information about the roles of specific WRKY DNA-binding transcription factors in plant defense. Results We analyzed the role of the WRKY25 transcription factor from Arabidopsis in plant defense against the bacterial pathogen Pseudomonas syringae. WRKY25 protein recognizes the TTGACC W-box sequences and its translational fusion with green fluorescent protein is localized to the nucleus. WRKY25 expression is responsive to general environmental stress. Analysis of stress-induced WRKY25 in the defense signaling mutants npr1, sid2, ein2 and coi1 further indicated that this gene is positively regulated by the salicylic acid (SA signaling pathway and negatively regulated by the jasmonic acid signaling pathway. Two independent T-DNA insertion mutants for WRKY25 supported normal growth of a virulent strain of P. syringae but developed reduced disease symptoms after infection. By contrast, Arabidopsis constitutively overexpressing WRKY25 supported enhanced growth of P. syringae and displayed increased disease symptom severity as compared to wild-type plants. These WRKY25-overexpressing plants also displayed reduced expression of the SA-regulated PR1 gene after the pathogen infection, despite normal levels of free SA. Conclusion The nuclear localization and sequence-specific DNA-binding activity support that WRKY25 functions as a transcription factor. Based on analysis of both T-DNA insertion mutants and transgenic overexpression lines, stress-induced WRKY25 functions as a negative regulator of SA-mediated defense responses to P. syringae. This

  11. Phosphatidylcholine synthesis is essential for HrpZ harpin secretion in plant pathogenic Pseudomonas syringae and non-pathogenic Pseudomonas sp. 593.

    Science.gov (United States)

    Xiong, Min; Long, Deliang; He, Huoguang; Li, Yang; Li, Yadong; Wang, Xingguo

    2014-01-01

    Pseudomonas syringae pv. syringae van Hall is important phytopathogenic bacterium of stone fruit trees, and able to elicit hypersensitive response (HR) in nonhost plants. The HrpZ, secreted via type III secretion system (T3SS) to the extracellular space of the plant, is a T3SS-dependent protein and a sole T3SS effector able to induce the host defense response outside host cells. We deleted the phosphatidylcholine synthase gene (pcs) of P. syringae pv. syringae van Hall CFCC 1336, and found that the 1336 pcs(-) mutant was unable to synthesize phosphatidylcholine and elicit a typical HR in soybean. Further studies showed that the 1336 pcs(-) mutant was unable to secrete HrpZ harpin but could express HrpZ protein in cytoplasm as effectively as the wild type. To confirm if phosphatidylcholine affects HrpZ harpin secretion, we introduced the hrpZ gene into the soil-dwelling bacterium Pseudomonas sp. 593 and the 593 pcs(-) mutant, which were unable to express HrpZ harpin and elicit HR in tobacco or soybean. Western blotting and HR assay showed that the 593H not only secreted HrpZ harpin but also caused a strong HR in tobacco and soybean. In contrast, the 593 pcs(-)H only expressed HrpZ protein in its cytoplasm at the wild type level, but did not secrete HrpZ harpin or elicit HR reaction. Our results demonstrate that phosphatidylcholine is essential for the secretion of HrpZ harpin in P. syringae pv. syringae van Hall and other Pseudomonas strains. Copyright © 2013 Elsevier GmbH. All rights reserved.

  12. Pathovars of Pseudomonas syringae Causing Bacterial Brown Spot and Halo Blight in Phaseolus vulgaris L. Are Distinguishable by Ribotyping

    Science.gov (United States)

    González, Ana J.; Landeras, Elena; Mendoza, M. Carmen

    2000-01-01

    Ribotyping was evaluated as a method to differentiate between Pseudomonas syringae pv. phaseolicola and pv. syringae strains causing bacterial brown spot and halo blight diseases in Phaseolus vulgaris L. Ribotyping, with restriction enzymes BglI and SalI and using the Escherichia coli rrnB operon as the probe, differentiated 11 and 14 ribotypes, respectively, and a combination of data from both procedures yielded 19 combined ribotypes. Cluster analysis of the combined ribotypes differentiated the pathovars phaseolicola and syringae, as well as different clonal lineages within these pathovars. The potential of ribotyping to screen for correlations between lineages and factors such as geographical region and/or bean varieties is also reported. PMID:10653764

  13. Inhibitory effect of Thymus vulgaris and Origanum vulgare essential oils on virulence factors of phytopathogenic Pseudomonas syringae strains.

    Science.gov (United States)

    Carezzano, M E; Sotelo, J P; Primo, E; Reinoso, E B; Paletti Rovey, M F; Demo, M S; Giordano, W F; Oliva, M de Las M

    2017-07-01

    Pseudomonas syringae is a phytopathogenic bacterium that causes lesions in leaves during the colonisation process. The damage is associated with production of many virulence factors, such as biofilm and phytotoxins. The essential oils of Thymus vulgaris (thyme) and Origanum vulgare (oregano) have been demonstrated to inhibit P. syringae. The aim of this study was to investigate the effects of T. vulgaris and O. vulgare essential oils on production of virulence factors of phytopathogenic P. syringae strains, including anti-biofilm and anti-toxins activities. The broth microdilution method was used for determination of MIC and biofilm inhibition assays. Coronatine, syringomycin and tabtoxin were pheno- and genotypically evaluated. Both oils showed good inhibitory activity against P. syringae, with MIC values from 1.43 to 11.5 mg·ml -1 for thyme and 5.8 to 11.6 mg·ml -1 for oregano. Biofilm formation, production of coronatine, syringomycin and tabtoxin were inhibited by thyme and oregano essential oil in most strains. The results presented here are promising, demonstrating the bactericidal activity and reduction of virulence factor production after treatment with thyme and oregano oil, providing insight into how they exert their antibacterial activity. These natural products could be considered in the future for the control of diseases caused by P. syringae. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  14. Ice nucleators, bacterial cells and Pseudomonas syringae in precipitation at Jungfraujoch

    Science.gov (United States)

    Stopelli, Emiliano; Conen, Franz; Guilbaud, Caroline; Zopfi, Jakob; Alewell, Christine; Morris, Cindy E.

    2017-03-01

    Ice nucleation is a means by which the deposition of an airborne microorganism can be accelerated under favourable meteorological conditions. Analysis of 56 snow samples collected at the high-altitude observatory Jungfraujoch (3580 m a.s.l.) revealed an order-of-magnitude-larger dynamic range of ice-nucleating particles active at -8 °C (INPs-8) compared to the total number of bacterial cells (of which on average 60 % was alive). This indicates a shorter atmospheric residence time for INPs-8. Furthermore, concentrations of INPs-8 decreased much faster, with an increasing fraction of water precipitated from the air mass prior to sampling, than the number of total bacterial cells. Nevertheless, at high wind speeds (> 50 km h-1) the ratio of INPs-8 to total bacterial cells largely remained in a range between 10-2 and 10-3, independent of prior precipitation, likely because of recent injections of particles in regions upwind. Based on our field observations, we conclude that ice nucleators travel shorter legs of distance with the atmospheric water cycle than the majority of bacterial cells. A prominent ice-nucleating bacterium, Pseudomonas syringae, has been previously supposed to benefit from this behaviour as a means to spread via the atmosphere and to colonise new host plants. Therefore, we targeted this bacterium with a selective cultivation approach. P. syringae was successfully isolated for the first time at such an altitude in 3 of 13 samples analysed. Colony-forming units of this species constituted a minor fraction (10-4) of the numbers of INPs-8 in these samples. Overall, our findings expand the geographic range of habitats where this bacterium has been found and corroborate theories on its robustness in the atmosphere and its propensity to spread to colonise new habitats.

  15. Defense Responses in Two Ecotypes of Lotus japonicus against Non-Pathogenic Pseudomonas syringae

    Science.gov (United States)

    Bordenave, Cesar D.; Escaray, Francisco J.; Menendez, Ana B.; Serna, Eva; Carrasco, Pedro; Ruiz, Oscar A.; Gárriz, Andrés

    2013-01-01

    Lotus japonicus is a model legume broadly used to study many important processes as nitrogen fixing nodule formation and adaptation to salt stress. However, no studies on the defense responses occurring in this species against invading microorganisms have been carried out at the present. Understanding how this model plant protects itself against pathogens will certainly help to develop more tolerant cultivars in economically important Lotus species as well as in other legumes. In order to uncover the most important defense mechanisms activated upon bacterial attack, we explored in this work the main responses occurring in the phenotypically contrasting ecotypes MG-20 and Gifu B-129 of L. japonicus after inoculation with Pseudomonas syringae DC3000 pv. tomato. Our analysis demonstrated that this bacterial strain is unable to cause disease in these accessions, even though the defense mechanisms triggered in these ecotypes might differ. Thus, disease tolerance in MG-20 was characterized by bacterial multiplication, chlorosis and desiccation at the infiltrated tissues. In turn, Gifu B-129 plants did not show any symptom at all and were completely successful in restricting bacterial growth. We performed a microarray based analysis of these responses and determined the regulation of several genes that could play important roles in plant defense. Interestingly, we were also able to identify a set of defense genes with a relative high expression in Gifu B-129 plants under non-stress conditions, what could explain its higher tolerance. The participation of these genes in plant defense is discussed. Our results position the L. japonicus-P. syringae interaction as a interesting model to study defense mechanisms in legume species. PMID:24349460

  16. E-2-hexenal promotes susceptibility to Pseudomonas syringae by activating jasmonic acid pathways in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Alessandra eScala

    2013-04-01

    Full Text Available Green Leaf Volatiles (GLVs are C6-molecules - alcohols, aldehydes and esters - produced by plants upon herbivory or during pathogen infection. Exposure to this blend of volatiles induces defence-related responses in neighboring undamaged plants, thus assigning a role to GLVs in regulating plant defences. Here we compared Arabidopsis thaliana ecotype Ler with a hydroperoxide lyase line, hpl1, unable to synthesize GLVs, for susceptibility to Pseudomonas syringae pv. tomato (DC3000. We found that the growth of DC3000 was significantly reduced in the hpl1 mutant. This phenomenon correlated with lower jasmonic acid (JA levels and higher salicylic acid (SA levels in the hpl1 mutant. Furthermore, upon infection, the JA-responsive genes VSP2 and LEC were only slightly or not induced, respectively, in hpl1. This suggests that the reduced growth of DC3000 in hpl1 plants is due to the constraint of JA-dependent responses. Treatment of hpl1 plants with E-2-hexenal, one of the more reactive GLVs, prior to infection with DC3000, resulted in increased growth of DC3000 in hpl1, thus complementing this mutant. Interestingly, the growth of DC3000 also increased in Ler plants treated with E-2-hexenal. This stronger growth was not dependent on the JA-signaling component MYC2, but on ORA59, an integrator of JA and ethylene signaling pathways, and on the production of coronatine by DC3000. GLVs may have multiple effects on plant-pathogen interactions, in this case reducing resistance to P. syringae via JA and ORA59.

  17. Apoplastic peroxidases are required for salicylic acid-mediated defense against Pseudomonas syringae.

    Science.gov (United States)

    Mammarella, Nicole D; Cheng, Zhenyu; Fu, Zheng Qing; Daudi, Arsalan; Bolwell, G Paul; Dong, Xinnian; Ausubel, Frederick M

    2015-04-01

    Reactive oxygen species (ROS) generated by NADPH oxidases or apoplastic peroxidases play an important role in the plant defense response. Diminished expression of at least two Arabidopsis thaliana peroxidase encoding genes, PRX33 (At3g49110) and PRX34 (At3g49120), as a consequence of anti-sense expression of a heterologous French bean peroxidase gene (asFBP1.1), were previously shown to result in reduced levels of ROS following pathogen attack, enhanced susceptibility to a variety of bacterial and fungal pathogens, and reduced levels of callose production and defense-related gene expression in response to the microbe associated molecular pattern (MAMP) molecules flg22 and elf26. These data demonstrated that the peroxidase-dependent oxidative burst plays an important role in the elicitation of pattern-triggered immunity (PTI). Further work reported in this paper, however, shows that asFBP1.1 antisense plants are not impaired in all PTI-associated responses. For example, some but not all flg22-elicited genes are induced to lower levels by flg22 in asFPB1.1, and callose deposition in asFPB1.1 is similar to wild-type following infiltration with a Pseudomonas syringae hrcC mutant or with non-host P. syringae pathovars. Moreover, asFPB1.1 plants did not exhibit any apparent defect in their ability to mount a hypersensitive response (HR). On the other hand, salicylic acid (SA)-mediated activation of PR1 was dramatically impaired in asFPB1.1 plants. In addition, P. syringae-elicited expression of many genes known to be SA-dependent was significantly reduced in asFBP1.1 plants. Consistent with this latter result, in asFBP1.1 plants the key regulator of SA-mediated responses, NPR1, showed both dramatically decreased total protein abundance and a failure to monomerize, which is required for its translocation into the nucleus. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Early Arabidopsis root hair growth stimulation by pathogenic strains of Pseudomonas syringae.

    Science.gov (United States)

    Pecenková, Tamara; Janda, Martin; Ortmannová, Jitka; Hajná, Vladimíra; Stehlíková, Zuzana; Žárský, Viktor

    2017-09-01

    Selected beneficial Pseudomonas spp. strains have the ability to influence root architecture in Arabidopsis thaliana by inhibiting primary root elongation and promoting lateral root and root hair formation. A crucial role for auxin in this long-term (1week), long-distance plant-microbe interaction has been demonstrated. Arabidopsis seedlings were cultivated in vitro on vertical plates and inoculated with pathogenic strains Pseudomonas syringae pv. maculicola (Psm) and P. syringae pv. tomato DC3000 (Pst), as well as Agrobacterium tumefaciens (Atu) and Escherichia coli (Eco). Root hair lengths were measured after 24 and 48h of direct exposure to each bacterial strain. Several Arabidopsis mutants with impaired responses to pathogens, impaired ethylene perception and defects in the exocyst vesicle tethering complex that is involved in secretion were also analysed. Arabidopsis seedling roots infected with Psm or Pst responded similarly to when infected with plant growth-promoting rhizobacteria; root hair growth was stimulated and primary root growth was inhibited. Other plant- and soil-adapted bacteria induced similar root hair responses. The most compromised root hair growth stimulation response was found for the knockout mutants exo70A1 and ein2. The single immune pathways dependent on salicylic acid, jasmonic acid and PAD4 are not directly involved in root hair growth stimulation; however, in the mutual cross-talk with ethylene, they indirectly modify the extent of the stimulation of root hair growth. The Flg22 peptide does not initiate root hair stimulation as intact bacteria do, but pretreatment with Flg22 prior to Psm inoculation abolished root hair growth stimulation in an FLS2 receptor kinase-dependent manner. These early response phenomena are not associated with changes in auxin levels, as monitored with the pDR5::GUS auxin reporter. Early stimulation of root hair growth is an effect of an unidentified component of living plant pathogenic bacteria. The root

  19. Detecção de bacteriocinas produzidas por bactérias fitopatogênicas dos gêneros Erwinia, Pseudomonas e Xanthomonas Detection of bacteriocins produced by plant pathogenic bacteria from the genera Erwinia, Pseudomonas and Xanthomonas

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    C.M.R. de Biagi

    1992-01-01

    Full Text Available A detecção da produção de bacteriocinas foi estudada em diferentes condições, utilizando-se linhagens de bactérias fitopatogênicas dos gêneros Erwinia, Pseudomonas e Xanthomonas. Obtiveram-se, respectivamente, 58,06%, 71,31% e 40,00% de linhagens produtoras no meio 523, que foi o mais indicado para detecção dessa produção. Uma maior concentração de ágar adicionada ao meio (1,5% produziu melhores resultados mas, a quantidade de meio nas placas não influenciou a detecção de bacteriocinas. O maior tempo de incubação utilizado (72 h. facilitou detecção de halos de produção de bacteriocinas. Irradiação com luz ultra-violeta em baixas doses parece facilitar a liberação de bacteriocinas, mas isso varia com a linhagem empregada.Detection of bacteriocin production was studied under distinct conditions using strains of plant pathogenic bacteria from the genera Erwinia, Pseudomonas and Xanthomonas. 58.06%, 79.31% and 40.00% of producing strains were found respectivelly in the three groups of bacteria using the 523 medium which was the best for the detection of bacteriocin production. Increasing agar concentrations added to the medium up to 1,5% improved the detection. The amount of medium added to the Petri dishes did not affect bacteriocin production. The longest incubation time (72h. improved the detection of haloe production. Ultra-violet irradiation in low dosages seems to improve the visualization of haloe prodution but this is dependent on the tested strains.

  20. Cytokinin production by Pseudomonas fluorescens G20-18 determines biocontrol activity against Pseudomonas syringae in Arabidopsis.

    Science.gov (United States)

    Großkinsky, Dominik K; Tafner, Richard; Moreno, María V; Stenglein, Sebastian A; García de Salamone, Inés E; Nelson, Louise M; Novák, Ondřej; Strnad, Miroslav; van der Graaff, Eric; Roitsch, Thomas

    2016-03-17

    Plant beneficial microbes mediate biocontrol of diseases by interfering with pathogens or via strengthening the host. Although phytohormones, including cytokinins, are known to regulate plant development and physiology as well as plant immunity, their production by microorganisms has not been considered as a biocontrol mechanism. Here we identify the ability of Pseudomonas fluorescens G20-18 to efficiently control P. syringae infection in Arabidopsis, allowing maintenance of tissue integrity and ultimately biomass yield. Microbial cytokinin production was identified as a key determinant for this biocontrol effect on the hemibiotrophic bacterial pathogen. While cytokinin-deficient loss-of-function mutants of G20-18 exhibit impaired biocontrol, functional complementation with cytokinin biosynthetic genes restores cytokinin-mediated biocontrol, which is correlated with differential cytokinin levels in planta. Arabidopsis mutant analyses revealed the necessity of functional plant cytokinin perception and salicylic acid-dependent defence signalling for this biocontrol mechanism. These results demonstrate microbial cytokinin production as a novel microbe-based, hormone-mediated concept of biocontrol. This mechanism provides a basis to potentially develop novel, integrated plant protection strategies combining promotion of growth, a favourable physiological status and activation of fine-tuned direct defence and abiotic stress resilience.

  1. Features of air masses associated with the deposition of Pseudomonas syringae and Botrytis cinerea by rain and snowfall.

    Science.gov (United States)

    Monteil, Caroline L; Bardin, Marc; Morris, Cindy E

    2014-11-01

    Clarifying the role of precipitation in microbial dissemination is essential for elucidating the processes involved in disease emergence and spread. The ecology of Pseudomonas syringae and its presence throughout the water cycle makes it an excellent model to address this issue. In this study, 90 samples of freshly fallen rain and snow collected from 2005-2011 in France were analyzed for microbiological composition. The conditions favorable for dissemination of P. syringae by this precipitation were investigated by (i) estimating the physical properties and backward trajectories of the air masses associated with each precipitation event and by (ii) characterizing precipitation chemistry, and genetic and phenotypic structures of populations. A parallel study with the fungus Botrytis cinerea was also performed for comparison. Results showed that (i) the relationship of P. syringae to precipitation as a dissemination vector is not the same for snowfall and rainfall, whereas it is the same for B. cinerea and (ii) the occurrence of P. syringae in precipitation can be linked to electrical conductivity and pH of water, the trajectory of the air mass associated with the precipitation and certain physical conditions of the air mass (i.e. temperature, solar radiation exposure, distance traveled), whereas these predictions are different for B. cinerea. These results are pertinent to understanding microbial survival, emission sources and atmospheric processes and how they influence microbial dissemination.

  2. Indole-3-acetaldehyde dehydrogenase-dependent auxin synthesis contributes to virulence of Pseudomonas syringae strain DC3000.

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    Sheri A McClerklin

    2018-01-01

    Full Text Available The bacterial pathogen Pseudomonas syringae modulates plant hormone signaling to promote infection and disease development. P. syringae uses several strategies to manipulate auxin physiology in Arabidopsis thaliana to promote pathogenesis, including its synthesis of indole-3-acetic acid (IAA, the predominant form of auxin in plants, and production of virulence factors that alter auxin responses in the host; however, the role of pathogen-derived auxin in P. syringae pathogenesis is not well understood. Here we demonstrate that P. syringae strain DC3000 produces IAA via a previously uncharacterized pathway and identify a novel indole-3-acetaldehyde dehydrogenase, AldA, that functions in IAA biosynthesis by catalyzing the NAD-dependent formation of IAA from indole-3-acetaldehyde (IAAld. Biochemical analysis and solving of the 1.9 Å resolution x-ray crystal structure reveal key features of AldA for IAA synthesis, including the molecular basis of substrate specificity. Disruption of aldA and a close homolog, aldB, lead to reduced IAA production in culture and reduced virulence on A. thaliana. We use these mutants to explore the mechanism by which pathogen-derived auxin contributes to virulence and show that IAA produced by DC3000 suppresses salicylic acid-mediated defenses in A. thaliana. Thus, auxin is a DC3000 virulence factor that promotes pathogenicity by suppressing host defenses.

  3. Genome, Proteome and Structure of a T7-Like Bacteriophage of the Kiwifruit Canker Phytopathogen Pseudomonas Syringae pv. Actinidiae

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    Rebekah A. Frampton

    2015-06-01

    Full Text Available Pseudomonas syringae pv. actinidiae is an economically significant pathogen responsible for severe bacterial canker of kiwifruit (Actinidia sp.. Bacteriophages infecting this phytopathogen have potential as biocontrol agents as part of an integrated approach to the management of bacterial canker, and for use as molecular tools to study this bacterium. A variety of bacteriophages were previously isolated that infect P. syringae pv. actinidiae, and their basic properties were characterized to provide a framework for formulation of these phages as biocontrol agents. Here, we have examined in more detail φPsa17, a phage with the capacity to infect a broad range of P. syringae pv. actinidiae strains and the only member of the Podoviridae in this collection. Particle morphology was visualized using cryo-electron microscopy, the genome was sequenced, and its structural proteins were analysed using shotgun proteomics. These studies demonstrated that φPsa17 has a 40,525 bp genome, is a member of the T7likevirus genus and is closely related to the pseudomonad phages φPSA2 and gh-1. Eleven structural proteins (one scaffolding were detected by proteomics and φPsa17 has a capsid of approximately 60 nm in diameter. No genes indicative of a lysogenic lifecycle were identified, suggesting the phage is obligately lytic. These features indicate that φPsa17 may be suitable for formulation as a biocontrol agent of P. syringae pv. actinidiae.

  4. Defence responses of arabidopsis thaliana to infection by pseudomonas syringae are regulated by the circadian clock

    KAUST Repository

    Bhardwaj, Vaibhav

    2011-10-31

    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 that the increased resistance to Pst DC3000 observed in the morning in Col-0 plants results from clock-mediated modulation of pathogen associated molecular pattern (PAMP)-triggered immunity. Analysis of publicly available microarray data revealed that a large number of Arabidopsis defence-related genes showed both diurnal- and circadian-regulation, including genes involved in the perception of the PAMP flagellin which exhibit a peak in expression in the morning. Accordingly, we observed that PAMP-triggered callose deposition was significantly higher in wild-type plants inoculated with Pst DC3000 hrpA in the subjective morning than in the evening, while no such temporal difference was evident in arrhythmic plants. Our results suggest that PAMP-triggered immune responses are modulated by the circadian clock and that temporal regulation allows plants to anticipate and respond more effectively to pathogen challenges in the daytime. © 2011 Bhardwaj et al.

  5. Identification, Cloning, and Characterization of l-Phenylserine Dehydrogenase from Pseudomonas syringae NK-15

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    Sakuko Ueshima

    2010-01-01

    Full Text Available The gene encoding d-phenylserine dehydrogenase from Pseudomonas syringae NK-15 was identified, and a 9,246-bp nucleotide sequence containing the gene was sequenced. Six ORFs were confirmed in the sequenced region, four of which were predicted to form an operon. A homology search of each ORF predicted that orf3 encoded l-phenylserine dehydrogenase. Hence, orf3 was cloned and overexpressed in Escherichia coli cells and recombinant ORF3 was purified to homogeneity and characterized. The purified ORF3 enzyme showed l-phenylserine dehydrogenase activity. The enzymological properties and primary structure of l-phenylserine dehydrogenase (ORF3 were quite different from those of d-phenylserine dehydrogenase previously reported. l-Phenylserine dehydrogenase catalyzed the NAD+-dependent oxidation of the β-hydroxyl group of l-β-phenylserine. l-Phenylserine and l-threo-(2-thienylserine were good substrates for l-phenylserine dehydrogenase. The genes encoding l-phenylserine dehydrogenase and d-phenylserine dehydrogenase, which is induced by phenylserine, are located in a single operon. The reaction products of both enzymatic reactions were 2-aminoacetophenone and CO2.

  6. The Italian inter-laboratory study on the detection of Pseudomonas syringae pv. actinide

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    Stefania LORETI

    2014-05-01

    Full Text Available A severe form of bacterial canker of kiwifruit, caused by Pseudomonas syringae pv. actinidiae (Psa, has been detected in all the main areas of cultivation of kiwifruit (Actinidia deliciosa and A. chinensis. Since 2010 several research groups have been assessing methods and procedures to detect and identify Psa, both from symptomatic and symptomless host material. In 2011, a study to compare Psa diagnostic methods was performed with reference to Psa strains and related pathovars, and with plant extracts or DNA obtained from healthy and naturally infected leaves, pollen or wood. The study revealed the strengths and the weaknesses of the assessed methods. The procedure included screening tests for Psa detection and for identification of Psa colonies. The methods assessed were bacterial isolation on generic and semi-selective media, PCR analysis (single, duplex and rep-PCR assay, the latter for identification only. The results highlighted the best performance of semi-selective with respect the generic media; the usefulness of the direct-PCR as screening tests for Psa detection; and the greater specificity of duplex-PCR and sensitivity of simple-PCR. The use of semi-selective medium for isolation and of two PCR-based methods - in parallel - for Psa detection are suggested. Both rep-PCR and duplex-PCR, were found to be specific, and are recommended as an identification test for this pathogen.

  7. Resistance Inducers Modulate Pseudomonas syringae pv. Tomato Strain DC3000 Response in Tomato Plants

    Science.gov (United States)

    Scalschi, Loredana; Camañes, Gemma; Llorens, Eugenio; Fernández-Crespo, Emma; López, María M.; García-Agustín, Pilar; Vicedo, Begonya

    2014-01-01

    The efficacy of hexanoic acid (Hx) as an inducer of resistance in tomato plants against Pseudomonas syringae pv. tomato DC3000 was previously demonstrated, and the plant response was characterized. Because little is known about the reaction of the pathogen to this effect, the goal of the present work was to determine whether the changes in the plant defence system affect the pathogen behaviour. This work provides the first demonstration of the response of the pathogen to the changes observed in plants after Hx application in terms of not only the population size but also the transcriptional levels of genes involved in quorum sensing establishment and pathogenesis. Therefore, it is possible that Hx treatment attenuates the virulence and survival of bacteria by preventing or diminishing the appearance of symptoms and controlling the growth of the bacteria in the mesophyll. It is interesting to note that the gene transcriptional changes in the bacteria from the treated plants occur at the same time as the changes in the plants. Hx is able to alter bacteria pathogenesis and survival only when it is applied as a resistance inducer because the changes that it promotes in plants affect the bacteria. PMID:25244125

  8. Crystal structures of Pseudomonas syringae pv. tomato DC3000 quinone oxidoreductase and its complex with NADPH

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xiaowei [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Hongmei; Gao, Yu; Li, Mei [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China); Chang, Wenrui, E-mail: wrchang@sun5.ibp.ac.cn [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101 (China)

    2009-12-18

    Zeta-crystallin-like quinone oxidoreductase is NAD(P)H-dependent and catalyzes one-electron reduction of certain quinones to generate semiquinone. Here we present the crystal structures of zeta-crystallin-like quinone oxidoreductase from Pseudomonas syringae pv. tomato DC3000 (PtoQOR) and its complexes with NADPH determined at 2.4 and 2.01 A resolutions, respectively. PtoQOR forms as a homologous dimer, each monomer containing two domains. In the structure of the PtoQOR-NADPH complex, NADPH locates in the groove between the two domains. NADPH binding causes obvious conformational changes in the structure of PtoQOR. The putative substrate-binding site of PtoQOR is wider than that of Escherichia coli and Thermus thermophilus HB8. Activity assays show that PtoQOR has weak 1,4-benzoquinone catalytic activity, and very strong reduction activity towards large substrates such as 9,10-phenanthrenequinone. We propose a model to explain the conformational changes which take place during reduction reactions catalyzed by PtoQOR.

  9. Layered basal defenses underlie non-host resistance of Arabidopsis to Pseudomonas syringae pv. phaseolicola.

    Science.gov (United States)

    Ham, Jong Hyun; Kim, Min Gab; Lee, Sang Yeol; Mackey, David

    2007-08-01

    Arabidopsis is a non-host for Pseudomonas syringae pv. phaseolicola NPS3121 (Pph), a bacterial pathogen of bean. Pph does not induce a hypersensitive response in Arabidopsis. Here we show that Arabidopsis instead resists Pph with multi-layered basal defense. Our approach was: (i) to identify defense readouts induced by Pph; (ii) to determine whether mutations in known Arabidopsis defense genes disrupt Pph-induced defense signaling; (iii) to determine whether heterologous type III effectors from pathogens of Arabidopsis suppress Pph-induced defense signaling, and (iv) to ascertain how basal defenses contribute to resistance against Pph by individually or multiply disrupting defense signaling pathways with mutations and heterologous type III effectors. We demonstrate that Pph elicits a minimum of three basal defense-signaling pathways in Arabidopsis. These pathways have unique readouts, including PR-1 protein accumulation and morphologically distinct types of callose deposition. Further, they require distinct defense genes, including PMR4, RAR1, SID2, NPR1, and PAD4. Finally, they are suppressed differentially by heterologous type III effectors, including AvrRpm1 and HopM1. Pph growth is enhanced only when multiple defense pathways are disrupted. For example, mutation of NPR1 or SID2 combined with the action of AvrRpm1 and HopM1 renders Arabidopsis highly susceptible to Pph. Thus, non-host resistance of Arabidopsis to Pph is based on multiple, individually effective layers of basal defense.

  10. PENGARUH SUMBER MINERAL TERHADAP PENEKANAN Erwinia carotovora OLEH PSEUDOMONAS PENDAR-FLUOR SECARA IN VITRO

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    Hardian Susilo Addy .

    2012-02-01

    Full Text Available Antimicrobial Stimulation of Fluorescent Pseudomonad to Inhibit Soft-rot Pathogen Caused by Erwinia carotovora subsp. Carotovora. This research was conducted to study effect of mineral sources on inhibition Erwinia carotovora by fluorescent pseudomonad. We used several mineral sources to stimulate antimicrobial substances from fluorescent pseudomonad that responsible to inhibit E. carotovora subsp. carotovora in vitro. The results showed that zinc 0,5 mM were the best to increase antagonistics of fluorescent psudomonad againts E. carotovora. Zinc were increased antimicrobial substances twohold compared with control without stimulant agent. Detection of antimicrobial substance using TLC showed that only one antimicrobial was detected with retention factor (Rf of 0,68 – 0,72. However, identification and characterization of that substance is still needed.

  11. Genome-wide DNA binding pattern of two-component system response regulator RhpR in Pseudomonas syringae

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    Tianhong Zhou

    2015-06-01

    Full Text Available Although Pseudomonas syringae uses the two-component system RhpRS to modulate the expression of type III secretion system (T3SS genes and pathogenicity, the molecular mechanisms and the regulon of RhpRS have yet to be fully demonstrated. We have performed a genome-wide analysis of RhpR binding to DNA prepared from P. syringae pv. phaseolicola in order to identify candidate direct targets of RhpR-mediated transcriptional regulation, as described in our recent article [1]. The data are available from NCBI Gene Expression Omnibus (GEO with the accession number GSE58533. Here we describe the detailed methods and data analyses of our RhpR ChIP-seq dataset.

  12. Structure of microcin B-like compounds produced by Pseudomonas syringae and species specificity of their antibacterial action.

    Science.gov (United States)

    Metelev, Mikhail; Serebryakova, Marina; Ghilarov, Dmitry; Zhao, Youfu; Severinov, Konstantin

    2013-09-01

    Escherichia coli microcin B (Ec-McB) is a posttranslationally modified antibacterial peptide containing multiple oxazole and thiazole heterocycles and targeting the DNA gyrase. We have found operons homologous to the Ec-McB biosynthesis-immunity operon mcb in recently sequenced genomes of several pathovars of the plant pathogen Pseudomonas syringae, and we produced two variants of P. syringae microcin B (Ps-McB) in E. coli by heterologous expression. Like Ec-McB, both versions of Ps-McB target the DNA gyrase, but unlike Ec-McB, they are active against various species of the Pseudomonas genus, including human pathogen P. aeruginosa. Through analysis of Ec-McB/Ps-McB chimeras, we demonstrate that three centrally located unmodified amino acids of Ps-McB are sufficient to determine activity against Pseudomonas, likely by allowing specific recognition by a transport system that remains to be identified. The results open the way for construction of McB-based antibacterial molecules with extended spectra of biological activity.

  13. Disruption of the carA gene in Pseudomonas syringae results in reduced fitness and alters motility.

    Science.gov (United States)

    Butcher, Bronwyn G; Chakravarthy, Suma; D'Amico, Katherine; Stoos, Kari Brossard; Filiatrault, Melanie J

    2016-08-24

    Pseudomonas syringae infects diverse plant species and is widely used in the study of effector function and the molecular basis of disease. Although the relationship between bacterial metabolism, nutrient acquisition and virulence has attracted increasing attention in bacterial pathology, there is limited knowledge regarding these studies in Pseudomonas syringae. The aim of this study was to investigate the function of the carA gene and the small RNA P32, and characterize the regulation of these transcripts. Disruption of the carA gene (ΔcarA) which encodes the predicted small chain of carbamoylphosphate synthetase, resulted in arginine and pyrimidine auxotrophy in Pseudomonas syringae pv. tomato DC3000. Complementation with the wild type carA gene was able to restore growth to wild-type levels in minimal medium. Deletion of the small RNA P32, which resides immediately upstream of carA, did not result in arginine or pyrimidine auxotrophy. The expression of carA was influenced by the concentrations of both arginine and uracil in the medium. When tested for pathogenicity, ΔcarA showed reduced fitness in tomato as well as Arabidopsis when compared to the wild-type strain. In contrast, mutation of the region encoding P32 had minimal effect in planta. ΔcarA also exhibited reduced motility and increased biofilm formation, whereas disruption of P32 had no impact on motility or biofilm formation. Our data show that carA plays an important role in providing arginine and uracil for growth of the bacteria and also influences other factors that are potentially important for growth and survival during infection. Although we find that the small RNA P32 and carA are co-transcribed, P32 does not play a role in the phenotypes that carA is required for, such as motility, cell attachment, and virulence. Additionally, our data suggests that pyrimidines may be limited in the apoplastic space of the plant host tomato.

  14. Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA.

    Science.gov (United States)

    Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

    2014-07-01

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant pathogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantly less virulent on both tomato and Arabidopsis thaliana. Moreover, infiltration of A. thaliana Col-0 leaves with DC3000 ΔaprA evoked a significantly higher level of expression of the defense-related genes FRK1 and PR-1 than did wild-type DC3000. In the flagellin receptor mutant fls2, pathogen virulence and defense-related gene activation did not differ between DC3000 and DC3000 ΔaprA. Together, these results suggest that AprA of DC3000 is important for evasion of recognition by the FLS2 receptor, allowing wild-type DC3000 to be more virulent on its host plant than AprA-deficient DC3000 ΔaprA. To provide further evidence for the role of DC3000 AprA in host immune evasion, we overexpressed the AprA inhibitory peptide AprI of DC3000 in A. thaliana to counteract the immune evasive capacity of DC3000 AprA. Ectopic expression of aprI in A. thaliana resulted in an enhanced level of resistance against wild-type DC3000, while the already elevated level of resistance against DC3000 ΔaprA remained unchanged. Together, these results indicate that evasion of host immunity by the alkaline protease AprA is important for full virulence of strain DC3000 and likely acts by preventing flagellin monomers from being recognized by its cognate immune receptor.

  15. Multilayered Regulation of Ethylene Induction Plays a Positive Role in Arabidopsis Resistance against Pseudomonas syringae.

    Science.gov (United States)

    Guan, Rongxia; Su, Jianbin; Meng, Xiangzong; Li, Sen; Liu, Yidong; Xu, Juan; Zhang, Shuqun

    2015-09-01

    Ethylene, a key phytohormone involved in plant-pathogen interaction, plays a positive role in plant resistance against fungal pathogens. However, its function in plant bacterial resistance remains unclear. Here, we report a detailed analysis of ethylene induction in Arabidopsis (Arabidopsis thaliana) in response to Pseudomonas syringae pv tomato DC3000 (Pst). Ethylene biosynthesis is highly induced in both pathogen/microbe-associated molecular pattern (PAMP)-triggered immunity and effector-triggered immunity (ETI), and the induction is potentiated by salicylic acid (SA) pretreatment. In addition, Pst actively suppresses PAMP-triggered ethylene induction in a type III secretion system-dependent manner. SA potentiation of ethylene induction is dependent mostly on MITOGEN-ACTIVATED PROTEIN KINASE6 (MPK6) and MPK3 and their downstream ACS2 and ACS6, two type I isoforms of 1-aminocyclopropane-1-carboxylic acid synthases (ACSs). ACS7, a type III ACS whose expression is enhanced by SA pretreatment, is also involved. Pst expressing the avrRpt2 effector gene (Pst-avrRpt2), which is capable of triggering ETI, induces a higher level of ethylene production, and the elevated portion is dependent on SALICYLIC ACID INDUCTION DEFICIENT2 and NONEXPRESSER OF PATHOGENESIS-RELATED GENE1, two key players in SA biosynthesis and signaling. High-order ACS mutants with reduced ethylene induction are more susceptible to both Pst and Pst-avrRpt2, demonstrating a positive role of ethylene in plant bacterial resistance mediated by both PAMP-triggered immunity and ETI. © 2015 American Society of Plant Biologists. All Rights Reserved.

  16. Differential secretome analysis of Pseudomonas syringae pv tomato using gel-free MS proteomics

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    Jörg eSchumacher

    2014-07-01

    Full Text Available The plant pathogen Pseudomonas syringae pv. tomato (DC3000 causes virulence by delivering effector proteins into host plant cells through its type three secretion system (T3SS. In response to the plant environment DC3000 expresses hypersensitive response and pathogenicity genes (hrp. Pathogenesis depends on the ability of the pathogen to manipulate the plant metabolism and to inhibit plant immunity, which depends to a large degree on the plant’s capacity to recognise both pathogen and microbial determinants (PAMP/MAMP-triggered immunity. We have developed and employed MS-based shotgun and targeted proteomics to (i elucidate the extracellular and secretome composition of DC3000 and (ii evaluate temporal features of the assembly of the T3SS and the secretion process together with its dependence of pH. The proteomic screen, under hrp inducing in vitro conditions, of extracellular and cytoplasmatic fractions indicated the segregated presence of not only T3SS implicated proteins such as HopK1, HrpK1, HrpA1 and Avrpto1, but also of proteins not usually associated with the T3SS or with pathogenicity. Using multiple reaction monitoring MS (MRM-MS to quantify HrpA1 and Avrpto1, we found that HrpA1 is rapidly expressed, at a strict pH-dependent rate and is post-translationally processed extracellularly. These features appear to not interfere with rapid Avrpto1 expression and secretion but may suggest some temporal post-translational regulatory mechanism of the T3SS assembly. The high specificity and sensitivity of the MRM-MS approach should provide a powerful tool to measure secretion and translocation in infected tissues.

  17. Functional analysis of the protein encoded by the virulence gene psvA of Pseudomonas syringae pv. eriobotryae

    OpenAIRE

    Kamiunten, Hiroshi; Sakamaki, Ikuko; Matsuo, Mitsuhiro

    2011-01-01

    The Pseudomonas syringae pv. eriobotryae (Pse) virulence gene psvA, (2193 bp), has been isolated but not been functionally characterized. The psvA gene was divided into two parts; the N-terninal region (psvAN, nucleotides (nt) 1-1386), and the C-terminal region (psvAC, nt 1387-2193). Functional analysis of the proteins encoded by psvAN and psvAC was carried out. The PsvAC shows sequence similarity to the Ulp1 endopeptidase family, which includes small ubiquitin-like modifier (SUMO) proteases....

  18. In-vitro antibacterial activities of the essential oils of aromatic plants against Erwinia herbicola (Lohnis) and pseudomonas putida (Kris Hamilton)

    OpenAIRE

    Pandey Abhay K.; Singh Pooja; Palni Uma T.; Tripathi N.N.

    2012-01-01

    This study was designed to examine in vitro antibacterial activities of essential oils extracted from 53 aromatic plants of Gorakhpur Division (UP, INDIA) for the control of two phytopathogenic bacteria namely Erwinia herbicola and Pseudomonas putida causing several post-harvest diseases in fruits and vegetables. Out of 53 oils screened, 8 oils such as Chenopodium ambrosioides, Citrus aurantium, Clausena pentaphylla, Hyptis suaveolens, Lippia alba, Mentha arvensis, Ocimum sanctum and Vi...

  19. Extensive Field Survey, Laboratory and Greenhouse Studies Reveal Complex Nature of Pseudomonas syringae-Associated Hazelnut Decline in Central Italy.

    Science.gov (United States)

    Lamichhane, Jay Ram; Bartoli, Claudia; Varvaro, Leonardo

    2016-01-01

    Pseudomonas avellanae (Pav) has been reported as the causal agent of bacterial decline and bacterial canker of hazelnut in Italy and Greece, respectively. Both hazelnut diseases were reported to be similar in terms of symptoms, severity and persistence. In this study, we found that both symptomatic and asymptomatic trees in the field were colonized by Pav. Multilocus Sequence Typing (MLST) analysis showed that Pav strains isolated during this study in Italy belong to the P. syringae phylogroup 1 and they are closely related to Pav strains previously isolated in Greece from hazelnut bacterial canker. On the other hand, strains isolated in earlier studies from hazelnut decline in Italy belong to both phylogroup 1 and 2 of P. syringae. Both phylogroup 1 strains of P. syringae from Greece and Italy are different than strains isolated in this study in terms of their capacity to excrete fluorescent pigments on different media. Despite the same plant genotype and cropping practices adopted, the incidence of hazelnut decline ranged from nearly 0 to 91% across our study sites. No disease developed on plants inoculated with Pav through wounding while leaf scar inoculations produced only mild disease symptoms. Based on our results and the previously reported correlation between pedo-climatic conditions and hazelnut decline, we conclude that hazelnut decline in central Italy could be incited by a combination of predisposing (adverse pedo-climatic conditions) and contributing factors (Pav). Because this is a true decline different from "bacterial canker" described in Greece, we refer to it as hazelnut decline (HD).

  20. Arabidopsis heterotrimeric G-proteins play a critical role in host and nonhost resistance against Pseudomonas syringae pathogens.

    Directory of Open Access Journals (Sweden)

    Seonghee Lee

    Full Text Available Heterotrimeric G-proteins have been proposed to be involved in many aspects of plant disease resistance but their precise role in mediating nonhost disease resistance is not well understood. We evaluated the roles of specific subunits of heterotrimeric G-proteins using knock-out mutants of Arabidopsis Gα, Gβ and Gγ subunits in response to host and nonhost Pseudomonas pathogens. Plants lacking functional Gα, Gβ and Gγ1Gγ2 proteins displayed enhanced bacterial growth and disease susceptibility in response to host and nonhost pathogens. Mutations of single Gγ subunits Gγ1, Gγ2 and Gγ3 did not alter bacterial disease resistance. Some specificity of subunit usage was observed when comparing host pathogen versus nonhost pathogen. Overexpression of both Gα and Gβ led to reduced bacterial multiplication of nonhost pathogen P. syringae pv. tabaci whereas overexpression of Gβ, but not of Gα, resulted in reduced bacterial growth of host pathogen P. syringae pv. maculicola, compared to wild-type Col-0. Moreover, the regulation of stomatal aperture by bacterial pathogens was altered in Gα and Gβ mutants but not in any of the single or double Gγ mutants. Taken together, these data substantiate the critical role of heterotrimeric G-proteins in plant innate immunity and stomatal modulation in response to P. syringae.

  1. Effector-triggered and pathogen-associated molecular pattern-triggered immunity differentially contribute to basal resistance to Pseudomonas syringae.

    Science.gov (United States)

    Zhang, Jie; Lu, Haibin; Li, Xinyan; Li, Yan; Cui, Haitao; Wen, Chi-Kuang; Tang, Xiaoyan; Su, Zhen; Zhou, Jian-Min

    2010-07-01

    Pathogens induce pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) in plants. PAMPs are microbial molecules recognized by host plants as nonself signals, whereas pathogen effectors are evolved to aid in parasitism but are sometimes recognized by specific intracellular resistance proteins. In the absence of detectable ETI determining classical incompatible interactions, basal resistance exists during compatible and nonhost interactions. What triggers the basal resistance has remained elusive. Here, we provide evidence that ETI contributes to basal resistance during both compatible and nonhost Arabidopsis-Pseudomonas syringae interactions. Mutations in RAR1 and NDR1, two genes required for ETI, compromise basal resistance in both compatible and nonhost interactions. Complete nonhost resistance to P. syringae pv. tabaci required a functional type III secretion system. PTI appears to play a greater role in nonhost resistance than basal resistance during compatible interactions, because abrogation of PTI compromises basal resistance during nonhost but not compatible interactions. Strikingly, simultaneous abrogation of ETI and flagellin-induced PTI rendered plants completely susceptible to the nonadapted bacterium P. syringae pv. tabaci, indicating that ETI and PTI act synergistically during nonhost resistance. Thus, both nonhost resistance and basal resistance to virulent bacteria can be unified under PTI and ETI.

  2. Biocontrol of postharvest decay using a new strain of Pseudomonas syringae CPA-5 in different cultivars of pome fruits

    Directory of Open Access Journals (Sweden)

    C. NUNES

    2008-12-01

    Full Text Available Epiphytic micro-organisms isolated from fruits and leaves surfaces of apples from different orchards were screened for antagonistic activity against Penicillium expansum. From all micro-organisms tested the new strain CPA-5 of Pseudomonas syringae, isolated from organic orchard, was selected. This strain was very effective against Botrytis cinerea, P. expansum and Rhizopus stolonifer at various antagonist and pathogen concentrations on ‘Golden Delicious’ apple, and ‘Blanquilla’, ‘Rocha’ and ‘Conference’ pear. Under cold storage conditions and in semi-commercial trials P. syringae (CPA-5 significantly reduced development of P. expansum and B. cinerea on ‘Golden Delicious’ apple, and ‘Blanquilla’ and ‘Rocha’ pears. Control of P. expansum equal to the fungicide imazalil was obtained with CPA-5 at 108cfu ml–1 on ‘Gold Delicious’ apple and ‘Rocha’ pear. The populations of P. syringae CPA-5 increased more than 100-fold during the first 50 days, and then remained stable on apple, and slightly decreased on pears. This indicates the high capacity of this antagonist to colonize wound surfaces of pome fruits under cold storage conditions.;

  3. The stealth episome: suppression of gene expression on the excised genomic island PPHGI-1 from Pseudomonas syringae pv. phaseolicola.

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    Scott A C Godfrey

    2011-03-01

    Full Text Available Pseudomonas syringae pv. phaseolicola is the causative agent of halo blight in the common bean, Phaseolus vulgaris. P. syringae pv. phaseolicola race 4 strain 1302A contains the avirulence gene avrPphB (syn. hopAR1, which resides on PPHGI-1, a 106 kb genomic island. Loss of PPHGI-1 from P. syringae pv. phaseolicola 1302A following exposure to the hypersensitive resistance response (HR leads to the evolution of strains with altered virulence. Here we have used fluorescent protein reporter systems to gain insight into the mobility of PPHGI-1. Confocal imaging of dual-labelled P. syringae pv. phaseolicola 1302A strain, F532 (dsRFP in chromosome and eGFP in PPHGI-1, revealed loss of PPHGI-1::eGFP encoded fluorescence during plant infection and when grown in vitro on extracted leaf apoplastic fluids. Fluorescence-activated cell sorting (FACS of fluorescent and non-fluorescent PPHGI-1::eGFP F532 populations showed that cells lost fluorescence not only when the GI was deleted, but also when it had excised and was present as a circular episome. In addition to reduced expression of eGFP, quantitative PCR on sub-populations separated by FACS showed that transcription of other genes on PPHGI-1 (avrPphB and xerC was also greatly reduced in F532 cells harbouring the excised PPHGI-1::eGFP episome. Our results show how virulence determinants located on mobile pathogenicity islands may be hidden from detection by host surveillance systems through the suppression of gene expression in the episomal state.

  4. Antimicrobial Effects of a Hexapetide KCM21 against Pseudomonas syringae pv. tomato DC3000 and Clavibacter michiganensis subsp. michiganensis

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    Jeahyuk Choi

    2014-09-01

    Full Text Available Antimicrobial peptides (AMPs are small but effective cationic peptides with variable length. In previous study, four hexapeptides were identified that showed antimicrobial activities against various phytopathogenic bacteria. KCM21, the most effective antimicrobial peptide, was selected for further analysis to understand its modes of action by monitoring inhibitory effects of various cations, time-dependent antimicrobial kinetics, and observing cell disruption by electron microscopy. The effects of KCM21 on Gram-negative strain, Pseudomonas syringae pv. tomato DC3000 and Gram-positive strain, Clavibacter michiganensis subsp. michiganensis were compared. Treatment with divalent cations such as Ca²⁺ and Mg²⁺ inhibited the bactericidal activities of KCM21 significantly against P. syringae pv. tomato DC3000. The bactericidal kinetic study showed that KCM21 killed both bacteria rapidly and the process was faster against C. michiganensis subsp. michiganensis. The electron microscopic analysis revealed that KCM21 induced the formation of micelles and blebs on the surface of P. syringae pv. tomato DC3000 cells, while it caused cell rupture against C. michiganensis subsp. michiganensis cells. The outer membrane alteration and higher sensitivity to Ca²⁺ suggest that KCM21 interact with the outer membrane of P. syringae pv. tomato DC3000 cells during the process of killing, but not with C. michiganensis subsp. michiganensis cells that lack outer membrane. Considering that both strains had similar sensitivity to KCM21 in LB medium, outer membrane could not be the main target of KCM21, instead common compartments such as cytoplasmic membrane or internal macromolecules might be a possible target(s of KCM21.

  5. Effects of Botrytis cinerea and Pseudomonas syringae infection on the antioxidant profile of Mesembryanthemum crystallinum C3/CAM intermediate plant.

    Science.gov (United States)

    Libik-Konieczny, Marta; Surówka, Ewa; Kuźniak, Elżbieta; Nosek, Michał; Miszalski, Zbigniew

    2011-07-01

    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 concentration of H(2)O(2) in C(3) plants 3 hpi, while a decrease in H(2)O(2) content was observed in CAM performing plants. The concentration of H(2)O(2) returned to the control level 24 and 48 hpi. Changes in H(2)O(2) content corresponded with the activity of guaiacol peroxidase (POD), mostly 3 hpi. We noted that its activity decreased significantly in C(3) plants and increased in CAM plants in response to inoculation with both pathogens. On the contrary, changes in the activity of CAT did not correlate with H(2)O(2) level. It increased significantly after interaction of C(3) plants with B. cinerea or P. syringae, but in CAM performing plants, the activity of this enzyme was unchanged. Inoculation with B. cinerea or P. syringae led to an increase in the total SOD activity in C(3) plants while CAM plants did not exhibit changes in the total SOD activity after interaction with both pathogens. In conclusion, the pathogen-induced changes in H(2)O(2) content and in SOD, POD and CAT activities in M. crystallinum leaves, were related to the photosynthetic metabolism type of the stressed plants rather than to the lifestyle of the invading pathogen. Copyright © 2011 Elsevier GmbH. All rights reserved.

  6. Characterization of novel bacteriophages for biocontrol of bacterial blight in leek caused by Pseudomonas syringae pv. porri

    Directory of Open Access Journals (Sweden)

    Sofie eRombouts

    2016-03-01

    Full Text Available Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum, is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4 and vB_PsyM_KIL5, and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b. Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the ‘KIL-like viruses’, related to the Felixounalikevirus genus, together with phage phiPsa374 from Pseudomonas syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3 and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods.

  7. Auxin promotes susceptibility to Pseudomonas syringae via a mechanism independent of suppression of salicylic acid-mediated defenses.

    Science.gov (United States)

    Mutka, Andrew M; Fawley, Stephen; Tsao, Tiffany; Kunkel, Barbara N

    2013-06-01

    Auxin is a key plant growth regulator that also impacts plant-pathogen interactions. Several lines of evidence suggest that the bacterial plant pathogen Pseudomonas syringae manipulates auxin physiology in Arabidopsis thaliana to promote pathogenesis. Pseudomonas syringae strategies to alter host auxin biology include synthesis of the auxin indole-3-acetic acid (IAA) and production of virulence factors that alter auxin responses in host cells. The application of exogenous auxin enhances disease caused by P. syringae strain DC3000. This is hypothesized to result from antagonism between auxin and salicylic acid (SA), a major regulator of plant defenses, but this hypothesis has not been tested in the context of infected plants. We further investigated the role of auxin during pathogenesis by examining the interaction of auxin and SA in the context of infection in plants with elevated endogenous levels of auxin. We demonstrated that elevated IAA biosynthesis in transgenic plants overexpressing the YUCCA 1 (YUC1) auxin biosynthesis gene led to enhanced susceptibility to DC3000. Elevated IAA levels did not interfere significantly with host defenses, as effector-triggered immunity was active in YUC1-overexpressing plants, and we observed only minor effects on SA levels and SA-mediated responses. Furthermore, a plant line carrying both the YUC1-overexpression transgene and the salicylic acid induction deficient 2 (sid2) mutation, which impairs SA synthesis, exhibited additive effects of enhanced susceptibility from both elevated auxin levels and impaired SA-mediated defenses. Thus, in IAA overproducing plants, the promotion of pathogen growth occurs independently of suppression of SA-mediated defenses. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  8. Transposon insertion libraries for the characterization of mutants from the kiwifruit pathogen Pseudomonas syringae pv. actinidiae

    Science.gov (United States)

    Mesarich, Carl H.; Rees-George, Jonathan; Gardner, Paul P.; Ghomi, Fatemeh Ashari; Gerth, Monica L.; Andersen, Mark T.; Rikkerink, Erik H. A.; Fineran, Peter C.

    2017-01-01

    Pseudomonas syringae pv. actinidiae (Psa), the causal agent of kiwifruit canker, is one of the most devastating plant diseases of recent times. We have generated two mini-Tn5-based random insertion libraries of Psa ICMP 18884. The first, a ‘phenotype of interest’ (POI) library, consists of 10,368 independent mutants gridded into 96-well plates. By replica plating onto selective media, the POI library was successfully screened for auxotrophic and motility mutants. Lipopolysaccharide (LPS) biosynthesis mutants with ‘Fuzzy-Spreader’-like morphologies were also identified through a visual screen. The second, a ‘mutant of interest’ (MOI) library, comprises around 96,000 independent mutants, also stored in 96-well plates, with approximately 200 individuals per well. The MOI library was sequenced on the Illumina MiSeq platform using Transposon-Directed Insertion site Sequencing (TraDIS) to map insertion sites onto the Psa genome. A grid-based PCR method was developed to recover individual mutants, and using this strategy, the MOI library was successfully screened for a putative LPS mutant not identified in the visual screen. The Psa chromosome and plasmid had 24,031 and 1,236 independent insertion events respectively, giving insertion frequencies of 3.65 and 16.6 per kb respectively. These data suggest that the MOI library is near saturation, with the theoretical probability of finding an insert in any one chromosomal gene estimated to be 97.5%. However, only 47% of chromosomal genes had insertions. This surprisingly low rate cannot be solely explained by the lack of insertions in essential genes, which would be expected to be around 5%. Strikingly, many accessory genes, including most of those encoding type III effectors, lacked insertions. In contrast, 94% of genes on the Psa plasmid had insertions, including for example, the type III effector HopAU1. These results suggest that some chromosomal sites are rendered inaccessible to transposon insertion, either

  9. Transcriptome changes in the phenylpropanoid pathway of Glycine max in response to Pseudomonas syringae infection

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    Gonzalez Delkin O

    2006-11-01

    Full Text Available Abstract Background Reports of plant molecular responses to pathogenic infections have pinpointed increases in activity of several genes of the phenylpropanoid pathway leading to the synthesis of lignin and flavonoids. The majority of those findings were derived from single gene studies and more recently from several global gene expression analyses. We undertook a global transcriptional analysis focused on the response of genes of the multiple branches of the phenylpropanoid pathway to infection by the Pseudomonas syringae pv. glycinea with or without the avirulence gene avrB to characterize more broadly the contribution of the multiple branches of the pathway to the resistance response in soybean. Transcript abundance in leaves was determined from analysis of soybean cDNA microarray data and hybridizations to RNA blots with specific gene probes. Results The majority of the genes surveyed presented patterns of increased transcript accumulation. Some increased rapidly, 2 and 4 hours after inoculation, while others started to accumulate slowly by 8 – 12 hours. In contrast, transcripts of a few genes decreased in abundance 2 hours post inoculation. Most interestingly was the opposite temporal fluctuation in transcript abundance between early responsive genes in defense (CHS and IFS1 and F3H, the gene encoding a pivotal enzyme in the synthesis of anthocyanins, proanthocyanidins and flavonols. F3H transcripts decreased rapidly 2 hours post inoculation and increased during periods when CHS and IFS transcripts decreased. It was also determined that all but one (CHS4 family member genes (CHS1, CHS2, CHS3, CHS5, CHS6 and CHS7/8 accumulated higher transcript levels during the defense response provoked by the avirulent pathogen challenge. Conclusion Based on the mRNA profiles, these results show the strong bias that soybean has towards increasing the synthesis of isoflavonoid phytoalexins concomitant with the down regulation of genes required for the

  10. Identification of the CvsSR regulon in Pseudomonas syringae reveals overlap with the Type-III secretion and AlgU regulons

    Science.gov (United States)

    Pseudomonas syringae pv. tomato DC3000 (Pto) lives epiphytically and endophytically during its infection cycle. Two-component systems (TCSs) and extracytoplasmic function (ECF) sigma factors are used by Pto to sense environmental changes within the leaf apoplast during pathogenesis. The TCS, CvsSR i...

  11. Role of nucleotide excision repair and photoreactivation in the solar UVB radiation survival of Pseudomonas syringae pv. syringae B728a.

    Science.gov (United States)

    Gunasekera, T S; Sundin, G W

    2006-05-01

    To assess the role of DNA repair and photoreactivation in the solar radiation survival of the plant pathogen and leaf surface epiphyte Pseudomonas syringae pv. syringae (Pss). Mutants of Pss B728a, with insertional mutations within the nucleotide excision repair gene uvrA, photolyase gene phr, or uvrA phr double mutants, were constructed to examine the importance of individual repair mechanisms in solar UV radiation (UVR) survival. The survival of either the uvrA mutant or the phr mutant was reduced by approx. 10(2)-fold following exposure to a dose of 4.5 kJ m(-2) solar UVB (290-320 nm wavelengths) while the uvrA phr double mutant was reduced >10(6)-fold by the same dose. We constructed a transcriptional fusion between the Pss recA promoter and gfp to examine the induction of the SOS response in wild-type and mutant strains. Initiation of the recA mediated SOS response was more rapid and peaked at higher levels in mutant strains suggesting both increased DNA damage in mutant strains and also that photoreactivation and nucleotide excision repair remove DNA damage as it is incurred which is reflected in a delay of recA expression. Visualization of expression of B728a cells containing the recA::gfp reporter on UVB-irradiated bean leaves highlighted the movement of cells to intercellular spaces over time and that SOS induction was detectable when leaves were irradiated 48 h following leaf inoculation. This study indicated that solar UVB is detrimental to Pss B728a, DNA repair mechanisms play an important role in strain survival and expression of the SOS regulon on leaf surfaces contributes to survival of UVR-exposed cells during plant colonization. This work links previous laboratory-based UVR analyses with solar UVB dose-response analyses and highlights the role of photoreactivation in delaying induction of the SOS response following solar irradiation. Knowledge of population dynamics following direct solar irradiation will enhance our understanding of the biology of

  12. Extensive Field Survey, Laboratory and Greenhouse Studies Reveal Complex Nature of Pseudomonas syringae-Associated Hazelnut Decline in Central Italy

    Science.gov (United States)

    Lamichhane, Jay Ram; Bartoli, Claudia; Varvaro, Leonardo

    2016-01-01

    Pseudomonas avellanae (Pav) has been reported as the causal agent of bacterial decline and bacterial canker of hazelnut in Italy and Greece, respectively. Both hazelnut diseases were reported to be similar in terms of symptoms, severity and persistence. In this study, we found that both symptomatic and asymptomatic trees in the field were colonized by Pav. Multilocus Sequence Typing (MLST) analysis showed that Pav strains isolated during this study in Italy belong to the P. syringae phylogroup 1 and they are closely related to Pav strains previously isolated in Greece from hazelnut bacterial canker. On the other hand, strains isolated in earlier studies from hazelnut decline in Italy belong to both phylogroup 1 and 2 of P. syringae. Both phylogroup 1 strains of P. syringae from Greece and Italy are different than strains isolated in this study in terms of their capacity to excrete fluorescent pigments on different media. Despite the same plant genotype and cropping practices adopted, the incidence of hazelnut decline ranged from nearly 0 to 91% across our study sites. No disease developed on plants inoculated with Pav through wounding while leaf scar inoculations produced only mild disease symptoms. Based on our results and the previously reported correlation between pedo-climatic conditions and hazelnut decline, we conclude that hazelnut decline in central Italy could be incited by a combination of predisposing (adverse pedo-climatic conditions) and contributing factors (Pav). Because this is a true decline different from “bacterial canker” described in Greece, we refer to it as hazelnut decline (HD). PMID:26840951

  13. Extensive Field Survey, Laboratory and Greenhouse Studies Reveal Complex Nature of Pseudomonas syringae-Associated Hazelnut Decline in Central Italy.

    Directory of Open Access Journals (Sweden)

    Jay Ram Lamichhane

    Full Text Available Pseudomonas avellanae (Pav has been reported as the causal agent of bacterial decline and bacterial canker of hazelnut in Italy and Greece, respectively. Both hazelnut diseases were reported to be similar in terms of symptoms, severity and persistence. In this study, we found that both symptomatic and asymptomatic trees in the field were colonized by Pav. Multilocus Sequence Typing (MLST analysis showed that Pav strains isolated during this study in Italy belong to the P. syringae phylogroup 1 and they are closely related to Pav strains previously isolated in Greece from hazelnut bacterial canker. On the other hand, strains isolated in earlier studies from hazelnut decline in Italy belong to both phylogroup 1 and 2 of P. syringae. Both phylogroup 1 strains of P. syringae from Greece and Italy are different than strains isolated in this study in terms of their capacity to excrete fluorescent pigments on different media. Despite the same plant genotype and cropping practices adopted, the incidence of hazelnut decline ranged from nearly 0 to 91% across our study sites. No disease developed on plants inoculated with Pav through wounding while leaf scar inoculations produced only mild disease symptoms. Based on our results and the previously reported correlation between pedo-climatic conditions and hazelnut decline, we conclude that hazelnut decline in central Italy could be incited by a combination of predisposing (adverse pedo-climatic conditions and contributing factors (Pav. Because this is a true decline different from "bacterial canker" described in Greece, we refer to it as hazelnut decline (HD.

  14. Characterization of Novel Bacteriophages for Biocontrol of Bacterial Blight in Leek Caused by Pseudomonas syringae pv. porri.

    Science.gov (United States)

    Rombouts, Sofie; Volckaert, Anneleen; Venneman, Sofie; Declercq, Bart; Vandenheuvel, Dieter; Allonsius, Camille N; Van Malderghem, Cinzia; Jang, Ho B; Briers, Yves; Noben, Jean P; Klumpp, Jochen; Van Vaerenbergh, Johan; Maes, Martine; Lavigne, Rob

    2016-01-01

    Pseudomonas syringae pv. porri, the causative agent of bacterial blight in leek (Allium porrum), is increasingly frequent causing problems in leek cultivation. Because of the current lack of control measures, novel bacteriophages were isolated to control this pathogen using phage therapy. Five novel phages were isolated from infected fields in Flanders (vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, vB_PsyM_KIL4, and vB_PsyM_KIL5), and were complemented with one selected host range mutant phage (vB_PsyM_KIL3b). Genome analysis of the phages revealed genome sizes between 90 and 94 kb and an average GC-content of 44.8%. Phylogenomic networking classified them into a novel clade, named the "KIL-like viruses," related to the Felixounalikevirus genus, together with phage phiPsa374 from P. syringae pv. actinidiae. In vitro characterization demonstrated the stability and lytic potential of these phages. Host range analysis confirmed heterogeneity within P. syringae pv. porri, leading to the development of a phage cocktail with a range that covers the entire set of 41 strains tested. Specific bio-assays demonstrated the in planta efficacy of phages vB_PsyM_KIL1, vB_PsyM_KIL2, vB_PsyM_KIL3, and vB_PsyM_KIL3b. In addition, two parallel field trial experiments on three locations using a phage cocktail of the six phages showed variable results. In one trial, symptom development was attenuated. These data suggest some potential for phage therapy in controlling bacterial blight of leek, pending optimization of formulation and application methods.

  15. Dynamics of membrane potential variation and gene expression induced by Spodoptera littoralis, Myzus persicae, and Pseudomonas syringae in Arabidopsis.

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    Irene Bricchi

    Full Text Available BACKGROUND: Biotic stress induced by various herbivores and pathogens invokes plant responses involving different defense mechanisms. However, we do not know whether different biotic stresses share a common response or which signaling pathways are involved in responses to different biotic stresses. We investigated the common and specific responses of Arabidopsis thaliana to three biotic stress agents: Spodoptera littoralis, Myzus persicae, and the pathogen Pseudomonas syringae. METHODOLOGY/PRINCIPAL FINDINGS: We used electrophysiology to determine the plasma membrane potential (V(m and we performed a gene microarray transcriptome analysis on Arabidopsis upon either herbivory or bacterial infection. V(m depolarization was induced by insect attack; however, the response was much more rapid to S. littoralis (30 min -2 h than to M. persicae (4-6 h. M. persicae differentially regulated almost 10-fold more genes than by S. littoralis with an opposite regulation. M. persicae modulated genes involved in flavonoid, fatty acid, hormone, drug transport and chitin metabolism. S. littoralis regulated responses to heat, transcription and ion transport. The latest Vm depolarization (16 h was found for P. syringae. The pathogen regulated responses to salicylate, jasmonate and to microorganisms. Despite this late response, the number of genes differentially regulated by P. syringae was closer to those regulated by S. littoralis than by M. persicae. CONCLUSIONS/SIGNIFICANCE: Arabidopsis plasma membranes respond with a V(m depolarization at times depending on the nature of biotic attack which allow setting a time point for comparative genome-wide analysis. A clear relationship between V(m depolarization and gene expression was found. At V(m depolarization timing, M. persicae regulates a wider array of Arabidopsis genes with a clear and distinct regulation than S. littoralis. An almost completely opposite regulation was observed between the aphid and the pathogen

  16. Cytokinins mediate resistance against Pseudomonas syringae in tobacco through increased antimicrobial phytoalexin synthesis independent of salicylic acid signaling.

    Science.gov (United States)

    Grosskinsky, Dominik K; Naseem, Muhammad; Abdelmohsen, Usama Ramadan; Plickert, Nicole; Engelke, Thomas; Griebel, Thomas; Zeier, Jürgen; Novák, Ondrej; Strnad, Miroslav; Pfeifhofer, Hartwig; van der Graaff, Eric; Simon, Uwe; Roitsch, Thomas

    2011-10-01

    Cytokinins are phytohormones that are involved in various regulatory processes throughout plant development, but they are also produced by pathogens and known to modulate plant immunity. A novel transgenic approach enabling autoregulated cytokinin synthesis in response to pathogen infection showed that cytokinins mediate enhanced resistance against the virulent hemibiotrophic pathogen Pseudomonas syringae pv tabaci. This was confirmed by two additional independent transgenic approaches to increase endogenous cytokinin production and by exogenous supply of adenine- and phenylurea-derived cytokinins. The cytokinin-mediated resistance strongly correlated with an increased level of bactericidal activities and up-regulated synthesis of the two major antimicrobial phytoalexins in tobacco (Nicotiana tabacum), scopoletin and capsidiol. The key role of these phytoalexins in the underlying mechanism was functionally proven by the finding that scopoletin and capsidiol substitute in planta for the cytokinin signal: phytoalexin pretreatment increased resistance against P. syringae. In contrast to a cytokinin defense mechanism in Arabidopsis (Arabidopsis thaliana) based on salicylic acid-dependent transcriptional control, the cytokinin-mediated resistance in tobacco is essentially independent from salicylic acid and differs in pathogen specificity. It is also independent of jasmonate levels, reactive oxygen species, and high sugar resistance. The novel function of cytokinins in the primary defense response of solanaceous plant species is rather mediated through a high phytoalexin-pathogen ratio in the early phase of infection, which efficiently restricts pathogen growth. The implications of this mechanism for the coevolution of host plants and cytokinin-producing pathogens and the practical application in agriculture are discussed.

  17. Constitutive Activity of the Arabidopsis MAP Kinase 3 Confers Resistance to Pseudomonas syringae and Drives Robust Immune Responses

    KAUST Repository

    Lang, Julien

    2017-08-02

    Mitogen Activated Protein Kinases (MAPKs) are known to be important mediators of plant responses to biotic and abiotic stresses. In a recent report, we enlarged the understanding of the Arabidopsis thaliana MPK3 functions showing that the expression of a constitutively active (CA) form of the protein led to auto-immune phenotypes. CA-MPK3 plants are dwarf and display defense responses that are characterized by the accumulation of salicylic acid and phytoalexins as well as by the upregulation of several defense genes. Consistently with these data, we present here results demonstrating that, compared to wild type controls, CA-MPK3 plants are more resistant to the hemibiotrophic pathogen Pseudomonas syringae DC3000. Based on our previous work, we also discuss the mechanisms of robust plant immunity controlled by sustained MPK3 activity, focusing especially on the roles of disease resistance proteins.

  18. Bigger is not always better: transmission and fitness burden of ∼1MB Pseudomonas syringae megaplasmid pMPPla107.

    Science.gov (United States)

    Romanchuk, Artur; Jones, Corbin D; Karkare, Kedar; Moore, Autumn; Smith, Brian A; Jones, Chelsea; Dougherty, Kevin; Baltrus, David A

    2014-05-01

    Horizontal gene transfer (HGT) is a widespread process that enables the acquisition of genes and metabolic pathways in single evolutionary steps. Previous reports have described fitness costs of HGT, but have largely focused on the acquisition of relatively small plasmids. We have previously shown that a Pseudomonas syringae pv. lachrymans strain recently acquired a cryptic megaplasmid, pMPPla107. This extrachromosomal element contributes hundreds of new genes to P. syringae and increases total genomic content by approximately 18%. However, this early work did not directly explore transmissibility, stability, or fitness costs associated with acquisition of pMPPla107. Here, we show that pMPPla107 is self-transmissible across a variety of diverse pseudomonad strains, on both solid agar and within shaking liquid cultures, with conjugation dependent on a type IV secretion system. To the best of our knowledge, this is the largest self-transmissible megaplasmid known outside of Sinorhizobium. This megaplasmid can be lost from all novel hosts although the rate of loss depends on medium type and genomic background. However, in contrast, pMPPla107 is faithfully maintained within the original parent strain (Pla107) even under direct negative selection during laboratory assays. These results suggest that Pla107 specific stabilizing mutations have occurred either on this strain's chromosome or within the megaplasmid. Lastly, we demonstrate that acquisition of pMPPla107 by strains other than Pla107 imparts severe (20%) fitness costs under competitive conditions in vitro. We show that pMPPla107 is capable of transmitting and maintaining itself across multiple Pseudomonas species, rendering it one of the largest conjugative elements discovered to date. The relative stability of pMPPla107, coupled with extensive fitness costs, makes it a tractable model system for investigating evolutionary and genetic mechanisms of megaplasmid maintenance and a unique testing ground to explore

  19. Pseudomonas syringae pv. actinidiae from recent outbreaks of kiwifruit bacterial canker belong to different clones that originated in China.

    Directory of Open Access Journals (Sweden)

    Margi I Butler

    Full Text Available A recently emerged plant disease, bacterial canker of kiwifruit (Actinidia deliciosa and A. chinensis, is caused by Pseudomonas syringae pv. actinidiae (PSA. The disease was first reported in China and Japan in the 1980s. A severe outbreak of PSA began in Italy in 2008 and has spread to other European countries. PSA was found in both New Zealand and Chile in 2010. To study the evolution of the pathogen and analyse the transmission of PSA between countries, genomes of strains from China and Japan (where the genus Actinidia is endemic, Italy, New Zealand and Chile were sequenced. The genomes of PSA strains are very similar. However, all strains from New Zealand share several single nucleotide polymorphisms (SNPs that distinguish them from all other PSA strains. Similarly, all the PSA strains from the 2008 Italian outbreak form a distinct clonal group and those from Chile form a third group. In addition to the rare SNPs present in the core genomes, there is abundant genetic diversity in a genomic island that is part of the accessory genome. The island from several Chinese strains is almost identical to the island present in the New Zealand strains. The island from a different Chinese strain is identical to the island present in the strains from the recent Italian outbreak. The Chilean strains of PSA carry a third variant of this island. These genomic islands are integrative conjugative elements (ICEs. Sequencing of these ICEs provides evidence of three recent horizontal transmissions of ICE from other strains of Pseudomonas syringae to PSA. The analyses of the core genome SNPs and the ICEs, combined with disease history, all support the hypothesis of an independent Chinese origin for both the Italian and the New Zealand outbreaks and suggest the Chilean strains also originate from China.

  20. Pseudomonas syringae pv. actinidiae from recent outbreaks of kiwifruit bacterial canker belong to different clones that originated in China.

    Science.gov (United States)

    Butler, Margi I; Stockwell, Peter A; Black, Michael A; Day, Robert C; Lamont, Iain L; Poulter, Russell T M

    2013-01-01

    A recently emerged plant disease, bacterial canker of kiwifruit (Actinidia deliciosa and A. chinensis), is caused by Pseudomonas syringae pv. actinidiae (PSA). The disease was first reported in China and Japan in the 1980s. A severe outbreak of PSA began in Italy in 2008 and has spread to other European countries. PSA was found in both New Zealand and Chile in 2010. To study the evolution of the pathogen and analyse the transmission of PSA between countries, genomes of strains from China and Japan (where the genus Actinidia is endemic), Italy, New Zealand and Chile were sequenced. The genomes of PSA strains are very similar. However, all strains from New Zealand share several single nucleotide polymorphisms (SNPs) that distinguish them from all other PSA strains. Similarly, all the PSA strains from the 2008 Italian outbreak form a distinct clonal group and those from Chile form a third group. In addition to the rare SNPs present in the core genomes, there is abundant genetic diversity in a genomic island that is part of the accessory genome. The island from several Chinese strains is almost identical to the island present in the New Zealand strains. The island from a different Chinese strain is identical to the island present in the strains from the recent Italian outbreak. The Chilean strains of PSA carry a third variant of this island. These genomic islands are integrative conjugative elements (ICEs). Sequencing of these ICEs provides evidence of three recent horizontal transmissions of ICE from other strains of Pseudomonas syringae to PSA. The analyses of the core genome SNPs and the ICEs, combined with disease history, all support the hypothesis of an independent Chinese origin for both the Italian and the New Zealand outbreaks and suggest the Chilean strains also originate from China.

  1. Origin of the Outbreak in France of Pseudomonas syringae pv. actinidiae Biovar 3, the Causal Agent of Bacterial Canker of Kiwifruit, Revealed by a Multilocus Variable-Number Tandem-Repeat Analysis.

    Science.gov (United States)

    Cunty, A; Cesbron, S; Poliakoff, F; Jacques, M-A; Manceau, C

    2015-10-01

    The first outbreaks of bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae biovar 3 were detected in France in 2010. P. syringae pv. actinidiae causes leaf spots, dieback, and canker that sometimes lead to the death of the vine. P. syringae pv. actinidifoliorum, which is pathogenic on kiwi as well, causes only leaf spots. In order to conduct an epidemiological study to track the spread of the epidemics of these two pathogens in France, we developed a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA). MLVA was conducted on 340 strains of P. syringae pv. actinidiae biovar 3 isolated in Chile, China, France, Italy, and New Zealand and on 39 strains of P. syringae pv. actinidifoliorum isolated in Australia, France, and New Zealand. Eleven polymorphic VNTR loci were identified in the genomes of P. syringae pv. actinidiae biovar 3 ICMP 18744 and of P. syringae pv. actinidifoliorum ICMP 18807. MLVA enabled the structuring of P. syringae pv. actinidiae biovar 3 and P. syringae pv. actinidifoliorum strains in 55 and 16 haplotypes, respectively. MLVA and discriminant analysis of principal components revealed that strains isolated in Chile, China, and New Zealand are genetically distinct from P. syringae pv. actinidiae strains isolated in France and in Italy, which appear to be closely related at the genetic level. In contrast, no structuring was observed for P. syringae pv. actinidifoliorum. We developed an MLVA scheme to explore the diversity within P. syringae pv. actinidiae biovar 3 and to trace the dispersal routes of epidemic P. syringae pv. actinidiae biovar 3 in Europe. We suggest using this MLVA scheme to trace the dispersal routes of P. syringae pv. actinidiae at a global level. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  2. NudC Nudix hydrolase from Pseudomonas syringae, but not its counterpart from Pseudomonas aeruginosa, is a novel regulator of intracellular redox balance required for growth, motility and biofilm formation.

    Science.gov (United States)

    Modzelan, Marta; Kujawa, Martyna; Głąbski, Krzysztof; Jagura-Burdzy, Grażyna; Kraszewska, Elzbieta

    2014-09-01

    Nudix pyrophosphatases, ubiquitous in all organisms, have not been well studied. Recent implications that some of them may be involved in response to stress and in pathogenesis indicate that they play important biological functions. We have investigated NudC Nudix proteins from the plant pathogen Pseudomonas syringae pv. tomato str. DC3000 and from the human pathogen Pseudomonas aeruginosa PAO1161. We found that these homologous enzymes are homodimeric and in vitro preferentially hydrolyse NADH. The P. syringae mutant strain deficient in NudC accumulated NADH and displayed significant defects in growth, motility and biofilm formation. The wild type copy of the nudC gene with its cognate promoter delivered in trans into the nudC mutant restored its fitness. However, introduction of the P. syringae nudC gene under the control of the strong tacp promoter into either P. syringae or P. aeruginosa cells had a toxic effect on both strains. Opposite to P. syringae NudC, the P. aeruginosa NudC deficiency as well as its overproduction had no visible impact on cells. Moreover, P. aeruginosa NudC does not compensate the lack of its counterpart in the P. syringae mutant. These results indicate that NudC from P. syringae, but not from P. aeruginosa is vital for bacteria. © 2014 John Wiley & Sons Ltd.

  3. Light Regulation of Swarming Motility in Pseudomonas syringae Integrates Signaling Pathways Mediated by a Bacteriophytochrome and a LOV Protein

    Science.gov (United States)

    Wu, Liang; McGrane, Regina S.; Beattie, Gwyn A.

    2013-01-01

    ABSTRACT The biological and regulatory roles of photosensory proteins are poorly understood for nonphotosynthetic bacteria. The foliar bacterial pathogen Pseudomonas syringae has three photosensory protein-encoding genes that are predicted to encode the blue-light-sensing LOV (light, oxygen, or voltage) histidine kinase (LOV-HK) and two red/far-red-light-sensing bacteriophytochromes, BphP1 and BphP2. We provide evidence that LOV-HK and BphP1 form an integrated network that regulates swarming motility in response to multiple light wavelengths. The swarming motility of P. syringae B728a deletion mutants indicated that LOV-HK positively regulates swarming motility in response to blue light and BphP1 negatively regulates swarming motility in response to red and far-red light. BphP2 does not detectably regulate swarming motility. The histidine kinase activity of each LOV-HK and BphP1 is required for this regulation based on the loss of complementation upon mutation of residues key to their kinase activity. Surprisingly, mutants lacking both lov and bphP1 were similar in motility to a bphP1 single mutant in blue light, indicating that the loss of bphP1 is epistatic to the loss of lov and also that BphP1 unexpectedly responds to blue light. Moreover, whereas expression of bphP1 did not alter motility under blue light in a bphP1 mutant, it reduced motility in a mutant lacking lov and bphP1, demonstrating that LOV-HK positively regulates motility by suppressing negative regulation by BphP1. These results are the first to show cross talk between the LOV protein and phytochrome signaling pathways in bacteria, and the similarity of this regulatory network to that of photoreceptors in plants suggests a possible common ancestry. PMID:23760465

  4. The Arabidopsis thaliana non-specific phospholipase C2 is involved in the response to Pseudomonas syringae attack.

    Science.gov (United States)

    Krcková, Zuzana; Kocourková, Daniela; Danek, Michal; Brouzdová, Jitka; Pejchar, Premysl; Janda, Martin; Pokotylo, Igor; Ott, Peter G; Valentová, Olga; Martinec, Jan

    2017-12-29

    The non-specific phospholipase C (NPC) is a new member of the plant phospholipase family that reacts to abiotic environmental stresses, such as phosphate deficiency, high salinity, heat and aluminium toxicity, and is involved in root development, silicon distribution and brassinolide signalling. Six NPC genes (NPC1-NPC6) are found in the Arabidopsis genome. The NPC2 isoform has not been experimentally characterized so far. The Arabidopsis NPC2 isoform was cloned and heterologously expressed in Escherichia coli. NPC2 enzyme activity was determined using fluorescent phosphatidylcholine as a substrate. Tissue expression and subcellular localization were analysed using GUS- and GFP-tagged NPC2. The expression patterns of NPC2 were analysed via quantitative real-time PCR. Independent homozygous transgenic plant lines overexpressing NPC2 under the control of a 35S promoter were generated, and reactive oxygen species were measured using a luminol-based assay. The heterologously expressed protein possessed phospholipase C activity, being able to hydrolyse phosphatidylcholine to diacylglycerol. NPC2 tagged with GFP was predominantly localized to the Golgi apparatus in Arabidopsis roots. The level of NPC2 transcript is rapidly altered during plant immune responses and correlates with the activation of multiple layers of the plant defence system. Transcription of NPC2 decreased substantially after plant infiltration with Pseudomonas syringae, flagellin peptide flg22 and salicylic acid treatments and expression of the effector molecule AvrRpm1. The decrease in NPC2 transcript levels correlated with a decrease in NPC2 enzyme activity. NPC2-overexpressing mutants showed higher reactive oxygen species production triggered by flg22. This first experimental characterization of NPC2 provides new insights into the role of the non-specific phospholipase C protein family. The results suggest that NPC2 is involved in the response of Arabidopsis to P. syringae attack.

  5. Extensive remodeling of the Pseudomonas syringae pv. avellanae type III secretome associated with two independent host shifts onto hazelnut

    Directory of Open Access Journals (Sweden)

    O’Brien Heath E

    2012-07-01

    Full Text Available Abstract Background Hazelnut (Corylus avellana decline disease in Greece and Italy is caused by the convergent evolution of two distantly related lineages of Pseudomonas syringae pv. avellanae (Pav. We sequenced the genomes of three Pav isolates to determine if their convergent virulence phenotype had a common genetic basis due to either genetic exchange between lineages or parallel evolution. Results We found little evidence for horizontal transfer (recombination of genes between Pav lineages, but two large genomic islands (GIs have been recently acquired by one of the lineages. Evolutionary analyses of the genes encoding type III secreted effectors (T3SEs that are translocated into host cells and are important for both suppressing and eliciting defense responses show that the two Pav lineages have dramatically different T3SE profiles, with only two shared putatively functional T3SEs. One Pav lineage has undergone unprecedented secretome remodeling, including the acquisition of eleven new T3SEs and the loss or pseudogenization of 15, including five of the six core T3SE families that are present in the other Pav lineage. Molecular dating indicates that divergence within both of the Pav lineages predates their observation in the field. This suggest that both Pav lineages have been cryptically infecting hazelnut trees or wild relatives for many years, and that the emergence of hazelnut decline in the 1970s may have been due to changes in agricultural practice. Conclusions These data show that divergent lineages of P. syringae can converge on identical disease etiology on the same host plant using different virulence mechanisms and that dramatic shifts in the arsenal of T3SEs can accompany disease emergence.

  6. Whole-genome sequence of Pseudomonas fluorescens EK007-RG4, a promising biocontrol agent against a broad range of bacteria, including the fire blight bacterium Erwinia amylovora

    DEFF Research Database (Denmark)

    Habibi, Roghayeh; Tarighi, Saeed; Behravan, Javad

    2017-01-01

    Here, we report the first draft whole-genome sequence of Pseudomonas fluorescens strain EK007-RG4, which was isolated from the phylloplane of a pear tree. P. fluorescens EK007-RG4 displays strong antagonism against Erwinia amylovora, the causal agent for fire blight disease, in addition to several...

  7. Comparative genomic analysis of two-component regulatory proteins in Pseudomonas syringae

    DEFF Research Database (Denmark)

    Lavin, J.L.; Kiil, Kristoffer; Resano, O.

    2007-01-01

    requires a complex array of TCS proteins to cope with diverse plant hosts, host responses, and environmental conditions. Results: Based on the genomic data, pattern searches with Hidden Markov Model (HMM) profiles have been used to identify putative HKs and RRs. The genomes of Psy B728a, Pto DC3000 and Pph...... (Pph) 1448A have been recently sequenced providing a major resource for comparative genomic analysis. A mechanism commonly found in bacteria for signal transduction is the two-component system (TCS), which typically consists of a sensor histidine kinase (HK) and a response regulator (RR). P. syringae...... 1448A were found to contain a large number of genes encoding TCS proteins, and a core of complete TCS proteins were shared between these genomes: 30 putative TCS clusters, 11 orphan HKs, 33 orphan RRs, and 16 hybrid HKs. A close analysis of the distribution of genes encoding TCS proteins revealed...

  8. The ECF sigma factor, PSPTO_1043, in Pseudomonas syringae pv. tomato DC3000 is induced by oxidative stress and regulates genes involved in oxidative stress response.

    Science.gov (United States)

    Butcher, Bronwyn G; Bao, Zhongmeng; Wilson, Janet; Stodghill, Paul; Swingle, Bryan; Filiatrault, Melanie; Schneider, David; Cartinhour, Samuel

    2017-01-01

    The bacterial plant pathogen Pseudomonas syringae adapts to changes in the environment by modifying its gene expression profile. In many cases, the response is mediated by the activation of extracytoplasmic function (ECF) sigma factors that direct RNA polymerase to transcribe specific sets of genes. In this study we focus on PSPTO_1043, one of ten ECF sigma factors in P. syringae pv. tomato DC3000 (DC3000). PSPTO_1043, together with PSPTO_1042, encode an RpoERsp/ChrR-like sigma/anti-sigma factor pair. Although this gene pair is unique to the P. syringae group among the pseudomonads, homologous genes can be found in photosynthetic genera such as Rhodospirillum, Thalassospira, Phaeospirillum and Parvibaculum. Using ChIP-Seq, we detected 137 putative PSPTO_1043 binding sites and identified a likely promoter motif. We characterized 13 promoter candidates, six of which regulate genes that appear to be found only in P. syringae. PSPTO_1043 responds to the presence of singlet oxygen (1O2) and tert-butyl hydroperoxide (tBOOH) and several of the genes regulated by PSPTO_1043 appear to be involved in response to oxidative stress.

  9. Silencing and heterologous expression of ppo-2 indicate a specific function of a single polyphenol oxidase isoform in resistance of dandelion (Taraxacum officinale) against Pseudomonas syringae pv. tomato.

    Science.gov (United States)

    Richter, Carolin; Dirks, Mareike E; Gronover, Christian Schulze; Prüfer, Dirk; Moerschbacher, Bruno M

    2012-02-01

    Dandelion (Taraxacum officinale) possesses an unusually high degree of disease resistance. As this plant exhibits high polyphenol oxidase (PPO) activity and PPO have been implicated in resistance against pests and pathogens, we analyzed the potential involvement of five PPO isoenzymes in the resistance of dandelion against Botrytis cinerea and Pseudomonas syringae pv. tomato. Only one PPO (ppo-2) was induced during infection, and ppo-2 promoter and β-glucuronidase marker gene fusions revealed strong induction of the gene surrounding lesions induced by B. cinerea. Specific RNAi silencing reduced ppo-2 expression only, and concomitantly increased plant susceptibility to P. syringae pv. tomato. At 4 days postinoculation, P. syringae pv. tomato populations were strongly increased in the ppo-2 RNAi lines compared with wild-type plants. When the dandelion ppo-2 gene was expressed in Arabidopsis thaliana, a plant having no PPO gene, active protein was formed and protein extracts of the transgenic plants exhibited substrate-dependent antimicrobial activity against P. syringae pv. tomato. These results clearly indicate a strong contribution of a specific, single PPO isoform to disease resistance. Therefore, we propose that specific PPO isoenzymes be included in a new family of pathogenesis-related (PR) proteins.

  10. Atmospheric CO2 Alters Resistance of Arabidopsis to Pseudomonas syringae by Affecting Abscisic Acid Accumulation and Stomatal Responsiveness to Coronatine.

    Science.gov (United States)

    Zhou, Yeling; Vroegop-Vos, Irene; Schuurink, Robert C; Pieterse, Corné M J; Van Wees, Saskia C M

    2017-01-01

    Atmospheric CO2 influences plant growth and stomatal aperture. Effects of high or low CO2 levels on plant disease resistance are less well understood. Here, resistance of Arabidopsis thaliana against the foliar pathogen Pseudomonas syringae pv. tomato DC3000 (Pst) was investigated at three different CO2 levels: high (800 ppm), ambient (450 ppm), and low (150 ppm). Under all conditions tested, infection by Pst resulted in stomatal closure within 1 h after inoculation. However, subsequent stomatal reopening at 4 h, triggered by the virulence factor coronatine (COR), occurred only at ambient and high CO2, but not at low CO2. Moreover, infection by Pst was reduced at low CO2 to the same extent as infection by mutant Pst cor(-) . Under all CO2 conditions, the ABA mutants aba2-1 and abi1-1 were as resistant to Pst as wild-type plants under low CO2, which contained less ABA. Moreover, stomatal reopening mediated by COR was dependent on ABA. Our results suggest that reduced ABA levels at low CO2 contribute to the observed enhanced resistance to Pst by deregulation of virulence responses. This implies that enhanced ABA levels at increasing CO2 levels may have a role in weakening plant defense.

  11. The hrp pathogenicity island of Pseudomonas syringae pv. tomato DC3000 is induced by plant phenolic acids.

    Science.gov (United States)

    Lee, Jun Seung; Ryu, Hye Ryun; Cha, Ji Young; Baik, Hyung Suk

    2015-10-01

    Plants produce a wide array of antimicrobial compounds, such as phenolic compounds, to combat microbial pathogens. The hrp PAI is one of the major virulence factors in the plant pathogen, Pseudomonas syringae. A major role of hrp PAI is to disable the plant defense system during bacterial invasion. We examined the influence of phenolic compounds on hrp PAI gene expression at low and high concentrations. There was approximately 2.5 times more hrpA and hrpZ mRNA in PtoDC3000 that was grown in minimal media (MM) supplemented with 10 -M of ortho-coumaric acid than in PtoDC3000 grown in MM alone. On the other hand, a significantly lower amount of hrpA mRNA was observed in bacteria grown in MM supplemented with a high concentration of phenolic compounds. To determine the regulation pathway for hrp PAI gene expression, we performed qRTPCR using gacS, gacA, and hrpS deletion mutants.

  12. Decreased abundance of type III secretion system-inducing signals in Arabidopsis mkp1 enhances resistance against Pseudomonas syringae

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Jeffrey C.; Wan, Ying; Kim, Young-Mo; Pasa-Tolic, Ljiljana; Metz, Thomas O.; Peck, Scott C.

    2014-04-21

    Many phytopathogenic bacteria use a type III secretion system (T3SS) to inject defense-suppressing effector proteins into host cells. Genes encoding the T3SS are induced at the start of infection, yet host signals that initiate T3SS gene expression are poorly understood. Here we identify several plant-derived metabolites that induce the T3SS in the bacterial pathogen Pseudomonas syringae pv tomato DC3000. In addition, we report that mkp1 (mapk phosphatase 1), an Arabidopsis mutant that is more resistant to bacterial infection, produces decreased levels of these T3SS-inducing metabolites. Consistent with the observed decrease in these metabolites, T3SS effector delivery by DC3000 was impaired in mkp1. Addition of the bioactive metabolites to the mkp1-DC3000 interaction fully restored T3SS effector delivery and suppressed enhanced resistance in mkp1. Together, these results demonstrate that DC3000 perceives multiple signals derived from plants to initiate their virulence program, and reveal a new layer of molecular communication between plants and these pathogenic bacteria.

  13. The kiwifruit emerging pathogen Pseudomonas syringae pv. actinidiae does not produce AHLs but possesses three luxR solos.

    Directory of Open Access Journals (Sweden)

    Hitendra Kumar Patel

    Full Text Available Pseudomonas syringae pv. actinidiae (Psa is an emerging phytopathogen causing bacterial canker disease in kiwifruit plants worldwide. Quorum sensing (QS gene regulation plays important roles in many different bacterial plant pathogens. In this study we analyzed the presence and possible role of N-acyl homoserine lactone (AHL quorum sensing in Psa. It was established that Psa does not produce AHLs and that a typical complete LuxI/R QS system is absent in Psa strains. Psa however possesses three putative luxR solos designated here as PsaR1, PsaR2 and PsaR3. PsaR2 belongs to the sub-family of LuxR solos present in many plant associated bacteria (PAB that binds and responds to yet unknown plant signal molecules. PsaR1 and PsaR3 are highly similar to LuxRs which bind AHLs and are part of the canonical LuxI/R AHL QS systems. Mutation in all the three luxR solos of Psa showed reduction of in planta survival and also showed additive effect if more than one solo was inactivated in double mutants. Gene promoter analysis revealed that the three solos are not auto-regulated and investigated their possible role in several bacterial phenotypes.

  14. Atmospheric CO2 Alters Resistance of Arabidopsis to Pseudomonas syringae by Affecting Abscisic Acid Accumulation and Stomatal Responsiveness to Coronatine

    Directory of Open Access Journals (Sweden)

    Yeling Zhou

    2017-05-01

    Full Text Available Atmospheric CO2 influences plant growth and stomatal aperture. Effects of high or low CO2 levels on plant disease resistance are less well understood. Here, resistance of Arabidopsis thaliana against the foliar pathogen Pseudomonas syringae pv. tomato DC3000 (Pst was investigated at three different CO2 levels: high (800 ppm, ambient (450 ppm, and low (150 ppm. Under all conditions tested, infection by Pst resulted in stomatal closure within 1 h after inoculation. However, subsequent stomatal reopening at 4 h, triggered by the virulence factor coronatine (COR, occurred only at ambient and high CO2, but not at low CO2. Moreover, infection by Pst was reduced at low CO2 to the same extent as infection by mutant Pst cor-. Under all CO2 conditions, the ABA mutants aba2-1 and abi1-1 were as resistant to Pst as wild-type plants under low CO2, which contained less ABA. Moreover, stomatal reopening mediated by COR was dependent on ABA. Our results suggest that reduced ABA levels at low CO2 contribute to the observed enhanced resistance to Pst by deregulation of virulence responses. This implies that enhanced ABA levels at increasing CO2 levels may have a role in weakening plant defense.

  15. A Non-targeted Metabolomics Approach Unravels the VOCs Associated with the Tomato Immune Response against Pseudomonas syringae

    Directory of Open Access Journals (Sweden)

    María Pilar López-Gresa

    2017-07-01

    Full Text Available Volatile organic compounds (VOCs emitted by plants are secondary metabolites that mediate the plant interaction with pathogens and herbivores. These compounds may perform direct defensive functions, i.e., acting as antioxidant, antibacterial, or antifungal agents, or indirectly by signaling the activation of the plant’s defensive responses. Using a non-targeted GC-MS metabolomics approach, we identified the profile of the VOCs associated with the differential immune response of the Rio Grande tomato leaves infected with either virulent or avirulent strains of Pseudomonas syringae DC3000 pv. tomato. The VOC profile of the tomato leaves infected with avirulent bacteria is characterized by esters of (Z-3-hexenol with acetic, propionic, isobutyric or butyric acids, and several hydroxylated monoterpenes, e.g., linalool, α-terpineol, and 4-terpineol, which defines the profile of an immunized plant response. In contrast, the same tomato cultivar infected with the virulent bacteria strain produced a VOC profile characterized by monoterpenes and SA derivatives. Interestingly, the differential VOCs emission correlated statistically with the induction of the genes involved in their biosynthetic pathway. Our results extend plant defense system knowledge and suggest the possibility for generating plants engineered to over-produce these VOCs as a complementary strategy for resistance.

  16. Pollen as a possible pathway for the dissemination of Pseudomonas syringae pv. actinide and bacterial canker of kiwifruit

    Directory of Open Access Journals (Sweden)

    Rodanthi TONTOU

    2014-09-01

    Full Text Available Pollen collected in a kiwifruit orchard with symptoms of bacterial canker and naturally contaminated by Pseudomonas syringae pv. actinidiae (Psa, was used to pollinate an experimental orchard, in order to confirm its role, under commercial orchard conditions, in disseminating the pathogen and, possibly, contributing to disease spread. A pollen lot, certified free from Psa, was used with the same methods as a control. Two pollination techniques were used: dusting (dry pollen and spraying (pollen suspension in water. The orchard was monitored during 2 years from experimental pollination, with regular sampling of flowers, fruits, leaves, and vines, to check for Psa as an epiphyte or endophyte, and for bacterial canker symptoms. Psa was recovered from flowers, fruitlets and leaves during the first season, mainly in plots where contaminated pollen had been sprayed in water suspension. From early August until harvesting time (mid-October, Psa detection was possible only on leaves. No symptoms developed during the first season after pollination. No endophytic Psa was detected in pruned vines in the following winter. During the second season, detection and isolation of Psa was erratic, but direct isolation was achieved from four plots. During the second season after pollination, typical leaf symptoms were observed on a few vines, and Psa was isolated and identified. Our results suggest that Psa could be disseminated via contaminated kiwifruit pollen as a pathway for spread of bacterial canker. However, further pollination experiments are needed to establish, beyond any doubt, whether contaminated pollen may contribute to possible disease outbreaks.

  17. A Strobilurin Fungicide Enhances the Resistance of Tobacco against Tobacco Mosaic Virus and Pseudomonas syringae pv tabaci1

    Science.gov (United States)

    Herms, Stefan; Seehaus, Kai; Koehle, Harald; Conrath, Uwe

    2002-01-01

    The strobilurin class of fungicides comprises a variety of synthetic plant-protecting compounds with broad-spectrum antifungal activity. In the present study, we demonstrate that a strobilurin fungicide, F 500 (Pyraclostrobin), enhances the resistance of tobacco (Nicotiana tabacum cv Xanthi nc) against infection by either tobacco mosaic virus (TMV) or the wildfire pathogen Pseudomonas syringae pv tabaci. F 500 was also active at enhancing TMV resistance in NahG transgenic tobacco plants unable to accumulate significant amounts of the endogenous inducer of enhanced disease resistance, salicylic acid (SA). This finding suggests that F 500 enhances TMV resistance in tobacco either by acting downstream of SA in the SA signaling mechanism or by functioning independently of SA. The latter assumption is the more likely because in infiltrated leaves, F 500 did not cause the accumulation of SA-inducible pathogenesis-related (PR)-1 proteins that often are used as conventional molecular markers for SA-induced disease resistance. However, accumulation of PR-1 proteins and the associated activation of the PR-1 genes were elicited upon TMV infection of tobacco leaves and both these responses were induced more rapidly in F 500-pretreated plants than in the water-pretreated controls. Taken together, our results suggest that F 500, in addition to exerting direct antifungal activity, may also protect plants by priming them for potentiated activation of subsequently pathogen-induced cellular defense responses. PMID:12226492

  18. A strobilurin fungicide enhances the resistance of tobacco against tobacco mosaic virus and Pseudomonas syringae pv tabaci.

    Science.gov (United States)

    Herms, Stefan; Seehaus, Kai; Koehle, Harald; Conrath, Uwe

    2002-09-01

    The strobilurin class of fungicides comprises a variety of synthetic plant-protecting compounds with broad-spectrum antifungal activity. In the present study, we demonstrate that a strobilurin fungicide, F 500 (Pyraclostrobin), enhances the resistance of tobacco (Nicotiana tabacum cv Xanthi nc) against infection by either tobacco mosaic virus (TMV) or the wildfire pathogen Pseudomonas syringae pv tabaci. F 500 was also active at enhancing TMV resistance in NahG transgenic tobacco plants unable to accumulate significant amounts of the endogenous inducer of enhanced disease resistance, salicylic acid (SA). This finding suggests that F 500 enhances TMV resistance in tobacco either by acting downstream of SA in the SA signaling mechanism or by functioning independently of SA. The latter assumption is the more likely because in infiltrated leaves, F 500 did not cause the accumulation of SA-inducible pathogenesis-related (PR)-1 proteins that often are used as conventional molecular markers for SA-induced disease resistance. However, accumulation of PR-1 proteins and the associated activation of the PR-1 genes were elicited upon TMV infection of tobacco leaves and both these responses were induced more rapidly in F 500-pretreated plants than in the water-pretreated controls. Taken together, our results suggest that F 500, in addition to exerting direct antifungal activity, may also protect plants by priming them for potentiated activation of subsequently pathogen-induced cellular defense responses.

  19. The Identification of Genes Important in Pseudomonas syringae pv. phaseolicola Plant Colonisation Using In Vitro Screening of Transposon Libraries.

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    Bharani Manoharan

    Full Text Available The bacterial plant pathogen Pseudomonas syringae pv. phaseolicola (Pph colonises the surface of common bean plants before moving into the interior of plant tissue, via wounds and stomata. In the intercellular spaces the pathogen proliferates in the apoplastic fluid and forms microcolonies (biofilms around plant cells. If the pathogen can suppress the plant's natural resistance response, it will cause halo blight disease. The process of resistance suppression is fairly well understood, but the mechanisms used by the pathogen in colonisation are less clear. We hypothesised that we could apply in vitro genetic screens to look for changes in motility, colony formation, and adhesion, which are proxies for infection, microcolony formation and cell adhesion. We made transposon (Tn mutant libraries of Pph strains 1448A and 1302A and found 106/1920 mutants exhibited alterations in colony morphology, motility and biofilm formation. Identification of the insertion point of the Tn identified within the genome highlighted, as expected, a number of altered motility mutants bearing mutations in genes encoding various parts of the flagellum. Genes involved in nutrient biosynthesis, membrane associated proteins, and a number of conserved hypothetical protein (CHP genes were also identified. A mutation of one CHP gene caused a positive increase in in planta bacterial growth. This rapid and inexpensive screening method allows the discovery of genes important for in vitro traits that can be correlated to roles in the plant interaction.

  20. Genome-wide identification of transcriptional start sites in the plant pathogen Pseudomonas syringae pv. tomato str. DC3000.

    Directory of Open Access Journals (Sweden)

    Melanie J Filiatrault

    Full Text Available RNA-Seq has provided valuable insights into global gene expression in a wide variety of organisms. Using a modified RNA-Seq approach and Illumina's high-throughput sequencing technology, we globally identified 5'-ends of transcripts for the plant pathogen Pseudomonas syringae pv. tomato str. DC3000. A substantial fraction of 5'-ends obtained by this method were consistent with results obtained using global RNA-Seq and 5'RACE. As expected, many 5'-ends were positioned a short distance upstream of annotated genes. We also captured 5'-ends within intergenic regions, providing evidence for the expression of un-annotated genes and non-coding RNAs, and detected numerous examples of antisense transcription, suggesting additional levels of complexity in gene regulation in DC3000. Importantly, targeted searches for sequence patterns in the vicinity of 5'-ends revealed over 1200 putative promoters and other regulatory motifs, establishing a broad foundation for future investigations of regulation at the genomic and single gene levels.

  1. Elicitation of Induced Resistance against Pectobacterium carotovorum and Pseudomonas syringae by Specific Individual Compounds Derived from Native Korean Plant Species

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    Choong-Min Ryu

    2013-10-01

    Full Text Available Plants have developed general and specific defense mechanisms for protection against various enemies. Among the general defenses, induced resistance has distinct characteristics, such as broad-spectrum resistance and long-lasting effectiveness. This study evaluated over 500 specific chemical compounds derived from native Korean plant species to determine whether they triggered induced resistance against Pectobacterium carotovorum supsp. carotovorum (Pcc in tobacco (Nicotiana tabacum and Pseudomonas syringae pv. tomato (Pst in Arabidopsis thaliana. To select target compound(s with direct and indirect (volatile effects, a new Petri-dish-based in vitro disease assay system with four compartments was developed. The screening assay showed that capsaicin, fisetin hydrate, jaceosidin, and farnesiferol A reduced the disease severity significantly in tobacco. Of these four compounds, capsaicin and jaceosidin induced resistance against Pcc and Pst, which depended on both salicylic acid (SA and jasmonic acid (JA signaling, using Arabidopsis transgenic and mutant lines, including npr1 and NahG for SA signaling and jar1 for JA signaling. The upregulation of the PR2 and PDF1.2 genes after Pst challenge with capsaicin pre-treatment indicated that SA and JA signaling were primed. These results demonstrate that capsaicin and jaceosidin can be effective triggers of strong induced resistance against both necrotrophic and biotrophic plant pathogens.

  2. Tissue-specific changes of glutamine synthetase activity in oats after rhizosphere infestation by Pseudomonas syringae pv. tabaci. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Knight, T.J. [Univ. of Southern Maine, Portland, ME (United States); Temple, S.; Sengupta-Gopalan, C. [New Mexico State Univ., Las Curces, NM (United States)] [and others

    1996-05-15

    Oats (Avena sativa L. lodi) tolerant of rhizosphere infestation by Pseudomonas syringae pv. tabaci when challenged by the pathogen experience tissue-specific alterations of ammonia assimilatory capabilities. Altered ammonia assimilatory potentials between root and leaf tissue result from selective inactivation of glutamine synthetase (GS) by the toxin Tabtoxinine-B-lactam (TBL). Root GS is sensitive and leaf GSs are resistant to TBL inactivation. With prolonged challenge by the pathogen root GS activity decreases but leaf GS specific activity increase. Higher leaf GS activity is due to decreased rates of degradation rather than increased GS synthesis. Higher leaf GS activity and elevated levels of GS polypeptide appear to result from a limited interaction between GS and TBL leading to the accumulation of a less active but more stable GS holoenzyme. Tolerant challenged oats besides surviving rhizosphere infestation, experience enhanced growth. A strong correlation exists between leaf GS activity and whole plant fresh weight, suggesting that tissue-specific changes in ammonia assimilatory capability provides the plant a more efficient mechanism for uptake and utilization of nitrogen.

  3. Variation in extragenic repetitive DNA sequences in Pseudomonas syringae and potential use of modified REP primers in the identification of closely related isolates

    Directory of Open Access Journals (Sweden)

    Elif Çepni

    2012-01-01

    Full Text Available In this study, Pseudomonas syringe pathovars isolated from olive, tomato and bean were identified by species-specific PCR and their genetic diversity was assessed by repetitive extragenic palindromic (REP-PCR. Reverse universal primers for REP-PCR were designed by using the bases of A, T, G or C at the positions of 1, 4 and 11 to identify additional polymorphism in the banding patterns. Binding of the primers to different annealing sites in the genome revealed additional fingerprint patterns in eight isolates of P. savastanoi pv. savastanoi and two isolates of P. syringae pv. tomato. The use of four different bases in the primer sequences did not affect the PCR reproducibility and was very efficient in revealing intra-pathovar diversity, particularly in P. savastanoi pv. savastanoi. At the pathovar level, the primer BOX1AR yielded shared fragments, in addition to five bands that discriminated among the pathovars P. syringae pv. phaseolicola, P. savastanoi pv. savastanoi and P. syringae pv. tomato. REP-PCR with a modified primer containing C produced identical bands among the isolates in a pathovar but separated three pathovars more distinctly than four other primers. Although REP-and BOX-PCRs have been successfully used in the molecular identification of Pseudomonas isolates from Turkish flora, a PCR based on inter-enterobacterial repetitive intergenic concensus (ERIC sequences failed to produce clear banding patterns in this study.

  4. Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA

    NARCIS (Netherlands)

    Pel, M.J.C.; Van Dijken, A.J.H.; Bardoel, B.W.; Seidl, M.F; Van der Ent, S.; Van Strijp, J.A.G.

    2014-01-01

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

  5. Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA

    NARCIS (Netherlands)

    Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

    Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

  6. Virulence determinants of Pseudomonas syringae strains isolated from grasses in the context of a small type III effector repertoire

    DEFF Research Database (Denmark)

    Dudnik, Alexey; Dudler, Robert

    2014-01-01

    derivative that inhibits the eukaryotic proteasome. In strains colonizing dicotyledonous plants, the compound was demonstrated to suppress the salicylic-acid-dependent defense pathway. Here, we analyze virulence factors of three strains colonizing wheat (Triticum aestivum): P. syringae pathovar syringae (Psy...

  7. Early Arabidopsis root hair growth stimulation by pathogenic strains of Pseudomonas syringae

    Czech Academy of Sciences Publication Activity Database

    Pečenková, Tamara; Janda, Martin; Ortmannová, Jitka; Hajná, Vladimíra; Stehlíková, Zuzana; Žárský, Viktor

    2017-01-01

    Roč. 120, č. 3 (2017), s. 437-446 ISSN 0305-7364 R&D Projects: GA ČR(CZ) GA15-14886S; GA ČR GA14-09685S Institutional support: RVO:61389030 Keywords : Arabidopsis * dde2/ein2/pad4/sid2 * exocyst * Flg22 * Pseudomonas * Root hair * vesicle trafficking Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.041, year: 2016

  8. Arabidopsis HARMLESS TO OZONE LAYER protein methylates a glucosinolate breakdown product and functions in resistance to Pseudomonas syringae pv. maculicola.

    Science.gov (United States)

    Nagatoshi, Yukari; Nakamura, Tatsuo

    2009-07-17

    Almost all of the chlorine-containing gas emitted from natural sources is methyl chloride (CH(3)Cl), which contributes to the destruction of the stratospheric ozone layer. Tropical and subtropical plants emit substantial amounts of CH(3)Cl. A gene involved in CH(3)Cl emission from Arabidopsis was previously identified and designated HARMLESS TO OZONE LAYER (hereafter AtHOL1) based on the mutant phenotype. Our previous studies demonstrated that AtHOL1 and its homologs, AtHOL2 and AtHOL3, have S-adenosyl-l-methionine-dependent methyltransferase activities. However, the physiological functions of AtHOLs have yet to be elucidated. In the present study, our comparative kinetic analyses with possible physiological substrates indicated that all of the AtHOLs have low activities toward chloride. AtHOL1 was highly reactive to thiocyanate (NCS(-)), a pseudohalide, synthesizing methylthiocyanate (CH(3)SCN) with a very high k(cat)/K(m) value. We demonstrated in vivo that substantial amounts of NCS(-) were synthesized upon tissue damage in Arabidopsis and that NCS(-) was largely derived from myrosinase-mediated hydrolysis of glucosinolates. Analyses with the T-DNA insertion Arabidopsis mutants (hol1, hol2, and hol3) revealed that only hol1 showed increased sensitivity to NCS(-) in medium and a concomitant lack of CH(3)SCN synthesis upon tissue damage. Bacterial growth assays indicated that the conversion of NCS(-) into CH(3)SCN dramatically increased antibacterial activities against Arabidopsis pathogens that normally invade the wound site. Furthermore, hol1 seedlings showed an increased susceptibility toward an Arabidopsis pathogen, Pseudomonas syringae pv. maculicola. Here we propose that AtHOL1 is involved in glucosinolate metabolism and defense against phytopathogens. Moreover, CH(3)Cl synthesized by AtHOL1 could be considered a byproduct of NCS(-) metabolism.

  9. Genomic and Gene-Expression Comparisons among Phage-Resistant Type-IV Pilus Mutants of Pseudomonas syringae pathovar phaseolicola.

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    Mark Sistrom

    Full Text Available Pseudomonas syringae pv. phaseolicola (Pph is a significant bacterial pathogen of agricultural crops, and phage Φ6 and other members of the dsRNA virus family Cystoviridae undergo lytic (virulent infection of Pph, using the type IV pilus as the initial site of cellular attachment. Despite the popularity of Pph/phage Φ6 as a model system in evolutionary biology, Pph resistance to phage Φ6 remains poorly characterized. To investigate differences between phage Φ6 resistant Pph strains, we examined genomic and gene expression variation among three bacterial genotypes that differ in the number of type IV pili expressed per cell: ordinary (wild-type, non-piliated, and super-piliated. Genome sequencing of non-piliated and super-piliated Pph identified few mutations that separate these genotypes from wild type Pph--and none present in genes known to be directly involved in type IV pilus expression. Expression analysis revealed that 81.1% of gene ontology (GO terms up-regulated in the non-piliated strain were down-regulated in the super-piliated strain. This differential expression is particularly prevalent in genes associated with respiration--specifically genes in the tricarboxylic acid cycle (TCA cycle, aerobic respiration, and acetyl-CoA metabolism. The expression patterns of the TCA pathway appear to be generally up and down-regulated, in non-piliated and super-piliated Pph respectively. As pilus retraction is mediated by an ATP motor, loss of retraction ability might lead to a lower energy draw on the bacterial cell, leading to a different energy balance than wild type. The lower metabolic rate of the super-piliated strain is potentially a result of its loss of ability to retract.

  10. Multilayered Regulation of Ethylene Induction Plays a Positive Role in Arabidopsis Resistance against Pseudomonas syringae1[OPEN

    Science.gov (United States)

    Guan, Rongxia; Su, Jianbin; Meng, Xiangzong; Li, Sen; Liu, Yidong; Xu, Juan; Zhang, Shuqun

    2015-01-01

    Ethylene, a key phytohormone involved in plant-pathogen interaction, plays a positive role in plant resistance against fungal pathogens. However, its function in plant bacterial resistance remains unclear. Here, we report a detailed analysis of ethylene induction in Arabidopsis (Arabidopsis thaliana) in response to Pseudomonas syringae pv tomato DC3000 (Pst). Ethylene biosynthesis is highly induced in both pathogen/microbe-associated molecular pattern (PAMP)-triggered immunity and effector-triggered immunity (ETI), and the induction is potentiated by salicylic acid (SA) pretreatment. In addition, Pst actively suppresses PAMP-triggered ethylene induction in a type III secretion system-dependent manner. SA potentiation of ethylene induction is dependent mostly on MITOGEN-ACTIVATED PROTEIN KINASE6 (MPK6) and MPK3 and their downstream ACS2 and ACS6, two type I isoforms of 1-aminocyclopropane-1-carboxylic acid synthases (ACSs). ACS7, a type III ACS whose expression is enhanced by SA pretreatment, is also involved. Pst expressing the avrRpt2 effector gene (Pst-avrRpt2), which is capable of triggering ETI, induces a higher level of ethylene production, and the elevated portion is dependent on SALICYLIC ACID INDUCTION DEFICIENT2 and NONEXPRESSER OF PATHOGENESIS-RELATED GENE1, two key players in SA biosynthesis and signaling. High-order ACS mutants with reduced ethylene induction are more susceptible to both Pst and Pst-avrRpt2, demonstrating a positive role of ethylene in plant bacterial resistance mediated by both PAMP-triggered immunity and ETI. PMID:26265775

  11. Protection of Arabidopsis thaliana against Leaf-Pathogenic Pseudomonas syringae by Sphingomonas Strains in a Controlled Model System ▿ †

    Science.gov (United States)

    Innerebner, Gerd; Knief, Claudia; Vorholt, Julia A.

    2011-01-01

    Diverse bacterial taxa live in association with plants without causing deleterious effects. Previous analyses of phyllosphere communities revealed the predominance of few bacterial genera on healthy dicotyl plants, provoking the question of whether these commensals play a particular role in plant protection. Here, we tested two of them, Methylobacterium and Sphingomonas, with respect to their ability to diminish disease symptom formation and the proliferation of the foliar plant pathogen Pseudomonas syringae pv. tomato DC3000 on Arabidopsis thaliana. Plants were grown under gnotobiotic conditions in the absence or presence of the potential antagonists and then challenged with the pathogen. No effect of Methylobacterium strains on disease development was observed. However, members of the genus Sphingomonas showed a striking plant-protective effect by suppressing disease symptoms and diminishing pathogen growth. A survey of different Sphingomonas strains revealed that most plant isolates protected A. thaliana plants from developing severe disease symptoms. This was not true for Sphingomonas strains isolated from air, dust, or water, even when they reached cell densities in the phyllosphere comparable to those of the plant isolates. This suggests that plant protection is common among plant-colonizing Sphingomonas spp. but is not a general trait conserved within the genus Sphingomonas. The carbon source profiling of representative isolates revealed differences between protecting and nonprotecting strains, suggesting that substrate competition plays a role in plant protection by Sphingomonas. However, other mechanisms cannot be excluded at this time. In conclusion, the ability to protect plants as shown here in a model system may be an unexplored, common trait of indigenous Sphingomonas spp. and may be of relevance under natural conditions. PMID:21421777

  12. Arabidopsis AtERF15 positively regulates immunity against Pseudomonas syringae pv. tomato DC3000 and Botrytis cinerea

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    Huijuan eZhang

    2015-09-01

    Full Text Available Upon pathogen infection, activation of immune response requires effective transcriptional reprogramming that regulates inducible expression of a large set of defense genes. A number of ethylene-responsive factor transcription factors have been shown to play critical roles in regulating immune responses in plants. In the present study, we explored the functions of Arabidopsis AtERF15 in immune responses against Pseudomonas syringae pv. tomato (Pst DC3000, a (hemibiotrophic bacterial pathogen, and Botrytis cinerea, a necrotrophic fungal pathogen. Expression of AtERF15 was induced by infection of Pst DC3000 and B. cinerea and by treatments with salicylic acid (SA and methyl jasmonate. Biochemical assays demonstrated that AtERF15 is a nucleus-localized transcription activator. The AtERF15-overexpressing (AtERF15-OE plants displayed enhanced resistance while the AtERF15-RNAi plants exhibited decreased resistance against Pst DC3000 and B. cinerea. Meanwhile, Pst DC3000- or B. cinerea-induced expression of defense genes was upregulated in AtERF15-OE plants but downregulated in AtERF15-RNAi plants, as compared to the expression in wild type plants. In response to infection with B. cinerea, the AtERF15-OE plants accumulated less reactive oxygen species (ROS while the AtERF15-RNAi plants accumulated more ROS. The flg22- and chitin-induced oxidative burst was abolished and expression levels of the pattern-triggered immunity-responsive genes AtFRK1 and AtWRKY53 were suppressed in AtER15-RNAi plants upon treatment with flg22 or chitin. Furthermore, SA-induced defense response was also partially impaired in the AtERF15-RNAi plants. These data demonstrate that AtERF15 is a positive regulator of multiple layers of the immune responses in Arabidopsis.

  13. Modeling and mapping the current and future distribution of Pseudomonas syringae pv. actinidiae under climate change in China.

    Science.gov (United States)

    Wang, Rulin; Li, Qing; He, Shisong; Liu, Yuan; Wang, Mingtian; Jiang, Gan

    2018-01-01

    Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is a major threat to the kiwifruit industry throughout the world and accounts for substantial economic losses in China. The aim of the present study was to test and explore the possibility of using MaxEnt (maximum entropy models) to predict and analyze the future large-scale distribution of Psa in China. Based on the current environmental factors, three future climate scenarios, which were suggested by the fifth IPCC report, and the current distribution sites of Psa, MaxEnt combined with ArcGIS was applied to predict the potential suitable areas and the changing trend of Psa in China. The jackknife test and correlation analysis were used to choose dominant climatic factors. The receiver operating characteristic curve (ROC) drawn by MaxEnt was used to evaluate the accuracy of the simulation. The results showed that under current climatic conditions, the area from latitude 25° to 36°N and from longitude 101° to 122°E is the primary potential suitable area of Psa in China. The highly suitable area (with suitability between 66 and 100) was mainly concentrated in Northeast Sichuan, South Shaanxi, most of Chongqing, West Hubei and Southwest Gansu and occupied 4.94% of land in China. Under different future emission scenarios, both the areas and the centers of the suitable areas all showed differences compared with the current situation. Four climatic variables, i.e., maximum April temperature (19%), mean temperature of the coldest quarter (14%), precipitation in May (11.5%) and minimum temperature in October (10.8%), had the largest impact on the distribution of Psa. The MaxEnt model is potentially useful for forecasting the future adaptive distribution of Psa under climate change, and it provides important guidance for comprehensive management.

  14. Comparative genomics of Pseudomonas syringae pathovar tomato reveals novel chemotaxis pathways associated with motility and plant pathogenicity

    Directory of Open Access Journals (Sweden)

    Christopher R. Clarke

    2016-10-01

    Full Text Available The majority of bacterial foliar plant pathogens must invade the apoplast of host plants through points of ingress, such as stomata or wounds, to replicate to high population density and cause disease. How pathogens navigate plant surfaces to locate invasion sites remains poorly understood. Many bacteria use chemical-directed regulation of flagellar rotation, a process known as chemotaxis, to move towards favorable environmental conditions. Chemotactic sensing of the plant surface is a potential mechanism through which foliar plant pathogens home in on wounds or stomata, but chemotactic systems in foliar plant pathogens are not well characterized. Comparative genomics of the plant pathogen Pseudomonas syringae pathovar tomato (Pto implicated annotated chemotaxis genes in the recent adaptations of one Pto lineage. We therefore characterized the chemosensory system of Pto. The Pto genome contains two primary chemotaxis gene clusters, che1 and che2. The che2 cluster is flanked by flagellar biosynthesis genes and similar to the canonical chemotaxis gene clusters of other bacteria based on sequence and synteny. Disruption of the primary phosphorelay kinase gene of the che2 cluster, cheA2, eliminated all swimming and surface motility at 21 °C but not 28 °C for Pto. The che1 cluster is located next to Type IV pili biosynthesis genes but disruption of cheA1 has no observable effect on twitching motility for Pto. Disruption of cheA2 also alters in planta fitness of the pathogen with strains lacking functional cheA2 being less fit in host plants but more fit in a non-host interaction.

  15. An in vitro study of the anti-biofilm properties of proanthocyanidin and chitosan in Pseudomonas syringae pv. papulans

    Science.gov (United States)

    Song, Kai

    Biofilm-forming bacteria are a form of planktonic microorganisms that can become resistant against conventional antibiotics. Because they are difficult to eradicate, biofilm-forming bacteria are extremely problematic for the medical industry areas. Thus, materials that can distort biofilm structure would be helpful for eliminating chronic infection and decreasing bacterial resistance. The primary objective of this study is to evaluate the anti-biofilm effect of two bio-derived substances, proanthocyanidin and chitosan. Proanthocyanidins are secondary plant metabolites that are reported to have antibiotic and antioxidant functions. Chitosan (poly [beta-(1, 4)-amino-2-deoxy-beta-D-glucose]) is a deacetylated derivative of chitin, which is abundant in the exoskeleton of crustaceans and insects. It is reported to be a suitable substitute for conventional fungicides and can enhance the proanthocyanidin content in plants when used as an agrochemical. Chitosan-tripolyphosphate (TPP) nanoparticles, which have good neutral water solubility and are nanoscale in size, can be used as carriers for gene and drug therapy and are thus favorable to be tested as a treatment method against bacterial biofilms. In this study, the anti-biofilm and antibacterial properties of proanthocyanidin, chitosan-TPP nanoparticles and proanthocyanidins-loaded chitosan-TPP nanoparticles were tested using the model plant bacterium, Pseudomonas syringae pv. papulans (Psp), a pathogen isolated from infected apples. At a lower concentration (1 mg/mL and 2.5 mg/mL), both chitosan nanoparticles and proanthocyanidins can postpone the formation of biofilms and eventually disrupted part of the biofilm. While higher concentration (above 5 mg/mL) of chitosan nanoparticles or proanthocyanidins can eliminate most of the biofilm in this study. PAC-loaded chitosan nanoparticles also can also distort biofilms. Both proanthocyanidins and chitosan-TPP nanoparticle showed a mild antibacterial property. PAC

  16. Allelic variation in two distinct Pseudomonas syringae flagellin epitopes modulates the strength of plant immune responses but not bacterial motility

    Science.gov (United States)

    Clarke, Christopher R.; Chinchilla, Delphine; Hind, Sarah R.; Taguchi, Fumiko; Miki, Ryuji; Ichinose, Yuki; Martin, Gregory B.; Leman, Scotland; Felix, Georg; Vinatzer, Boris A.

    2013-01-01

    Summary The bacterial flagellin (FliC) epitopes flg22 and flgII-28 are microbe-associated molecular patterns (MAMPs). While flg22 is recognized by many plant species via the pattern recognition receptor FLS2, neither the flgII-28 receptor nor the extent of flgII-28 recognition by different plant families is known.Here we tested the significance of flgII-28 as a MAMP and the importance of allelic diversity in flg22 and flgII-28 in plant–pathogen interactions using purified peptides and a Pseudomonas syringae ΔfliC mutant complemented with different fliC alleles.Plant genotype and allelic diversity in flg22 and flgII-28 were found to significantly affect the plant immune response but not bacterial motility. Recognition of flgII-28 is restricted to a number of Solanaceous species. While the flgII-28 peptide does not trigger any immune response in Arabidopsis, mutations in both flg22 and flgII-28 have FLS2-dependent effects on virulence. However, expression of a tomato allele of FLS2 does not confer to Nicotiana benthamiana the ability to detect flgII-28 and tomato plants silenced for FLS2 are not altered in flgII-28 recognition.Therefore, MAMP diversification is an effective pathogen virulence strategy and flgII-28 appears to be perceived by a yet unidentified receptor in the Solanaceae although it has an FLS2-dependent virulence effect in Arabidopsis. PMID:23865782

  17. The predicted protein product of a pathogenicity locus from Pseudomonas syringae pv. phaseolicola is homologous to a highly conserved domain of several procaryotic regulatory proteins.

    OpenAIRE

    Grimm, C.; Panopoulos, N J

    1989-01-01

    A ca. 20-kilobase (kb) region (hrp) that controls the interaction of Pseudomonas syringae pv. phaseolicola with its host (pathogenicity) and nonhost plants (hypersensitive reaction) was previously cloned and partially characterized. In this study we defined the limits and determined the nucleotide sequence of a hrp locus (hrpS), located near the right end of the hrp cluster. The largest open reading frame (ORF302) in hrpS has a coding capacity for a 302-amino-acid polypeptide. The predicted a...

  18. Transcriptional profile of Pseudomonas syringae pv. phaseolicola NPS3121 in response to tissue extracts from a susceptible Phaseolus vulgaris L. cultivar

    Directory of Open Access Journals (Sweden)

    Martínez-Antonio Agustino

    2009-12-01

    Full Text Available Abstract Background Pseudomonas syringae pv. phaseolicola is a Gram-negative plant-pathogenic bacterium that causes "halo blight" disease of beans (Phaseolus vulgaris L.. This disease affects both foliage and pods, and is a major problem in temperate areas of the world. Although several bacterial genes have been determined as participants in pathogenesis, the overall process still remains poorly understood, mainly because the identity and function of many of the genes are largely unknown. In this work, a genomic library of P. syringae pv. phaseolicola NPS3121 was constructed and PCR amplification of individual fragments was carried out in order to print a DNA microarray. This microarray was used to identify genes that are differentially expressed when bean leaf extracts, pod extracts or apoplastic fluid were added to the growth medium. Results Transcription profiles show that 224 genes were differentially expressed, the majority under the effect of bean leaf extract and apoplastic fluid. Some of the induced genes were previously known to be involved in the first stages of the bacterial-plant interaction and virulence. These include genes encoding type III secretion system proteins and genes involved in cell-wall degradation, phaseolotoxin synthesis and aerobic metabolism. On the other hand, most repressed genes were found to be involved in the uptake and metabolism of iron. Conclusion This study furthers the understanding of the mechanisms involved, responses and the metabolic adaptation that occurs during the interaction of P. syringae pv. phaseolicola with a susceptible host plant.

  19. Allele-specific virulence attenuation of the Pseudomonas syringae HopZ1a type III effector via the Arabidopsis ZAR1 resistance protein.

    Science.gov (United States)

    Lewis, Jennifer D; Wu, Ronald; Guttman, David S; Desveaux, Darrell

    2010-04-01

    Plant resistance (R) proteins provide a robust surveillance system to defend against potential pathogens. Despite their importance in plant innate immunity, relatively few of the approximately 170 R proteins in Arabidopsis have well-characterized resistance specificity. In order to identify the R protein responsible for recognition of the Pseudomonas syringae type III secreted effector (T3SE) HopZ1a, we assembled an Arabidopsis R gene T-DNA Insertion Collection (ARTIC) from publicly available Arabidopsis thaliana insertion lines and screened it for plants lacking HopZ1a-induced immunity. This reverse genetic screen revealed that the Arabidopsis R protein HOPZ-activated resistance 1 (ZAR1; At3g50950) is required for recognition of HopZ1a in Arabidopsis. ZAR1 belongs to the coiled-coil (CC) class of nucleotide binding site and leucine-rich repeat (NBS-LRR) containing R proteins; however, the ZAR1 CC domain phylogenetically clusters in a clade distinct from other related Arabidopsis R proteins. ZAR1-mediated immunity is independent of several genes required by other R protein signaling pathways, including NDR1 and RAR1, suggesting that ZAR1 possesses distinct signaling requirements. The closely-related T3SE protein, HopZ1b, is still recognized by zar1 Arabidopsis plants indicating that Arabidopsis has evolved at least two independent R proteins to recognize the HopZ T3SE family. Also, in Arabidopsis zar1 plants HopZ1a promotes P. syringae growth indicative of an ancestral virulence function for this T3SE prior to the evolution of recognition by the host resistance protein ZAR1. Our results demonstrate that the Arabidopsis resistance protein ZAR1 confers allele-specific recognition and virulence attenuation of the Pseudomonas syringae T3SE protein HopZ1a.

  20. Allele-specific virulence attenuation of the Pseudomonas syringae HopZ1a type III effector via the Arabidopsis ZAR1 resistance protein.

    Directory of Open Access Journals (Sweden)

    Jennifer D Lewis

    2010-04-01

    Full Text Available Plant resistance (R proteins provide a robust surveillance system to defend against potential pathogens. Despite their importance in plant innate immunity, relatively few of the approximately 170 R proteins in Arabidopsis have well-characterized resistance specificity. In order to identify the R protein responsible for recognition of the Pseudomonas syringae type III secreted effector (T3SE HopZ1a, we assembled an Arabidopsis R gene T-DNA Insertion Collection (ARTIC from publicly available Arabidopsis thaliana insertion lines and screened it for plants lacking HopZ1a-induced immunity. This reverse genetic screen revealed that the Arabidopsis R protein HOPZ-activated resistance 1 (ZAR1; At3g50950 is required for recognition of HopZ1a in Arabidopsis. ZAR1 belongs to the coiled-coil (CC class of nucleotide binding site and leucine-rich repeat (NBS-LRR containing R proteins; however, the ZAR1 CC domain phylogenetically clusters in a clade distinct from other related Arabidopsis R proteins. ZAR1-mediated immunity is independent of several genes required by other R protein signaling pathways, including NDR1 and RAR1, suggesting that ZAR1 possesses distinct signaling requirements. The closely-related T3SE protein, HopZ1b, is still recognized by zar1 Arabidopsis plants indicating that Arabidopsis has evolved at least two independent R proteins to recognize the HopZ T3SE family. Also, in Arabidopsis zar1 plants HopZ1a promotes P. syringae growth indicative of an ancestral virulence function for this T3SE prior to the evolution of recognition by the host resistance protein ZAR1. Our results demonstrate that the Arabidopsis resistance protein ZAR1 confers allele-specific recognition and virulence attenuation of the Pseudomonas syringae T3SE protein HopZ1a.

  1. A draft genome sequence and functional screen reveals the repertoire of type III secreted proteins of Pseudomonas syringae pathovar tabaci 11528

    Directory of Open Access Journals (Sweden)

    Dangl Jeffery L

    2009-08-01

    Full Text Available Abstract Background Pseudomonas syringae is a widespread bacterial pathogen that causes disease on a broad range of economically important plant species. Pathogenicity of P. syringae strains is dependent on the type III secretion system, which secretes a suite of up to about thirty virulence 'effector' proteins into the host cytoplasm where they subvert the eukaryotic cell physiology and disrupt host defences. P. syringae pathovar tabaci naturally causes disease on wild tobacco, the model member of the Solanaceae, a family that includes many crop species as well as on soybean. Results We used the 'next-generation' Illumina sequencing platform and the Velvet short-read assembly program to generate a 145X deep 6,077,921 nucleotide draft genome sequence for P. syringae pathovar tabaci strain 11528. From our draft assembly, we predicted 5,300 potential genes encoding proteins of at least 100 amino acids long, of which 303 (5.72% had no significant sequence similarity to those encoded by the three previously fully sequenced P. syringae genomes. Of the core set of Hrp Outer Proteins that are conserved in three previously fully sequenced P. syringae strains, most were also conserved in strain 11528, including AvrE1, HopAH2, HopAJ2, HopAK1, HopAN1, HopI, HopJ1, HopX1, HrpK1 and HrpW1. However, the hrpZ1 gene is partially deleted and hopAF1 is completely absent in 11528. The draft genome of strain 11528 also encodes close homologues of HopO1, HopT1, HopAH1, HopR1, HopV1, HopAG1, HopAS1, HopAE1, HopAR1, HopF1, and HopW1 and a degenerate HopM1'. Using a functional screen, we confirmed that hopO1, hopT1, hopAH1, hopM1', hopAE1, hopAR1, and hopAI1' are part of the virulence-associated HrpL regulon, though the hopAI1' and hopM1' sequences were degenerate with premature stop codons. We also discovered two additional HrpL-regulated effector candidates and an HrpL-regulated distant homologue of avrPto1. Conclusion The draft genome sequence facilitates the

  2. An insight into the photodynamic approach versus copper formulations in the control of Pseudomonas syringae pv. actinidiae in kiwi plants.

    Science.gov (United States)

    Jesus, Vânia; Martins, Diana; Branco, Tatiana; Valério, Nádia; Neves, Maria G P M S; Faustino, Maria A F; Reis, Luís; Barreal, Esther; Gallego, Pedro P; Almeida, Adelaide

    2017-12-15

    In the last decade, the worldwide production of kiwi fruit has been highly affected by Pseudomonas syringae pv. actinidiae (Psa), a phytopathogenic bacterium; this has led to severe economic losses that are seriously affecting the kiwi fruit trade. The available treatments for this disease are still scarce, with the most common involving frequently spraying the orchards with copper derivatives, in particular cuprous oxide (Cu2O). However, these copper formulations should be avoided due to their high toxicity; therefore, it is essential to search for new approaches for controlling Psa. Antimicrobial photodynamic therapy (aPDT) may be an alternative approach to inactivate Psa. aPDT consists in the use of a photosensitizer molecule (PS) that absorbs light and by transference of the excess of energy or electrons to molecular oxygen forms highly reactive oxygen species (ROS) that can affect different molecular targets, thus being very unlikely to lead to the development of microbe resistance. The aim of the present study was to evaluate the effectiveness of aPDT to photoinactivate Psa, using the porphyrin Tetra-Py+-Me and different light intensities. The degree of inactivation of Psa was assessed using the PS at 5.0 μM under low irradiance (4.0 mW cm-2). Afterward, ex vivo experiments, using artificially contaminated kiwi leaves, were conducted with a PS at 50 μM under 150 mW cm-2 and sunlight irradiation. A reduction of 6 log in the in vitro assays after 90 min of irradiation was observed. In the ex vivo tests, the decrease was lower, approximately 1.8 log reduction at an irradiance of 150 mW cm-2, 1.2 log at 4.0 mW cm-2, and 1.5 log under solar radiation. However, after three successive cycles of treatment under 150 mW cm-2, a 4 log inactivation was achieved. No negative effects were observed on leaves after treatment. Assays using Cu2O were also performed at the recommended concentration by law (50 g h L-1) and at concentrations 10 times lower, in which at

  3. A genetic screen reveals Arabidopsis stomatal and/or apoplastic defenses against Pseudomonas syringae pv. tomato DC3000.

    Directory of Open Access Journals (Sweden)

    Weiqing Zeng

    2011-10-01

    Full Text Available Bacterial infection of plants often begins with colonization of the plant surface, followed by entry into the plant through wounds and natural openings (such as stomata, multiplication in the intercellular space (apoplast of the infected tissues, and dissemination of bacteria to other plants. Historically, most studies assess bacterial infection based on final outcomes of disease and/or pathogen growth using whole infected tissues; few studies have genetically distinguished the contribution of different host cell types in response to an infection. The phytotoxin coronatine (COR is produced by several pathovars of Pseudomonas syringae. COR-deficient mutants of P. s. tomato (Pst DC3000 are severely compromised in virulence, especially when inoculated onto the plant surface. We report here a genetic screen to identify Arabidopsis mutants that could rescue the virulence of COR-deficient mutant bacteria. Among the susceptible to coronatine-deficient Pst DC3000 (scord mutants were two that were defective in stomatal closure response, two that were defective in apoplast defense, and four that were defective in both stomatal and apoplast defense. Isolation of these three classes of mutants suggests that stomatal and apoplastic defenses are integrated in plants, but are genetically separable, and that COR is important for Pst DC3000 to overcome both stomatal guard cell- and apoplastic mesophyll cell-based defenses. Of the six mutants defective in bacterium-triggered stomatal closure, three are defective in salicylic acid (SA-induced stomatal closure, but exhibit normal stomatal closure in response to abscisic acid (ABA, and scord7 is compromised in both SA- and ABA-induced stomatal closure. We have cloned SCORD3, which is required for salicylic acid (SA biosynthesis, and SCORD5, which encodes an ATP-binding cassette (ABC protein, AtGCN20/AtABCF3, predicted to be involved in stress-associated protein translation control. Identification of SCORD5 begins to

  4. In-vitro antibacterial activities of the essential oils of aromatic plants against Erwinia herbicola (Lohnis and pseudomonas putida (Kris Hamilton

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    Pandey Abhay K.

    2012-01-01

    Full Text Available This study was designed to examine in vitro antibacterial activities of essential oils extracted from 53 aromatic plants of Gorakhpur Division (UP, INDIA for the control of two phytopathogenic bacteria namely Erwinia herbicola and Pseudomonas putida causing several post-harvest diseases in fruits and vegetables. Out of 53 oils screened, 8 oils such as Chenopodium ambrosioides, Citrus aurantium, Clausena pentaphylla, Hyptis suaveolens, Lippia alba, Mentha arvensis, Ocimum sanctum and Vitex negundo completely inhibited the growth of test bacteria. Furthermore MIC & MBC values of C. ambrosioides oil were least for Erw. herbicola (0.25 & 2.0 μl/ml and Ps. putida (0.12 & 1.0 μl/ml respectively than other 7 oils as well as Agromycin and Streptomycin drugs used in current study. GC and GC-MS analysis of Chenopodium oil revealed presence of 125 major and minor compounds, out of them, 14 compounds were recognized. The findings concluded that Chenopodium oil may be regarded as safe antibacterial agent for the management of post-harvest diseases of fruits and vegetables.

  5. Influence of infection of soybean seeds with Peronospora manshurica and Pseudomonas syringae pv. glycinea on protein, oil and fatty acids content

    Directory of Open Access Journals (Sweden)

    J. Marcinkowska

    2013-12-01

    Full Text Available The effect of soybean seed infection by Peronospora manshurica and Pseudomonas syringae pv. glycinea on the chemical content of some soybean lines and varieties susceptible to both pathogens was estimated. The amount of protein and oil was determined for soybean seed samples collected from two different localities in 1980. In P. manshurica oospore-encrusted seeds protein content was higher and oil content lower than in healthy ones. It could be seen especially in samples of the 'Acme' variety cultivated in both localities. Seed infection by P. syringae pv. glycinea occasionally influenced the protein, oil and fatty acid content as compared with the control. This was noted only in single cases. Analysis of fatty acid composition demonstrated a higher free fatty acid content in soybean seed infected by P. manshurica. These results showed undoubtedly the influence of pathogens, specially seed-borne fungi on the chemical soybean seed composition. This analysis can be an introduction for more detailed investigations on the effect of these or other pathogens on soybean seed yield quality.

  6. Arabidopsis GH3-LIKE DEFENSE GENE 1 is required for accumulation of salicylic acid, activation of defense responses and resistance to Pseudomonas syringae.

    Science.gov (United States)

    Jagadeeswaran, Guru; Raina, Surabhi; Acharya, Biswa R; Maqbool, Shahina B; Mosher, Stephen L; Appel, Heidi M; Schultz, Jack C; Klessig, Daniel F; Raina, Ramesh

    2007-07-01

    In Arabidopsis, the GH3-like gene family consists of 19 members, several of which have been shown to adenylate the plant hormones jasmonic acid, indole acetic acid and salicylic acid (SA). In some cases, this adenylation has been shown to catalyze hormone conjugation to amino acids. Here we report molecular characterization of the GH3-LIKE DEFENSE GENE 1 (GDG1), a member of the GH3-like gene family, and show that GDG1 is an important component of SA-mediated defense against the bacterial pathogen Pseudomonas syringae. Expression of GDG1 is induced earlier and to a higher level in response to avirulent pathogens compared to virulent pathogens. gdg1 null mutants are compromised in several pathogen defense responses, including activation of defense genes and resistance against virulent and avirulent bacterial pathogens. Accumulation of free and glucoside-conjugated SA (SAG) in response to pathogen infection is compromised in gdg1 mutants. All defense-related phenotypes of gdg1 can be rescued by external application of SA, suggesting that gdg1 mutants are defective in the SA-mediated defense pathway(s) and that GDG1 functions upstream of SA. Our results suggest that GDG1 contributes to both basal and resistance gene-mediated inducible defenses against P. syringae (and possibly other pathogens) by playing a critical role in regulating the levels of pathogen-inducible SA. GDG1 is allelic to the PBS3 (avrPphB susceptible) gene.

  7. Molecular basis of a microbe-mediated enhancement of symbiotic N/sub 2/-fixation. [Rhizobium meliloti; Pseudomonas syringae pv. tabaci

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, P.J.; Knight, T.J.

    1987-04-01

    Improvement of biological nitrogen fixation represents a potential source of both increased food production and decreased dependence on costly chemical fertilizer. They report the results of an investigation of the molecular basis of a unique, microbial-mediated mechanism for increased growth and nitrogen fixation rates in alfalfa. Inoculation of alfalfa plants with both Rhizobium meliloti and Pseudomonas syringae pv tabaci provides increased growth and N/sub 2/-fixation rates of alfalfa. Tabaci produces tabtoxinine-..beta..-lactam (T..beta..L), an exocellular product and glutamine synthetase (GS) inhibitor. The association of this pathogen with nodulating alfalfa plants appears to alter the normal regulation of nitrogen fixation such that nitrogenase activity is stimulated and GS activity is inhibited. Studies of the soluble amino acids in these nodules and the activities of the ammonia assimilatory enzymes indicate alternative pathways of ammonia assimilation are being employed.

  8. Thienopyrimidine-type compounds protect Arabidopsis plants against the hemibiotrophic fungal pathogen Colletotrichum higginsianum and bacterial pathogen Pseudomonas syringae pv. maculicola.

    Science.gov (United States)

    Narusaka, Mari; Narusaka, Yoshihiro

    2017-03-04

    Plant activators activate systemic acquired resistance-like defense responses or induced systemic resistance, and thus protect plants from pathogens. We screened a chemical library composed of structurally diverse small molecules. We isolated six plant immune-inducing thienopyrimidine-type compounds and their analogous compounds. It was observed that the core structure of thienopyrimidine plays a role in induced resistance in plants. Furthermore, we highlight the protective effect of thienopyrimidine-type compounds against both hemibiotrophic fungal pathogen, Colletotrichum higginsianum, and bacterial pathogen, Pseudomonas syringae pv. maculicola, in Arabidopsis thaliana. We suggest that thienopyrimidine-type compounds could be potential lead compounds as novel plant activators, and can be useful and effective agrochemicals against various plant diseases.

  9. Antibacterial Activity of Cinnamaldehyde and Estragole Extracted from Plant Essential Oils against Pseudomonas syringae pv. actinidiae Causing Bacterial Canker Disease in Kiwifruit

    Science.gov (United States)

    Song, Yu-Rim; Choi, Min-Seon; Choi, Geun-Won; Park, Il-Kwon; Oh, Chang-Sik

    2016-01-01

    Pseudomonas syringae pv. actinidiae (Psa) causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs) originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant antibacterial activity by only the liquid culture assay, while cinnamaldehyde exhibited antibacterial activity by both assays. The minimum inhibitory concentrations (MICs) of estragole and cinnamaldehyde by the liquid culture assay were 1,250 and 2,500 ppm, respectively. The MIC of cinnamaldehyde by the vapor diffusion assay was 5,000 ppm. Based on the formation of clear zones or the decrease of optical density caused by these compounds, they might kill the bacterial cells and this feature might be useful for managing the bacterial canker disease in kiwifruit. PMID:27493612

  10. Antibacterial Activity of Cinnamaldehyde and Estragole Extracted from Plant Essential Oils against Pseudomonas syringae pv. actinidiae Causing Bacterial Canker Disease in Kiwifruit

    Directory of Open Access Journals (Sweden)

    Yu-Rim Song

    2016-08-01

    Full Text Available Pseudomonas syringae pv. actinidiae (Psa causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant antibacterial activity by only the liquid culture assay, while cinnamaldehyde exhibited antibacterial activity by both assays. The minimum inhibitory concentrations (MICs of estragole and cinnamaldehyde by the liquid culture assay were 1,250 and 2,500 ppm, respectively. The MIC of cinnamaldehyde by the vapor diffusion assay was 5,000 ppm. Based on the formation of clear zones or the decrease of optical density caused by these compounds, they might kill the bacterial cells and this feature might be useful for managing the bacterial canker disease in kiwifruit.

  11. Development of SCAR markers for rapid and specific detection of Pseudomonas syringae pv. morsprunorum races 1 and 2, using conventional and real-time PCR.

    Science.gov (United States)

    Kałużna, Monika; Albuquerque, Pedro; Tavares, Fernando; Sobiczewski, Piotr; Puławska, Joanna

    2016-04-01

    Specific primers were developed to detect the causal agent of stone fruit bacterial canker using conventional and real-time polymerase chain reaction (PCR) methods. PCR melting profile (PCR MP) used for analysis of diversity of Pseudomonas syringae strains, allowed to pinpoint the amplified fragments specific for P. syringae pv. morsprunorum race 1 (Psm1) and race 2 (Psm2), which were sequenced. Using obtained data, specific sequence characterised amplified region (SCAR) primers were designed. Conventional and real-time PCRs, using genomic DNA isolated from different bacterial strains belonging to the Pseudomonas genus, confirmed the specificity of selected primers. Additionally, the specificity of the selected DNA regions for Psm1 and Psm2 was confirmed by dot blot hybridisation. Conventional and real-time PCR assays enabled accurate detection of Psm1 and Psm2 in pure cultures and in plant material. For conventional PCR, the detection limits were the order of magnitude ~10(0) cfu/reaction for Psm1 and 10(1) cfu/reaction for Psm2 in pure cultures, while in plant material were 10(0)-10(1) cfu/reaction using primers for Psm1 and 3 × 10(2) cfu/reaction using primers for Psm2. Real-time PCR assays with SYBR Green I showed a higher limit of detection (LOD) - 10(0) cfu/reaction in both pure culture and in plant material for each primer pairs designed, which corresponds to 30-100 and 10-50 fg of DNA of Psm1 and Psm2, respectively. To our knowledge, this is the first PCR-based method for detection of the causal agents of bacterial canker of stone fruit trees.

  12. Molecular characterization of Pseudomonas syringae pv. tomato isolates from Tanzania

    DEFF Research Database (Denmark)

    Shenge, K.C.; Stephan, D.; Mabagala, R. B.

    2008-01-01

    pathogenicity assays on tomato, carbon source utilization by the Biolog Microplate system, polymerase chain reaction and restriction fragment length polymorphism (RFLP) analysis. All the P. syringae pv. tomato isolates produced bacterial speck symptoms on susceptible tomato (cv. ‘Tanya') seedlings. Metabolic...... fingerprinting profiles revealed diversity among the isolates, forming several clusters. Some geographic differentiation was observed in principal component analysis, with isolates from Arusha region being more diverse than those from Iringa and Morogoro regions. The Biolog system was efficient....... syringae pv. tomato isolates in Tanzania that differ significantly from those used to create the Biolog database. RFLP analysis showed that the isolates were highly conserved in their hrpZ gene. The low level of genomic diversity within the pathogen in Tanzania shows that there is a possibility to use...

  13. Transgenic expression of antimicrobial peptide D2A21 confers resistance to diseases incited by Pseudomonas syringae pv. tabaci and Xanthomonas citri, but not Candidatus Liberibacter asiaticus.

    Directory of Open Access Journals (Sweden)

    Guixia Hao

    Full Text Available Citrus Huanglongbing (HLB associated with 'Candidatus Liberibacter asiaticus' (Las and citrus canker disease incited by Xanthomonas citri are the most devastating citrus diseases worldwide. To control citrus HLB and canker disease, we previously screened over forty antimicrobial peptides (AMPs in vitro for their potential application in genetic engineering. D2A21 was one of the most active AMPs against X. citri, Agrobacterium tumefaciens and Sinorhizobium meliloti with low hemolysis activity. Therefore, we conducted this work to assess transgenic expression of D2A21 peptide to achieve citrus resistant to canker and HLB. We generated a construct expressing D2A21 and initially transformed tobacco as a model plant. Transgenic tobacco expressing D2A21 was obtained by Agrobacterium-mediated transformation. Successful transformation and D2A21 expression was confirmed by molecular analysis. We evaluated disease development incited by Pseudomonas syringae pv. tabaci in transgenic tobacco. Transgenic tobacco plants expressing D2A21 showed remarkable disease resistance compared to control plants. Therefore, we performed citrus transformations with the same construct and obtained transgenic Carrizo citrange. Gene integration and gene expression in transgenic plants were determined by PCR and RT-qPCR. Transgenic Carrizo expressing D2A21 showed significant canker resistance while the control plants showed clear canker symptoms following both leaf infiltration and spray inoculation with X. citri 3213. Transgenic Carrizo plants were challenged for HLB evaluation by grafting with Las infected rough lemon buds. Las titer was determined by qPCR in the leaves and roots of transgenic and control plants. However, our results showed that transgenic plants expressing D2A21 did not significantly reduce Las titer compared to control plants. We demonstrated that transgenic expression of D2A21 conferred resistance to diseases incited by P. syringae pv. tabaci and X. citri

  14. Cytokinins Mediate Resistance against Pseudomonas syringae in Tobacco through Increased Antimicrobial Phytoalexin Synthesis Independent of Salicylic Acid Signaling1[W][OA

    Science.gov (United States)

    Großkinsky, Dominik K.; Naseem, Muhammad; Abdelmohsen, Usama Ramadan; Plickert, Nicole; Engelke, Thomas; Griebel, Thomas; Zeier, Jürgen; Novák, Ondřej; Strnad, Miroslav; Pfeifhofer, Hartwig; van der Graaff, Eric; Simon, Uwe; Roitsch, Thomas

    2011-01-01

    Cytokinins are phytohormones that are involved in various regulatory processes throughout plant development, but they are also produced by pathogens and known to modulate plant immunity. A novel transgenic approach enabling autoregulated cytokinin synthesis in response to pathogen infection showed that cytokinins mediate enhanced resistance against the virulent hemibiotrophic pathogen Pseudomonas syringae pv tabaci. This was confirmed by two additional independent transgenic approaches to increase endogenous cytokinin production and by exogenous supply of adenine- and phenylurea-derived cytokinins. The cytokinin-mediated resistance strongly correlated with an increased level of bactericidal activities and up-regulated synthesis of the two major antimicrobial phytoalexins in tobacco (Nicotiana tabacum), scopoletin and capsidiol. The key role of these phytoalexins in the underlying mechanism was functionally proven by the finding that scopoletin and capsidiol substitute in planta for the cytokinin signal: phytoalexin pretreatment increased resistance against P. syringae. In contrast to a cytokinin defense mechanism in Arabidopsis (Arabidopsis thaliana) based on salicylic acid-dependent transcriptional control, the cytokinin-mediated resistance in tobacco is essentially independent from salicylic acid and differs in pathogen specificity. It is also independent of jasmonate levels, reactive oxygen species, and high sugar resistance. The novel function of cytokinins in the primary defense response of solanaceous plant species is rather mediated through a high phytoalexin-pathogen ratio in the early phase of infection, which efficiently restricts pathogen growth. The implications of this mechanism for the coevolution of host plants and cytokinin-producing pathogens and the practical application in agriculture are discussed. PMID:21813654

  15. Functional Characterization of Key Residues in Regulatory Proteins HrpG and HrpV of Pseudomonas syringae pv. tomato DC3000.

    Science.gov (United States)

    Jovanovic, Milija; Waite, Christopher; James, Ellen; Synn, Nicholas; Simpson, Timothy; Kotta-Loizou, Ioly; Buck, Martin

    2017-08-01

    The plant pathogen Pseudomonas syringae pv. tomato DC3000 uses a type III secretion system (T3SS) to transfer effector proteins into the host. The expression of T3SS proteins is controlled by the HrpL σ factor. Transcription of hrpL is σ(54)-dependent and bacterial enhancer-binding proteins HrpR and HrpS coactivate the hrpL promoter. The HrpV protein imposes negative control upon HrpR and HrpS through direct interaction with HrpS. HrpG interacts with HrpV and relieves such negative control. The sequence alignments across Hrp group I-type plant pathogens revealed conserved HrpV and HrpG amino acids. To establish structure-function relationships in HrpV and HrpG, either truncated or alanine substitution mutants were constructed. Key functional residues in HrpV and HrpG are found within their C-terminal regions. In HrpG, L101 and L105 are indispensable for the ability of HrpG to directly interact with HrpV and suppress HrpV-dependent negative regulation of HrpR and HrpS. In HrpV, L108 and G110 are major determinants for interactions with HrpS and HrpG. We propose that mutually exclusive binding of HrpS and HrpG to the same binding site of HrpV governs a transition from negative control to activation of the HrpRS complex leading to HrpL expression and pathogenicity of P. syringae.

  16. The presence of INA proteins on the surface of single cells of Pseudomonas syringae R10.79 isolated from rain

    Science.gov (United States)

    Šantl-Temkiv, Tina; Ling, Meilee; Holm, Stine; Finster, Kai; Boesen, Thomas

    2016-04-01

    One of the important open questions in atmospheric ice nucleation is the impact of bioaerosols on the ice content of mix phase clouds (DeMott and Prenni 2010). Biogenic ice nuclei have a unique capacity of facilitating ice formation at temperatures between -1 and -10 °C. The model biogenic ice nuclei are produced by a few species of plant-surface bacteria, such as Pseudomonas syringae, that are commonly transported through the atmosphere. These bacterial species have highly specialized proteins, the so-called ice nucleation active (INA) proteins, which are exposed at the outer membrane surface of the cell where they promote ice particle formation. The mechanisms behind the onset of INA protein synthesis in single bacterial cells are not well understood. We performed a laboratory study in order to (i) investigate the presence of INA proteins on single bacterial cells and (ii) understand the conditions that induce INA protein production. We previously isolated an INA-positive strain of Pseudomonas syringae from rain samples collected in Denmark. Bacterial cells initiated ice nucleation activity at temperatures ≤-2°C and the cell fragments at temperatures ≤-8°C (Šantl-Temkiv et al 2015). We determined the amino-acid sequence of the INA protein and used the sequence to produce custom-made antibodies (GenScript, Germany). These antibodies were used to specifically stain and visualize the INA protein on the surfaces of single cells, which can then be quantified by a technique called flow cytometry. The synthesis of INA proteins by individual cells was followed during a batch growth experiment. An unusually high proportion of cells that were adapting to the new conditions prior to growth produced INA proteins (~4.4% of all cells). A smaller fraction of actively growing cells was carrying INA proteins (~1.2 % of all cells). The cells that stopped growing due to unfavorable conditions had the lowest fraction of cells carrying INA proteins (~0.5 % of all cells). To

  17. The Arabidopsis thaliana cysteine-rich receptor-like kinase CRK20 modulates host responses to Pseudomonas syringae pv. tomato DC3000 infection

    KAUST Repository

    Ederli, Luisa

    2011-10-01

    In plants, the cysteine-rich repeat kinases (CRKs) are a sub-family of receptor-like protein kinases that contain the DUF26 motif in their extracellular domains. It has been shown that in Arabidopsis thaliana, CRK20 is transcriptionally induced by pathogens, salicylic acid and ozone (O3). However, its role in responses to biotic and abiotic stress remains to be elucidated. To determine the function of CRK20 in such responses, two CRK20 loss-of-function mutants, crk20-1 and crk20-2, were isolated from public collections of Arabidopsis T-DNA tagged lines and examined for responses to O3 and Pseudomonas syringae pv. tomato (Pst) DC3000. crk20-1 and crk20-2 showed similar O3 sensitivities and no differences in the expression of defense genes when compared with the wild-type. However, pathogen growth was significantly reduced, while there were no differences in the induction of salicylic acid related defense genes or salicylic acid accumulation. Furthermore, correlation analysis of CRK20 gene expression suggests that it has a role in the control of H2O and/or nutrient transport. We therefore propose that CRK20 promotes conditions that are favorable for Pst DC3000 growth in Arabidopsis, possibly through the regulation of apoplastic homeostasis, and consequently, of the environment of this biotrophic pathogen. © 2011 Elsevier GmbH.

  18. Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Geun Cheol eSong

    2015-10-01

    Full Text Available 3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 M and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR gene expression levels associated with defense signaling through SA, JA, and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved salicylic acid (SA and jasmonic acid (JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

  19. Plant innate immunity induced by flagellin suppresses the hypersensitive response in non-host plants elicited by Pseudomonas syringae pv. averrhoi.

    Science.gov (United States)

    Wei, Chia-Fong; Hsu, Shih-Tien; Deng, Wen-Ling; Wen, Yu-Der; Huang, Hsiou-Chen

    2012-01-01

    A new pathogen, Pseudomonas syringae pv. averrhoi (Pav), which causes bacterial spot disease on carambola was identified in Taiwan in 1997. Many strains of this pathovar have been isolated from different locations and several varieties of hosts. Some of these strains, such as HL1, are nonmotile and elicit a strong hypersensitive response (HR) in nonhost tobacco leaves, while other strains, such as PA5, are motile and elicit a weak HR. Based on the image from a transmission electron microscope, the results showed that HL1 is flagellum-deficient and PA5 has normal flagella. Here we cloned and analyzed the fliC gene and glycosylation island from Pav HL1 and PA5. The amino acid sequences of FliC from HL1 and PA5 are identical to P. s. pvs. tabaci (Pta), glycinea and phaseolicola and share very high similarity with other pathovars of P. syringae. In contrast to the flagellin mutant PtaΔfliC, PA5ΔfliC grows as well as wild type in the host plant, but it elicits stronger HR than wild type does in non-host plants. Furthermore, the purified Pav flagellin, but not the divergent flagellin from Agrobacterium tumefaciens, is able to impair the HR induced by PA5ΔfliC. PA5Δfgt1 possessing nonglycosylated flagella behaved as its wild type in both bacterial growth in host and HR elicitation. Flagellin was infiltrated into tobacco leaves either simultaneously with flagellum-deficient HL1 or prior to the inoculation of wild type HL1, and both treatments impaired the HR induced by HL1. Moreover, the HR elicited by PA5 and PA5ΔfliC was enhanced by the addition of cycloheximide, suggesting that the flagellin is one of the PAMPs (pathogen-associated molecular patterns) contributed to induce the PAMP-triggered immunity (PTI). Taken together, the results shown in this study reveal that flagellin in Pav is capable of suppressing HR via PTI induction during an incompatible interaction.

  20. Plant innate immunity induced by flagellin suppresses the hypersensitive response in non-host plants elicited by Pseudomonas syringae pv. averrhoi.

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    Chia-Fong Wei

    Full Text Available A new pathogen, Pseudomonas syringae pv. averrhoi (Pav, which causes bacterial spot disease on carambola was identified in Taiwan in 1997. Many strains of this pathovar have been isolated from different locations and several varieties of hosts. Some of these strains, such as HL1, are nonmotile and elicit a strong hypersensitive response (HR in nonhost tobacco leaves, while other strains, such as PA5, are motile and elicit a weak HR. Based on the image from a transmission electron microscope, the results showed that HL1 is flagellum-deficient and PA5 has normal flagella. Here we cloned and analyzed the fliC gene and glycosylation island from Pav HL1 and PA5. The amino acid sequences of FliC from HL1 and PA5 are identical to P. s. pvs. tabaci (Pta, glycinea and phaseolicola and share very high similarity with other pathovars of P. syringae. In contrast to the flagellin mutant PtaΔfliC, PA5ΔfliC grows as well as wild type in the host plant, but it elicits stronger HR than wild type does in non-host plants. Furthermore, the purified Pav flagellin, but not the divergent flagellin from Agrobacterium tumefaciens, is able to impair the HR induced by PA5ΔfliC. PA5Δfgt1 possessing nonglycosylated flagella behaved as its wild type in both bacterial growth in host and HR elicitation. Flagellin was infiltrated into tobacco leaves either simultaneously with flagellum-deficient HL1 or prior to the inoculation of wild type HL1, and both treatments impaired the HR induced by HL1. Moreover, the HR elicited by PA5 and PA5ΔfliC was enhanced by the addition of cycloheximide, suggesting that the flagellin is one of the PAMPs (pathogen-associated molecular patterns contributed to induce the PAMP-triggered immunity (PTI. Taken together, the results shown in this study reveal that flagellin in Pav is capable of suppressing HR via PTI induction during an incompatible interaction.

  1. The Arabidopsis thaliana lectin receptor kinase LecRK-I.9 is required for full resistance to Pseudomonas syringae and affects jasmonate signalling.

    Science.gov (United States)

    Balagué, Claudine; Gouget, Anne; Bouchez, Olivier; Souriac, Camille; Haget, Nathalie; Boutet-Mercey, Stéphanie; Govers, Francine; Roby, Dominique; Canut, Hervé

    2017-09-01

    On microbial attack, plants can detect invaders and activate plant innate immunity. For the detection of pathogen molecules or cell wall damage, plants employ receptors that trigger the activation of defence responses. Cell surface proteins that belong to large families of lectin receptor kinases are candidates to function as immune receptors. Here, the function of LecRK-I.9 (At5g60300), a legume-type lectin receptor kinase involved in cell wall-plasma membrane contacts and in extracellular ATP (eATP) perception, was studied through biochemical, gene expression and reverse genetics approaches. In Arabidopsis thaliana, LecRK-I.9 expression is rapidly, highly and locally induced on inoculation with avirulent strains of Pseudomonas syringae pv. tomato (Pst). Two allelic lecrk-I.9 knock-out mutants showed decreased resistance to Pst. Conversely, over-expression of LecRK-I.9 led to increased resistance to Pst. The analysis of defence gene expression suggests an alteration of both the salicylic acid (SA) and jasmonic acid (JA) signalling pathways. In particular, LecRK-I.9 expression during plant-pathogen interaction was dependent on COI1 (CORONATINE INSENSITIVE 1) and JAR1 (JASMONATE RESISTANT 1) components, and JA-responsive transcription factors (TFs) showed altered levels of expression in plants over-expressing LecRK-I.9. A similar misregulation of these TFs was obtained by JA treatment. This study identified LecRK-I.9 as necessary for full resistance to Pst and demonstrated its involvement in the control of defence against pathogens through a regulation of JA signalling components. The role of LecRK-I.9 is discussed with regard to the potential molecular mechanisms linking JA signalling to cell wall damage and/or eATP perception. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  2. The Arabidopsis lectin receptor kinase LecRK-V.5 represses stomatal immunity induced by Pseudomonas syringae pv. tomato DC3000.

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    Marie Desclos-Theveniau

    2012-02-01

    Full Text Available Stomata play an important role in plant innate immunity by limiting pathogen entry into leaves but molecular mechanisms regulating stomatal closure upon pathogen perception are not well understood. Here we show that the Arabidopsis thaliana L-type lectin receptor kinase-V.5 (LecRK-V.5 negatively regulates stomatal immunity. Loss of LecRK-V.5 function increased resistance to surface inoculation with virulent bacteria Pseudomonas syringae pv tomato DC3000. Levels of resistance were not affected after infiltration-inoculation, suggesting that LecRK-V.5 functions at an early defense stage. By contrast, lines overexpressing LecRK-V.5 were more susceptible to Pst DC3000. Enhanced resistance in lecrk-V.5 mutants was correlated with constitutive stomatal closure, while increased susceptibility phenotypes in overexpression lines were associated with early stomatal reopening. Lines overexpressing LecRK-V.5 also demonstrated a defective stomatal closure after pathogen-associated molecular pattern (PAMP treatments. LecRK-V.5 is rapidly expressed in stomatal guard cells after bacterial inoculation or treatment with the bacterial PAMP flagellin. In addition, lecrk-V.5 mutants guard cells exhibited constitutive accumulation of reactive oxygen species (ROS and inhibition of ROS production opened stomata of lecrk-V.5. LecRK-V.5 is also shown to interfere with abscisic acid-mediated stomatal closure signaling upstream of ROS production. These results provide genetic evidences that LecRK-V.5 negatively regulates stomatal immunity upstream of ROS biosynthesis. Our data reveal that plants have evolved mechanisms to reverse bacteria-mediated stomatal closure to prevent long-term effect on CO(2 uptake and photosynthesis.

  3. The Pseudomonas syringae type III effector AvrRpm1 induces significant defenses by activating the Arabidopsis nucleotide-binding leucine-rich repeat protein RPS2.

    Science.gov (United States)

    Kim, Min Gab; Geng, Xueqing; Lee, Sang Yeol; Mackey, David

    2009-02-01

    Plant disease resistance (R) proteins recognize potential pathogens expressing corresponding avirulence (Avr) proteins through 'gene-for-gene' interactions. RPM1 is an Arabidopsis R-protein that triggers a robust defense response upon recognizing the Pseudomonas syringae effector AvrRpm1. Avr-proteins of phytopathogenic bacteria include type III effector proteins that are often capable of enhancing virulence when not recognized by an R-protein. In rpm1 plants, AvrRpm1 suppresses basal defenses induced by microbe-associated molecular patterns. Here, we show that expression of AvrRpm1 in rpm1 plants induced PR-1, a classical defense marker, and symptoms including chlorosis and necrosis. PR-1 expression and symptoms were reduced in plants with mutations in defense signaling genes (pad4, sid2, npr1, rar1, and ndr1) and were strongly reduced in rpm1 rps2 plants, indicating that AvrRpm1 elicits defense signaling through the Arabidopsis R-protein, RPS2. Bacteria expressing AvrRpm1 grew more on rpm1 rps2 than on rpm1 plants. Thus, independent of its classical 'gene-for-gene' activation of RPM1, AvrRpm1 also induces functionally relevant defenses that are dependent on RPS2. Finally, AvrRpm1 suppressed host defenses and promoted the growth of type III secretion mutant bacteria equally well in rps2 and RPS2 plants, indicating that virulence activity of over-expressed AvrRpm1 predominates over defenses induced by weak activation of RPS2.

  4. Tomato Sl3-MMP, a member of the Matrix metalloproteinase family, is required for disease resistance against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000.

    Science.gov (United States)

    Li, Dayong; Zhang, Huijuan; Song, Qiuming; Wang, Lu; Liu, Shixia; Hong, Yongbo; Huang, Lei; Song, Fengming

    2015-06-14

    Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases. MMPs have been characterized in detail in mammals and shown to play key roles in many physiological and pathological processes. Although MMPs in some plant species have been identified, the function of MMPs in biotic stress responses remains elusive. A total of five MMP genes were identified in tomato genome. qRT-PCR analysis revealed that expression of Sl-MMP genes was induced with distinct patterns by infection of Botrytis cinerea and Pseudomonas syringae pv. tomato (Pst) DC3000 and by treatment with defense-related hormones such as salicylic acid, jasmonic acid and ethylene precursor 1-amino cyclopropane-1-carboxylic acid. Virus-induced gene silencing (VIGS)-based knockdown of individual Sl-MMPs and disease assays indicated that silencing of Sl3-MMP resulted in reduced resistance to B. cinerea and Pst DC3000, whereas silencing of other four Sl-MMPs did not affect the disease resistance against these two pathogens. The Sl3-MMP-silenced tomato plants responded with increased accumulation of reactive oxygen species and alerted expression of defense genes after infection of B. cinerea. Transient expression of Sl3-MMP in leaves of Nicotiana benthamiana led to an enhanced resistance to B. cinerea and upregulated expression of defense-related genes. Biochemical assays revealed that the recombinant mature Sl3-MMP protein had proteolytic activities in vitro with distinct preferences for specificity of cleavage sites. The Sl3-MMP protein was targeted onto the plasma membrane of plant cells when transiently expressed in onion epidermal cells. VIGS-based knockdown of Sl3-MMP expression in tomato and gain-of-function transient expression of Sl3-MMP in N. benthamiana demonstrate that Sl3-MMP functions as a positive regulator of defense response against B. cinerea and Pst DC3000.

  5. Overexpression of Nictaba-Like Lectin Genes from Glycine max Confers Tolerance towards Pseudomonas syringae Infection, Aphid Infestation and Salt Stress in Transgenic Arabidopsis Plants

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    Sofie Van Holle

    2016-10-01

    Full Text Available Plants have evolved a sophisticated immune system that allows them to recognize invading pathogens by specialized receptors. Carbohydrate-binding proteins or lectins are part of this immune system and especially the lectins that reside in the nucleocytoplasmic compartment are known to be implicated in biotic and abiotic stress responses. The class of Nictaba-like lectins (NLL groups all proteins with homology to the tobacco (Nicotiana tabacum lectin, known as a stress-inducible lectin. Here we focus on two Nictaba homologs from soybean (Glycine max, referred to as GmNLL1 and GmNLL2. Confocal laser scanning microscopy of fusion constructs with the green fluorescent protein either transiently expressed in Nicotiana benthamiana leaves or stably transformed in tobacco BY-2 suspension cells revealed a nucleocytoplasmic localization for the GmNLLs under study. RT-qPCR analysis of the transcript levels for the Nictaba-like lectins in soybean demonstrated that the genes are expressed in several tissues throughout the development of the plant. Furthermore, it was shown that salt treatment, Phytophthora sojae infection and Aphis glycines infestation trigger the expression of particular NLL genes. Stress experiments with Arabidopsis lines overexpressing the NLLs from soybean yielded an enhanced tolerance of the plant towards bacterial infection (Pseudomonas syringae, insect infestation (Myzus persicae and salinity. Our data showed a better performance of the transgenic lines compared to wild type plants, indicating that the NLLs from soybean are implicated in the stress response. These data can help to further elucidate the physiological importance of the Nictaba-like lectins from soybean, which can ultimately lead to the design of crop plants with a better tolerance to changing environmental conditions.

  6. Natural variation for responsiveness to flg22, flgII-28, and csp22 and Pseudomonas syringae pv. tomato in heirloom tomatoes.

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    Selvakumar Veluchamy

    Full Text Available Tomato (Solanum lycopersicum L. is susceptible to many diseases including bacterial speck caused by Pseudomonas syringae pv. tomato. Bacterial speck disease is a serious problem worldwide in tomato production areas where moist conditions and cool temperatures occur. To enhance breeding of speck resistant fresh-market tomato cultivars we identified a race 0 field isolate, NC-C3, of P. s. pv. tomato in North Carolina and used it to screen a collection of heirloom tomato lines for speck resistance in the field. We observed statistically significant variation among the heirloom tomatoes for their response to P. s. pv. tomato NC-C3 with two lines showing resistance approaching a cultivar that expresses the Pto resistance gene, although none of the heirloom lines have Pto. Using an assay that measures microbe-associated molecular pattern (MAMP-induced production of reactive oxygen species (ROS, we investigated whether the heirloom lines showed differential responsiveness to three bacterial-derived peptide MAMPs: flg22 and flgII-28 (from flagellin and csp22 (from cold shock protein. Significant differences were observed for MAMP responsiveness among the lines, although these differences did not correlate strongly with resistance or susceptibility to bacterial speck disease. The identification of natural variation for MAMP responsiveness opens up the possibility of using a genetic approach to identify the underlying loci and to facilitate breeding of cultivars with enhanced disease resistance. Towards this goal, we discovered that responsiveness to csp22 segregates as a single locus in an F2 population of tomato.

  7. A Proposal for a Genome Similarity-Based Taxonomy for Plant-Pathogenic Bacteria that Is Sufficiently Precise to Reflect Phylogeny, Host Range, and Outbreak Affiliation Applied to Pseudomonas syringae sensu lato as a Proof of Concept.

    Science.gov (United States)

    Vinatzer, Boris A; Weisberg, Alexandra J; Monteil, Caroline L; Elmarakeby, Haitham A; Sheppard, Samuel K; Heath, Lenwood S

    2017-01-01

    Taxonomy of plant pathogenic bacteria is challenging because pathogens of different crops often belong to the same named species but current taxonomy does not provide names for bacteria below the subspecies level. The introduction of the host range-based pathovar system in the 1980s provided a temporary solution to this problem but has many limitations. The affordability of genome sequencing now provides the opportunity for developing a new genome-based taxonomic framework. We already proposed to name individual bacterial isolates based on pairwise genome similarity. Here, we expand on this idea and propose to use genome similarity-based codes, which we now call life identification numbers (LINs), to describe and name bacterial taxa. Using 93 genomes of Pseudomonas syringae sensu lato, LINs were compared with a P. syringae genome tree whereby the assigned LINs were found to be informative of a majority of phylogenetic relationships. LINs also reflected host range and outbreak association for strains of P. syringae pathovar actinidiae, a pathovar for which many genome sequences are available. We conclude that LINs could provide the basis for a new taxonomic framework to address the shortcomings of the current pathovar system and to complement the current taxonomic system of bacteria in general.

  8. Biological relevance of volatile organic compounds emitted during the pathogenic interactions between apple plants and Erwinia amylovora.

    Science.gov (United States)

    Cellini, Antonio; Buriani, Giampaolo; Rocchi, Lorenzo; Rondelli, Elena; Savioli, Stefano; Rodriguez Estrada, Maria T; Cristescu, Simona M; Costa, Guglielmo; Spinelli, Francesco

    2016-11-15

    Volatile organic compounds emitted during the infection of apple (Malus pumila var. domestica) plants by Erwinia amylovora or Pseudomonas syringae pv. syringae were studied by gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry, and used to treat uninfected plants. Infected plants showed a disease-specific emission of volatile organic compounds, including several bio-active compounds, such as hexenal isomers and 2,3-butanediol. Leaf growth promotion and a higher resistance to the pathogen, expressed as a lower bacterial growth and migration in plant tissues, were detected in plants exposed to volatile compounds from E. amylovora-infected plants. Transcriptional analysis revealed the activation of salicylic acid synthesis and signal transduction in healthy plants exposed to volatiles produced by E. amylovora-infected neighbour plants. In contrast, in the same plants, salicylic acid-dependent responses were repressed after infection, whereas oxylipin metabolism was activated. These results clarify some metabolic and ecological aspects of the pathogenic adaptation of E. amylovora to its host. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  9. The hrpZ gene of Pseudomonas syringae pv. phaseolicola enhances resistance to rhizomania disease in transgenic Nicotiana benthamiana and sugar beet.

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    Ourania I Pavli

    Full Text Available To explore possible sources of transgenic resistance to the rhizomania-causing Beet necrotic yellow vein virus (BNYVV, Nicotiana benthamiana plants were constructed to express the harpin of Pseudomonas syringae pv. phaseolicola (HrpZ(Psph. The HrpZ protein was expressed as an N-terminal fusion to the PR1 signal peptide (SP/HrpZ to direct harpin accumulation to the plant apoplast. Transgene integration was verified by mPCR in all primary transformants (T0, while immunoblot analysis confirmed that the protein HrpZ(Psph was produced and the signal peptide was properly processed. Neither T0 plants nor selfed progeny (T1 showed macroscopically visible necrosis or any other macroscopic phenotypes. However, plants expressing the SP/HrpZ(Psph showed increased vigor and grew faster in comparison with non-transgenic control plants. Transgenic resistance was assessed after challenge inoculation with BNYVV on T1 progeny by scoring of disease symptoms and by DAS-ELISA at 20 and 30 dpi. Transgenic and control lines showed significant differences in terms of the number of plants that became infected, the timing of infection and the disease symptoms displayed. Plants expressing the SP/HrpZ(Psph developed localized leaf necrosis in the infection area and had enhanced resistance upon challenge with BNYVV. In order to evaluate the SP/HrpZ-based resistance in the sugar beet host, A. rhizogenes-mediated root transformation was exploited as a transgene expression platform. Upon BNYVV inoculation, transgenic sugar beet hairy roots showed high level of BNYVV resistance. In contrast, the aerial non-transgenic parts of the same seedlings had virus titers that were comparable to those of the seedlings that were untransformed or transformed with wild type R1000 cells. These findings indicate that the transgenically expressed SP/HrpZ protein results in enhanced rhizomania resistance both in a model plant and sugar beet, the natural host of BNYVV. Possible molecular

  10. Bactérias endofíticas no controle e inibição in vitro de Pseudomonas syringae pv tomato, agente da pinta bacteriana do tomateiro Control with endophytic bacteria and in vitro inhibition of Pseudomonas syringae pv tomato, agent of bacterial speck of tomato

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    Juliana Resende Campos Silva

    2008-08-01

    Full Text Available Para avaliar o potencial de 53 isolados de bactérias endofíticas no controle da pinta bacteriana do tomateiro (Lycopersicum esculentum Mill., realizaram-se seleções massais em casa-de-vegetação e a seguir foi avaliado, in vitro, o antagonismo desses isolados sobre a bactéria desafiante Pseudomonas syringae pv. tomato (Pst. A inoculação das bactérias endofíticas foi feita por microbiolização das sementes de tomate cv. Santa Clara e da desafiante (Pst por pulverização. Aos 7, 14 e 21 dias após a inoculação da Pst, foram realizadas as avaliações da severidade da pinta bacteriana, bem como da altura das plantas. As espécies e os isolados bacterianos mais eficazes na redução da severidade da pinta bacteriana foram: Acinetobacter johnsonii (isolado 10, Bacillus pumilus (isolados 3, 12, 20, 39, 51, Paenibacillus macerans (isolados 37 e 47, PIM 11, Bacillus sphaericus (isolado 45, B. amyloliquefaciens (isolado 50, TOM 2, TOM 24 e Staphylococcus aureus (isolado 18. Mais de 50% dos isolados eficazes na redução da severidade foram da espécie Bacillus pumilus. Das espécies endofíticas mais eficazes na redução da severidade da pinta bacteriana, Bacillus pumilus e B. amyloliquefaciens inibiram também o crescimento da Pst in vitro.Vários dos isolados promoveram também o crescimento das plantas.To asses the potential of fifty three isolates of endophytic bacteria on the control of Pseudomonas syringae pv. tomato (Pst in tomato (Lycopersicum esculentum Mill., several screening were done in greenhouse followed by in vitro studies on antagonism of those isolates to Pst. The inoculation of endophytic bacteria was done by microbiolization of tomato cv Santa Clara seeds. The challenging bacterium (Pst inoculation was done by spraying. At 7, 14 and 21 days after Pst inoculation the assessment of bacterial speck severity was done, and height of plants was also measured. The most efficient endophytic species and isolates in reducing

  11. Fire blight disease reactome: RNA-seq transcriptional profile of apple host plant defense responses to Erwinia amylovora pathogen infection.

    Science.gov (United States)

    Kamber, Tim; Buchmann, Jan P; Pothier, Joël F; Smits, Theo H M; Wicker, Thomas; Duffy, Brion

    2016-02-17

    The molecular basis of resistance and susceptibility of host plants to fire blight, a major disease threat to pome fruit production globally, is largely unknown. RNA-sequencing data from challenged and mock-inoculated flowers were analyzed to assess the susceptible response of apple to the fire blight pathogen Erwinia amylovora. In presence of the pathogen 1,080 transcripts were differentially expressed at 48 h post inoculation. These included putative disease resistance, stress, pathogen related, general metabolic, and phytohormone related genes. Reads, mapped to regions on the apple genome where no genes were assigned, were used to identify potential novel genes and open reading frames. To identify transcripts specifically expressed in response to E. amylovora, RT-PCRs were conducted and compared to the expression patterns of the fire blight biocontrol agent Pantoea vagans strain C9-1, another apple pathogen Pseudomonas syringae pv. papulans, and mock inoculated apple flowers. This led to the identification of a peroxidase superfamily gene that was lower expressed in response to E. amylovora suggesting a potential role in the susceptibility response. Overall, this study provides the first transcriptional profile by RNA-seq of the host plant during fire blight disease and insights into the response of susceptible apple plants to E. amylovora.

  12. Pseudomnas syringae – a Pathogen of Fruit Trees in Serbia

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    Veljko Gavrilović

    2009-01-01

    Full Text Available Data about symptomatology, pathogenicity and bacteriological characteristics of Pseudomonas syringae, and PCR methods for fast and reliable detection of the pathogen are given in this paper. P. syringae has been experimentaly proved as a pathogen of pear, apple, apricot, plum cherry, and raspberry, and pathogen strains have also been isolated from necrotic peach buds. Two pathogen varieties, syringae and morsprunorum, were found in our research in Serbia, the former being dominant on fruit trees.The most reliable method for detection of this bacteria is PCR, using BOX and REP primers. This method has also revealed significant differences among the strains originating from fruit trees in Serbia. Thus, it was proved that the population of P. syringae in Serbia is heterogeneous, which is very important for future epidemiologocal studies. Control of this pathogen includes mechanical, cultural and chemical measures, but integrated approach is very important for sustainable control.

  13. 'Preventie belangrijkste troef tegen Erwinia'

    NARCIS (Netherlands)

    Doorn, van J.

    2012-01-01

    De bollenteelt en -handel ondervindt aanzienlijke schade van de bacterieziekte Erwinia. Onderzoek wijst uit dat preventie het belangrijkste wapen is. Mogelijk bieden ook stofjes die de afweer van planten verbeteren een oplossing.

  14. Screening for resistance against Pseudomonas syringae in rice-FOX Arabidopsis lines identified a putative receptor-like cytoplasmic kinase gene that confers resistance to major bacterial and fungal pathogens in Arabidopsis and rice.

    Science.gov (United States)

    Dubouzet, Joseph G; Maeda, Satoru; Sugano, Shoji; Ohtake, Miki; Hayashi, Nagao; Ichikawa, Takanari; Kondou, Youichi; Kuroda, Hirofumi; Horii, Yoko; Matsui, Minami; Oda, Kenji; Hirochika, Hirohiko; Takatsuji, Hiroshi; Mori, Masaki

    2011-05-01

    Approximately 20,000 of the rice-FOX Arabidopsis transgenic lines, which overexpress 13,000 rice full-length cDNAs at random in Arabidopsis, were screened for bacterial disease resistance by dip inoculation with Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The identities of the overexpressed genes were determined in 72 lines that showed consistent resistance after three independent screens. Pst DC3000 resistance was verified for 19 genes by characterizing other independent Arabidopsis lines for the same genes in the original rice-FOX hunting population or obtained by reintroducing the genes into ecotype Columbia by floral dip transformation. Thirteen lines of these 72 selections were also resistant to the fungal pathogen Colletotrichum higginsianum. Eight genes that conferred resistance to Pst DC3000 in Arabidopsis have been introduced into rice for overexpression, and transformants were evaluated for resistance to the rice bacterial pathogen, Xanthomonas oryzae pv. oryzae. One of the transgenic rice lines was highly resistant to Xanthomonas oryzae pv. oryzae. Interestingly, this line also showed remarkably high resistance to Magnaporthe grisea, the fungal pathogen causing rice blast, which is the most devastating rice disease in many countries. The causal rice gene, encoding a putative receptor-like cytoplasmic kinase, was therefore designated as BROAD-SPECTRUM RESISTANCE 1. Our results demonstrate the utility of the rice-FOX Arabidopsis lines as a tool for the identification of genes involved in plant defence and suggest the presence of a defence mechanism common between monocots and dicots. © 2010 The Authors. Plant Biotechnology Journal © 2010 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  15. Characterization of quorum sensing-controlled transcriptional regulator MarR and Rieske (2Fe-2S) cluster-containing protein (Orf5), which are involved in resistance to environmental stresses in Pseudomonas syringae pv. tabaci 6605.

    Science.gov (United States)

    Taguchi, Fumiko; Inoue, Yuko; Suzuki, Tomoko; Inagaki, Yoshishige; Yamamoto, Mikihiro; Toyoda, Kazuhiro; Noutoshi, Yoshiteru; Shiraishi, Tomonori; Ichinose, Yuki

    2015-05-01

    Pseudomonas syringae pv. tabaci 6605 (Pta6605) produces acyl homoserine lactones (AHLs), quorum sensing (QS) molecules that are indispensable for virulence in host tobacco infection. Genome-wide transcriptional profiling of several QS-defective mutants revealed that the expression of the genes encoding the MarR family transcriptional regulator (MarR) and a Rieske 2Fe-2S cluster-containing protein (Orf5) located adjacent to psyI, a gene encoding AHL synthetase, are significantly repressed. Exogenous application of AHL recovered the expression of both marR and orf5 genes in the ΔpsyI mutant, indicating that AHL positively regulates the expression of these genes. To investigate the role of these genes in the virulence of Pta6605, ΔmarR and Δorf5 mutants were generated. Both mutants showed decreased swimming and swarming motilities, decreased survival ability under oxidative and nitrosative stresses and, consequently, reduced virulence on host tobacco plants. Transmission electron micrographs showed that the structure of the cell membranes of ΔmarR and Δorf5 mutants was severely damaged. Furthermore, not only the ratio of dead cells, but also the amount of flagella, extracellular DNA and protein released into the culture supernatant, was significantly increased in both mutants, indicating that the disruption of marR and orf5 genes might induce structural changes in the membrane and cell lysis. Because both mutants showed partly similar expression profiles, both gene products might be involved in the same regulatory cascades that are required for QS-dependent survival under environmentally stressed conditions. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  16. TaNAC1 acts as a negative regulator of stripe rust resistance in wheat, enhances susceptibility to Pseudomonas syringae, and promotes lateral root development in transgenic Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Fengtao; Lin, Ruiming; Feng, Jing; Chen, Wanquan; Qiu, Dewen; Xu, Shichang

    2015-01-01

    Plant-specific NAC transcription factors (TFs) constitute a large family and play important roles in regulating plant developmental processes and responses to environmental stresses, but only some of them have been investigated for effects on disease reaction in cereal crops. Virus-induced gene silencing (VIGS) is an effective strategy for rapid functional analysis of genes in plant tissues. In this study, TaNAC1, encoding a new member of the NAC1 subgroup, was cloned from bread wheat and characterized. It is a TF localized in the cell nucleus, and contains an activation domain in its C-terminal. TaNAC1 was strongly expressed in wheat roots and was involved in responses to infection by the obligate pathogen Puccinia striiformis f. sp. tritici and defense-related hormone treatments such as salicylic acid (SA), methyl jasmonate, and ethylene. Knockdown of TaNAC1 with barley stripe mosaic virus-induced gene silencing (BSMV-VIGS) enhanced stripe rust resistance. TaNAC1-overexpression in Arabidopsis thaliana plants gave enhanced susceptibility, attenuated systemic-acquired resistance to Pseudomonas syringae DC3000, and promoted lateral root development. Jasmonic acid-signaling pathway genes PDF1.2 and ORA59 were constitutively expressed in transgenic plants. TaNAC1 overexpression suppressed the expression levels of resistance-related genes PR1 and PR2 involved in SA signaling and AtWRKY70, which functions as a connection node between the JA- and SA-signaling pathways. Collectively, TaNAC1 is a novel NAC member of the NAC1 subgroup, negatively regulates plant disease resistance, and may modulate plant JA- and SA-signaling defense cascades.

  17. TaNAC1 acts as a negative regulator of stripe rust resistance in wheat, enhances susceptibility to Pseudomonas syringae, and promotes lateral root development in transgenic Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Fengtao eWang

    2015-02-01

    Full Text Available Plant-specific NAC transcription factors constitute a large family and play important roles in regulating plant developmental processes and responses to environmental stresses, but only some of them have been investigated for effects on disease reaction in cereal crops. Virus-induced gene silencing (VIGS is an effective strategy for rapid functional analysis of genes in plant tissues. In this study, TaNAC1, encoding a new member of the NAC1 subgroup, was cloned from bread wheat and characterized. It is a transcription factor localized in the cell nucleus, and contains an activation domain in its C-terminal. TaNAC1 was strongly expressed in wheat roots and was involved in responses to infection by the obligate pathogen Puccinia striiformis f. sp. tritici and defense-related hormone treatments such as salicylic acid, methyl jasmonate and ethylene. Knockdown of TaNAC1 with barley stripe mosaic virus-induced gene silencing (BSMV-VIGS enhanced stripe rust resistance. TaNAC1-overexpression in Arabidopsis plants gave enhanced susceptibility, attenuated systemic-acquired resistance to Pseudomonas syringae DC3000, and promoted lateral root development. Jasmonic acid-signaling pathway genes PDF1.2 and ORA59 were constitutively expressed in transgenic plants. TaNAC1 overexpression suppressed the expression levels of resistance-related genes PR1 and PR2 involved in SA signaling and AtWRKY70, which functions as a connection node between the JA- and SA-signaling pathways. Collectively, TaNAC1 is a novel NAC member of the NAC1 subgroup, negatively regulates plant disease resistance, and may modulate plant JA- and SA-signaling defense cascades.

  18. Imposed glutathione-mediated redox switch modulates the tobacco wound-induced protein kinase and salicylic acid-induced protein kinase activation state and impacts on defence against Pseudomonas syringae

    Science.gov (United States)

    Matern, Sanja; Peskan-Berghoefer, Tatjana; Gromes, Roland; Kiesel, Rebecca Vazquez; Rausch, Thomas

    2015-01-01

    The role of the redox-active tripeptide glutathione in plant defence against pathogens has been studied extensively; however, the impact of changes in cellular glutathione redox potential on signalling processes during defence reactions has remained elusive. This study explored the impact of elevated glutathione content on the cytosolic redox potential and on early defence signalling at the level of mitogen-activated protein kinases (MAPKs), as well as on subsequent defence reactions, including changes in salicylic acid (SA) content, pathogenesis-related gene expression, callose depositions, and the hypersensitive response. Wild-type (WT) Nicotiana tabacum L. and transgenic high-glutathione lines (HGL) were transformed with the cytosol-targeted sensor GRX1-roGFP2 to monitor the cytosolic redox state. Surprisingly, HGLs displayed an oxidative shift in their cytosolic redox potential and an activation of the tobacco MAPKs wound-induced protein kinase (WIPK) and SA-induced protein kinase (SIPK). This activation occurred in the absence of any change in free SA content, but was accompanied by constitutively increased expression of several defence genes. Similarly, rapid activation of MAPKs could be induced in WT tobacco by exposure to either reduced or oxidized glutathione. When HGL plants were challenged with adapted or non-adapted Pseudomonas syringae pathovars, the cytosolic redox shift was further amplified and the defence response was markedly increased, showing a priming effect for SA and callose; however, the initial and transient hyperactivation of MAPK signalling was attenuated in HGLs. The results suggest that, in tobacco, MAPK and SA signalling may operate independently, both possibly being modulated by the glutathione redox potential. Possible mechanisms for redox-mediated MAPK activation are discussed. PMID:25628332

  19. Simultaneous interaction of Arabidopsis thaliana with Bradyrhizobium Sp. strain ORS278 and Pseudomonas syringae pv. tomato DC3000 leads to complex transcriptome changes.

    Science.gov (United States)

    Cartieaux, Fabienne; Contesto, Céline; Gallou, Adrien; Desbrosses, Guilhem; Kopka, Joachim; Taconnat, Ludivine; Renou, Jean-Pierre; Touraine, Bruno

    2008-02-01

    Induced systemic resistance (ISR) is a process elicited by telluric microbes, referred to as plant growth-promoting rhizobacteria (PGPR), that protect the host plant against pathogen attacks. ISR has been defined from studies using Pseudomonas strains as the biocontrol agent. Here, we show for the first time that a photosynthetic Bradyrhizobium sp. strain, ORS278, also exhibits the ability to promote ISR in Arabidopsis thaliana, indicating that the ISR effect may be a widespread ability. To investigate the molecular bases of this response, we performed a transcriptome analysis designed to reveal the changes in gene expression induced by the PGPR, the pathogen alone, or by both. The results confirm the priming pattern of ISR described previously, meaning that a set of genes, of which the majority was predicted to be influenced by jasmonic acid or ethylene, was induced upon pathogen attack when plants were previously colonized by PGPR. The analysis and interpretation of transcriptome data revealed that 12-oxo-phytodienoic acid, an intermediate of the jasmonic acid biosynthesis pathway, is likely to be an actor in the signaling cascade involved in ISR. In addition, we show that the PGPR counterbalanced the pathogen-induced changes in expression of a series of genes.

  20. Flavohaemoglobin HmpX from Erwinia chrysanthemi confers nitrosative stress tolerance and affects the plant hypersensitive reaction by intercepting nitric oxide produced by the host.

    Science.gov (United States)

    Boccara, Martine; Mills, Catherine E; Zeier, Jürgen; Anzi, Chiara; Lamb, Chris; Poole, Robert K; Delledonne, Massimo

    2005-07-01

    Host cells respond to infection by generating nitric oxide (NO) as a cytotoxic weapon to facilitate killing of invading microbes. Bacterial flavohaemoglobins are well-known scavengers of NO and play a crucial role in protecting animal pathogens from nitrosative stress during infection. Erwinia chrysanthemi, which causes macerating diseases in a wide variety of plants, possesses a flavohaemoglobin (HmpX) whose function in plant pathogens has remained unclear. Here we show that HmpX consumes NO and prevents inhibition by NO of cell respiration, indicating a role in protection from nitrosative stress. Furthermore, infection of Saintpaulia ionantha plants with an HmpX-deficient mutant of E. chrysanthemi revealed that the lack of NO scavenging activity causes the accumulation of unusually high levels of NO in host tissue and triggers hypersensitive cell death. Introduction of the wild-type hmpX gene in an incompatible strain of Pseudomonas syringae had a dramatic effect on the hypersensitive cell death in soya bean cell suspensions, and markedly reduced the development of macroscopic symptoms in Arabidopsis thaliana plants. These observations indicate that HmpX not only protects against nitrosative stress but also attenuates host hypersensitive reaction during infection by intercepting NO produced by the plant for the execution of the hypersensitive cell death programme.

  1. Virus-induced Gene Silencing-based Functional Analyses Revealed the Involvement of Several Putative Trehalose-6-Phosphate Synthase/Phosphatase Genes in Disease Resistance against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000 in Tomato

    Directory of Open Access Journals (Sweden)

    Huijuan Zhang

    2016-08-01

    Full Text Available Trehalose and its metabolism have been demonstrated to play important roles in control of plant growth, development and stress responses. However, direct genetic evidence supporting the functions of trehalose and its metabolism in defense response against pathogens is lacking. In the present study, genome-wide characterization of putative trehalose-related genes identified 11 SlTPSs for trehalose-6-phosphate synthase, 8 SlTPPs for trehalose-6-phosphate phosphatase and one SlTRE1 for trehalase in tomato genome. Nine SlTPSs, 4 SlTPPs and SlTRE1 were selected for functional analyses to explore their involvement in tomato disease resistance. Some selected SlTPSs, SlTPPs and SlTRE1 responded with distinct expression induction patterns to Botrytis cinerea and Pseudomonas syringae pv. tomato (Pst DC3000 as well as to defense signaling hormones (e.g. salicylic acid, jasmonic acid and a precursor of ethylene. Virus-induced gene silencing-mediated silencing of SlTPS3, SlTPS4 or SlTPS7 led to deregulation of ROS accumulation and attenuated the expression of defense-related genes upon pathogen infection and thus deteriorated the resistance against B. cinerea or Pst DC3000. By contrast, silencing of SlTPS5 or SlTPP2 led to an increased expression of the defense-related genes upon pathogen infection and conferred an increased resistance against Pst DC3000. Silencing of SlTPS3, SlTPS4, SlTPS5, SlTPS7 or SlTPP2 affected trehalose level in tomato plants with or without infection of B. cinerea or Pst DC3000. These results demonstrate that SlTPS3, SlTPS4, SlTPS5, SlTPS7 and SlTPP2 play roles in resistance against B. cinerea and Pst DC3000, implying the importance of trehalose and tis metabolism in regulation of defense response against pathogens in tomato.

  2. The Pseudomonas aeruginosa oxyvinylglycine L-2-amino-4-methoxy-trans-3-butenoic acid inhibits growth of Erwinia amylovora and acts as a weak seed germination-arrest factor

    Science.gov (United States)

    The Pseudomonas aeruginosa antimetabolite L-2-amino-4-methoxy-trans-3-butenoic acid (AMB) is demonstrated to share biological activities with 4-formylaminooxyvinylglycine, a related molecule produced by Pseudomonas fluorescens WH6. We found that culture filtrates of a P. aeruginosa strain overproduc...

  3. Les traits d'histoire de vie de la bactérie phytopathogène et glaçogène Pseudomonas syringae: un lien entre l'agriculture et les processus atmosphériques de la Terre

    OpenAIRE

    Morris, Cindy E.

    2014-01-01

    La bactérie ubiquiste Pseudomonas syringae a la capacité assez unique de rompre la surfusion d’eau à des températures avoisinant 0°C. Cette capacité lui permet être acteur dans le changement de phase d’eau et de participer au cycle d’eau. A travers sa présence dans l’atmosphère en tant qu’aérosol provenant des surfaces des feuilles, elle entre en contact avec les gouttes d’eau dans les nuages où elle déclenche la prise en glace nécessaire pour la formation des précipitations. Piégé dans les ...

  4. Characteristics of Bacterial Strains from Pseudomonas Genera Isolated from Diseased Plum Trees

    Directory of Open Access Journals (Sweden)

    Veljko Gavrilović

    2008-01-01

    Full Text Available Characteristics of Pseudomonas syringae strains isolated from diseased plum trees are presented is this paper. Based on pathogenic, biochemical and physiological characteristics, isolated starins were divided into two groups: First group of strains, isolated from diseased plum branches with symptoms of suden decay, was simillar to Pseudomonas syringae pv. syringae; second group of strains, isolated from necrotic flower buds on plum trees, exhibited characteristics simillar to Pseudomonas syringae pv. morsprunorum. In addition, phytopathogenic fungi belonging to genera Phomopsis, Botryosphaeria and Leucostoma, were also isolated from diseased plum trees. Further study of these pathogens and their role in the epidemiology of suden plum trees decay is in progress.

  5. Diversity of small RNAs expressed in Pseudomonas species

    DEFF Research Database (Denmark)

    Gomez-Lozano, Mara; Marvig, Rasmus Lykke; Molina-Santiago, Carlos

    2015-01-01

    RNA sequencing (RNA-seq) has revealed several hundreds of previously undetected small RNAs (sRNAs) in all bacterial species investigated, including strains of Pseudomonas aeruginosa, Pseudomonas putida and Pseudomonas syringae. Nonetheless, only little is known about the extent of conservation of...

  6. Veredeling brengt inzicht in Erwinia-resistentie

    NARCIS (Netherlands)

    Snijder, R.; Paasen, van M.Q.P.; Tuyl, van J.M.

    2000-01-01

    Plant Research International, het voormalige CPRO-DLO, doet in opdracht van zes bedrijven onderzoek naar resistentiebronnen binnen Zantedeschia. Kort verslag van de resistentietoets voor Erwinia-rot en de eerste resultaten binnen het sortiment

  7. Enhanced symbiotic nitrogen fixation with P. syringae pv tabaci

    Energy Technology Data Exchange (ETDEWEB)

    Langston-Unkefer, P.J.; Knight, T.J. (Los Alamos National Lab., NM (USA) New Mexico State Univ., Las Cruces (USA)); Sengupta-Gopalan, C. (New Mexico State Univ., Las Cruces (USA))

    1989-04-01

    Infestation of legumes such as alfalfa and soybeans with the plant pathogen Pseudomonas syringae pv. tabaci is accompanied by increased plant growth, nodulation, overall nitrogen fixation, and total assimilated nitrogen. These effects are observed only in plants infested with Tox{sup +} pathogen; the toxin is tabtoxinine-{beta}-lactam, an active site-directed irreversible inhibitor of glutamine synthetase. The key to the legumes survival of this treatment is the insensitivity of the nodule-specific form of glutamine synthetase to the toxin. As expected, significant changes are observed in ammonia assimilation in these plants. The biochemical and molecular biological consequences of this treatment are being investigated.

  8. Soft rot erwiniae: from genes to genomes.

    Science.gov (United States)

    Toth, Ian K; Bell, Kenneth S; Holeva, Maria C; Birch, Paul R J

    2003-01-01

    SUMMARY The soft rot erwiniae, Erwinia carotovora ssp. atroseptica (Eca), E. carotovora ssp. carotovora (Ecc) and E. chrysanthemi (Ech) are major bacterial pathogens of potato and other crops world-wide. We currently understand much about how these bacteria attack plants and protect themselves against plant defences. However, the processes underlying the establishment of infection, differences in host range and their ability to survive when not causing disease, largely remain a mystery. This review will focus on our current knowledge of pathogenesis in these organisms and discuss how modern genomic approaches, including complete genome sequencing of Eca and Ech, may open the door to a new understanding of the potential subtlety and complexity of soft rot erwiniae and their interactions with plants. The soft rot erwiniae are members of the Enterobacteriaceae, along with other plant pathogens such as Erwinia amylovora and human pathogens such as Escherichia coli, Salmonella spp. and Yersinia spp. Although the genus name Erwinia is most often used to describe the group, an alternative genus name Pectobacterium was recently proposed for the soft rot species. Ech mainly affects crops and other plants in tropical and subtropical regions and has a wide host range that includes potato and the important model host African violet (Saintpaulia ionantha). Ecc affects crops and other plants in subtropical and temperate regions and has probably the widest host range, which also includes potato. Eca, on the other hand, has a host range limited almost exclusively to potato in temperate regions only. Disease symptoms: Soft rot erwiniae cause general tissue maceration, termed soft rot disease, through the production of plant cell wall degrading enzymes. Environmental factors such as temperature, low oxygen concentration and free water play an essential role in disease development. On potato, and possibly other plants, disease symptoms may differ, e.g. blackleg disease is associated

  9. Comparative analysis of metabolic networks provides insight into the evolution of plant pathogenic and nonpathogenic lifestyles in Pseudomonas.

    Science.gov (United States)

    Mithani, Aziz; Hein, Jotun; Preston, Gail M

    2011-01-01

    Plant pathogenic pseudomonads such as Pseudomonas syringae colonize plant surfaces and tissues and have been reported to be nutritionally specialized relative to nonpathogenic pseudomonads. We performed comparative analyses of metabolic networks reconstructed from genome sequence data in order to investigate the hypothesis that P. syringae has evolved to be metabolically specialized for a plant pathogenic lifestyle. We used the metabolic network comparison tool Rahnuma and complementary bioinformatic analyses to compare the distribution of 1,299 metabolic reactions across nine genome-sequenced strains of Pseudomonas, including three strains of P. syringae. The two pathogenic Pseudomonas species analyzed, P. syringae and the opportunistic human pathogen P. aeruginosa, each displayed a high level of intraspecies metabolic similarity compared with nonpathogenic Pseudomonas. The three P. syringae strains lacked a significant number of reactions predicted to be present in all other Pseudomonas strains analyzed, which is consistent with the hypothesis that P. syringae is adapted for growth in a nutritionally constrained environment. Pathway predictions demonstrated that some of the differences detected in metabolic network comparisons could account for differences in amino acid assimilation ability reported in experimental analyses. Parsimony analysis and reaction neighborhood approaches were used to model the evolution of metabolic networks and amino acid assimilation pathways in pseudomonads. Both methods supported a model of Pseudomonas evolution in which the common ancestor of P. syringae had experienced a significant number of deletion events relative to other nonpathogenic pseudomonads. We discuss how the characteristic metabolic features of P. syringae could reflect adaptation to a pathogenic lifestyle.

  10. Pseudomonas savastanoi pv. savastanoi: some like it knot.

    Science.gov (United States)

    Ramos, Cayo; Matas, Isabel M; Bardaji, Leire; Aragón, Isabel M; Murillo, Jesús

    2012-12-01

    wounds. Populations are very unevenly distributed in the plant, and suffer drastic fluctuations throughout the year, with maximum numbers of bacteria occurring during rainy and warm months. Populations of P. savastanoi pv. savastanoi are normally associated with nonpathogenic bacteria, both epiphytically and endophytically, and have been demonstrated to form mutualistic consortia with Erwinia toletana and Pantoea agglomerans, which could result in increased bacterial populations and disease symptoms. Based on preventive measures, mostly sanitary and cultural practices. Integrated control programmes benefit from regular applications of copper formulations, which should be maintained for at least a few years for maximum benefit. Olive cultivars vary in their susceptibility to olive knot, but there are no known cultivars with full resistance to the pathogen. http://www.pseudomonas-syringae.org/; http://genome.ppws.vt.edu/cgi-bin/MLST/home.pl; ASAP access to the P. savastanoi pv. savastanoi NCPPB 3335 genome sequence https://asap.ahabs.wisc.edu/asap/logon.php. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

  11. Toets op Erwinia in hyacint bijna praktijkklaar

    NARCIS (Netherlands)

    Dwarswaard, A.; PPO Bomen-bollen,

    2008-01-01

    Erwinia chrysanthemi houdt al enkele jaren de gemoederen in hyacint flink bezig. PPO en BKD werken in een van de onderzoeksprojecten naar deze bacterie samen aan de ontwikkeling van een toetsmethode voor de praktijk. PPO-onderzoeker Joop van Doorn en Hoofd laboratorium Ton van Schadewijk van de BKD

  12. Ziek en Zeer : Erwinia chrysanthemi in Amaryllidaceae

    NARCIS (Netherlands)

    Vink, P.

    2011-01-01

    In dit artikel een verslag van het onderzoek naar de gevoeligheid van narcissen voor de bacterie Erwinia chrysanthemi (tegenwoordig Dickeya dadantii). Uit een infectieproef is gebleken dat deze bacterie tijdens een reguliere bollenteelt in Lisse niet in staat was om narcisbollen aan te tasten. Toch

  13. Microbial contaminants of cultured Hibiscus cannabinus and Telfaria ...

    African Journals Online (AJOL)

    The bacterial isolates includes Pseudomonas syringae pv phaseolicoli, Bacillus licheniformis, Bacillus subtilis, Corynebacterium sp and Erwinia sp. While fungal contaminats includes Alterneria tenius, Aspergillus niger, Aspergillus fumigatus and Fusarium culmorum. Possible sources of contamination and means of ...

  14. Comparative Genomics of Erwinia amylovora and Related Erwinia Species—What do We Learn?

    Directory of Open Access Journals (Sweden)

    Youfu Zhao

    2011-09-01

    Full Text Available Erwinia amylovora, the causal agent of fire blight disease of apples and pears, is one of the most important plant bacterial pathogens with worldwide economic significance. Recent reports on the complete or draft genome sequences of four species in the genus Erwinia, including E. amylovora, E. pyrifoliae, E. tasmaniensis, and E. billingiae, have provided us near complete genetic information about this pathogen and its closely-related species. This review describes in silico subtractive hybridization-based comparative genomic analyses of eight genomes currently available, and highlights what we have learned from these comparative analyses, as well as genetic and functional genomic studies. Sequence analyses reinforce the assumption that E. amylovora is a relatively homogeneous species and support the current classification scheme of E. amylovora and its related species. The potential evolutionary origin of these Erwinia species is also proposed. The current understanding of the pathogen, its virulence mechanism and host specificity from genome sequencing data is summarized. Future research directions are also suggested.

  15. Erwinia chrysanthemi in Amaryllidaceae : voortgezet diagnostisch onderzoek 2007

    NARCIS (Netherlands)

    Vink, P.

    2008-01-01

    De laatste jaren zien we bij veel bloembollen uit de familie van de Liliaceae, Iridaceae, Cannaceae en Compositae (hyacint, Muscari, Zantedeschia, Dahlia) problemen met een ernstige bacterieziekte die wordt veroorzaakt door Erwinia chrysanthemi. Metname bij hyacinten is deze ziekte problematisch

  16. Gezamenlijke toetsontwikkeling op Erwinia chrysanthemi in volle gang

    NARCIS (Netherlands)

    Doorn, van J.; Dees, R.H.L.; Martin, W.S.; Vreeburg, P.J.M.; Leeuwen, van P.J.

    2009-01-01

    Erwinia bezorgde menig ondernemer de afgelopen jaren de nodige hoofdbrekens. Onderzoek door PPO reikte al een aantal oplossingen aan. Nader onderzoek is gedaan naar de mogelijkheid om partijen te toetsen. In dit artkel de achtergronden bij dit onderzoek

  17. Erwinia in Zantedeschia : volgen van partijen en toetsen op tolerantie

    NARCIS (Netherlands)

    Leeuwen, van P.J.; Martin, W.S.; Dees, R.H.L.; Trompert, J.P.T.; Doorn, van J.

    2012-01-01

    De bloembollen- en de aardappelsector trekken gezamenlijk op binnen het koepel project Deltaplan Erwinia om het Erwiniaprobleem aan te pakken. Voor Zantedeschia is alleen de Erwiniabacteriesoort Pectobacterium carotovorum subsp. carotovorum (Pcc) een groot probleem. De afgelopen jaren is onderzocht

  18. Genome-wide analysis of bacterial determinants of plant growth promotion and induced systemic resistance by Pseudomonas fluorescens

    NARCIS (Netherlands)

    Cheng, Xu; Etalo, Desalegn W.; van de Mortel, Judith E.; Dekkers, Ester; Nguyen, Linh; Medema, Marnix H; Raaijmakers, Jos M.

    2017-01-01

    Pseudomonas fluorescens strain SS101 (Pf.SS101) promotes growth of Arabidopsis thaliana, enhances greening and lateral root formation, and induces systemic resistance (ISR) against the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Here, targeted and untargeted approaches were adopted to

  19. Monitoring of Erwinia amylovora in Montenegro

    Directory of Open Access Journals (Sweden)

    Dragana Radunović

    2015-09-01

    Full Text Available Recent studies of Erwinia amylovora in Montenegro, conducted from 2012 to 2014, indicated that the bacterium was widespread in the northern, continental part of the country, where the most important fruit-growing regions are situated. The presence of the bacterium was confirmed on quince, pear, apple, medlar and hawthorn. Pathogenic, cultural and biochemical characteristics of E. amylovora strains sampled from pome fruit species and indigenous flora in Montenegro had been studied previously. In the present study, serological tests were used for identification of E. amylovora strains originating from pome fruit trees and indigenous plants. Monitoring of E. amylovora and collection of samples with symptoms of bacterial fire blight from different hosts and locations were performed in Montenegro from 2012 to 2014. Isolation of the bacterium on nutrient medium produced a large number of isolates, whose pathogenicity was confirmed on immature pear fruits. Twenty-seven strains of the bacterium, originating from three pome fruit species (quince, pear and apple and one indigenous species (hawthorn were selected for serological analyses. Two applied serological methods, ELISA and IF test, enabled rapid detection of the bacterium and simultaneous examination of a large number of samples over a short period of time. Serological analyses showed high homogeneity in antigenic structure of the studied E. amylovora strains sampled from quince, pear, apple and hawthorn from nine locations in Montenegro.

  20. Extracellular polysaccharide of Erwinia chrysanthemi A350 and ribotyping of Erwinia chrysanthemi spp.

    Science.gov (United States)

    Gray, J S; Yang, B Y; Montgomery, R

    2000-03-10

    Erwinia chrysanthemi spp. are gram-negative bacterial phytopathogens causing soft rots in a number of plants. The structure of the extracellular polysaccharide (EPS) produced by the E. chrysanthemi strain A350, which is a lacZ- mutant of the wild type strain 3937, pathogenic to Saintpaulia, has been determined using a combination of chemical and physical techniques including methylation analysis, low-pressure gel-filtration and anion-exchange chromatography, high-pH anion-exchange chromatography, partial acid hydrolysis, mass spectrometry and 1- and 2D NMR spectroscopy. In contrast to the structures of the EPS reported for other strains of E. chrysanthemi, the EPS from strain A350 contains D-GalA, together with L-Rhap and D-Galp in a 1:4:1 ratio. Evidence is presented for the following hexasaccharide repeat unit: [structure: see text] All the Erwinia chrysanthemi spp. studied to date have been analyzed by ribotyping and collated into families, which are consistent with the related structures of their EPS.

  1. Erwinia chrysanthemi ook bij ploffers in Dahlia boosdoener

    NARCIS (Netherlands)

    Leeuwen, van P.J.; Trompert, J.P.T.

    2006-01-01

    Sinds een aantal jaren komt bij de stekproduktie van Dahlia veel uitval voor door ploffers. Na het verhogen van de kastemperatuur vallen de knollen natrot weg. Bovendien kan verdere besmetting snel om zich heen grijpen. Onderzoek heeft aangetoond dat de bacterie Erwinia chrysanthemi de veroorzaker

  2. Resistance to Erwinia spp. in potato (Solanum tuberosum L.)

    NARCIS (Netherlands)

    Allefs, S.

    1995-01-01

    Blackleg is a disease of potato, Solanum tuberosum , which is caused by the bacteria Erwinia carotovora subsp. carotovora ( Ecc ), E.c. subsp. atroseptica ( Eca ) or

  3. Comparison of the complete genome sequences of Pseudomonassyringae pv. syringae B728a and pv. tomato DC3000.

    Energy Technology Data Exchange (ETDEWEB)

    Feil, Helene; Feil, William S.; Chain, Patrick; Larimer, Frank; DiBartolo, Genevieve; Copeland, Alex; Lykidis, Athanasios; Trong,Stephen; Nolan, Matt; Goltsman, Eugene; Thiel, James; Malfatti,Stephanie; Loper, Joyce E.; Lapidus, Alla; Detter, John C.; Land, Miriam; Richardson, Paul M.; Kyrpides, Nikos C.; Ivanova, Natalia; Lindow, StevenE.

    2005-04-01

    The complete genomic sequence of Pseudomonas syringaepathovar syringae B728a (Pss B728a), has been determined and is comparedwith that of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Thesetwo pathovars of this economically important species of plant pathogenicbacteria differ in host range and apparent patterns of interaction withplants, with Pss having a more pronounced epiphytic stage of growth andhigher abiotic stress tolerance and Pst DC3000 having a more pronouncedapoplastic growth habitat. The Pss B728a genome (6.1 megabases) containsa circular chromosome and no plasmid, whereas the Pst DC3000 genome is6.5 mbp in size, composed of a circular chromosome and two plasmids.While a high degree of similarity exists between the two sequencedPseudomonads, 976 protein-encoding genes are unique to Pss B728a whencompared to Pst DC3000, including large genomic islands likely tocontribute to virulence and host specificity. Over 375 repetitiveextragenic palindromic sequences (REPs) unique to Pss B728a when comparedto Pst DC3000 are widely distributed throughout the chromosome except in14 genomic islands, which generally had lower GC content than the genomeas a whole. Content of the genomic islands vary, with one containing aprophage and another the plasmid pKLC102 of P. aeruginosa PAO1. Among the976 genes of Pss B728a with no counterpart in Pst DC3000 are thoseencoding for syringopeptin (SP), syringomycin (SR), indole acetic acidbiosynthesis, arginine degradation, and production of ice nuclei. Thegenomic comparison suggests that several unique genes for Pss B728a suchas ectoine synthase, DNA repair, and antibiotic production may contributeto epiphytic fitness and stress tolerance of this organism. Pseudomonassyringae, a member of the gamma subgroup of the Proteobacteria, is awidespread bacterial pathogen of many plant species. The species P.syringae is subdivided into approximately 50 pathovars based onpathogenicity and host range. P. syringae is capable of

  4. [Pseudomonas genus bacteria on weeds].

    Science.gov (United States)

    Gvozdiak, R I; Iakovleva, L M; Pasichnik, L A; Shcherbina, T N; Ogorodnik, L E

    2005-01-01

    It has been shown in the work that the weeds (couch-grass and ryegrass) may be affected by bacterial diseases in natural conditions, Pseudomonas genus bacteria being their agents. The isolated bacteria are highly-aggressive in respect of the host-plant and a wide range of cultivated plants: wheat, rye, oats, barley, apple-tree and pear-tree. In contrast to highly aggressive bacteria isolated from the affected weeds, bacteria-epi phytes isolated from formally healthy plants (common amaranth, orache, flat-leaved spurge, field sow thistle, matricary, common coltsfoot, narrow-leaved vetch) and identified as P. syringae pv. coronafaciens, were characterized by weak aggression. A wide range of ecological niches of bacteria evidently promote their revival and distribution everywhere in nature.

  5. First report of the crucifer pathogen Pseudomonas cannabina pv. alisalensis causing bacterial blight on radish (Raphanus sativus) in Germany

    Science.gov (United States)

    Pseudomonas cannabina pv. alisalensis is a severe pathogen of crucifers across the U.S. We compared a strain isolated from diseased radish (Raphanus sativus) in Germany to pathotypes and additional strains of P. cannabina pv. alisalensis and P. syringae pv. maculicola. We demonstrated that the patho...

  6. Biochemical Basis of Apple Leaf Resistance to Erwinia amylovora Infection

    Directory of Open Access Journals (Sweden)

    Marija Viljevac

    2009-01-01

    Full Text Available Erwinia amylovora is the most frequently found necrogenic bacterium on apple (Malus domestica Borkh. trees, which causes progressive necrosis and blight of host plants. Rapid spread of bacteria through the host tissue can lead to the loss of entire trees in one growing season. In this work, the aim is to investigate long-lasting biochemical responses in leaves of two apple cultivars (Enterprise and Golden delicious. Several histochemical (polyphenols, suberin and callose and biochemical parameters (total polyphenols, superoxide dismutase – SOD, ascorbate peroxidase – APX and guaiacol peroxidase – GPOD were screened 60 days after Erwinia inoculation in order to find their potential correlation with plant resistance mechanisms to the pathogen attack. Differential susceptibility to the pathogen attack observed between the investigated cultivars was in accordance with previous studies that characterized Enterprise as less susceptible and Golden delicious as more susceptible cultivar. Infected leaves of Golden delicious expressed symptoms seen as large brown areas at the abaxial side mostly placed at the leaf margin and necrosis also found peripherally, while damage in Enterprise leaves was observed as small brown spots and sporadic leaf edge necrosis. Increased SOD and GPOD activities combined with decreased polyphenol content as well as wide cuticle suberization in cultivar Enterprise should be considered as reliable biochemical parameters characterizing its ability to develop certain resistance to the pathogen infection. Furthermore, the absence of callose deposition in leaves of Enterprise confirmed our findings that thick suberized cuticle is likely the main defense mechanism that enables long-term efficient protection of apple leaves against biotic stress caused by Erwinia attack.

  7. Erwinia teleogrylli sp. nov., a Bacterial Isolate Associated with a Chinese Cricket.

    Directory of Open Access Journals (Sweden)

    Bo Liu

    Full Text Available A bacterial isolate (SCU-B244T was obtained in China from crickets (Teleogryllus occipitalis living in cropland deserted for approximately 10 years. The isolated bacteria were Gram-negative, facultatively anaerobic, oxidase-negative rods. A preliminary analysis of the 16S rRNA gene sequence indicated that the strain belongs to either the genus Erwinia or Pantoea. Analysis of multilocus sequence typing based on concatenated partial atpD, gyrB and infB gene sequences and physiological and biochemical characteristics indicated that the strain belonged to the genus Erwinia, as member of a new species as it was distinct from other known Erwinia species. Further analysis of the 16S rRNA gene showed SCU-B244T to have 94.71% identity to the closest species of that genus, Erwinia oleae (DSM 23398T, which is below the threshold of 97% used to discriminate bacterial species. DNA-DNA hybridization results (5.78±2.52% between SCU-B244T and Erwinia oleae (DSM 23398T confirmed that SCU-B244T and Erwinia oleae (DSM 23398T represent different species combined with average nucleotide identity values which range from 72.42% to 74.41. The DNA G+C content of SCU-B244T was 55.32 mol%, which also differs from that of Erwinia oleae (54.7 to 54.9 mol%. The polyphasic taxonomic approach used here confirmed that the strain belongs to the Erwinia group and represents a novel species. The name Erwinia teleogrylli sp. nov. is proposed for this novel taxon, for which the type strain is SCU-B244T (= CGMCC 1.12772T = DSM 28222T = KCTC 42022T.

  8. Effects of atmospheric conditions on ice nucleation activity of Pseudomonas

    Directory of Open Access Journals (Sweden)

    C. Glaux

    2012-11-01

    Full Text Available Although ice nuclei from bacterial origin are known to be efficient at the highest temperatures known for ice catalysts, quantitative data are still needed to assess their role in cloud processes. Here we studied the effects of three typical cloud conditions (i acidic pH (ii NO2 and O3 exposure and (iii UV-A exposure on the ice nucleation activity (INA of four Pseudomonas strains. Three of the Pseudomonas syringae strains were isolated from cloud water and the phyllosphere and Pseudomonas fluorescens strain CGina-01 was isolated from Antarctic glacier ice melt. Among the three conditions tested, acidic pH caused the most significant effects on INA likely due to denaturation of the ice nucleation protein complex. Exposure to NO2 and O3 gases had no significant or only weak effects on the INA of two P. syringae strains whereas the INA of P. fluorescens CGina-01 was significantly affected. The INA of the third P. syringae strain showed variable responses to NO2 and O3 exposure. These differences in the INA of different Pseudomonas suggest that the response to atmospheric conditions could be strain-specific. After UV-A exposure, a substantial loss of viability of all four strains was observed whereas their INA decreased only slightly. This corroborates the notion that under certain conditions dead bacterial cells can maintain their INA. Overall, the negative effects of the three environmental factors on INA were more significant at the warmer temperatures. Our results suggest that in clouds where temperatures are near 0 °C, the importance of bacterial ice nucleation in precipitation processes could be reduced by some environmental factors.

  9. Siderophore‐mediated upregulation of Arabidopsis ferritin expression in response to Erwinia chrysanthemi infection

    National Research Council Canada - National Science Library

    Dellagi, Alia; Rigault, Martine; Segond, Diego; Roux, Camille; Kraepiel, Yvan; Cellier, Françoise; Briat, Jean‐François; Gaymard, Frédéric; Expert, Dominique

    2005-01-01

    ... ). To investigate whether iron sequestration in ferritins is a part of an iron‐withholding defense system induced in response to bacterial invasion, we used Arabidopsis thaliana as a susceptible host for the pathogenic bacterium Erwinia chrysanthemi...

  10. Isolation and Identification of L-asparaginase producing Erwinia strains which isolated from Potato Farms

    Directory of Open Access Journals (Sweden)

    Arastoo Badoei-Dalfard

    2016-09-01

    Full Text Available Introduction: L-Asparaginase can be effectively used for the treatment of lymphoblastic leukemia. The rapid growth of cancer cells are needed for L-asparagine abundant storage. L-asparaginase catalyzes the hydrolysis of L-asparagine into L-aspartic acid and ammonia. The purpose of this study was to isolate and identify the L-asparaginase producing Erwinia strains from the potato farms of Jiroft. Materials and methods: Pectolytic Erwinia species isolated from crumbling potato in M9 medium. The desired L-asparaginase producing bacteria were isolated based on the color changes. Biochemical-microbial and the plant pathogenicity tests of these strains were also investigated with potato and geranium. The L-asparaginase production and molecular detection of these Erwinia strains were also investigated. Results: In this study, L-asparaginase producing Erwinia was isolated on the CVP and M9 mediums. The inoculation of Erwinia strains on the potato and geranium plants showed that Er8 and Er11 species have the ability to cause plant pathogenicity. Results showed that the maximum pathogenicity of Er8 and Er11 was observed after 48 and 15 h of inoculation in potato and geranium plants, respectively. 16S rDNA sequencing and phylogenetic analyses exhibited that Er8 and Er11 strains were similar to Erwinia chrysanthemi with 98% homology. Discussion and conclusion: Because of several applications of the Erwinia L-asparaginase in various fields, isolated Erwinia and their L-asparaginase can be suitable for applied utilization.

  11. Structural Characterization of Core Region in Erwinia amylovora Lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Angela Casillo

    2017-03-01

    Full Text Available Erwinia amylovora (E. amylovora is the first bacterial plant pathogen described and demonstrated to cause fire blight, a devastating plant disease affecting a wide range of species including a wide variety of Rosaceae. In this study, we reported the lipopolysaccharide (LPS core structure from E. amylovora strain CFBP1430, the first one for an E. amylovora highly pathogenic strain. The chemical characterization was performed on the mutants waaL (lacking only the O-antigen LPS with a complete LPS-core, wabH and wabG (outer-LPS core mutants. The LPSs were isolated from dry cells and analyzed by means of chemical and spectroscopic methods. In particular, they were subjected to a mild acid hydrolysis and/or a hydrazinolysis and investigated in detail by one and two dimensional Nuclear Magnetic Resonance (NMR spectroscopy and ElectroSpray Ionization Fourier Transform-Ion Cyclotron Resonance (ESI FT-ICR mass spectrometry.

  12. Vegetative propagation of Syringa vulgaris L. in vitro.

    NARCIS (Netherlands)

    Pierik, R.L.M.; Steegmans, H.H.M.; Elias, A.A.; Stiekema, O.T.J.; Velde, van der A.J.

    1988-01-01

    Excised shoot tips from adult Syringa vulgaris L. plants were rejuvenated by repeated subculturing in vitro. The number of subcultures required to rejuvenate the shoots was strongly dependent on the age and genotype of the plant material. Three rootstocks (K8, A2 and A3) and 5 cultivars

  13. Effect of osmotic stress on plant growth promoting Pseudomonas spp.

    Science.gov (United States)

    Sandhya, V; Ali, Sk Z; Venkateswarlu, B; Reddy, Gopal; Grover, Minakshi

    2010-10-01

    In this study we isolated and screened drought tolerant Pseudomonas isolates from arid and semi arid crop production systems of India. Five isolates could tolerate osmotic stress up to -0.73 MPa and possessed multiple PGP properties such as P-solubilization, production of phytohormones (IAA, GA and cytokinin), siderophores, ammonia and HCN however under osmotic stress expression of PGP traits was low compared to non-stressed conditions. The strains were identified as Pseudomonas entomophila, Pseudomonas stutzeri, Pseudomonas putida, Pseudomonas syringae and Pseudomonas monteilli respectively on the basis of 16S rRNA gene sequence analysis. Osmotic stress affected growth pattern of all the isolates as indicated by increased mean generation time. An increase level of intracellular free amino acids, proline, total soluble sugars and exopolysaccharides was observed under osmotic stress suggesting bacterial response to applied stress. Further, strains GAP-P45 and GRFHYTP52 showing higher levels of EPS and osmolytes (amino acids and proline) accumulation under stress as compared to non-stress conditions, also exhibited higher expression of PGP traits under stress indicating a relationship between stress response and expression of PGP traits. We conclude that isolation and screening of indigenous, stress adaptable strains possessing PGP traits can be a method for selection of efficient stress tolerant PGPR strains.

  14. Identification of Erwinia species isolated from apples and pears by differential PCR.

    Science.gov (United States)

    Gehring, I; Geider, K

    2012-04-01

    Many pathogenic and epiphytic bacteria isolated from apples and pears belong to the genus Erwinia; these include the species E. amylovora, E. pyrifoliae, E. billingiae, E. persicina, E. rhapontici and E. tasmaniensis. Identification and classification of freshly isolated bacterial species often requires tedious taxonomic procedures. To facilitate routine identification of Erwinia species, we have developed a PCR method based on species-specific oligonucleotides (SSOs) from the sequences of the housekeeping genes recA and gpd. Using species-specific primers that we report here, differentiation was done with conventional PCR (cPCR) and quantitative PCR (qPCR) applying two consecutive primer annealing temperatures. The specificity of the primers depends on terminal Single Nucleotide Polymorphisms (SNPs) that are characteristic for the target species. These PCR assays enabled us to distinguish eight Erwinia species, as well as to identify new Erwinia isolates from plant surfaces. When performed with mixed bacterial cultures, they only detected a single target species. This method is a novel approach to classify strains within the genus Erwinia by PCR and it can be used to confirm other diagnostic data, especially when specific PCR detection methods are not already available. The method may be applied to classify species within other bacterial genera. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Detection of soft rot Erwinia spp. on seed potatoes: conductimetry versus dilution plating, PCR and serological assays

    NARCIS (Netherlands)

    Fraaije, B.A.; Appels, M.; Boer, de S.H.; Vuurde, van J.W.L.; Bulk, van den R.W.

    1997-01-01

    Automated conductance measurements in polypectate medium were used for the detection of pathogenic soft rot Erwinia spp. in potato peel extracts. The detection threshold for Erwinia carotovora subsp. atroseptica (Eca) in inoculated peel extracts was ca. 104 colony forming units (cfu) ml-1 when

  16. Cytokinin production by Pseudomonas fluorescens G20-18 determines biocontrol activity against Pseudomonas syringae in Arabidopsis

    Czech Academy of Sciences Publication Activity Database

    Grosskinsky, D. K.; Tafner, R.; Moreno, M. V.; Stenglein, S. A.; Garcia de Salamone, I. E.; Nelson, L. M.; Novák, Ondřej; Strnad, Miroslav; van der Graaff, E.; Roitsch, Thomas

    2016-01-01

    Roč. 6, MAR 17 (2016), s. 23310 ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1204; GA ČR GA15-22322S; GA MŠk(CZ) LO1415 Institutional support: RVO:61389030 ; RVO:67179843 Keywords : GROWTH-PROMOTING RHIZOBACTERIA * PLANT -GROWTH * SALICYLIC-ACID Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.259, year: 2016

  17. E-2-hexenal promotes susceptibility to Pseudomonas syringae by activating jasmonic acid pathways in Arabidopsis.

    NARCIS (Netherlands)

    Scala, A.; Mirabella, R.; Mugo, C.; Matsui, K.; Haring, M.A.; Schuurink, R.C.

    2013-01-01

    Green leaf volatiles (GLVs) are C6-molecules - alcohols, aldehydes, and esters - produced by plants upon herbivory or during pathogen infection. Exposure to this blend of volatiles induces defense-related responses in neighboring undamaged plants, thus assigning a role to GLVs in regulating plant

  18. The metabolic transition during disease following infection of Arabidopsis thaliana by Pseudomonas syringae pv. tomato

    National Research Council Canada - National Science Library

    Ward, Jane L; Forcat, Silvia; Beckmann, Manfred; Bennett, Mark; Miller, Sonia J; Baker, John M; Hawkins, Nathaniel D; Vermeer, Cornelia P; Lu, Chuan; Lin, Wanchang; Truman, William M; Beale, Michael H; Draper, John; Mansfield, John W; Grant, Murray

    2010-01-01

    ... suppress basal and effector-triggered immune responses. In this study, we examined the metabolic changes associated with establishment of disease using analytical techniques that interrogated a range of chemistries...

  19. Erwinia aphidicola, a new species isolated from pea aphid, Acyrthosiphon pisum.

    Science.gov (United States)

    Harada, Hosami; Oyaizu, Hiroshi; Kosako, Yoshimasa; Ishikawa, Hajime

    1997-12-01

    Five strains of Gram-negative, oxidase-negative, facultatively anaerobic, fermentative, motile, rod-shaped bacterium with the general characteristics of the family Enterobacteriaceae were isolated from the gut of multiple specimens of the pea aphid. All the strains caused aphid mortality when ingested by insects via a synthetic diet. The results of biochemical tests showed that these strains are most related to Erwinia herbicola and Pantoea agglomerans. According to DNA-DNA hybridization, the five strains showed more than 96% relatedness to each other, indicating that these organisms are members of a single species. These strains were most closely related to Erwinia herbicola (22% DNA relatedness). Phenotypic differentiation of these strains from Erwinia herbicola, which was also detected from aphid gut, was based on negative reactions in tests of yellow pigment production, gelatin liquefaction, acid production from inulin, starch and dulcitol, and positive acid production from melibiose, inositol, cellobiose and glycerol. On the basis of these data, the name Erwinia aphidicola is proposed for the new organism. The type strain is strain X 001 (=IAM 14479).

  20. A Stringent and Broad Screen of Solanum spp. tolerance Against Erwinia Bacteria Using a Petiole Test

    NARCIS (Netherlands)

    Rietman, H.; Finkers, H.J.; Evers, L.; Zouwen, van der P.S.; Wolf, van der J.M.; Visser, R.G.F.

    2014-01-01

    Blackleg and stem rot caused by coliform bacteria belonging to Dickeya spp. and Pectobacterium spp. (both referred to as Erwinia in this paper) are a problem for potato growers worldwide and no sources of high tolerance are currently present in the cultivated S. tuberosum gene pool. To find sources

  1. Characterization of the RcsC sensor kinase from Erwinia amylovora and other enterobacteria

    Science.gov (United States)

    RcsC is a hybrid sensor kinase which contains a sensor domain, a histidine kinase domain and a receiver domain. We have previously demonstrated that, while the Erwinia amylovora rcsC mutant produces more amylovoran than the wild type strain in vitro, the mutant remains avirulent on both immature pea...

  2. Effectieve kolonisatie van aardappelplanten door Dickeya-soorten (Erwinia chrysanthemi) : themanummer fytobacteriologie

    NARCIS (Netherlands)

    Wolf, van der J.M.; Czajkowski, R.L.; Velvis, H.

    2009-01-01

    De bacterieziekten zwartbenigheid en stengelnatrot, veroorzaakt door Pectobacterium en Dickeya (Erwinia)- soorten, berokkenen grote schade aan de pootaardappelteelt. Bij PRI en HZPC wordt onderzoek verricht naar de verspreiding van deze pathogenen tijdens teelt- en (na)oogst. Het was al bekend dat

  3. High-throughput screening of Erwinia chrysanthemi pectin methylesterase variants using carbohydrate microarrays

    DEFF Research Database (Denmark)

    Øbro, Jens; Sørensen, Iben; Derkx, Patrick

    2009-01-01

    the activity of a series of variant enzymes based on the PME from the important pathogen Erwinia chrysanthemi. A library of 99 E. chrysanthemi PME mutants was created in which seven amino acids were altered by various different substitutions. Each mutant PME was incubated with a highly methyl esterified lime...

  4. Cutaneous infection and bactaeremia caused by Erwinia billingiae: a case report

    Directory of Open Access Journals (Sweden)

    M. Prod'homme

    2017-09-01

    Full Text Available Cellulitis and erysipelas are common skin infections usually caused by Staphylococcus aureus and streptococci. Gram-negative rods are rarely implicated. We report here a case of dermohypodermitis and bactaeremia caused by Erwinia billingiae, a Gram-negative bacteria usually pathogenic and epiphytic to pome fruit tree.

  5. Cutaneous infection and bactaeremia caused byErwinia billingiae: a case report.

    Science.gov (United States)

    Prod'homme, M; Micol, L A; Weitsch, S; Gassend, J-L; Martinet, O; Bellini, C

    2017-09-01

    Cellulitis and erysipelas are common skin infections usually caused by Staphylococcus aureus and streptococci. Gram-negative rods are rarely implicated. We report here a case of dermohypodermitis and bactaeremia caused by Erwinia billingiae , a Gram-negative bacteria usually pathogenic and epiphytic to pome fruit tree.

  6. Cutaneous infection and bactaeremia caused by Erwinia billingiae: a case report

    OpenAIRE

    Prod'homme, M.; Micol, L.A.; Weitsch, S.; Gassend, J.-L.; Martinet, O.; Bellini, C.

    2017-01-01

    Cellulitis and erysipelas are common skin infections usually caused by Staphylococcus aureus and streptococci. Gram-negative rods are rarely implicated. We report here a case of dermohypodermitis and bactaeremia caused by Erwinia billingiae, a Gram-negative bacteria usually pathogenic and epiphytic to pome fruit tree.

  7. Bacterial leaf rot of Aloe vera L., caused byErwinia chrysanthemi biovar 3

    NARCIS (Netherlands)

    Laat, de P.C.A.; Verhoeven, J.T.W.; Danse, J.D.

    1994-01-01

    A severe attack of the bacteriumErwinia chrysantemi biovar 3 on the succulentAloe vera on the Carribean island of Aruba is described. Biochemical and pathological characteristics of strains are presented, including results of successful inoculation experiments onAloe vera. This is the first report

  8. The presence and survival of soft rot (Erwinia) in flower bulb production systems

    NARCIS (Netherlands)

    Doorn, van J.; Vreeburg, P.J.M.; Leeuwen, van P.J.; Dees, R.H.L.

    2011-01-01

    Soft rot is causing increasing damage in the flower bulb industry. Bulbous ornamentals such as Hyacinthus, Dahlia, Iris, Muscari, Freesia and Zantedeschia can be infected. Soft rot in flower bulbs is mainly caused by Dickeya spp. (Dickeya spp.) and Erwinia carotovora subsp. carotovora

  9. Beheersing van Erwinia in bolgewassen : agressief snot en witsnot in hyacint, Zantedeschia, Dahlia en andere bloembolgewassen

    NARCIS (Netherlands)

    Doorn, van J.; Vreeburg, P.J.M.; Leeuwen, van P.J.

    2008-01-01

    De afgelopen acht jaar is in toenemende mate bacterierot (zachtrot, agressief rot) opgetreden in bloembolgewassen zoals hyacint, Muscari, Dahlia en iris. Ook in Freesia en Amaryllis zijn problemen; vooral de pootaardappelsector heeft grote schade door met name Erwinia chrysanthemi (agressief snot).

  10. Genetic islands in pome fruit pathogenic and nonpathogenic Erwinia species and related plasmids

    Directory of Open Access Journals (Sweden)

    Pablo eLlop

    2015-08-01

    Full Text Available New pathogenic bacteria species belonging to the genus Erwinia associated with pome fruit trees (Erwinia pyrifoliae, E. piriflorinigrans, E. uzenensis have been increasingly described in the last years, and comparative analyses have found that all these species share several genetic characteristics. Studies at different level (whole genome comparison, virulence genes, plasmid content, etc. show a high intraspecies homogeneity (i.e. among E. amylovora strains and also abundant similarities appear between the different Erwinia species: presence of plasmids of similar size in the pathogenic species; high similarity in several genes associated with exopolysaccharide production and hence, with virulence, as well as in some other genes, in the chromosomes. Many genetic similarities have been observed also among some of the plasmids (and genomes from the pathogenic species and E. tasmaniensis or E. billingiae, two epiphytic species on the same hosts. The amount of genetic material shared in this genus varies from individual genes to clusters, genomic islands and genetic material that even may constitute a whole plasmid. Recent research on evolution of erwinias point out the horizontal transfer acquisition of some genomic islands that were subsequently lost in some species and several pathogenic traits that are still present. How this common material has been obtained and is efficiently maintained in different species belonging to the same genus sharing a common ecological niche provides an idea of the origin and evolution of the pathogenic Erwinia and the interaction with nonpathogenic species present in the same niche, and the role of the genes that are conserved in all of them.

  11. Genetic control of resistance to soft rot caused by Erwinia carotovora subsp carotovora in Zantedeschia spp. (Araceae), section Aestivae

    NARCIS (Netherlands)

    Snijder, R.C.; Lindhout, W.H.; Tuyl, van J.M.

    2004-01-01

    The pattern of heredity of resistance to Erwinia carotovora subsp. carotovora in Zantedeschia spp. is investigated. Four species with different resistance levels (Z. albomaculata, Z. elliotiana, Z. pentlandii, Z. rehmannii) were compared to their reciprocal offspring. The occurrence of

  12. Genome comparison of the epiphytic bacteria Erwinia billingiae and E. tasmaniensis with the pear pathogen E. pyrifoliae

    National Research Council Canada - National Science Library

    Kube, Michael; Migdoll, Alexander M; Gehring, Isabel; Heitmann, Katja; Mayer, Yvonne; Kuhl, Heiner; Knaust, Florian; Geider, Klaus; Reinhardt, Richard

    2010-01-01

    .... Important pathogens such as Erwinia amylovora, the causative agent of fire blight and E. pyrifoliae causing bacterial shoot blight of pear in Asia belong to this genus. The species E. tasmaniensis and E...

  13. Pseudomonas aeruginosa in Healthcare Settings

    Science.gov (United States)

    ... Sepsis Sharps Safety - CDC Transplant Safety Vaccine Safety Pseudomonas aeruginosa in Healthcare Settings Recommend on Facebook Tweet Share ... aeruginosa . Pseudomonas aeruginosa What types of infections does Pseudomonas aeruginosa cause? Serious Pseudomonas infections usually occur in people ...

  14. Erwinia mallotivora sp., a new pathogen of papaya (Carica papaya) in Peninsular Malaysia.

    Science.gov (United States)

    Amin, Noriha Mat; Bunawan, Hamidun; Redzuan, Rohaiza Ahmad; Jaganath, Indu Bala S

    2010-12-24

    Erwinia mallotivora was isolated from papaya infected with dieback disease showing the typical symptoms of greasy, water-soaked lesions and spots on leaves. Phylogenetic analysis of 16S rRNA gene sequences showed that the strain belonged to the genus Erwinia and was united in a monophyletic group with E. mallotivora DSM 4565 (AJ233414). Earlier studies had indicated that the causal agent for this disease was E. papayae. However, our current studies, through Koch's postulate, have confirmed that papaya dieback disease is caused by E. mallotivora. To our knowledge, this is the first new discovery of E. mallotivora as a causal agent of papaya dieback disease in Peninsular Malaysia. Previous reports have suggested that E. mallotivora causes leaf spot in Mallotus japonicus. However, this research confirms it also to be pathogenic to Carica papaya.

  15. Erwinia mallotivora sp., a New Pathogen of Papaya (Carica papaya in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Noriha Mat Amin

    2010-12-01

    Full Text Available Erwinia mallotivora was isolated from papaya infected with dieback disease showing the typical symptoms of greasy, water-soaked lesions and spots on leaves. Phylogenetic analysis of 16S rRNA gene sequences showed that the strain belonged to the genus Erwinia and was united in a monophyletic group with E. mallotivora DSM 4565 (AJ233414. Earlier studies had indicated that the causal agent for this disease was E. papayae. However, our current studies, through Koch’s postulate, have confirmed that papaya dieback disease is caused by E. mallotivora. To our knowledge, this is the first new discovery of E. mallotivora as a causal agent of papaya dieback disease in Peninsular Malaysia. Previous reports have suggested that E. mallotivora causes leaf spot in Mallotus japonicus. However, this research confirms it also to be pathogenic to Carica papaya.

  16. The Phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) Is a Pathogen of the Pea Aphid†

    OpenAIRE

    Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

    2006-01-01

    Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, eit...

  17. Draft Genome Sequence of Erwinia tracheiphila, an Economically Important Bacterial Pathogen of Cucurbits.

    Science.gov (United States)

    Shapiro, Lori R; Scully, Erin D; Roberts, Dana; Straub, Timothy J; Geib, Scott M; Park, Jihye; Stephenson, Andrew G; Salaau Rojas, Erika; Liu, Quin; Beattie, Gwyn; Gleason, Mark; De Moraes, Consuelo M; Mescher, Mark C; Fleischer, Shelby G; Kolter, Roberto; Pierce, Naomi; Zhaxybayeva, Olga

    2015-06-04

    Erwinia tracheiphila is one of the most economically important pathogens of cucumbers, melons, squashes, pumpkins, and gourds in the northeastern and midwestern United States, yet its molecular pathology remains uninvestigated. Here, we report the first draft genome sequence of an E. tracheiphila strain isolated from an infected wild gourd (Cucurbita pepo subsp. texana) plant. The genome assembly consists of 7 contigs and includes a putative plasmid and at least 20 phage and prophage elements. Copyright © 2015 Shapiro et al.

  18. Regulation and role in pathogenicity of Erwinia chrysanthemi 3937 pectin methylesterase.

    Science.gov (United States)

    Boccara, M; Chatain, V

    1989-07-01

    The gene pem, encoding the pectin methylesterase (PME) of Erwinia chrysanthemi 3937, was cloned and mutagenized by mini-Mu transposable elements. A second gene, pecY, which could act as a negative regulator of PME was found 5' to the pem gene. A PME-E. chrysanthemi derivative inoculate onto Saintpaulia plants was shown to be clearly noninvasive, demonstrating the important role of this enzyme in soft rot disease.

  19. Bacteriocin-resistant mutants of Erwinia chrysanthemi: possible involvement of iron acquisition in phytopathogenicity.

    Science.gov (United States)

    Expert, D; Toussaint, A

    1985-07-01

    A series of bacteriocin-resistant mutants of Erwinia chrysanthemi 3937JRH were unable to elicit soft-rot symptoms on saintpaulia plants. The loss of pathogenicity was correlated with the disappearance of one to three outer membrane polypeptides (molecular weights, about 80,000 to 90,000) whose production in wild-type strains was greatly enhanced under iron-limited growth conditions. The mutants did not exhibit altered extracellular pectinolytic or cellulolytic activities.

  20. Papel de una región cromosómica de Pseudomonas savastanoi pv. savastanoi NCPPB 3335 en la virulencia en plantas de olivo lignificadas

    OpenAIRE

    Caballo-Ponce, Eloy; van Dillewijn, Pieter; Wittich, Regina Michaela; Ramos Rodríguez, Cayo

    2014-01-01

    El genoma del patógeno de olivo Pseudomonas savastanoi pv. savastanoi (Psv) NCPPB 3335 (58.1% G+C) presenta una región cromosómica de aproximadamente 15 kb, denominada VR8 (60.4% G+C), ausente en los genomas de todos los patovares secuenciados del complejo Pseudomonas syringae que infectan plantas herbáceas, pero presente en los patovares patógenos de plantas leñosas. El análisis de esta región mediante retrotranscipción (RT)-PCR reveló la existencia de 4 posibles operones y el gen AER-1900 (...

  1. EFEKTIFITAS DAYA HAMBAT BAKTERI Streptomyces sp TERHADAP Erwinia sp PENYEBAB PENYAKIT BUSUK REBAH PADA TANAMAN LIDAH BUAYA (Aloe barbadensis Mill

    Directory of Open Access Journals (Sweden)

    SARMILA TASNIM

    2013-05-01

    Full Text Available Streptomyces sp was conducted from December 2010 - June 2011 at the Laboratoryof Microbiology, Biology Department, Math and Science Faculty, UdayanaUniversity Bukit Jimbaran-Bali. Implementation stages of the research consisted ofisolation and testing of the antibiotic activity Streptomyces sp to inhibit growthbacterial pathogens Erwinia sp as a cause of disease in plants fallen foul (Soft rot ofAloe barbadensis Mill.The results of this study have eight isolates of Streptomyces spwith macroscopic and microscopic characters are varied. Furthermore, all isolateswere obtained and then tested against antibiotic activity to inhibit growth the bacteriaErwinia sp. Test results obtained by Streptomyces sp that has the most effective ininhibiting the ability of the bacteria Erwinia sp isolates are Streptomyces sp2for (45%.

  2. Absence of phosphatidylcholine in bacterial membranes facilitates translocation of Sec-dependent β-lactamase AmpC from cytoplasm to periplasm in two Pseudomonas strains.

    Science.gov (United States)

    Liu, Xin; Sun, Yufang; Cao, Fang; Xiong, Min; Yang, Sheng; Li, Yang; Yu, Xuejing; Li, Yadong; Wang, Xingguo

    2017-05-01

    Phosphatidylcholine (PC) is a rare membrane lipid in bacteria but crucial for virulence of various plant and animal pathogens. The pcs- mutant lacking PC in bacterial membranes of Pseudomonas syringae pv. syringae van Hall 1336 displayed more ampicillin resistance. Ampicillin susceptibility tests gave an IC50 (half maximal inhibitory concentration) of 52 mg/ml for Pseudomonas syringae pv. syringae van Hall 1336, 53 mg/ml for the complemented strain 1336 RM (pcs-/+) and 90 mg/ml for the 1336 pcs- mutant. Activity assay of β-lactamase in periplasmic extracts gave 0.050 U/mg for the 1336 wild type, 0.052 U/mg for the 1336RM (pcs-/+), 0.086 U/mg for the 1336 pcs- mutant. Analysis by western blotting showed that the content of AmpC enzyme was markedly different in periplasmic extracts between the wild-type and pcs- mutant strains. Reverse transcriptase PCR also showed that the presence or absence of PC in bacterial membranes did not affect the transcription of ampC gene. The phenotype of the pcs- mutant was able to be recovered to the wild type by introducing a wild-type pcs gene into the pcs- mutant. Similar results were also obtained from the soil-dwelling bacterium Pseudomonas sp. 593. Our results demonstrate that the absence of PC in bacterial membranes facilitates the translocation of Sec-dependent β-lactamase AmpC from cytoplasm to periplasm, and the enhanced ampicillin-resistance in the pcs- strains mainly comes from effective translocation of AmpC via Sec-pathway. Copyright © 2016. Published by Elsevier Ltd.

  3. The phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) is a pathogen of the pea aphid.

    Science.gov (United States)

    Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

    2006-03-01

    Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research.

  4. The Phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) Is a Pathogen of the Pea Aphid†

    Science.gov (United States)

    Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

    2006-01-01

    Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research. PMID:16517643

  5. Molecular characterization and pathogenicity of Erwinia spp. associated with pineapple [Ananas comosus (L.) Merr.] and papaya (Carica papaya L.)

    OpenAIRE

    Ramachandran Kogeethavani; Manaf Uyub Abdul; Zakaria Latiffah

    2015-01-01

    The Erwinia species are well-known pathogens of economic importance in Malaysia causing serious damage to high-value fruit crops that include pineapple [Ananas comosus (L.) Merr.] and papaya (Carica papaya L.).The 16S rRNA sequence using eubacteria fD1 and rP2 primers, identified two bacteria species; Dickeya zeae from pineapple heart rot, and Erwinia mallotivora from papaya dieback. Phylogenetic analysis based on the neighbor-joining method indicated that all the bacterial isolates clustered...

  6. Biology of the fire blight pathogen Erwinia amylovora in oligotrophic environments: survival responses and virulence

    OpenAIRE

    Delgado Santander, Ricardo

    2016-01-01

    Erwinia amylovora es una bacteria fitopatógena de la familia Enterobacteriaceae, responsable del fuego bacteriano de las rosáceas. Los efectos destructivos de este patógeno sobre frutos, flores y prácticamente todos los órganos de las plantas hospedadoras afectadas constituyen una amenaza importante para la producción de pera y manzana, y suponen graves pérdidas económicas anuales en todo el mundo. E. amylovora está clasificada como un organismo de cuarentena en la Unión Europea y en otros pa...

  7. Novas ocorrências de Erwinia carotovora subsp. carotovora e de E. chrysanthemi

    Directory of Open Access Journals (Sweden)

    Irene M. G. Almeida

    1997-05-01

    Full Text Available Em continuidade a trabalhos de caracterização de bactérias pectinolíticas do gênero Eruia ocorrendo no Brasil, são relacionadas novas ocorrências dessas fitobactérias em plantios comerciais, que ocasionam podridão mole em cinco espécies de plantas ornamentais. Testes bioquímicas, fisiológicos, culturais e de patogenicidade permitiram comprovar a ocorrência de Erwinia carotovora subsp. carotovora em plantas de afelandra, amarílis e copo-de-leite, e de Erwiniachr santhemiemcordilineekalanchoe.

  8. Role of endoglucanases in Erwinia chrysanthemi 3937 virulence on Saintpaulia ionantha.

    Science.gov (United States)

    Boccara, M; Aymeric, J L; Camus, C

    1994-03-01

    The role of endoglucanases (endoglucanases Z and Y) in Erwinia chrysanthemi pathogenicity on Saintpaulia ionantha was assessed by mutagenizing cloned cel genes (celZ and celY) and recombining them with the chromosomal alleles. Strains with an omega interposon in celZ, a deletion in celY, or a double cel mutant were as virulent as the wild-type strain. However, in the strain with a deletion in celY, a delay in the appearance of symptoms was observed, and then maceration progressed as in plants infected with the wild-type strain, suggesting that E. chrysanthemi endoglucanases play a minor role in soft rot disease development.

  9. Comparative Genomic Analyses of Multiple Pseudomonas Strains Infecting Corylus avellana Trees Reveal the Occurrence of Two Genetic Clusters with Both Common and Distinctive Virulence and Fitness Traits.

    Directory of Open Access Journals (Sweden)

    Simone Marcelletti

    Full Text Available The European hazelnut (Corylus avellana is threatened in Europe by several pseudomonads which cause symptoms ranging from twig dieback to tree death. A comparison of the draft genomes of nine Pseudomonas strains isolated from symptomatic C. avellana trees was performed to identify common and distinctive genomic traits. The thorough assessment of genetic relationships among the strains revealed two clearly distinct clusters: P. avellanae and P. syringae. The latter including the pathovars avellanae, coryli and syringae. Between these two clusters, no recombination event was found. A genomic island of approximately 20 kb, containing the hrp/hrc type III secretion system gene cluster, was found to be present without any genomic difference in all nine pseudomonads. The type III secretion system effector repertoires were remarkably different in the two groups, with P. avellanae showing a higher number of effectors. Homologue genes of the antimetabolite mangotoxin and ice nucleation activity clusters were found solely in all P. syringae pathovar strains, whereas the siderophore yersiniabactin was only present in P. avellanae. All nine strains have genes coding for pectic enzymes and sucrose metabolism. By contrast, they do not have genes coding for indolacetic acid and anti-insect toxin. Collectively, this study reveals that genomically different Pseudomonas can converge on the same host plant by suppressing the host defence mechanisms with the use of different virulence weapons. The integration into their genomes of a horizontally acquired genomic island could play a fundamental role in their evolution, perhaps giving them the ability to exploit new ecological niches.

  10. Molecular detection of Erwinia psidii in guava plants under greenhouse and field conditions

    Directory of Open Access Journals (Sweden)

    Claudênia Ferreira da Silva

    2016-09-01

    Full Text Available ABSTRACT: Erwinia psidii causes bacterial blight of guava ( Psidium guajava , an important disease of this crop in Brazil. The pathogen affects branches and twigs of guava trees, reducing yield significantly. Bacterial dissemination often occurs through contaminated but asymptomatic propagating plant material. The objectives of this research were to evaluate the use of BIO-PCR and conventional PCR to detect E. psidii in inoculated guava plants grown in a greenhouse and in symptomatic and asymptomatic trees from guava orchards. Erwinia psidii strain IBSBF 1576 was inoculated (107CFU mL-1 into young guava shoots and plant tissue was analysed at 0, 5, 10, and 15 days after inoculation. Symptoms were observed after 5 days and all inoculated shoots were PCR positive at all times, by both BIO-PCR and conventional PCR. Under natural infection conditions, 40 samples were tested by BIO-PCR from each of three guava orchards, 20 showing symptoms and 20 asymptomatic. PCR was positive for 58 out of 60 symptomatic samples (96.7% and for 6.7% of asymptomatic samples, showing that the method can be used to detect the pathogen at early stages of infection. This PCR method may be used as a diagnostic tool to assess bacterial survival, dissemination and disease outbreaks.

  11. Survival of Erwinia amylovora in mature apple fruit calyces through the viable but nonculturable (VBNC) state.

    Science.gov (United States)

    Ordax, M; Biosca, E G; Wimalajeewa, S C; López, M M; Marco-Noales, E

    2009-07-01

    Survival of Erwinia amylovora, causal agent of fire blight in pome fruits and other rosaceous plants, was monitored inside mature apples calyces under some storage conditions utilized in fruit. Apple fruit calyces inoculated with two E. amylovora strains and their respective GFP-marked strains were maintained at 26 degrees and 5 degrees C, and the effect of copper treatment was assayed at 0.01 and 0.1 mmol l(-1) CuSO4. In nontreated apples at 26 degrees C, part of the population of E. amylovora survived in the 'viable but nonculturable' (VBNC) state, whereas at 5 degrees C the majority of the population retained culturability. In copper-treated apples, the whole population adopted the VBNC state irrespective of temperature. Regardless of temperature, copper and inoculum dose, VBNC cells recovered culturability and pathogenicity in King's B broth or by host plant passage. Erwinia amylovora survived for at least 35 days in mature apple calyces. Besides, the ability of the pathogen in the VBNC state to regain culturability and pathogenicity suggests that the apple fruit could be a potential carrier of E. amylovora contributing to the spreading of fire blight disease. The risk of E. amylovora dissemination through mature fruit transport, although low, has been demonstrated, and should be considered in pest risk assessments.

  12. Fermentation of D-xylose and L-arabinose to ethanol by Erwinia chrysanthemi

    Energy Technology Data Exchange (ETDEWEB)

    Tolan, J.S.; Finn, R.K.

    1987-09-01

    Erwinia spp. are gram-negative facultative anaerobes within the family Enterobacteriacae which possess several desirable traits for the conversion of pentose sugars to ethanol, such as the ability to ferment a broad range of carbohydrates and the ease with which they can be genetically modified. Twenty-eight strains of Erwinia carotovora and E. chrysanthemi were screened for the ability to ferment D-xylose to ethanol. E. chrysanthemi B374 was chosen for further study on the basis of its superior (4%) ethanol tolerance. They have characterized the fermentation of D-xylose and L-arabinose by the wild type and mutants which bear plasmids containing the pyruvate decarboxylase gene from Zymomonas mobilis. Expression of the gene markedly increased the yields of ethanol (from 0.7 up to 1.45 mol/mol of xylose) and decreased the yields of formate, acetate, and lactate. However, the cells with pyruvate decarboxylase grew only one-fourth as fast as the wild type and tolerated only 2% ethanol. Alcohol tolerance was stimulated by the addition of yeast extract to the growth medium. Xylose catabolism was characterized by a high saturation constant K/sub s/ (4.5 mM).

  13. Resistance to Erwinia amylovora in immature pears induced by acibenzolar-S-methyl in the orchard

    Directory of Open Access Journals (Sweden)

    A. Mazzucchi

    2009-01-01

    Full Text Available A field trial was carried out to determine whether resistance to Erwinia amylovora could be induced in unripe pears with acibenzolar-S-methyl (ASM, comparing the effectiveness of ASM with a formulate of copper hydroxide. The random block trial was carried out in a commercial pear orchard between June 15 and 29. The treatments were applied in mid-June. Unripe pears were collected from the trees immediately and 1, 2, 4, 7 and 14 days after treatment, and inoculated in the greenhouse within 2–3 hours with a constant dose of a virulent strain of Erwinia amylovora. After inoculation, the pears were stored in a moist chamber at 25±2°C in a greenhouse, and after 8 days the diameter of each surface lesion was measured as well as its width and depth inside the pulp. In the fruits of ASM treated trees there was a reduction in the lesion diameter of the peripheral tissues around the inoculation holes, but not in the deep pulp tissues. Specifically, the symptoms appeared to be milder in the peripheral tissues even 7 and 14 days after treatment with ASM, especially at the lower concentration. The copper compound gave protection to the immature pears for not more than 4 days. These results justify the use of ASM for the protection of unripe fruit in the spring-early summer period to control bacterial fire blight in pear orchards.

  14. Signaling requirements for Erwinia amylovora-induced disease resistance, callose deposition, and cell growth in the nonhost Arabidopsis thaliana

    Science.gov (United States)

    Erwinia amylovora is the causal agent of the fire blight disease in some plants of the Rosaceae family. The nonhost plant Arabidopsis serves as a powerful system to dissect mechanisms of resistance to E. amylovora. Although not yet known to mount gene-for-gene resistance to E. amylovora, we found ...

  15. Symbiotic bacteria (Erwinia sp.) in the gut of Frankliniella occidentalis (Thysanoptera: Thripidae) do not affect its ability to transmit tospovirus

    NARCIS (Netherlands)

    de Vries, E.J.; van de Wetering, F.; van der Hoek, M.M.; Jacobs, G.; Breeuwer, J.A.J.

    2012-01-01

    Tomato spotted wilt virus (TSWV) is one of the most harmful plant viruses and one of its most important vectors is the western flower thrips [Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)]. Recently, we reported the close association of Erwinia sp. gut bacteria with this species of

  16. Diet-dependent effects of gut bacteria on their insect host: the symbiosis of Erwinia spec. and western flower thrips

    NARCIS (Netherlands)

    de Vries, E.J.; Jacobs, G.; Sabelis, M.W.; Menken, S.B.J.; Breeuwer, J.A.J.

    2004-01-01

    Studies on bacteria in the gut of insect species are numerous, but their focus is hardly ever on the impact on host performance. We showed earlier that Erwinia bacteria occur in the gut of western flower thrips, most probably acquired during feeding. Here, we investigate whether thrips gain a net

  17. Investigation of Viability of Pantoea agglomerans (Formerly Erwinia herbicola) After Aerosolization From Media Containing Enriching and Coating Chemicals

    Science.gov (United States)

    2008-02-01

    Final Sep) 2005 - Set 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Investigation of Viability of Pantoea agglomerans (Formerly Erwinia DAAD 19-02-D...in this report was authorized under Contract No. DAAD 19- 02-D-0001, Task No. 02149. The work was started in September 2005 and completed in

  18. Rotting softly and stealthily.

    Science.gov (United States)

    Toth, Ian K; Birch, Paul R J

    2005-08-01

    The soft rot erwiniae, which are plant pathogens on potato and other crops world-wide, synthesize and secrete large quantities of plant cell wall degrading enzymes that are responsible for the soft rot phenotype, earning them the epithet 'brute force' pathogens. They have been distinguished from classic 'stealth' pathogens, such as Pseudomonas syringae, which possesses an extensive battery of Type III secreted effector proteins and phytotoxins to manipulate and suppress host defences. However, recent studies, including whole-genome sequencing, are revealing many components of stealth pathogenesis within the soft rot erwiniae (SRE), suggesting that 'stealth' and 'brute force' should not be regarded as mutually exclusive modes of pathogenesis.

  19. Monocyte Profiles in Critically Ill Patients With Pseudomonas Aeruginosa Sepsis

    Science.gov (United States)

    2017-02-02

    Pseudomonas Infections; Pseudomonas Septicemia; Pseudomonas; Pneumonia; Pseudomonal Bacteraemia; Pseudomonas Urinary Tract Infection; Pseudomonas Gastrointestinal Tract Infection; Sepsis; Sepsis, Severe; Critically Ill

  20. Primera detección en España de necrosis bacteriana de la dipladenia y caracterización fenotípica de su agente causal (Pseudomonas savastanoi)

    OpenAIRE

    Caballo-Ponce, Eloy; Ramos, Cayo

    2017-01-01

    La dipladenia (género Mandevilla) es una planta nativa de Suramérica con un creciente interés en el sector ornamental, cuyo mercado anual está estimado en 300-400 millones de euros. Las infecciones causadas por Pseudomonas savastanoi, una de las diez especies integrantes del complejo Pseudomonas syringae, suponen una importante amenaza para este mercado. La necrosis bacteriana de la dipladenia, provocada por P. savastanoi, se caracteriza por la aparición de manchas necróticas r...

  1. Pseudomonas Lipopeptide Biosurfactants

    DEFF Research Database (Denmark)

    Bonnichsen, Lise

    Pseudomonas lipopetide biosurfactants are amphiphilic molecules with a broad range of natural functions. Due to their surface active properties, it has been suggested that Pseudomonas lipopetides potentially play a role in biodegradation of hydrophobic compounds and have essential functions...... in biofilm formation, however, detailed studies of these roles have not yet been carried out. The overall aim of this PhD project was therefore to elucidate in more depth the roles played by Pseudomonas lipopetides in pollutant biodegradation and biofilm formation. This study investigated the effect...... of the Pseudomonas lipopeptides belonging to different structural groups on important biodegradation parameters, mainly; solubilization and emulsification of hydrophobic pollutants (alkanes and PAHs) and increase of cell surface hydrophobicity of bacterial degraders. Ultimately, it was tested if these parameters led...

  2. Simplification of vacuole structure during plant cell death triggered by culture filtrates of Erwinia carotovora.

    Science.gov (United States)

    Hirakawa, Yumi; Nomura, Toshihisa; Hasezawa, Seiichiro; Higaki, Takumi

    2015-01-01

    Vacuoles are suggested to play crucial roles in plant defense-related cell death. During programmed cell death, previous live cell imaging studies have observed vacuoles to become simpler in structure and have implicated this simplification as a prelude to the vacuole's rupture and consequent lysis of the plasma membrane. Here, we examined dynamics of the vacuole in cell cycle-synchronized tobacco BY-2 (Nicotiana tabacum L. cv. Bright Yellow 2) cells during cell death induced by application of culture filtrates of Erwinia carotovora. The filtrate induced death in about 90% of the cells by 24 h. Prior to cell death, vacuole shape simplified and endoplasmic actin filaments disassembled; however, the vacuoles did not rupture until after plasma membrane integrity was lost. Instead of facilitating rupture, the simplification of vacuole structure might play a role in the retrieval of membrane components needed for defense-related cell death. © 2014 Institute of Botany, Chinese Academy of Sciences.

  3. The suitability of Finnish climate for fire blight (Erwinia amylovora epidemics on apple

    Directory of Open Access Journals (Sweden)

    Mariela Marinova-Todorova

    2015-03-01

    Full Text Available Fire blight, which is an important disease of apples and pears, has never been detected in continental Finland. In this study the suitability of the Finnish climate for apple blossom blight infections by Erwinia amylovora was evaluated with the epidemiological model MaryblytTM. This was done in fourteen locations, and for two apple cultivars differing in flowering times. Climatic conditions were predicted to be suitable for blossom infections in 18 - 51% of the years, and the annual period of suitable conditions was predicted to last up to two to five days, depending on the location and apple cultivar. The suitable period was predicted to be longer in some locations in central Finland than in those in the southernmost parts of the country. Based on these results the official surveys that are carried out to confirm the absence of fire blight in Finland cannot be targeted only to some parts of the country.

  4. Podridão em cravo causada por Erwinia carotovora subsp. carotovora no Brasil.

    Directory of Open Access Journals (Sweden)

    Irene M. G. Almeida

    2000-05-01

    Full Text Available De fevereiro a abril de 1999, coletaram-se estacas e mudas de cravo (Dianthus caryophyllus em propriedades dos municípios paulistas de Atibaia e Santo Antônio de Posse. Esse material apresentava sintomas caracterizados por não-emissão de raízes ou por podridão de raízes, colo e folhas basais, diferindo daqueles da doença denominada "slow wilt" e dos de escurecimento de vasos e necrose na região do colo, haste e folhas, já relatados em cravo. A partir de material com tais sintomas, isolaram-se bactérias, caracterizadas, mediante testes bioquímicos, culturais, fisiológicos e de patogenicidade, como Erwinia carotovora subsp. carotovora. Trata-se do primeiro relato desse patógeno em cravo no Brasil.

  5. Flavohaemoglobin HmpX: a new pathogenicity determinant in Erwinia chrysanthemi strain 3937.

    Science.gov (United States)

    Favey, S; Labesse, G; Vouille, V; Boccara, M

    1995-04-01

    Unlike wild-type Erwinia chrysanthemi strain 3937, which fully macerates inoculated Saintpaulia plants, HmpX- mutants produce necrotic lesions or no symptoms. The hmpX gene was sequenced and the corresponding protein sequence analysed. We show that HmpX belongs to a family of flavohaemoproteins (HMP), previously identified in two yeasts and in Escherichia coli. Comparisons of protein sequences at the secondary structure level by hydrophobic cluster analysis have shown that HmpX possesses two functional regions, a haemoglobin domain in its N-terminal part and a flavin reductase domain in its C-terminal part. In an HmpX- strain, the synthesis of pectate lyases, which are pathogenicity determinants in E. chrysanthemi, was reduced in conditions of low oxygen tension. Using gus fusion in hmpX, it was shown that hmpX transcription was induced in coculture with tobacco cells. A putative function for HmpX is discussed.

  6. Systemic virulence of Erwinia chrysanthemi 3937 requires a functional iron assimilation system.

    Science.gov (United States)

    Enard, C; Diolez, A; Expert, D

    1988-06-01

    In Erwinia chrysanthemi, conditions of iron starvation initiate production of a catechol-type siderophore and enhance production of three outer membrane polypeptides. Twenty-two mutants affected in the different stages of this iron assimilation system were isolated by mini-Mu insertion mutagenesis. All of them failed to induce systemic soft rot on axenically grown Saintpaulia plants. From the siderophore auxotrophs and the iron uptake mutants, clones having recovered the missing function(s) were isolated by using the in vivo cloning vector pULB113 (RP4::mini-Mu). An R-prime plasmid containing a ca. 35.5-kilobase-pair DNA insert was identified. Restoration of the iron functions restored partially, if not completely, the virulence of the parental strain.

  7. Erwinia amylovora pyrC mutant causes fire blight despite pyrimidine auxotrophy.

    Science.gov (United States)

    Ramos, L S; Sinn, J P; Lehman, B L; Pfeufer, E E; Peter, K A; McNellis, T W

    2015-06-01

    Erwinia amylovora bacteria cause fire blight disease, which affects apple and pear production worldwide. The Erw. amylovora pyrC gene encodes a predicted dihydroorotase enzyme involved in pyrimidine biosynthesis. Here, we discovered that the Erw. amylovora pyrC244::Tn5 mutant was a uracil auxotroph. Unexpectedly, the Erw. amylovora pyrC244::Tn5 mutant grew as well as the wild-type in detached immature apple and pear fruits. Fire blight symptoms caused by the pyrC244::Tn5 mutant in immature apple and pear fruits were attenuated compared to those caused by the wild-type. The pyrC244::Tn5 mutant also caused severe fire blight symptoms in apple tree shoots. A plasmid-borne copy of the wild-type pyrC gene restored prototrophy and symptom induction in apple and pear fruit to the pyrC244::Tn5 mutant. These results suggest that Erw. amylovora can obtain sufficient pyrimidine from the host to support bacterial growth and fire blight disease development, although de novo pyrimidine synthesis by Erw. amylovora is required for full symptom development in fruits. Significance and impact of the study: This study provides information about the fire blight host-pathogen interaction. Although the Erwinia amylovora pyrC mutant was strictly auxotrophic for pyrimidine, it grew as well as the wild-type in immature pear and apple fruits and caused severe fire blight disease in apple trees. This suggests that Erw. amylovora can obtain sufficient pyrimidines from host tissue to support growth and fire blight disease development. This situation contrasts with findings in some human bacterial pathogens, which require de novo pyrimidine synthesis for growth in host blood, for example. © 2015 The Society for Applied Microbiology.

  8. The cyclic AMP receptor protein is the main activator of pectinolysis genes in Erwinia chrysanthemi.

    Science.gov (United States)

    Reverchon, S; Expert, D; Robert-Baudouy, J; Nasser, W

    1997-06-01

    The main virulence factors of the phytopathogenic bacterium Erwinia chrysanthemi are pectinases that cleave pectin, a major constituent of the plant cell wall. Although physiological studies suggested that pectinase production in Erwinia species is subjected to catabolite repression, the direct implication of the cyclic AMP receptor protein (CRP) in this regulation has never been demonstrated. To investigate the role of CRP in pectin catabolism, we cloned the E. chrysanthemi crp gene by complementation of an Escherichia coli crp mutation and then constructed E. chrysanthemi crp mutants by reverse genetics. The carbohydrate fermentation phenotype of the E. chrysanthemi crp mutants is similar to that of an E. coli crp mutant. Furthermore, these mutants are unable to grow on pectin or polygalacturonate as the sole carbon source. Analysis of the nucleotide sequence of the E. chrysanthemi crp gene revealed the presence of a 630-bp open reading frame (ORF) that codes for a protein highly similar to the CRP of E. coli. Using a crp::uidA transcriptional fusion, we demonstrated that the E. chrysanthemi CRP represses its own expression, probably via a mechanism similar to that described for the E. coli crp gene. Moreover, in the E. chrysanthemi crp mutants, expression of pectinase genes (pemA, pelB, pelC, pelD, and pelE) and of genes of the intracellular part of the pectin degradation pathway (ogl, kduI, and kdgT), which are important for inducer formation and transport, is dramatically reduced in induced conditions. In contrast, expression of pelA, which encodes a pectate lyase important for E. chrysanthemi pathogenicity, seems to be negatively regulated by CRP. The E. chrysanthemi crp mutants have greatly decreased maceration capacity in potato tubers, chicory leaves, and celery petioles as well as highly diminished virulence on saintpaulia plants. These findings demonstrate that CRP plays a crucial role in expression of the pectinolysis genes and in the pathogenicity of E

  9. Inhibition of Erwinia chrysanthemi growth to different concentrations of folic acid: possible use of folic acid as bacteriostatic agent and fortifying of Solanum tuberosum potato

    Directory of Open Access Journals (Sweden)

    Andrea Marcelo Correa

    2017-05-01

    Full Text Available Introduction:The enterobacteria of the Erwinia spp genus produce disease in potatoes, which is a tuber of mass consumption. The regulation of DNA methylation can regulate the proliferation of Erwinia in such a way that the concentrations of folic acid may have an effect on the microorganism pathogenic ability. On the other hand, the folic acid prevents the appearance of neural tube defects in humans. Objective: To evaluate folic acid as a bacteriostatic agent of Erwinia and, at the same time, as part of the fortification of mass consumption food such as the potatoes. Materials and methods: The biochemical characterization of the Erwinia chrysanthemi was carried out and its growth compared to different concentrations of folic acid was studied. Results: When increasing the concentrations of the vitamin from 0.3 µg/L up to 6.8 µg/L, the bacterial growth of Erwinia chrysanthemi is inhibited. The vitamin inhibits the growth in cultivation of Erwinia chrysanthemi and acts as a bacteriostatic agent. This aspect is of great importance given that, theoretically, if potatoes were fortified with micro-nutrient, this would act against the infectious agent and, at the same time, contribute to the adequate intake of the vitamin in the general population.

  10. Evaluación de rutas alternativas de síntesis de IAA en el complejo Pseudomonas syringae.

    OpenAIRE

    Pintado, Adrián; Pérez-Martínez, Isabel; Ramos, Cayo

    2016-01-01

    El ácido indol-3-acético (IAA) es una fitohormona perteneciente al grupo de las auxinas cuya producción está ampliamente distribuida entre bacterias asociadas a plantas. El IAA está implicado, entre otros procesos, en proliferación celular y maduración de las plantas. Además, se ha descrito el papel de esta hormona en la regulación de la expresión génica en bacterias. En bacterias fitopatógenas, se han descrito varias rutas de síntesis de IAA, siendo la mejor caracterizada la r...

  11. Effect of overexpressing rsmA from Pseudomonas aeruginosa on virulence of select phytotoxin-producing strains of P. syringae

    Science.gov (United States)

    The GacS/GacA two-component system functions mechanistically in conjunction with the global post-transcriptional regulator RsmA to allow pseudomonads and other bacteria to adapt to changing environmental stimuli. Analysis of this Gac/Rsm signal transduction pathway in phytotoxin-producing pathovars...

  12. Comparative genomics of pseudomonas syringae pathovar tomato reveals novel chemotaxis pathways associated with motility and plant pathogenicity

    Science.gov (United States)

    The majority of bacterial foliar plant pathogens must invade the apoplast of host plants through points of ingress, such as stomata or wounds, replicate to high population density and cause disease. How pathogens navigate plant surfaces to locate invasion sites remains poorly understood. Many bacter...

  13. Dual regulation role of GH3.5 in salicylic acid and auxin signaling during Arabidopsis-Pseudomonas syringae interaction.

    Science.gov (United States)

    Zhang, Zhongqin; Li, Qun; Li, Zhimiao; Staswick, Paul E; Wang, Muyang; Zhu, Ying; He, Zuhua

    2007-10-01

    Salicylic acid (SA) plays a central role in plant disease resistance, and emerging evidence indicates that auxin, an essential plant hormone in regulating plant growth and development, is involved in plant disease susceptibility. GH3.5, a member of the GH3 family of early auxin-responsive genes in Arabidopsis (Arabidopsis thaliana), encodes a protein possessing in vitro adenylation activity on both indole-3-acetic acid (IAA) and SA. Here, we show that GH3.5 acts as a bifunctional modulator in both SA and auxin signaling during pathogen infection. Overexpression of the GH3.5 gene in an activation-tagged mutant gh3.5-1D led to elevated accumulation of SA and increased expression of PR-1 in local and systemic tissues in response to avirulent pathogens. In contrast, two T-DNA insertional mutations of GH3.5 partially compromised the systemic acquired resistance associated with diminished PR-1 expression in systemic tissues. The gh3.5-1D mutant also accumulated high levels of free IAA after pathogen infection and impaired different resistance-gene-mediated resistance, which was also observed in the GH3.6 activation-tagged mutant dfl1-D that impacted the auxin pathway, indicating an important role of GH3.5/GH3.6 in disease susceptibility. Furthermore, microarray analysis showed that the SA and auxin pathways were simultaneously augmented in gh3.5-1D after infection with an avirulent pathogen. The SA pathway was amplified by GH3.5 through inducing SA-responsive genes and basal defense components, whereas the auxin pathway was derepressed through up-regulating IAA biosynthesis and down-regulating auxin repressor genes. Taken together, our data reveal novel regulatory functions of GH3.5 in the plant-pathogen interaction.

  14. Polymyxin P is the active principle in suppressing phytopathogenic Erwinia spp. by the biocontrol rhizobacterium Paenibacillus polymyxa M-1.

    Science.gov (United States)

    Niu, Ben; Vater, Joachim; Rueckert, Christian; Blom, Jochen; Lehmann, Maik; Ru, Jin-Jiang; Chen, Xiao-Hua; Wang, Qi; Borriss, Rainer

    2013-06-18

    Nine gene clusters dedicated to nonribosomal synthesis of secondary metabolites with possible antimicrobial action, including polymyxin and fusaricidin, were detected within the whole genome sequence of the plant growth-promoting rhizobacterium (PGPR) Paenibacillus polymyxa M-1. To survey the antimicrobial compounds expressed by M-1 we analyzed the active principle suppressing phytopathogenic Erwinia spp. P. polymyxa M-1 suppressed the growth of phytopathogenic Erwinia amylovora Ea 273, and E. carotovora, the causative agents of fire blight and soft rot, respectively. By MALDI-TOF mass spectrometry and reversed-phase high-performance liquid chromatography (RP-HPLC), two antibacterial compounds bearing molecular masses of 1190.9 Da and 1176.9 Da were detected as being the two components of polymyxin P, polymyxin P1 and P2, respectively. The active principle acting against the two Erwinia strains was isolated from TLC plates and identified by postsource decay (PSD)-MALDI-TOF mass spectrometry as polymyxin P1 and polymyxin P2. These findings were corroborated by domain structure analysis of the polymyxin (pmx) gene cluster detected in the M-1 chromosome which revealed that corresponding to the chemical structure of polymyxin P, the gene cluster is encoding D-Phe in position 6 and L-Thr in position 7. Identical morphological changes in the cell wall of the bacterial phytopathogens treated with either crude polymyxin P or culture supernatant of M-1 corroborated that polymyxin P is the main component of the biocontrol effect exerted by strain M-1 against phytopathogenic Erwinia spp.

  15. Molecular characterization and pathogenicity of Erwinia spp. associated with pineapple [Ananas comosus (L. Merr.] and papaya (Carica papaya L.

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    Ramachandran Kogeethavani

    2015-12-01

    Full Text Available The Erwinia species are well-known pathogens of economic importance in Malaysia causing serious damage to high-value fruit crops that include pineapple [Ananas comosus (L. Merr.] and papaya (Carica papaya L..The 16S rRNA sequence using eubacteria fD1 and rP2 primers, identified two bacteria species; Dickeya zeae from pineapple heart rot, and Erwinia mallotivora from papaya dieback. Phylogenetic analysis based on the neighbor-joining method indicated that all the bacterial isolates clustered in their own taxa and formed monophyletic clades. From the pathogenicity test, all isolates of D. zeae and E. mallotivora showed pathogenic reactions on their respective host plants. Genetic variability of these isolates was assessed using repetitive sequence-based PCR (rep-PCR fingerprinting. The results indicated interspecies, and intraspecies variation in both species’ isolates. There were more polymorphic bands shown by rep-PCR fingerprints than enterobacterial repetitive intergenic consensus (ERIC and BOX- PCRs, however both species’ isolates produced distinguishable banding patterns. Unweighted pair-group method with arithmetic averages (UPGMA cluster analysis indicated that all Dickeya and Erwinia isolates from the same species were grouped in the same main cluster. Similarity among the isolates ranged from 77 to 99%. Sequencing of 16S rRNA using eubacteria fD1 and rP2 primers, and rep-PCR fingerprinting revealed diversity among Dickeya and Erwinia isolates. But this method appears to be reliable for discriminating isolates from pineapple heart rot and papaya dieback.

  16. Characteristics of blooming and pollen in flowers of two Syringa species (f. Oleaceae

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    Bożena Denisow

    2014-01-01

    Full Text Available The observations were conducted in long-term sequence studies in the years 2006, 2009, 2013, in the Lublin area, Poland (51o 16’ N, 22o 30’ E. The flowering phenology, diurnal pattern of blooming, pollen production and insect visitation to the shrubs of Syringa oblata Lindl. var. dilatata (Nakai Rehd. and S. meyeri ‘Palibin’ Schn. were examined. Syringa oblata var. dilatata and S. meyeri ‘Palibin’ blo- omed from the mid May till mid June. The species are characteristic of early morning diurnal pattern of blooming, with approx. of 60% of daily instalment of flowers opened before 9.00 (GMT + 2h. Both species studied had the corolla tube 2-fold deeper during the pollen shedding phase compared to bud stage (mean = 14.9 mm ± 3.2 SD vs. 7.8 mm ± 2.8. No species effect was found for the size of anthers, for the mass of pollen produced in anthers and for the pollen viability. A constant number of 2 stamens in the flowers of Syringa species entailed the pollen yield was derivative mainly to the number of developed flowers. Therefore significant differences were noted for the pollen yield between individual shrubs (mean 0.9 kg for S. meyeri ‘Palibin’, and 8.1 kg/ha for S. oblata var. dilatata . The Syringa oblata var. dilatata and S. meyeri ‘Palibin’ due to their attractive flowering period, and the abundance of blooming are suitable for different ornamental designs in urban areas. Unfortunately, despite the entomophilous flower traits, the insect visitors appeared sporadically.

  17. Pectate lyase PelI of Erwinia chrysanthemi 3937 belongs to a new family.

    Science.gov (United States)

    Shevchik, V E; Robert-Baudouy, J; Hugouvieux-Cotte-Pattat, N

    1997-12-01

    Erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pel4, pelB, pelC, pelD, and pelE genes and a set of secondary pectate lyases, two of which, pelL and pelZ, have been already identified. We cloned the pelI gene, encoding a ninth pectate lyase of E. chrysanthemi 3937. The pelI reading frame is 1,035 bases long, corresponding to a protein of 344 amino acids including a typical amino-terminal signal sequence of 19 amino acids. The purified mature PelI protein has an isoelectric point of about 9 and an apparent molecular mass of 34 kDa. PelI has a preference for partially methyl esterified pectin and presents an endo-cleaving activity with an alkaline pH optimum and an absolute requirement for Ca2+ ions. PelI is an extracellular protein secreted by the Out secretory pathway of E. chrysanthemi. The PelI protein is very active in the maceration of plant tissues. A pelI mutant displayed reduced pathogenicity on chicory leaves, but its virulence did not appear to be affected on potato tubers or Saintpaulia ionantha plants. The pelI gene constitutes an independent transcriptional unit. As shown for the other pel genes, the transcription of pelI is dependent on various environmental conditions. It is induced by pectic catabolic products and affected by growth phase, oxygen limitation, temperature, nitrogen starvation, and catabolite repression. Regulation of pelI expression appeared to be dependent on the three repressors of pectinase synthesis, KdgR, PecS, and PecT, and on the global activator of sugar catabolism, cyclic AMP receptor protein. A functional KdgR binding site was identified close to the putative pelI promoter. Analysis of the amino acid sequence of PelI revealed high homology with a pectate lyase from Erwinia carotovora subsp. carotovora (65% identity) and low homology with pectate lyases of the phytopathogenic fungus Nectria haematococca (Fusarium solani). This finding indicates that PelI belongs to pectate lyase class

  18. Pseudomonas cichorii as the causal agent of midrib rot, an emerging disease of greenhouse-grown butterhead lettuce in Flanders.

    Science.gov (United States)

    Cottyn, Bart; Heylen, Kim; Heyrman, Jeroen; Vanhouteghem, Katrien; Pauwelyn, Ellen; Bleyaert, Peter; Van Vaerenbergh, Johan; Höfte, Monica; De Vos, Paul; Maes, Martine

    2009-05-01

    Bacterial midrib rot of greenhouse-grown butterhead lettuce (Lactuca sativa L. var. capitata) is an emerging disease in Flanders (Belgium) and fluorescent pseudomonads are suspected to play an important role in the disease. Isolations from infected lettuces, collected from 14 commercial greenhouses in Flanders, yielded 149 isolates that were characterized polyphasically, which included morphological characteristics, pigmentation, pathogenicity tests by both injection and spraying of lettuce, LOPAT characteristics, FAME analysis, BOX-PCR fingerprinting, 16S rRNA and rpoB gene sequencing, as well as DNA-DNA hybridization. Ninety-eight isolates (66%) exhibited a fluorescent pigmentation and were associated with the genus Pseudomonas. Fifty-five of them induced an HR+ (hypersensitive reaction in tobacco leaves) response. The other 43 fluorescent isolates were most probably saprophytic bacteria and about half of them were able to cause rot on potato tuber slices. BOX-PCR genomic fingerprinting was used to assess the genetic diversity of the Pseudomonas midrib rot isolates. The delineated BOX-PCR patterns matched quite well with Pseudomonas morphotypes defined on the basis of colony appearance and variation in fluorescent pigmentation. 16S rRNA and rpoB gene sequence analyses allowed most of the fluorescent isolates to be allocated to Pseudomonas, and they belonged to either the Pseudomonas fluorescens group, Pseudomonas putida group, or the Pseudomonas cichorii/syringae group. In particular, the isolates allocated to this latter group constituted the vast majority of HR+ isolates and were identified as P. cichorii by DNA-DNA hybridization. They were demonstrated by spray-inoculation tests on greenhouse-grown lettuce to induce the midrib rot disease and could be re-isolated from lesions of inoculated plants. Four HR+ non-fluorescent isolates associated with one sample that showed an atypical midrib rot were identified as Dickeya sp.

  19. Production of endo-pectate lyase by two stage cultivation of Erwinia carotovora

    Energy Technology Data Exchange (ETDEWEB)

    Fukuoka, Satoshi; Kobayashi, Yoshiaki

    1987-02-26

    The productivity of endo-pectate lyase from Erwinia carotovora GIR 1044 was found to be greatly improved by two stage cultivation: in the first stage the bacterium was grown with an inducing carbon source, e.g., pectin, and in the second stage it was cultivated with glycerol, xylose, or fructose with the addition of monosodium L-glutamate as nitrogen source. In the two stage cultivation using pectin or glycerol as the carbon source the enzyme activity reached 400 units/ml, almost 3 times as much as that of one stage cultivation in a 10 liter fermentor. Using two stage cultivation in the 200 liter fermentor improved enzyme productivity over that in the 10 liter fermentor, with 500 units/ml of activity. Compared with the cultivation in Erlenmeyer flasks, fermentor cultivation improved enzyme productivity. The optimum cultivating conditions were agitation of 480 rpm with aeration of 0.5 vvm at 28 /sup 0/C. (4 figs, 4 tabs, 14 refs)

  20. Survival Strategy of Erwinia amylovora against Copper: Induction of the Viable-but-Nonculturable State

    Science.gov (United States)

    Ordax, Mónica; Marco-Noales, Ester; López, María M.; Biosca, Elena G.

    2006-01-01

    Copper compounds, widely used to control plant-pathogenic bacteria, have traditionally been employed against fire blight, caused by Erwinia amylovora. However, recent studies have shown that some phytopathogenic bacteria enter into the viable-but-nonculturable (VBNC) state in the presence of copper. To determine whether copper kills E. amylovora or induces the VBNC state, a mineral medium without copper or supplemented with 0.005, 0.01, or 0.05 mM Cu2+ was inoculated with 107 CFU/ml of this bacterium and monitored over 9 months. Total and viable cell counts were determined by epifluorescence microscopy using the LIVE/DEAD kit and by flow cytometry with 5-cyano-2,3-ditolyl tetrazolium chloride and SYTO 13. Culturable cells were counted on King's B nonselective solid medium. Changes in the bacterial morphology in the presence of copper were observed by scanning electron microscopy. E. amylovora entered into the VBNC state at all three copper concentrations assayed, much faster when the copper concentration increased. The addition of different agents which complex copper allowed the resuscitation (restoration of culturability) of copper-induced VBNC cells. Finally, copper-induced VBNC cells were virulent only for the first 5 days, while resuscitated cells always regained their pathogenicity on immature fruits over 9 months. These results have shown, for the first time, the induction of the VBNC state in E. amylovora as a survival strategy against copper. PMID:16672494

  1. High-throughput screening of Erwinia chrysanthemi pectin methylesterase variants using carbohydrate microarrays.

    Science.gov (United States)

    Øbro, Jens; Sørensen, Iben; Derkx, Patrick; Madsen, Christian T; Drews, Martin; Willer, Martin; Mikkelsen, Jørn D; Willats, William G T

    2009-04-01

    Pectin methylesterases (PMEs) catalyse the removal of methyl esters from the homogalacturonan (HG) backbone domain of pectin, a ubiquitous polysaccharide in plant cell walls. The degree of methyl esterification (DE) impacts upon the functional properties of HG within cell walls and plants produce numerous PMEs that act upon HG in muro. Many microbial plant pathogens also produce PMEs, the activity of which renders HG more susceptible to cleavage by pectin lyase and polygalacturonase enzymes and hence aids cell wall degradation. We have developed a novel microarray-based approach to investigate the activity of a series of variant enzymes based on the PME from the important pathogen Erwinia chrysanthemi. A library of 99 E. chrysanthemi PME mutants was created in which seven amino acids were altered by various different substitutions. Each mutant PME was incubated with a highly methyl esterified lime pectin substrate and, after digestion the enzyme/substrate mixtures were printed as microarrays. The loss of activity that resulted from certain mutations was detected by probing arrays with a mAb (JIM7) that preferentially binds to HG with a relatively high DE. Active PMEs therefore resulted in diminished JIM7 binding to the lime pectin substrate, whereas inactive PMEs did not. Our findings demonstrate the feasibility of our approach for rapidly testing the effects on PME activity of substituting a wide variety of amino acids at different positions.

  2. Purification, Characterization, and Effect of Thiol Compounds on Activity of the Erwinia carotovora L-Asparaginase

    Directory of Open Access Journals (Sweden)

    Suchita C. Warangkar

    2010-01-01

    Full Text Available L-asparaginase was extracted from Erwinia carotovora and purified by ammonium sulfate fractionation (60–70%, Sephadex G-100, CM cellulose, and DEAE sephadex chromatography. The apparent Mr of enzyme under nondenaturing and denaturing conditions was 150 kDa and 37±0.5 kDa, respectively. L-asparaginase activity was studied in presence of thiols, namely, L-cystine (Cys, L-methionine (Met, N-acetyl cysteine (NAC, and reduced glutathione (GSH. Kinetic parameters in presence of thiols (10–400 M showed an increase in Vmax values (2000, 2223, 2380, 2500, and control 1666.7 moles mg−1min−1 and a decrease in K values (0.086, 0.076, 0.062, 0.055 and control 0.098 mM indicating nonessential mode of activation. KA values displayed propensity to bind thiols. A decrease in Vmax/K ratio in concentration plots showed inverse relationship between free thiol groups (NAC and GSH and bound thiol group (Cys and Met. Enzyme activity was enhanced in presence of thiol protecting reagents like dithiothreitol (DTT, 2-mercaptoethanol (2-ME, and GSH, but inhibited by p-chloromercurybenzoate (PCMB and iodoacetamide (IA.

  3. Erwinia amylovora – the Causal Agent of Root Collar Necrosis of Apple Trees

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    Veljko Gavrilović

    2008-01-01

    Full Text Available A large-scale outbreak of fire blight symptoms caused by Erwinia amylovora was recorded in pome fruit trees during 2007. In addition to fruit necrosis and shoot blight as the typical disease symptoms, dark purple necrosis was observed in the root collar area girdling the trunk just above the ground and thus withering the whole apple tree. Since similar symptoms on apple trees could be caused by E. amylovora or one of several phytopathogenic fungi of the genera Phomopsis and Phytophthora, an investigation was conducted to identify the causal agent of this disease. Levan-producing, nonfluorescent bacteria were isolated from diseased samples. The isolated strains produced HR in tobacco leaves and necrosis of artificially inoculated, immature pear fruits, followed by oozing of bacterial exudate, a characterisitic of E. amylovora. Based on the results of pathogenicity tests, biochemical characteristics, ELISA test and PCR analysis, it was confirmed that the investigated strainsbelonged to E. amylovora, causing the root collar necrosis of apple trees as an atypical symptom of this bacterium in Serbia. The explanation of this symptom may be that the vegetative rootstocks were infected with E. amylovora. Therefore, the development of diagnostic protocols for detection of E. amylovora in apple rootstock is very important for health inspections of planting materials.

  4. Fire blight (Erwinia amylovora [Burrill] Winslow in Morocco: importance, geographical distribution and characterization

    Directory of Open Access Journals (Sweden)

    M'Barek FATMI

    2011-09-01

    Full Text Available Fire blight, caused by Erwinia amylovora, was detected in Morocco in 2006 and has spread rapidly throughout the most important pome fruit-producing regions. Surveys were carried out in 2009 in the main pome fruit-growing areas in Morocco to evaluate the current situation of the disease in the country, particularly in the El Hajeb region, where important losses due to this pathogen were recorded. Samples showing symptoms associated with the disease were collected from affected apple (Malus domestica, pear (Pyrus communis and quince (Cydonia oblonga trees and processed for the isolation and purification of the causal agent. Other isolates collected in the period 2006–2008 were also included in this study. All the isolates were identified to genus and species levels using morphological, biochemical and serological tests. Confi rmation tests were carried out using classical PCR and Real-time PCR. Forty eight Moroccan isolates were confirmed to belong to E. amylovora. Fingerprinting methods (rep-PCR and fAFLP showed a diversity of the isolates and resulted in grouping them in four separate subgroups. This study suggests that Moroccan isolates of  E. amylovora have multiple geographical origins.

  5. Medfly Ceratitis capitata as Potential Vector for Fire Blight Pathogen Erwinia amylovora: Survival and Transmission.

    Directory of Open Access Journals (Sweden)

    Mónica Ordax

    Full Text Available Monitoring the ability of bacterial plant pathogens to survive in insects is required for elucidating unknown aspects of their epidemiology and for designing appropriate control strategies. Erwinia amylovora is a plant pathogenic bacterium that causes fire blight, a devastating disease in apple and pear commercial orchards. Studies on fire blight spread by insects have mainly focused on pollinating agents, such as honeybees. However, the Mediterranean fruit fly (medfly Ceratitis capitata (Diptera: Tephritidae, one of the most damaging fruit pests worldwide, is also common in pome fruit orchards. The main objective of the study was to investigate whether E. amylovora can survive and be transmitted by the medfly. Our experimental results show: i E. amylovora can survive for at least 8 days inside the digestive tract of the medfly and until 28 days on its external surface, and ii medflies are able to transmit the bacteria from inoculated apples to both detached shoots and pear plants, being the pathogen recovered from lesions in both cases. This is the first report on E. amylovora internalization and survival in/on C. capitata, as well as the experimental transmission of the fire blight pathogen by this insect. Our results suggest that medfly can act as a potential vector for E. amylovora, and expand our knowledge on the possible role of these and other insects in its life cycle.

  6. Insecticidal Bacillus thuringiensis Silences Erwinia carotovora Virulence by a New Form of Microbial Antagonism, Signal Interference

    Science.gov (United States)

    Dong, Yi-Hu; Zhang, Xi-Fen; Xu, Jin-Ling; Zhang, Lian-Hui

    2004-01-01

    It is commonly known that bacteria may produce antibiotics to interfere with the normal biological functions of their competitors in order to gain competitive advantages. Here we report that Bacillus thuringiensis suppressed the quorum-sensing-dependent virulence of plant pathogen Erwinia carotovora through a new form of microbial antagonism, signal interference. E. carotovora produces and responds to acyl-homoserine lactone (AHL) quorum-sensing signals to regulate antibiotic production and expression of virulence genes, whereas B. thuringiensis strains possess AHL-lactonase, which is a potent AHL-degrading enzyme. B. thuringiensis did not seem to interfere with the normal growth of E. carotovora; rather, it abolished the accumulation of AHL signal when they were cocultured. In planta, B. thuringiensis significantly decreased the incidence of E. carotovora infection and symptom development of potato soft rot caused by the pathogen. The biocontrol efficiency is correlated with the ability of bacterial strains to produce AHL-lactonase. While all the seven AHL-lactonase-producing B. thuringiensis strains provided significant protection against E. carotovora infection, Bacillus fusiformis and Escherichia coli strains that do not process AHL-degradation enzyme showed little effect in biocontrol. Mutation of aiiA, the gene encoding AHL-lactonase in B. thuringiensis, resulted in a substantial decrease in biocontrol efficacy. These results suggest that signal interference mechanisms existing in natural ecosystems could be explored as a new version of antagonism for prevention of bacterial infections. PMID:14766576

  7. Medfly Ceratitis capitata as Potential Vector for Fire Blight Pathogen Erwinia amylovora: Survival and Transmission

    Science.gov (United States)

    Ordax, Mónica; Piquer-Salcedo, Jaime E.; Santander, Ricardo D.; Sabater-Muñoz, Beatriz; Biosca, Elena G.; López, María M.; Marco-Noales, Ester

    2015-01-01

    Monitoring the ability of bacterial plant pathogens to survive in insects is required for elucidating unknown aspects of their epidemiology and for designing appropriate control strategies. Erwinia amylovora is a plant pathogenic bacterium that causes fire blight, a devastating disease in apple and pear commercial orchards. Studies on fire blight spread by insects have mainly focused on pollinating agents, such as honeybees. However, the Mediterranean fruit fly (medfly) Ceratitis capitata (Diptera: Tephritidae), one of the most damaging fruit pests worldwide, is also common in pome fruit orchards. The main objective of the study was to investigate whether E. amylovora can survive and be transmitted by the medfly. Our experimental results show: i) E. amylovora can survive for at least 8 days inside the digestive tract of the medfly and until 28 days on its external surface, and ii) medflies are able to transmit the bacteria from inoculated apples to both detached shoots and pear plants, being the pathogen recovered from lesions in both cases. This is the first report on E. amylovora internalization and survival in/on C. capitata, as well as the experimental transmission of the fire blight pathogen by this insect. Our results suggest that medfly can act as a potential vector for E. amylovora, and expand our knowledge on the possible role of these and other insects in its life cycle. PMID:25978369

  8. Kinetic Properties of α-Galactosidase and the Localization of Total Proteins in Erwinia chrysanthemi

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    John Morgan Brand

    2004-01-01

    Full Text Available Erwinia chrysanthemi is an enterobacterium that causes soft-rot in plants in general, resulting in enormous economic losses annually. For the pathogen to survive in the host plant, it has to use the readily assimilable compounds from the host fluids and degrade the host tissue. To accomplish this, E. chrysanthemi produces several extracellular and intracellular enzymes. Among the intracellular enzymes there is a special digestive class, the galactosidases, which can be either periplasmic or cytoplasmic. α-Galactosidase is known to degrade melibiose and raffinose into glucose and galactose, and into galactose and sucrose respectively. The aim of the present study was to investigate the kinetic properties of α-galactosidase in E. chrysanthemi, and the localization of total proteins, after culturing it in the presence of raffinose and melibiose. The α-galactosidase that degrades melibiose seems to be the same enzyme that is also responsible for the breakdown of raffinose in E. chrysanthemi. It is localized mainly in the cytoplasm with a fraction of between 2.4 and 5.4 % localized in the periplasm. The majority of E. chrysanthemi proteins have cytoplasmic localization.

  9. Characterization of the Erwinia chrysanthemi gan Locus, Involved in Galactan Catabolism▿ †

    Science.gov (United States)

    Delangle, Aurélie; Prouvost, Anne-France; Cogez, Virginie; Bohin, Jean-Pierre; Lacroix, Jean-Marie; Cotte-Pattat, Nicole Hugouvieux

    2007-01-01

    β-1,4-Galactan is a major component of the ramified regions of pectin. Analysis of the genome of the plant pathogenic bacteria Erwinia chrysanthemi revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. The predicted transport system would comprise a specific porin GanL and an ABC transporter made of four proteins, GanFGK2. Degradation of galactans would be catalyzed by the periplasmic 1,4-β-endogalactanase GanA, which released oligogalactans from trimer to hexamer. After their transport through the inner membrane, oligogalactans would be degraded into galactose by the cytoplasmic 1,4-β-exogalactanase GanB. Mutants affected for the porin or endogalactanase were unable to grow on galactans, but they grew on galactose and on a mixture of galactotriose, galactotetraose, galactopentaose, and galactohexaose. Mutants affected for the periplasmic galactan binding protein, the transporter ATPase, or the exogalactanase were only able to grow on galactose. Thus, the phenotypes of these mutants confirmed the functionality of the gan locus in transport and catabolism of galactans. These mutations did not affect the virulence of E. chrysanthemi on chicory leaves, potato tubers, or Saintpaulia ionantha, suggesting an accessory role of galactan utilization in the bacterial pathogeny. PMID:17644603

  10. Characterization and virulence properties of Erwinia chrysanthemi lipopolysaccharide-defective, phi EC2-resistant mutants.

    Science.gov (United States)

    Schoonejans, E; Expert, D; Toussaint, A

    1987-09-01

    Outer membrane alterations were characterized in spontaneous mutants of the Erwinia chrysanthemi 3937jRH, which were selected for resistance to bacteriophage phi EC2. All but one of the mutants analyzed were affected in their lipopolysaccharide (LPS) structure, lacking the entire heterogeneous region of apparent high molecular weight present in the wild-type E. chrysanthemi LPS. At least two 3937jRH mutants, one selected as phi EC2 resistant (RH6065) and the other previously selected (D. Expert and A. Toussaint, J. Bacteriol. 163:221-227, 1985) as bacteriocin resistant (R1456), were cross-resistant to bacteriophage Mu and had rough LPSs with an altered core structure. Two phi EC2r mutants (RH6053 and RH6065) were most severely affected in their outer membrane integrity and also lost their virulence on saintpaulia plants, although they still possessed normal extracellular levels of pectinolytic and cellulolytic activities. The two Mur mutants RH6065 and R1456 were also able to induce systemic resistance in the challenged plant. All the other phi EC2r mutants retained the virulence of 393jRH.

  11. Iron Deficiency Induced by Chrysobactin in Saintpaulia Leaves Inoculated with Erwinia chrysanthemi.

    Science.gov (United States)

    Neema, C.; Laulhere, J. P.; Expert, D.

    1993-07-01

    In this communication, we examine the fate of iron during soft rot pathogenesis caused by Erwinia chrysanthemi on its host, Saintpaulia ionantha. The spread of soft rot caused by this enterobacterium was previously shown to depend on a functional genetic locus encoding a high-affinity iron assimilation system involving the catechol-type siderophore chrysobactin. Leaf intercellular fluid from healthy plants was analyzed with regard to the iron content and its availability for bacterial growth. It was compared to the fluid from diseased plants for the presence of strong iron ligands, using a new approach based on the iron-binding property of an ion-exchange resin. Further characterization allowed the identification of chrysobactin in diseased tissues, thus providing the first evidence for the external release of a microbial siderophore during pathogenesis. Competition for nutritional iron was also studied through a plant-bacterial cell system: iron incorporated into plant ferritin appeared to be considerably reduced in bacteria-treated suspension soybean cells. The same effect was visualized during treatment of soybean cells with axenic leaf intercellular fluid from E. chrysanthemi-inoculated saintpaulia leaves or with chrysobactin.

  12. The PecT repressor coregulates synthesis of exopolysaccharides and virulence factors in Erwinia chrysanthemi.

    Science.gov (United States)

    Condemine, G; Castillo, A; Passeri, F; Enard, C

    1999-01-01

    Erwinia chrysanthemi 3937 synthesizes an exopolysaccharide (EPS) composed of rhamnose, galactose, and galacturonic acid. Fourteen transcriptional fusions in genes required for EPS synthesis, named eps, were obtained by Tn5-B21 mutagenesis. Eleven of them are clustered on the chromosome and are repressed by PecT, a regulator of pectate lyase synthesis. In addition, expression of these fusions is repressed by the catabolite regulatory protein, CRP, and induced in low osmolarity medium. The three other mutations are located in genes that are not regulated by pecT. A 13-kb DNA fragment containing pecT-regulated eps genes has been cloned. All the genes identified on this fragment are transcribed in the same orientation and could form a large operon. The promoter region of this operon has been sequenced. It contains a JUMP-start sequence, a sequence required for the expression of polysaccharide-associated operons. E. chrysanthemi 3937 produces a systemic soft rot on its host Saintpaulia ionantha. An eps mutant was less efficient than the wild-type strain in initiating a maceration symptom, suggesting that production of EPS is required for the full expression of the E. chrysanthemi virulence.

  13. Characterization of the Erwinia chrysanthemi Gan locus, involved in galactan catabolism.

    Science.gov (United States)

    Delangle, Aurélie; Prouvost, Anne-France; Cogez, Virginie; Bohin, Jean-Pierre; Lacroix, Jean-Marie; Cotte-Pattat, Nicole Hugouvieux

    2007-10-01

    beta-1,4-Galactan is a major component of the ramified regions of pectin. Analysis of the genome of the plant pathogenic bacteria Erwinia chrysanthemi revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. The predicted transport system would comprise a specific porin GanL and an ABC transporter made of four proteins, GanFGK(2). Degradation of galactans would be catalyzed by the periplasmic 1,4-beta-endogalactanase GanA, which released oligogalactans from trimer to hexamer. After their transport through the inner membrane, oligogalactans would be degraded into galactose by the cytoplasmic 1,4-beta-exogalactanase GanB. Mutants affected for the porin or endogalactanase were unable to grow on galactans, but they grew on galactose and on a mixture of galactotriose, galactotetraose, galactopentaose, and galactohexaose. Mutants affected for the periplasmic galactan binding protein, the transporter ATPase, or the exogalactanase were only able to grow on galactose. Thus, the phenotypes of these mutants confirmed the functionality of the gan locus in transport and catabolism of galactans. These mutations did not affect the virulence of E. chrysanthemi on chicory leaves, potato tubers, or Saintpaulia ionantha, suggesting an accessory role of galactan utilization in the bacterial pathogeny.

  14. Sucrose isomerase and its mutants from Erwinia rhapontici can synthesise α-arbutin.

    Science.gov (United States)

    Zhou, Xing; Zheng, Yuantao; Wei, Xingming; Yang, Kedi; Yang, Xiangkai; Wang, Yuting; Xu, Liming; Du, Liqin; Huang, Ribo

    2011-10-01

    Sucrose isomerase (SI) from Erwinia rhapontici is an intramolecular isomerase that is normally used to synthesise isomaltulose from sucrose by a mechanism of intramolecular transglycosylation. In this study, it was found that SI could synthesise α-arbutin using hydroquinone and sucrose as substrates, via an intermolecular transglycosylation reaction. Five phenylalanine residues (F185, F186, F205, F297, and F321) in the catalytic pocket of SI were chosen for sitedirected mutagenesis. Mutants F185I, F321I, and F321W, whose hydrolytic activities were enhanced after the mutation, could synthesise α-arbutin through intermolecular transglycosylation with a more than two-fold increase in the molar transfer ratio compared with wild type SI. The F297A mutant showed a strong ability to synthesise a novel α-arbutin derivative and a four-fold increase in its specific activity for intermolecular transglycosylation over the wild type. Our findings may lead to a new way to synthesise novel glucoside products such as α-arbutin derivatives by simply manipulating the Phe residues in the catalytic pocket. From the structure superposition, our strategy of manipulating these Phe residues may be applicable to other similar transglycosylating enzymes.

  15. [Multiple change of phenotype, conjugated with the loss of yellow pigmentation of Erwinia herbicola].

    Science.gov (United States)

    Tovkach, F I; Tovkach, A F

    2004-01-01

    It has been shown that the loss of yellow pigmentation (phenotype Crt) of nonphotosynthesizing epiphyte bacterium Erwinia herbicola is accompanied by the loss of prototrophicity (phenotype Thi). Most Crt Thi-variants change the character of sensitivity to temperate erwiniophage E105 and bacteriocins (phenotype Ph/Bn). Some of them become sensitive to the killer effect of their own bacteriocins--autocins (phenotype Au). Multiple change of the phenotype in E. herbicola occurs so spontaneously as under variable growing of bacteria at the optimal and supraoptimal growth temperature. It is also established that the cells of one of the strains stop synthesizing the additional carotenoid or synthesize the changed products. It is shown that carotenoid synthesis in the cells of E. herbicola g157/5k may be reduced by means of transduction of the Crt phenotype by lipid-containing bacteriophage UA1. Multiple change of the phenotype connected with the loss of yellow pigmentation by E. herbicola was referred to the phenomenon of the population dissociation which is similar to that in E. carotovora.

  16. Characterization of the biocontrol activity of pseudomonas fluorescens strain X reveals novel genes regulated by glucose.

    Directory of Open Access Journals (Sweden)

    Gerasimos F Kremmydas

    Full Text Available Pseudomonas fluorescens strain X, a bacterial isolate from the rhizosphere of bean seedlings, has the ability to suppress damping-off caused by the oomycete Pythium ultimum. To determine the genes controlling the biocontrol activity of strain X, transposon mutagenesis, sequencing and complementation was performed. Results indicate that, biocontrol ability of this isolate is attributed to gcd gene encoding glucose dehydrogenase, genes encoding its co-enzyme pyrroloquinoline quinone (PQQ, and two genes (sup5 and sup6 which seem to be organized in a putative operon. This operon (named supX consists of five genes, one of which encodes a non-ribosomal peptide synthase. A unique binding site for a GntR-type transcriptional factor is localized upstream of the supX putative operon. Synteny comparison of the genes in supX revealed that they are common in the genus Pseudomonas, but with a low degree of similarity. supX shows high similarity only to the mangotoxin operon of Ps. syringae pv. syringae UMAF0158. Quantitative real-time PCR analysis indicated that transcription of supX is strongly reduced in the gcd and PQQ-minus mutants of Ps. fluorescens strain X. On the contrary, transcription of supX in the wild type is enhanced by glucose and transcription levels that appear to be higher during the stationary phase. Gcd, which uses PQQ as a cofactor, catalyses the oxidation of glucose to gluconic acid, which controls the activity of the GntR family of transcriptional factors. The genes in the supX putative operon have not been implicated before in the biocontrol of plant pathogens by pseudomonads. They are involved in the biosynthesis of an antimicrobial compound by Ps. fluorescens strain X and their transcription is controlled by glucose, possibly through the activity of a GntR-type transcriptional factor binding upstream of this putative operon.

  17. Inhibition of Pseudomonas aeruginosa virulence: characterization of the AprA-AprI interface and species selectivity.

    Science.gov (United States)

    Bardoel, Bart W; van Kessel, Kok P M; van Strijp, Jos A G; Milder, Fin J

    2012-01-20

    Pseudomonas aeruginosa secretes the virulence factor alkaline protease (AprA) to enhance its survival. AprA cleaves one of the key microbial recognition molecules, monomeric flagellin, and thereby diminishes Toll-like receptor 5 activation. In addition, AprA degrades host proteins such as complement proteins and cytokines. P. aeruginosa encodes a highly potent inhibitor of alkaline protease (AprI) that is solely located in the periplasm where it is presumed to protect periplasmic proteins against secreted AprA. We set out to study the enzyme-inhibitor interactions in more detail in order to provide a basis for future drug development. Structural and mutational studies reveal that the conserved N-terminal residues of AprI occupy the protease active site and are essential for inhibitory activity. We constructed peptides mimicking the N-terminus of AprI; however, these were incapable of inhibiting AprA-mediated flagellin cleavage. Furthermore, we expressed and purified AprI of P. aeruginosa and the homologous (37% sequence identity) AprI of Pseudomonas syringae, which remarkably show species specificity for their cognate protease. Exchange of the first five N-terminal residues between AprI of P. syringae and P. aeruginosa did not affect the observed specificity, whereas exchange of only six residues located at the AprI surface that contacts the protease did abolish specificity. These findings are elementary steps toward the design of molecules derived from the natural inhibitor of the virulence factor AprA and their use in therapeutic applications in Pseudomonas and other Gram-negative infections. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. PENGARUH APLIKASI PSEUDOMONAS FLUORESCENS P60 TERHADAP MUTU PATOLOGIS, MUTU FISIOLOGIS, DAN PERTUMBUHAN BIBIT PADI IR 64

    Directory of Open Access Journals (Sweden)

    Lisa Navitasari

    2014-08-01

    Full Text Available Effect of Pseudomonas fluorescens P60 on pathological and physiological quality and growth of rice IR 64  seedlings. The research objectives were (1 detection and identification of seed-borne pathogens of IR 64 rice, (2 testing Pseudomonas fluorescents P60 in inhibiting the in vitro growth of seed-borne pathogens colonies, (3 testing P. fluorescents P60 for pathological and physiological seed quality, and (4 testing P. fluorescents P60 on the growth of seedlings in the greenhouse. The results showed that some seed-borne pathogens can be found both on farmers’ IR 64 rice and factory’s; they were Aspergillus flavus, Alternaria padwickii, Pseudomonas glumae, and P. syringae. Application of P. flourescens P60 was able to inhibit the in vitrogrowth of colonies of all seed-borne pathogens, except P. syringae.  Related to pathological quality, the effect of P. flourescens P60 on percentage of seed-borne pathogens attack did not significantly different from that of benomil but smaller than distilled water. On the physiological quality of seeds, treatment of P. flourescens P60 has the same effect with benomil and distilled water, with  germination rate was more than 80%. In the greenhouse study,treatment of seed immersion time  in P. flourescens P60 suspension showed that the effect of immersion time as long as15 minutes and 25 minutes on  seedling height, root length, and seedling dry weightdid not significantly different. were. However, 25 minutes immersion time resulted in fresh seedling weight and root dry weight higher than that of 15 minutes immersion time.

  19. Production of glucosyltransferase by Erwinia sp. using experimental design and response surface methodology Produção de glicosiltransferase por Erwinia sp. utilizando planejamento experimental e metodologia de superfície de resposta

    Directory of Open Access Journals (Sweden)

    Haroldo Yukio Kawaguti

    2005-09-01

    Full Text Available Glucosyltransferase produced by strain Erwinia sp. is an intracellular enzyme that catalyzes the formation of isomaltulose from sucrose. Isomaltulose is a non-cariogenic reducing dissacharide commercially used in foods. Response surface methodology and 2³-factorial central composite design were employed to optimize a fermentation medium for the production of glucosyltransferase by Erwinia sp. in shaken flasks at 200 rpm and 30ºC. The three variables involved in this study were sugar cane molasses (SCM, corn steep liquor (CSL and yeast extract Prodex Lac SD (YEP. The statistical analysis of the results showed that, in the range studied, all the factors had a significant effect on glucosyltransferase production and the optimum medium composition for enzyme production was (in g l-1 SCM-100, CSL-60 and YEP-8, which lead to a glucosyltransferase activity of 6.65 U mL-1.A glicosiltransferase obtida pela linhagem Erwinia sp. é uma enzima intracelular que catalisa a conversão de sacarose em isomaltulose. A isomaltulose é um dissacarídeo redutor, não cariogênico e comercialmente utilizado em alimentos como substituto da sacarose. A metodologia de superfície de resposta e planejamento fatorial composto central-2³ foram utilizados para otimizar o meio de cultivo para a produção de glicosiltransferase de Erwinia sp. em frascos sob agitação a 200 rpm e 30ºC. As três variáveis independentes envolvidas no estudo foram o melaço de cana de açúcar, a água de maceração de milho e o extrato de levedura Prodex Lac SD. As análises estatísticas dos resultados mostraram que, dentro da faixa estudada das concentrações dos componentes de meio de cultivo, todas as variáveis apresentaram efeito significativo na produção de glicosiltransferase. O meio de cultivo otimizado foi composto de 100 gL-1 de melaço de cana de açúcar, 60 gL-1 de água de maceração de milho e 8 gL-1 de extrato de levedura Prodex Lac SD, apresentando atividade de

  20. Pseudomonas orientalis F9: A Potent Antagonist against Phytopathogens with Phytotoxic Effect in the Apple Flower

    Directory of Open Access Journals (Sweden)

    Veronika Zengerer

    2018-02-01

    Full Text Available In light of public concerns over the use of pesticides and antibiotics in plant protection and the subsequent selection for spread of resistant bacteria in the environment, it is inevitable to broaden our knowledge about viable alternatives, such as natural antagonists and their mode of action. The genus Pseudomonas is known for its metabolic versatility and genetic plasticity, encompassing pathogens as well as antagonists. We characterized strain Pseudomonas orientalis F9, an isolate from apple flowers in a Swiss orchard, and determined its antagonistic activity against several phytopathogenic bacteria, in particular Erwinia amylovora, the causal agent of fire blight. P. orientalis F9 displayed antagonistic activity against a broad suite of phytopathogenic bacteria in the in vitro tests. The promising results from this analysis led to an ex vivo assay with E. amylovora CFBP1430Rif and P. orientalis F9 infected detached apple flowers. F9 diminished the fire blight pathogen in the flowers but also revealed phytotoxic traits. The experimental results were discussed in light of the complete genome sequence of F9, which revealed the strain to carry phenazine genes. Phenazines are known to contribute to antagonistic activity of bacterial strains against soil pathogens. When tested in the cress assay with Pythium ultimum as pathogen, F9 showed results comparable to the known antagonist P. protegens CHA0.

  1. Antagonistic intestinal microflora produces antimicrobial substance inhibitory to Pseudomonas species and other spoilage organisms.

    Science.gov (United States)

    Hatew, Bayissa; Delessa, Tenagne; Zakin, Vered; Gollop, Natan

    2011-10-01

    Chicken intestine harbors a vast number of bacterial strains. In the present study, antimicrobial substance produced by lactic acid bacteria (LAB) isolated from the gastrointestinal tract of healthy chicken was detected, characterized, and purified. Based on 16S rRNA sequencing, the bacteria were identified as Lactobacillus plantarum vN. The antimicrobial substance produced by this bacterium was designated vN-1 and exhibited a broad-spectrum of activity against many important pathogenic and spoilage microorganisms, including Pseudomonas aeruginosa, Staphylococcus aureus, Micrococcus luteus, Salmonella Typhimurium, and Erwinia amylovova. vN-1 was determined to be thermostable, insensitive to pH values ranging from 2.0 to 8.0, resistant to various organic solvents and to enzymatic inactivation. The inhibition kinetics displayed a bactericidal mode of action. This study revealed an antimicrobial substance with low molecular mass of less than 1 kDa as determined by ultrafiltration and having features not previously reported for LAB isolated from chicken intestines. The detection of this antimicrobial substance addresses an important aspect of biotechnological control agents of spoilage caused by Pseudomonas spp. and promises the possibility for preservation of refrigerated poultry meat. Practical Application:  The newly characterized antimicrobial substance and designated as vN-1 may have the potential to be used in food preservation. © 2011 Institute of Food Technologists®

  2. Caracterização de bactérias do género Erwinia causando podridões em plantas ornamentais no Brasil.

    Directory of Open Access Journals (Sweden)

    Irene M.G. Almeida

    1996-05-01

    Full Text Available São descritas as ocorrências de fito-bacterioses em plantios comerciais, ocasionando podridão mole em seis espécies de plantas ornamentais. Testes bioquímicos, fisiológicos, culturais e de patogenicidade permitiram cons-tatar a ocorrência de Erwinia carotovora subsp. carotovora em plantas de comigo-ninguém-pode e orquídea (Phalaenopsis, e de Erwinia chrysanthemi em amarilis, comigo-ninguém-pode, filodendro, orquídeas (Miltonia e Phalaenopsis e violeta africana.

  3. [Phytochemical and pharmacological progress on peeled stem of Syringa pinnatifolia, a Mongolian folk medicine].

    Science.gov (United States)

    Su, Guo-zhu; Chen, Jie; Cao, Yuan; Bai, Rui-feng; Chen, Su-yi-le; Tu, Peng-fei; Chai, Xing-yun

    2015-11-01

    The peeled stem of Syringa pinnatifolia is a Mongolia folk medicine, mainly distributed in Helan mountain, inner Mongolia and Ningxia provinces of China. It has been used for the treatment of cardiopalmus, angina pectoris, and cardiopulmonary diseases for a long history. Contemporary research revealed the presence of major lignans, sesquitepenes, and essential oils, and showed myocardial ischemia related diseases. This review summarizes the plant origins, taxonomic disputes, phytochemical and pharmacological research progress, hopefully to provide reference for full medicinal utilization, clarification of biological effective substance, and drug development.

  4. Molecular cloning and characterization of an Erwinia carotovora subsp. carotovora pectin lyase gene that responds to DNA-damaging agents.

    OpenAIRE

    McEvoy, J L; Murata, H; Chatterjee, A K

    1990-01-01

    recA-mediated production of pectin lyase (PNL) and the bacteriocin carotovoricin occurs in Erwinia carotovora subsp. carotovora 71 when this organism is subjected to agents that damage or inhibit the synthesis of DNA. The structural gene pnlA was isolated from a strain 71 cosmid gene library following mobilization of the cosmids into a moderate PNL producer, strain 193. The cosmid complemented pnl::Tn5 but not ctv::Tn5 mutations. A constitutive level of PNL activity was detected in RecA+ and ...

  5. Population Structure of Pseudomonas aeruginosa

    National Research Council Canada - National Science Library

    Lutz Wiehlmann; Gerd Wagner; Nina Cramer; Benny Siebert; Peter Gudowius; Gracia Morales; Thilo Köhler; Christian van Delden; Christian Weinel; Peter Slickers; Burkhard Tümmler

    2007-01-01

    The metabolically versatile Gram-negative bacterium Pseudomonas aeruginosa inhabits terrestrial, aquatic, animal-, human-, and plant-host-associated environments and is an important causative agent...

  6. Role of motility and chemotaxis in the pathogenesis of Dickeya dadantii 3937 (ex Erwinia chrysanthemi 3937).

    Science.gov (United States)

    Antúnez-Lamas, María; Cabrera-Ordóñez, Ezequiel; López-Solanilla, Emilia; Raposo, Rosa; Trelles-Salazar, Oswaldo; Rodríguez-Moreno, Andrés; Rodríguez-Palenzuela, Pablo

    2009-02-01

    Dickeya dadantii 3937 (ex Erwinia chrysanthemi), a member of the Enterobacteriaceae, causes soft rot in many economically important crops. A successful pathogen has to reach the interior of the plant in order to cause disease. To study the role of motility and chemotaxis in the pathogenicity of D. dadantii 3937, genes involved in the chemotactic signal transduction system (cheW, cheB, cheY and cheZ) and in the structure of the flagellar motor (motA) were mutagenized. All the mutant strains grew like the wild-type in culture media, and the production and secretion of pectolytic enzymes was not affected. As expected, the swimming ability of the mutant strains was reduced with respect to the wild-type: motA (94%), cheY (80%), cheW (74%), cheB (54%) and cheZ (48%). The virulence of the mutant strains was analysed in chicory, Saintpaulia and potato. The mutant strains were also tested for their capability to enter into Arabidopsis leaves. All the mutants showed a significant decrease of virulence in certain hosts; however, the degree of virulence reduction varied depending on the virulence assay. The ability to penetrate Arabidopsis leaves was impaired in all the mutants, whereas the capacity to colonize potato tubers after artificial inoculation was affected in only two mutant strains. In general, the virulence of the mutants could be ranked as motA

  7. Global effect of indole-3-acetic acid biosynthesis on multiple virulence factors of Erwinia chrysanthemi 3937.

    Science.gov (United States)

    Yang, Shihui; Zhang, Qiu; Guo, Jianhua; Charkowski, Amy O; Glick, Bernard R; Ibekwe, A Mark; Cooksey, Donald A; Yang, Ching-Hong

    2007-02-01

    Production of the plant hormone indole-3-acetic acid (IAA) is widespread among plant-associated microorganisms. The non-gall-forming phytopathogen Erwinia chrysanthemi 3937 (strain Ech3937) possesses iaaM (ASAP16562) and iaaH (ASAP16563) gene homologues. In this work, the null knockout iaaM mutant strain Ech138 was constructed. The IAA production by Ech138 was reduced in M9 minimal medium supplemented with l-tryptophan. Compared with wild-type Ech3937, Ech138 exhibited reduced ability to produce local maceration, but its multiplication in Saintpaulia ionantha was unaffected. The pectate lyase production of Ech138 was diminished. Compared with wild-type Ech3937, the expression levels of an oligogalacturonate lyase gene, ogl, and three endopectate lyase genes, pelD, pelI, and pelL, were reduced in Ech138 as determined by a green fluorescent protein-based fluorescence-activated cell sorting promoter activity assay. In addition, the transcription of type III secretion system (T3SS) genes, dspE (a putative T3SS effector) and hrpN (T3SS harpin), was found to be diminished in the iaaM mutant Ech138. Compared with Ech3937, reduced expression of hrpL (a T3SS alternative sigma factor) and gacA but increased expression of rsmA in Ech138 was also observed, suggesting that the regulation of T3SS and pectate lyase genes by IAA biosynthesis might be partially due to the posttranscriptional regulation of the Gac-Rsm regulatory pathway.

  8. PR genes of apple: identification and expression in response to elicitors and inoculation with Erwinia amylovora

    Directory of Open Access Journals (Sweden)

    Kim Jihyun F

    2006-10-01

    Full Text Available Abstract Background In the past decade, much work has been done to dissect the molecular basis of the defence signalling pathway in plants known as Systemic Acquired Resistance (SAR. Most of the work has been carried out in model species such as Arabidopsis, with little attention paid to woody plants. However within the range of species examined, components of the pathway seem to be highly conserved. In this study, we attempted to identify downstream components of the SAR pathway in apple to serve as markers for its activation. Results We identified three pathogenesis related (PR genes from apple, PR-2, PR-5 and PR-8, which are induced in response to inoculation with the apple pathogen, Erwinia amylovora, but they are not induced in young apple shoots by treatment with known elicitors of SAR in herbaceous plants. We also identified three PR-1-like genes from apple, PR-1a, PR-1b and PR-1c, based solely on sequence similarity to known PR-1 genes of model (intensively researched herbaceous plants. The PR-1-like genes were not induced in response to inoculation with E. amylovora or by treatment with elicitors; however, each showed a distinct pattern of expression. Conclusion Four PR genes from apple were partially characterized. PR-1a, PR-2, PR-5 and PR-8 from apple are not markers for SAR in young apple shoots. Two additional PR-1-like genes were identified through in-silico analysis of apple ESTs deposited in GenBank. PR-1a, PR-1b and PR-1c are not involved in defence response or SAR in young apple shoots; this conclusion differs from that reported previously for young apple seedlings.

  9. Erwinia amylovora CRISPR elements provide new tools for evaluating strain diversity and for microbial source tracking.

    Directory of Open Access Journals (Sweden)

    Gayle C McGhee

    Full Text Available Clustered regularly interspaced short palindromic repeats (CRISPRs comprise a family of short DNA repeat sequences that are separated by non repetitive spacer sequences and, in combination with a suite of Cas proteins, are thought to function as an adaptive immune system against invading DNA. The number of CRISPR arrays in a bacterial chromosome is variable, and the content of each array can differ in both repeat number and in the presence or absence of specific spacers. We utilized a comparative sequence analysis of CRISPR arrays of the plant pathogen Erwinia amylovora to uncover previously unknown genetic diversity in this species. A total of 85 E. amylovora strains varying in geographic isolation (North America, Europe, New Zealand, and the Middle East, host range, plasmid content, and streptomycin sensitivity/resistance were evaluated for CRISPR array number and spacer variability. From these strains, 588 unique spacers were identified in the three CRISPR arrays present in E. amylovora, and these arrays could be categorized into 20, 17, and 2 patterns types, respectively. Analysis of the relatedness of spacer content differentiated most apple and pear strains isolated in the eastern U.S. from western U.S. strains. In addition, we identified North American strains that shared CRISPR genotypes with strains isolated on other continents. E. amylovora strains from Rubus and Indian hawthorn contained mostly unique spacers compared to apple and pear strains, while strains from loquat shared 79% of spacers with apple and pear strains. Approximately 23% of the spacers matched known sequences, with 16% targeting plasmids and 5% targeting bacteriophage. The plasmid pEU30, isolated in E. amylovora strains from the western U.S., was targeted by 55 spacers. Lastly, we used spacer patterns and content to determine that streptomycin-resistant strains of E. amylovora from Michigan were low in diversity and matched corresponding streptomycin-sensitive strains

  10. Horizontal Gene Acquisitions, Mobile Element Proliferation, and Genome Decay in the Host-Restricted Plant Pathogen Erwinia Tracheiphila.

    Science.gov (United States)

    Shapiro, Lori R; Scully, Erin D; Straub, Timothy J; Park, Jihye; Stephenson, Andrew G; Beattie, Gwyn A; Gleason, Mark L; Kolter, Roberto; Coelho, Miguel C; De Moraes, Consuelo M; Mescher, Mark C; Zhaxybayeva, Olga

    2016-03-18

    Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains of the cucurbit bacterial wilt pathogen Erwinia tracheiphila (Enterobacteriaceae) isolated from infected squash plants in New York, Pennsylvania, Kentucky, and Michigan. These genomes exhibit a high proportion of recent horizontal gene acquisitions, invasion and remarkable amplification of mobile genetic elements, and pseudogenization of approximately 20% of the coding sequences. These genome attributes indicate that E. tracheiphila recently emerged as a host-restricted pathogen. Furthermore, chromosomal rearrangements associated with phage and transposable element proliferation contribute to substantial differences in gene content and genetic architecture between the six E. tracheiphila strains and other Erwinia species. Together, these data lead us to hypothesize that E. tracheiphila has undergone recent evolution through both genome decay (pseudogenization) and genome expansion (horizontal gene transfer and mobile element amplification). Despite evidence of dramatic genomic changes, the six strains are genetically monomorphic, suggesting a recent population bottleneck and emergence into E. tracheiphila's current ecological niche. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  11. Erwinia amylovora Novel Plasmid pEI70: Complete Sequence, Biogeography, and Role in Aggressiveness in the Fire Blight Phytopathogen

    Science.gov (United States)

    Llop, Pablo; Cabrefiga, Jordi; Smits, Theo H. M.; Dreo, Tanja; Barbé, Silvia; Pulawska, Joanna; Bultreys, Alain; Blom, Jochen; Duffy, Brion; Montesinos, Emilio; López, María M.

    2011-01-01

    Comparative genomics of several strains of Erwinia amylovora, a plant pathogenic bacterium causal agent of fire blight disease, revealed that its diversity is primarily attributable to the flexible genome comprised of plasmids. We recently identified and sequenced in full a novel 65.8 kb plasmid, called pEI70. Annotation revealed a lack of known virulence-related genes, but found evidence for a unique integrative conjugative element related to that of other plant and human pathogens. Comparative analyses using BLASTN showed that pEI70 is almost entirely included in plasmid pEB102 from E. billingiae, an epiphytic Erwinia of pome fruits, with sequence identities superior to 98%. A duplex PCR assay was developed to survey the prevalence of plasmid pEI70 and also that of pEA29, which had previously been described in several E. amylovora strains. Plasmid pEI70 was found widely dispersed across Europe with frequencies of 5–92%, but it was absent in E. amylovora analyzed populations from outside of Europe. Restriction analysis and hybridization demonstrated that this plasmid was identical in at least 13 strains. Curing E. amylovora strains of pEI70 reduced their aggressiveness on pear, and introducing pEI70 into low-aggressiveness strains lacking this plasmid increased symptoms development in this host. Discovery of this novel plasmid offers new insights into the biogeography, evolution and virulence determinants in E. amylovora. PMID:22174857

  12. Production of isomaltulose obtained by Erwinia sp. cells submitted to different treatments and immobilized in calcium alginate

    Directory of Open Access Journals (Sweden)

    Haroldo Yukio Kawaguti

    2011-03-01

    Full Text Available In recent decades, there has been an increase in the studies of isomaltulose obtainment, due to its physicochemical properties and physiological health benefits. These properties, which include low cariogenicity, low glycemic index and greater stability, allow the use of this sweetener as a substitute for sucrose in foods; besides the fact that it can be converted to isomalt, a dietary non-cariogenic sugar alcohol used in pharmaceuticals as well as in the food industry. Isomaltulose (6-O-α-D-glucopyronosyl-1-6-D-fructofuranose is a disaccharide reducer obtained by the enzymatic conversion of sucrose - the α-glucosyltransferase enzyme. Different treatments were performed for the preparation of whole cells; lysed cells; and crude enzyme extract of Erwinia sp. D12 strain immobilized in calcium alginate. The packed bed column of granules, containing Erwinia sp. cells sonicated and immobilized in calcium alginate (CSI, reached a maximum conversion of 53-59% sucrose into isomaltulose and it presented activity for 480 hours. The converted syrup was purified and the isomaltulose crystallization was performed through the lowering of temperature. The isomaltulose crystals presented purity of 96.5%.

  13. Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Maria; Bjarnsholt, Thomas; Givskov, Michael

    2014-01-01

    The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form...... biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling...

  14. Ferric Uptake Regulator Fur Is Conditionally Essential in Pseudomonas aeruginosa.

    Science.gov (United States)

    Pasqua, Martina; Visaggio, Daniela; Lo Sciuto, Alessandra; Genah, Shirley; Banin, Ehud; Visca, Paolo; Imperi, Francesco

    2017-11-15

    In Pseudomonas aeruginosa, the ferric uptake regulator (Fur) protein controls both metabolism and virulence in response to iron availability. Differently from other bacteria, attempts to obtain fur deletion mutants of P. aeruginosa failed, leading to the assumption that Fur is an essential protein in this bacterium. By investigating a P. aeruginosa conditional fur mutant, we demonstrate that Fur is not essential for P. aeruginosa growth in liquid media, biofilm formation, and pathogenicity in an insect model of infection. Conversely, Fur is essential for growth on solid media since Fur-depleted cells are severely impaired in colony formation. Transposon-mediated random mutagenesis experiments identified pyochelin siderophore biosynthesis as a major cause of the colony growth defect of the conditional fur mutant, and deletion mutagenesis confirmed this evidence. Impaired colony growth of pyochelin-proficient Fur-depleted cells does not depend on oxidative stress, since Fur-depleted cells do not accumulate higher levels of reactive oxygen species (ROS) and are not rescued by antioxidant agents or overexpression of ROS-detoxifying enzymes. Ectopic expression of pch genes revealed that pyochelin production has no inhibitory effects on a fur deletion mutant of Pseudomonas syringae pv. tabaci, suggesting that the toxicity of the pch locus in Fur-depleted cells involves a P. aeruginosa-specific pathway(s).IMPORTANCE Members of the ferric uptake regulator (Fur) protein family are bacterial transcriptional repressors that control iron uptake and storage in response to iron availability, thereby playing a crucial role in the maintenance of iron homeostasis. While fur null mutants of many bacteria have been obtained, Fur appears to be essential in Pseudomonas aeruginosa for still unknown reasons. We obtained Fur-depleted P. aeruginosa cells by conditional mutagenesis and showed that Fur is dispensable for planktonic growth, while it is required for colony formation. This is

  15. Halogenated furanones from the red alga, Delisea pulchra, inhibit carbapenem antibiotic synthesis and exoenzyme virulence factor production in the phytopathogen Erwinia carotovora

    DEFF Research Database (Denmark)

    Manefield, M.; Welch, M.; Givskov, Michael Christian

    2001-01-01

    The plant pathogen Erwinia carotovora regulates expression of virulence factors and antibiotic production via an N-3- oxohexanoyl-L-homoserine lactone (3-oxo-C6-HSL) dependent quorum sensing mechanism. The marine alga Delisea pulchra produces halogenated furanones known to antagonise 3-oxo-C6-HSL...

  16. Replication arrest is a major threat to growth at low temperature in Antarctic Pseudomonas syringae Lz4W.

    Science.gov (United States)

    Sinha, Anurag K; Pavankumar, Theetha L; Kamisetty, Srinivasulu; Mittal, Pragya; Ray, Malay K

    2013-08-01

    Chromosomal damage was detected previously in the recBCD mutants of the Antarctic bacterium Pseudomonas syringae Lz4W, which accumulated linear chromosomal DNA leading to cell death and growth inhibition at 4°C. RecBCD protein generally repairs DNA double-strand breaks by RecA-dependent homologous recombination pathway. Here we show that ΔrecA mutant of P. syringae is not cold-sensitive. Significantly, inactivation of additional DNA repair genes ruvAB rescued the cold-sensitive phenotype of ΔrecBCD mutant. The ΔrecA and ΔruvAB mutants were UV-sensitive as expected. We propose that, at low temperature DNA replication encounters barriers leading to frequent replication fork (RF) arrest and fork reversal. RuvAB binds to the reversed RFs (RRFs) having Holliday junction-like structures and resolves them upon association with RuvC nuclease to cause linearization of the chromosome, a threat to cell survival. RecBCD prevents this by degrading the RRFs, and facilitates replication re-initiation. This model is consistent with our observation that low temperature-induced DNA lesions do not evoke SOS response in P. syringae. Additional studies show that two other repair genes, radA (encoding a RecA paralogue) and recF are not involved in providing cold resistance to the Antarctic bacterium. © 2013 John Wiley & Sons Ltd.

  17. Draft genome sequence analysis of a Pseudomonas putida W15Oct28 strain with antagonistic activity to Gram-positive and Pseudomonas sp. pathogens.

    Directory of Open Access Journals (Sweden)

    Lumeng Ye

    Full Text Available Pseudomonas putida is a member of the fluorescent pseudomonads known to produce the yellow-green fluorescent pyoverdine siderophore. P. putida W15Oct28, isolated from a stream in Brussels, was found to produce compound(s with antimicrobial activity against the opportunistic pathogens Staphylococcus aureus, Pseudomonas aeruginosa, and the plant pathogen Pseudomonas syringae, an unusual characteristic for P. putida. The active compound production only occurred in media with low iron content and without organic nitrogen sources. Transposon mutants which lost their antimicrobial activity had the majority of insertions in genes involved in the biosynthesis of pyoverdine, although purified pyoverdine was not responsible for the antagonism. Separation of compounds present in culture supernatants revealed the presence of two fractions containing highly hydrophobic molecules active against P. aeruginosa. Analysis of the draft genome confirmed the presence of putisolvin biosynthesis genes and the corresponding lipopeptides were found to contribute to the antimicrobial activity. One cluster of ten genes was detected, comprising a NAD-dependent epimerase, an acetylornithine aminotransferase, an acyl CoA dehydrogenase, a short chain dehydrogenase, a fatty acid desaturase and three genes for a RND efflux pump. P. putida W15Oct28 genome also contains 56 genes encoding TonB-dependent receptors, conferring a high capacity to utilize pyoverdines from other pseudomonads. One unique feature of W15Oct28 is also the presence of different secretion systems including a full set of genes for type IV secretion, and several genes for type VI secretion and their VgrG effectors.

  18. Evaluation of Likelihood of Co-Occurrence of Erwinia amylovora with Mature Fruit of Winter Pear.

    Science.gov (United States)

    Temple, Todd N; Stockwell, Virginia O; Pusey, P Lawrence; Johnson, Kenneth B

    2007-10-01

    ABSTRACT Phytosanitary concerns about fire blight prohibit export of U.S.-grown pears to some countries without this disease. To examine these concerns, we evaluated the potential for co-occurrence of Erwinia amylovora with mature, symptomless winter pear fruit by inoculation experiments and by survey of commercial orchards. Immature pear and apple fruit were inoculated in orchards with E. amylovora strain 153N as resuspended lyophilized cells or as ooze from diseased tissues. Regardless of inoculum source, population size of Ea153N on fruit declined by an order of magnitude every 3 to 4 days during the first 2 weeks after inoculation; at 56 days after inoculation, Ea153N was not detected, except on 1 of 450 fruit with 4 colony forming units (CFU). After inoculation of flowers, calyx-end survival of Ea153N on pear and apple fruit declined from high populations at petal fall to a few cells at harvest, with no detection of the pathogen after a 7-week cold storage. Migration of Ea153N into symptomless pear fruit from diseased branches was evaluated by enrichment assay and nested polymerase chain reaction of internal fruit core tissues; these assays failed to detect the pathogen in healthy fruit from diseased trees. At harvest, E. amylovora could not be detected on 5,599 of 5,600 fruit of d'Anjou pear sampled from commercial orchards in major production areas of the Pacific Northwest; one fruit yielded 32 CFU of the pathogen. Postharvest, mature pear fruit contaminated with Ea153N and subsequently wounded required a dose of >10,000 cells at the wound site to allow for persistence of the pathogen through a 7-week-cold storage. We conclude that epiphytic E. amylovora shows similar survival characteristics on both pear and apple fruit, this pathogen is not an endophyte within mature symptomless pear fruit, its presence is exceptionally rare on commercially produced fruit, and that epiphytic survival of E. amylovora through a postharvest chilling period is unlikely given

  19. Erwinia carotovora elicitors and Botrytis cinerea activate defense responses in Physcomitrella patens

    Directory of Open Access Journals (Sweden)

    Bentancor Marcel

    2007-10-01

    Full Text Available Abstract Background Vascular plants respond to pathogens by activating a diverse array of defense mechanisms. Studies with these plants have provided a wealth of information on pathogen recognition, signal transduction and the activation of defense responses. However, very little is known about the infection and defense responses of the bryophyte, Physcomitrella patens, to well-studied phytopathogens. The purpose of this study was to determine: i whether two representative broad host range pathogens, Erwinia carotovora ssp. carotovora (E.c. carotovora and Botrytis cinerea (B. cinerea, could infect Physcomitrella, and ii whether B. cinerea, elicitors of a harpin (HrpN producing E.c. carotovora strain (SCC1 or a HrpN-negative strain (SCC3193, could cause disease symptoms and induce defense responses in Physcomitrella. Results B. cinerea and E.c. carotovora were found to readily infect Physcomitrella gametophytic tissues and cause disease symptoms. Treatments with B. cinerea spores or cell-free culture filtrates from E.c. carotovoraSCC1 (CF(SCC1, resulted in disease development with severe maceration of Physcomitrella tissues, while CF(SCC3193 produced only mild maceration. Although increased cell death was observed with either the CFs or B. cinerea, the occurrence of cytoplasmic shrinkage was only visible in Evans blue stained protonemal cells treated with CF(SCC1 or inoculated with B. cinerea. Most cells showing cytoplasmic shrinkage accumulated autofluorescent compounds and brown chloroplasts were evident in a high proportion of these cells. CF treatments and B. cinerea inoculation induced the expression of the defense-related genes: PR-1, PAL, CHS and LOX. Conclusion B. cinerea and E.c. carotovora elicitors induce a defense response in Physcomitrella, as evidenced by enhanced expression of conserved plant defense-related genes. Since cytoplasmic shrinkage is the most common morphological change observed in plant PCD, and that harpins and B

  20. Characterization of indigoidine biosynthetic genes in Erwinia chrysanthemi and role of this blue pigment in pathogenicity.

    Science.gov (United States)

    Reverchon, Sylvie; Rouanet, Carine; Expert, Dominique; Nasser, William

    2002-02-01

    In the plant-pathogenic bacterium Erwinia chrysanthemi production of pectate lyases, the main virulence determinant, is modulated by a complex network involving several regulatory proteins. One of these regulators, PecS, also controls the synthesis of a blue pigment identified as indigoidine. Since production of this pigment is cryptic in the wild-type strain, E. chrysanthemi ind mutants deficient in indigoidine synthesis were isolated by screening a library of Tn5-B21 insertions in a pecS mutant. These ind mutations were localized close to the regulatory pecS-pecM locus, immediately downstream of pecM. Sequence analysis of this DNA region revealed three open reading frames, indA, indB, and indC, involved in indigoidine biosynthesis. No specific function could be assigned to IndA. In contrast, IndB displays similarity to various phosphatases involved in antibiotic synthesis and IndC reveals significant homology with many nonribosomal peptide synthetases (NRPS). The IndC product contains an adenylation domain showing the signature sequence DAWCFGLI for glutamine recognition and an oxidation domain similar to that found in various thiazole-forming NRPS. These data suggest that glutamine is the precursor of indigoidine. We assume that indigoidine results from the condensation of two glutamine molecules that have been previously cyclized by intramolecular amide bond formation and then dehydrogenated. Expression of ind genes is strongly derepressed in the pecS background, indicating that PecS is the main regulator of this secondary metabolite synthesis. DNA band shift assays support a model whereby the PecS protein represses indA and indC expression by binding to indA and indC promoter regions. The regulatory link, via pecS, between indigoidine and virulence factor production led us to explore a potential role of indigoidine in E. chrysanthemi pathogenicity. Mutants impaired in indigoidine production were unable to cause systemic invasion of potted Saintpaulia ionantha

  1. Characterization of the pelL gene encoding a novel pectate lyase of Erwinia chrysanthemi 3937.

    Science.gov (United States)

    Lojkowska, E; Masclaux, C; Boccara, M; Robert-Baudouy, J; Hugouvieux-Cotte-Pattat, N

    1995-06-01

    Erwinia chrysanthemi 3937 secretes five major isoenzymes of pectate lyases encoded by the pelA, pelB, pelC, pelD and pelE genes. Recently, a new set of pectate lyases was identified in E. chrysanthemi mutants deleted of those pel genes. We cloned the pelL gene, encoding one of these secondary pectate lyases of E. chrysanthemi 3937, from a genomic bank of a strain deleted of the five major pel genes. The nucleotide sequence of the region containing the pelL gene was determined. The pelL reading frame is 1275 bases long, corresponding to a protein of 425 amino acids including a typical amino-terminal signal sequence of 25 amino acids. Comparison of the amino acid sequences of PelL and the exo-pectate lyase PelX of E. chrysanthemi EC16 revealed a low homology, limited to 220 residues of the central part of the proteins. No homology was detected with other bacterial pectinolytic enzymes. Regulation of pelL transcription was analysed using gene fusion. As shown for the other pel genes, the transcription of pelL is dependent on various environmental conditions. It is induced by pectic catabolic products and affected by growth phase, temperature, iron starvation, osmolarity, anaerobiosis, nitrogen starvation and catabolite repression. Regulation of pelL expression appeared to be independent of the KdgR repressor, which controls all the steps of pectin catabolism. In contrast, the pecS gene, which is involved in regulation of the synthesis of the major pectate lyases and of cellulase, also appeared to be involved in pelL expression. The PelL protein is able to macerate plant tissue. This enzyme has a basic isoelectric point, presents an endo-cleaving activity on polygalacturonate or partially methylated pectin, with a basic pH optimum and an absolute requirement for Ca2+. The pelL mutant displayed a reduced virulence on potato tubers and Saintpaulia ionantha plants, demonstrating the important role of this enzyme in soft-rot disease.

  2. Characterization of the exopolygalacturonate lyase PelX of Erwinia chrysanthemi 3937.

    Science.gov (United States)

    Shevchik, V E; Kester, H C; Benen, J A; Visser, J; Robert-Baudouy, J; Hugouvieux-Cotte-Pattat, N

    1999-03-01

    Erwinia chrysanthemi 3937 secretes several pectinolytic enzymes, among which eight isoenzymes of pectate lyases with an endo-cleaving mode (PelA, PelB, PelC, PelD, PelE, PelI, PelL, and PelZ) have been identified. Two exo-cleaving enzymes, the exopolygalacturonate lyase, PelX, and an exo-poly-alpha-D-galacturonosidase, PehX, have been previously identified in other E. chrysanthemi strains. Using a genomic bank of a 3937 mutant with the major pel genes deleted, we cloned a pectinase gene identified as pelX, encoding the exopolygalacturonate lyase. The deduced amino acid sequence of the 3937 PelX is very similar to the PelX of another E. chrysanthemi strain, EC16, except in the 43 C-terminal amino acids. PelX also has homology to the endo-pectate lyase PelL of E. chrysanthemi but has a N-terminal extension of 324 residues. The transcription of pelX, analyzed by gene fusions, is dependent on several environmental conditions. It is induced by pectic catabolic products and affected by growth phase, oxygen limitation, nitrogen starvation, and catabolite repression. Regulation of pelX expression is dependent on the KdgR repressor, which controls almost all the steps of pectin catabolism, and on the global activator of sugar catabolism, cyclic AMP receptor protein. In contrast, PecS and PecT, two repressors of the transcription of most pectate lyase genes, are not involved in pelX expression. The pelX mutant displayed reduced pathogenicity on chicory leaves, but its virulence on potato tubers or Saintpaulia ionantha plants did not appear to be affected. The purified PelX protein has no maceration activity on plant tissues. Tetragalacturonate is the best substrate of PelX, but PelX also has good activity on longer oligomers. Therefore, the estimated number of binding subsites for PelX is 4, extending from subsites -2 to +2. PelX and PehX were shown to be localized in the periplasm of E. chrysanthemi 3937. PelX catalyzed the formation of unsaturated digalacturonates by

  3. Predictive modelling of the combined effect of temperature and water activity on the in vitro growth of Erwinia spp. infecting potato tubers in Belgium

    Directory of Open Access Journals (Sweden)

    Moh, AA.

    2011-01-01

    Full Text Available Erwinia carotovora ssp. atroseptica (Eca, Erwinia carotovora ssp. carotovora (Ecc and Erwinia chrysanthemi (Ech, are the main cause of potato tuber decay (soft rot in storage and stem rot in the field (blackleg. The bacteria are characterized by the production of several extracellular pectic enzymes among them Pectate Lyase (PEL activity is the most important key of pathogenesis. It has been reported that ecological parameters such as humidity and temperature, greatly influence the disease development. The objective of this work was to determine the in vitro effect of water activity (0.960, 0.980, 0.997 and temperature (10, 15 and 20°C and their interactions on the growth parameters of Eca, Ecc and Ech using optical density (OD measurement. The maximum specific growth rate (µmax was calculated under each aw-temperature combinations for the three Erwinia species. Statistical analysis showed a significant effect of aw and temperature on µmax. We noticed that Eca and Ecc grow faster than Ech in our condition. A second aim of this work was to monitor the PEL specific activity under the combined effect of these two factors (aw-temperature. Our results showed an increase of PEL specific activity with the temperature whatever are the bacterial strains. But contrary to growth, this research did not show an increase of PEL specific activity with aw except the treatment at 15 and 20°C for all bacteria strains. According to our obtained results on growth and PEL production we concluded that Eca 03034/1 and Ecc 030033 had the same ecological behavior comparatively to Ech 03/016/1 in the range of the values of the two factors (aw and temperature investigated here. To our knowledge, this research is the first publication which pointed out the combined in vitro effect of aw and temperature on the growth of Erwinia genius according to literature data.

  4. [Meningoencephalitis caused by Pseudomonas cepacia].

    Science.gov (United States)

    Pérez Monrás, Miriam Fina; Batlle Almodóvar, María del Carmen; González, Cernero; Tamargo Martínez, Isis; Meneses, Félix Dickinson

    2006-01-01

    A case of meningoencephalitis of bacterial etiology caused by Pseudomonas cepacia was described. The strain was received at the Reference Laboratory of Bacterial Acute Respiratory Infections of "Pedro Kouri" Institute of Tropical Medicine, where its microbiological identification was confirmed. This isolation was a finding in an adult immunocompetent patient. The evolution was favourable with no sequelae for his future life. Pseudomona cepacia has been associated with respiratory infections in patients with cystic fibrosis. Patients with Pseudomonas cepacia may be asymptomatic or present fatal acute and fulminant infection.

  5. Pseudomonas aeruginosa biofilm infections

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2014-01-01

    Bacteria in natural, industrial and clinical settings predominantly live in biofilms, i.e., sessile structured microbial communities encased in self-produced extracellular matrix material. One of the most important characteristics of microbial biofilms is that the resident bacteria display...... a remarkable increased tolerance toward antimicrobial attack. Biofilms formed by opportunistic pathogenic bacteria are involved in devastating persistent medical device-associated infections, and chronic infections in individuals who are immune-compromised or otherwise impaired in the host defense. Because...... the use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially...

  6. Erwinia chrysanthemi: pectolytic bacterium causing soft rot outbreaks of arracacha in Brazil Erwinia chrysanthemi: bactéria pectolítica envolvida na "mela" da mandioquinha-salsa no Brasil

    Directory of Open Access Journals (Sweden)

    Gilmar Paulo Henz

    2006-10-01

    Full Text Available The objetive of this work was to identify the pectolytic bacteria associated with soft rot of arracacha roots in Brazil. From 1998 to 2001, 227 isolates of Erwinia spp. were obtained from arracacha roots and identified by biochemical and physiological tests (pectolytic activity, lecithinase, a-methyl glucoside, phosphatase, erythromycin sensivity, growth at 37ºC. Of these isolates, 89.9% were identified as E. chrysanthemi (Ech, 9.7% as E. carotovora subsp. carotovora (Ecc and 0.5% as E. carotovora subsp. atroseptica. The identity of seventeen out of twenty representative isolates of Ech and Ecc was confirmed by PCR (primers '149f', 'L1r', 'ADE1', 'ADE2'.O objetivo deste trabalho foi identificar as bactérias pectolíticas envolvidas na podridão-mole de raízes de mandioquinha-salsa no Brasil. De 1998 a 2001, 227 isolados de Erwinia spp. foram obtidos de raízes de mandioquinha-salsa e identificados por testes bioquímicos e fisiológicos (atividade pectolítica, lecitinase, a-methyl glucosídeo, fosfatase, sensibilidade à eritromicina, crescimento a 37ºC. Destes isolados, 89,9% foram identificados como E. chrysanthemi (Ech, 9,7% como E. carotovora subsp. carotovora (Ecc e somente 0,5% como E. carotovora subsp. atroseptica. A identidade de 20 isolados representativos de Ech e Ecc foi confirmada por PCR (primers '149f', 'L1r', 'ADE1', 'ADE2', com exceção de dois isolados de Ech e um de Ecc.

  7. Transcriptome Analysis of Syringa oblata Lindl. Inflorescence Identifies Genes Associated with Pigment Biosynthesis and Scent Metabolism.

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    Jian Zheng

    Full Text Available Syringa oblata Lindl. is a woody ornamental plant with high economic value and characteristics that include early flowering, multiple flower colors, and strong fragrance. Despite a long history of cultivation, the genetics and molecular biology of S. oblata are poorly understood. Transcriptome and expression profiling data are needed to identify genes and to better understand the biological mechanisms of floral pigments and scents in this species. Nine cDNA libraries were obtained from three replicates of three developmental stages: inflorescence with enlarged flower buds not protruded, inflorescence with corolla lobes not displayed, and inflorescence with flowers fully opened and emitting strong fragrance. Using the Illumina RNA-Seq technique, 319,425,972 clean reads were obtained and were assembled into 104,691 final unigenes (average length of 853 bp, 41.75% of which were annotated in the NCBI non-redundant protein database. Among the annotated unigenes, 36,967 were assigned to gene ontology categories and 19,956 were assigned to eukaryoticorthologous groups. Using the Kyoto Encyclopedia of Genes and Genomes pathway database, 12,388 unigenes were sorted into 286 pathways. Based on these transcriptomic data, we obtained a large number of candidate genes that were differentially expressed at different flower stages and that were related to floral pigment biosynthesis and fragrance metabolism. This comprehensive transcriptomic analysis provides fundamental information on the genes and pathways involved in flower secondary metabolism and development in S. oblata, providing a useful database for further research on S. oblata and other plants of genus Syringa.

  8. Pseudomonas folliculitis in Arabian baths.

    Science.gov (United States)

    Molina-Leyva, Alejandro; Ruiz-Ruigomez, Maria

    2013-07-14

    A 35-year-old man presented with a painful cutaneous skin eruption that was localized on the upper trunk. He stated that the previous weekend he had attended an Arabian bath. The physical examination revealed multiple hair follicle-centered papulopustules surrounded by an erythematous halo. A clinical diagnosis of pseudomonas folliculitis was made and treatment was prescribed. Afterwards Pseudomonas aeruginosa was isolated from a pustule culture. Pseudomonas folliculitis is a bacterial infection of the hair follicles. The most common reservoirs include facilities with hot water and complex piping systems that are difficult to clean, such as hot tubs and bathtubs. Despite adequate or high chlorine levels, Pseudomonas aeruginosa can grow within a biofilm.

  9. Final screening assessment for Pseudomonas putida ATCC 12633, Pseudomonas putida ATCC 31483, Pseudomonas putida ATCC 31800, Pseudomonas putida ATCC 700369

    National Research Council Canada - National Science Library

    2017-01-01

    "Pursuant to paragraph 74(b) of the Canadian Environmental Protection Act, 1999 (CEPA), the Minister of the Environment and the Minister of Health have conducted a screening assessment on four strains of Pseudomonas putida...

  10. Chronic Pseudomonas aeruginosa cervical osteomyelitis

    Directory of Open Access Journals (Sweden)

    Sujeet Kumar Meher

    2016-01-01

    Full Text Available Pseudomonas aeruginosa is a rare cause of osteomyelitis of the cervical spine and is usually seen in the background of intravenous drug use and immunocompromised state. Very few cases of osteomyelitis of the cervical spine caused by pseudomonas aeruginosa have been reported in otherwise healthy patients. This is a case presentation of a young female, who in the absence of known risk factors for cervical osteomyelitis presented with progressively worsening neurological signs and symptoms.

  11. Genome comparison of the epiphytic bacteria Erwinia billingiae and E. tasmaniensis with the pear pathogen E. pyrifoliae

    Directory of Open Access Journals (Sweden)

    Kuhl Heiner

    2010-06-01

    Full Text Available Abstract Background The genus Erwinia includes plant-associated pathogenic and non-pathogenic Enterobacteria. Important pathogens such as Erwinia amylovora, the causative agent of fire blight and E. pyrifoliae causing bacterial shoot blight of pear in Asia belong to this genus. The species E. tasmaniensis and E. billingiae are epiphytic bacteria and may represent antagonists for biocontrol of fire blight. The presence of genes that are putatively involved in virulence in E. amylovora and E. pyrifoliae is of special interest for these species in consequence. Results Here we provide the complete genome sequences of the pathogenic E. pyrifoliae strain Ep1/96 with a size of 4.1 Mb and of the non-pathogenic species E. billingiae strain Eb661 with a size of 5.4 Mb, de novo determined by conventional Sanger sequencing and next generation sequencing techniques. Genome comparison reveals large inversions resulting from homologous recombination events. Furthermore, comparison of deduced proteins highlights a relation of E. billingiae strain Eb661 to E. tasmaniensis strain Et1/99 and a distance to E. pyrifoliae for the overall gene content as well as for the presence of encoded proteins representing virulence factors for the pathogenic species. Pathogenicity of E. pyrifoliae is supposed to have evolved by accumulation of potential virulence factors. E. pyrifoliae carries factors for type III secretion and cell invasion. Other genes described as virulence factors for E. amylovora are involved in the production of exopolysaccharides, the utilization of plant metabolites such as sorbitol and sucrose. Some virulence-associated genes of the pathogenic species are present in E. tasmaniensis but mostly absent in E. billingiae. Conclusion The data of the genome analyses correspond to the pathogenic lifestyle of E. pyrifoliae and underlines the epiphytic localization of E. tasmaniensis and E. billingiae as a saprophyte.

  12. Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa

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    Carlos Eduardo Domenech

    2011-01-01

    Full Text Available Pseudomonas aeruginosa synthesizes phosphorylcholine phosphatase (PchP when grown on choline, betaine, dimethylglycine or carnitine. In the presence of Mg2+ or Zn2+, 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 synthesis may reflect an adaptive response of P. aeruginosa to environmental conditions. Bioinformatic and biochemistry studies shown that PchP contains two sites for alkylammonium compounds (AACs: one in the catalytic site near the metal ion-phosphoester pocket, and another in an inhibitory site responsible for the binding of the alkylammonium moiety. Both sites could be close to each other and interact through the residues 42E, 43E and 82YYY84. Zn2+ is better activator than Mg2+ at pH 5.0 and it is more effective at alleviating the inhibition produced by the entry of Pcho or different AACs in the inhibitory site. We postulate that Zn2+ induces at pH 5.0 a conformational change in the active center that is communicated to the inhibitory site, producing a compact or closed structure. However, at pH 7.4, this effect is not observed because to the hydrolysis of the [Zn2+L2−1L20(H2O2] complex, which causes a change from octahedral to tetrahedral in the metal coordination geometry. This enzyme is also present in P. fluorescens, P. putida, P. syringae, and other organisms. We have recently crystallized PchP and solved its structure.

  13. Identification of a bacterial pectin acetyl esterase in Erwinia chrysanthemi 3937.

    Science.gov (United States)

    Shevchik, V E; Hugouvieux-Cotte-Pattat, N

    1997-06-01

    Erwinia chrysanthemi causes soft-rot diseases of various plants by enzymatic degradation of the pectin in plant cell walls. The structural complexity of pectin requires the combined action of several pectinases for its efficient breakdown. Three types of pectinases have so far been identified in E. chrysanthemi: two pectin methyl esterases (PemA, PemB), a polygalacturonase (PehX), and eight pectate lyases (PelA, PelB, PelC, PelD, PelE, PelL, PelZ, PelX). We report in this paper the analysis of a novel enzyme, the pectin acetyl esterase encoded by the paeY gene. No bacterial form of pectin acetyl esterases has been described previously, while plant tissues and some pectinolytic fungi were found to produce similar enzymes. The paeY gene is present in a cluster of five pectinase-encoding genes, pelA-pelE-pelD-paeY-pemA. The paeY open reading frame is 1650 bases long and encodes a 551-residue precursor protein of 60704Da, including a 25-amino-acid signal peptide. PaeY shares one region of homology with a rhamnogalacturonan acetyl esterase of Aspergillus aculeatus. To characterize the enzyme, the paeY gene was overexpressed and its protein product was purified. PaeY releases acetate from sugar-beet pectin and from various synthetic substrates. Moreover, the enzyme was shown to act in synergy with other pectinases. The de-esterification rate by PaeY increased after previous demethylation of the pectins by PemA and after depolymerization of the pectin by pectate lyases. In addition, the degradation of sugar-beet pectin by pectate lyases is favoured after the removal of methyl and acetyl groups by PemA and PaeY, respectively. The paeY gene was first identified on the basis of its regulation, which shares several characteristics with that of other pectinases. Analysis of the paeY transcription, using gene fusions, revealed that it is induced by pectic catabolic products and is affected by growth phase, oxygen limitation and catabolite repression. Regulation of pae

  14. Mobile genetic elements in the genome of the beneficial rhizobacterium Pseudomonas fluorescens Pf-5.

    Science.gov (United States)

    Mavrodi, Dmitri V; Loper, Joyce E; Paulsen, Ian T; Thomashow, Linda S

    2009-01-13

    Pseudomonas fluorescens Pf-5 is a plant-associated bacterium that inhabits the rhizosphere of a wide variety of plant species and and produces secondary metabolites suppressive of fungal and oomycete plant pathogens. The Pf-5 genome is rich in features consistent with its commensal lifestyle, and its sequence has revealed attributes associated with the strain's ability to compete and survive in the dynamic and microbiologically complex rhizosphere habitat. In this study, we analyzed mobile genetic elements of the Pf-5 genome in an effort to identify determinants that might contribute to Pf-5's ability to adapt to changing environmental conditions and/or colonize new ecological niches. Sequence analyses revealed that the genome of Pf-5 is devoid of transposons and IS elements and that mobile genetic elements (MGEs) are represented by prophages and genomic islands that collectively span over 260 kb. The prophages include an F-pyocin-like prophage 01, a chimeric prophage 03, a lambdoid prophage 06, and decaying prophages 02, 04 and 05 with reduced size and/or complexity. The genomic islands are represented by a 115-kb integrative conjugative element (ICE) PFGI-1, which shares plasmid replication, recombination, and conjugative transfer genes with those from ICEs found in other Pseudomonas spp., and PFGI-2, which resembles a portion of pathogenicity islands in the genomes of the plant pathogens Pseudomonas syringae and P. viridiflava. Almost all of the MGEs in the Pf-5 genome are associated with phage-like integrase genes and are integrated into tRNA genes. Comparative analyses reveal that MGEs found in Pf-5 are subject to extensive recombination and have evolved in part via exchange of genetic material with other Pseudomonas spp. having commensal or pathogenic relationships with plants and animals. Although prophages and genomic islands from Pf-5 exhibit similarity to MGEs found in other Pseudomonas spp., they also carry a number of putative niche-specific genes that

  15. Immobilization of Erwinia sp. D12 Cells in Alginate-Gelatin Matrix and Conversion of Sucrose into Isomaltulose Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Haroldo Yukio Kawaguti

    2011-01-01

    Full Text Available Isomaltulose is a noncariogenic reducing disaccharide and also a structural isomer of sucrose and is used by the food industry as a sucrose replacement. It is obtained through enzymatic conversion of microbial sucrose isomerase. An Erwinia sp. D12 strain is capable of converting sucrose into isomaltulose. The experimental design technique was used to study the influence of immobilization parameters on converting sucrose into isomaltulose in a batch process using shaken Erlenmeyer flasks. We assessed the effect of gelatin and transglutaminase addition on increasing the reticulation of granules of Erwinia sp. D12 cells immobilized in alginate. Independent parameters, sodium alginate concentration, cell mass concentration, CaCl2 concentration, gelatin concentration, and transglutaminase concentration had all a significant effect (P<0.05 on isomaltulose production. Erwinia sp. D12 cells immobilized in 3.0% (w/v sodium alginate, 47.0% (w/v cell mass, 0.3 molL-1 CaCl2, 1.7% (w/v gelatin and 0.15% (w/v transglutaminase presented sucrose conversion into isomaltulose, of around 50–60% in seven consecutive batches.

  16. Discovery of ADP-ribosylation and other plant defense pathway elements through expression profiling of four different Arabidopsis-Pseudomonas R-avr interactions.

    Science.gov (United States)

    Adams-Phillips, Lori; Wan, Jinrong; Tan, Xiaoping; Dunning, F Mark; Meyers, Blake C; Michelmore, Richard W; Bent, Andrew F

    2008-05-01

    A dissection of plant defense pathways was initiated through gene expression profiling of the responses of a single Arabidopsis thaliana genotype to isogenic Pseudomonas syringae strains expressing one of four different cloned avirulence (avr) genes. Differences in the expression profiles elicited by different resistance (R)-avr interactions were observed. A role for poly(ADP-ribosyl)ation in plant defense responses was suggested initially by the upregulated expression of genes encoding NUDT7 and poly(ADP-ribose) glycohydrolase in multiple R-avr interactions. Gene knockout plant lines were tested for 20 candidate genes identified by the expression profiling, and Arabidopsis NUDT7 mutants allowed less growth of virulent P. syringae (as previously reported) but also exhibited a reduced hypersensitive-response phenotype. Inhibitors of poly(ADP-ribose) polymerase (PARP) disrupted FLS2-mediated basal defense responses such as callose deposition. EIN2 (ethylene response) and IXR1 and IXR2 (cellulose synthase) mutants impacted the FLS2-mediated responses that occur during PARP inhibition, whereas no impacts were observed for NPR1, PAD4, or NDR1 mutants. In the expression profiling work, false-positive selection and grouping of genes was reduced by requiring simultaneous satisfaction of statistical significance criteria for each of three separate analysis methods, and by clustering genes based on statistical confidence values for each gene rather than on average fold-change of transcript abundance.

  17. Reference: 490 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available tration. The heterologous expression in yeast was utilized to verify that the AtP...TR3 protein transports di-and tripeptides. The T-DNA insert in the Atptr3-1 mutant in the Arabidopsis ecotype C24 re...tr3-2 mutant of the Col-0 ecotype. The AtPTR3 expression was shown to be regulated by several signalling com...d in the SA and JA signalling mutants. The Atptr3 mutant plants had increased susceptibility to virulent pat...hogenic bacteria Erwinia carotovora subsp. carotovora and Pseudomonas syringae pv. tomato, and produced more re

  18. The antibacterial activity of syringopicroside, its metabolites and natural analogues from syringae folium

    KAUST Repository

    Zhou, Zhengyuan

    2016-02-18

    In the present study, the in vitro antibacterial activity of an effective fraction (ESF) from Syringae Folium (SF) on Methicillin-resistant Staphylococcus aureus (MRSA) was evaluated and then its in vivo activity was evaluated by using the MRSA-infected mouse peritonitis model. The ESF showed a significant in vitro and in vivo activity on decreasing the Minimum Inhibitory Concentrations (MICs) and increasing the survival rate of mouse from 42.8% to 100%. Six iridoid glucosides (IGs) of ESF were characterized by UPLC-TOF-MS method and also isolated by column chromatography. Most of them showed in vitro anti MRSA activity. Syringopicroside (Sy), the major compound of IGs, was found to increase the survival rate from 42.8% to 92.8% of the MRSA-infected mouse, which revealed Sy is also the main active components of ESF. In order to know why the effect of oral administration of SF is better than its injections in clinic and the metabolites of Sy, seven metabolites of Sy were isolated from rat urine and identified on the basis of NMR and MS spectra. Most of metabolites possessed stronger in vitro anti-MRSA activity than that of Sy, which furtherly proved the clinical result.

  19. [Clinico-pharmacological trial of the preparation streptobicillin depot-syringae mammariae].

    Science.gov (United States)

    Tsolov, S; Lashev, L; Gerganova, E

    1982-01-01

    Streptobicillin depot-syringae mammariae contains: benzathin-penicillin--1,200,000 UI, streptomycin sulfa--1,000,000 UI, vitamin A oleosum--15,000 UI in a suitable base up to 10 ml. It is intended for the therapy and prophylaxis of inapparent mastitis of cows during the dry period. The preparation was tested in a total of 301 udder quarts of cows in terms of tolerance (general and local), depot effect, residual amounts, bactericidic effect, and therapeutic effect. The preparation was found to be well tolerated by the body and the parenchyma of the udder. The duration of its effect was 25 days. No residual amounts were found in the milk during the following lactation. The bactericidic effect in vitro reached 92.4 per cent, and in vivo--87.3 per cent of the cases. Positive therapeutic effect was found in 87.1 per cent of the cases, with subclinical mastitis it being 80.2 per cent, with latent infections--96.2 per cent, with secretion disturbances--94.3 per cent. Results revealed that the preparation was suitable to control inapparent mastitis in cows during the dry period.

  20. Transcriptional profile of P. syringae pv. phaseolicola NPS3121 at low temperature: physiology of phytopathogenic bacteria.

    Science.gov (United States)

    Arvizu-Gómez, Jackeline Lizzeta; Hernández-Morales, Alejandro; Aguilar, Juan Ramiro Pacheco; Álvarez-Morales, Ariel

    2013-04-12

    Low temperatures play key roles in the development of most plant diseases, mainly because of their influence on the expression of various virulence factors in phytopathogenic bacteria. Thus far, studies regarding this environmental parameter have focused on specific themes and little is known about phytopathogenic bacteria physiology under these conditions. To obtain a global view regarding phytopathogenic bacteria strategies in response to physiologically relevant temperature changes, we used DNA microarray technology to compare the gene expression profile of the model bacterial pathogen P. syringae pv. phaseolicola NPS3121 grown at 18°C and 28°C. A total of 236 differentially regulated genes were identified, of which 133 were up-regulated and 103 were down-regulated at 18°C compared to 28°C. The majority of these genes are involved in pathogenicity and virulence processes. In general, the results of this study suggest that the expression profile obtained may be related to the fact that low temperatures induce oxidative stress in bacterial cells, which in turn influences the expression of iron metabolism genes. The expression also appears to be correlated with the profile expression obtained in genes related to motility, biofilm production, and the type III secretion system. From the data obtained in this study, we can begin to understand the strategies used by this phytopathogen during low temperature growth, which can occur in host interactions and disease development.

  1. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Kirketerp-Møller, K.; Kristiansen, S.

    2007-01-01

    bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa...

  2. Sequence determination and analysis of three plasmids of Pseudomonas sp. GLE121, a psychrophile isolated from surface ice of Ecology Glacier (Antarctica).

    Science.gov (United States)

    Dziewit, Lukasz; Grzesiak, Jakub; Ciok, Anna; Nieckarz, Marta; Zdanowski, Marek K; Bartosik, Dariusz

    2013-09-01

    Pseudomonas sp. GLE121 (a psychrophilic Antarctic strain) carries three plasmids: pGLE121P1 (6899 bp), pGLE121P2 (8330 bp) and pGLE121P3 (39,583 bp). Plasmids pGLE121P1 and pGLE121P2 show significant sequence similarity to members of the IncP-9 and IncP-7 incompatibility groups, respectively, while the largest replicon, pGLE121P3, is highly related to plasmid pNCPPB880-40 of Pseudomonas syringae pathovar tomato NCPPB880. All three plasmids have a narrow host range, limited to members of the genus Pseudomonas. Plasmid pGLE121P3 encodes a conjugal transfer system, while pGLE121P1 carries only a putative MOB module, conserved in many mobilizable plasmids. Plasmid pGLE121P3 contains an additional load of genetic information, including a pair of genes with homology to the rulAB operon, responsible for ultraviolet radiation (UVR) tolerance. Given the increasing UV exposure in Antarctic regions, the expression of these genes is likely to be an important adaptive response. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Expression of the dspA/E gene of Erwinia amylovora in non-host plant Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Hasan Murat Aksoy

    2017-01-01

    Full Text Available In the Erwinia amylovora genome, the hrp gene cluster containing the dspA/E/EB/F operon plays a crucial role in mediating the pathogenicity and the hypersensitive response (HR in the host plant. The role of the dspA/E gene derived from E. amylovora was investigated by monitoring the expression of the β-glucuronidase (GUS reporter system in transgenic Arabidopsis thaliana cv. Pri-Gus seedlings. A mutant ΔdspA/E strain of E. amylovora was generated to contain a deletion of the dspA/E gene for the purpose of this study. Two-week-old seedlings of GUS transgenic Arabidopsis were vacuum-infiltrated with the wild-type and the mutant (ΔdspA/E E. amylovora strains. The Arabidopsis seedlings were fixed and stained for GUS activity after 3–5 days following infiltration. The appearance of dense spots with blue staining on the Arabidopsis leaves indicated the typical characteristic of GUS activity. This observation indicated that the wild-type E. amylovora strain had induced a successful and efficient infection on the A. thaliana Pri-Gus leaves. In contrast, there was no visible GUS expression on leaf tissues which were inoculated with the ΔdspA/E mutant E. amylovora strain. These results indicate that the dspA/E gene is required by the bacterial cells to induce HR in non-host plants.

  4. Comparative genomics of 12 strains of Erwinia amylovora identifies a pan-genome with a large conserved core.

    Directory of Open Access Journals (Sweden)

    Rachel A Mann

    Full Text Available The plant pathogen Erwinia amylovora can be divided into two host-specific groupings; strains infecting a broad range of hosts within the Rosaceae subfamily Spiraeoideae (e.g., Malus, Pyrus, Crataegus, Sorbus and strains infecting Rubus (raspberries and blackberries. Comparative genomic analysis of 12 strains representing distinct populations (e.g., geographic, temporal, host origin of E. amylovora was used to describe the pan-genome of this major pathogen. The pan-genome contains 5751 coding sequences and is highly conserved relative to other phytopathogenic bacteria comprising on average 89% conserved, core genes. The chromosomes of Spiraeoideae-infecting strains were highly homogeneous, while greater genetic diversity was observed between Spiraeoideae- and Rubus-infecting strains (and among individual Rubus-infecting strains, the majority of which was attributed to variable genomic islands. Based on genomic distance scores and phylogenetic analysis, the Rubus-infecting strain ATCC BAA-2158 was genetically more closely related to the Spiraeoideae-infecting strains of E. amylovora than it was to the other Rubus-infecting strains. Analysis of the accessory genomes of Spiraeoideae- and Rubus-infecting strains has identified putative host-specific determinants including variation in the effector protein HopX1(Ea and a putative secondary metabolite pathway only present in Rubus-infecting strains.

  5. Carboxymethyl-cellulase from Erwinia chrysanthemi. II. Purification and partial characterization of an endo-. beta. -1,4-glucanase

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, M.H.; Chambost, J.P.; Magnan, M.; Cattaneo, J.

    1984-01-01

    The extracellular carboxymethyl-cellulase of Erwinia chrysanthemi, strain 3665, had a marked tendency to form aggregates when concentration and/or storage time of culture supernatant were increased. In submitting an unconcentrated glycerol culture supernatant to ion exchange chromatography, one major endo-..beta..-1,4,-glucanase could be isolated with a high degree of purity and partially characterized. The molecular size was 45 kd. The pI was 4.3. The enzyme rapidly decreased the viscosity of carboxymethyl-cellulose with a slow increase in the reducing sugars produced. It displayed its highest activity towards carboxymethyl-cellulose at a pH between 6.2 and 7.5. It had a significant capacity to hydrolyze amorphous cellulose such as phosphoric acid-swollen cellulose. The major products of this degradation were cellobiose and cellotriose. It exhibited a very low activity on microcrystalline cellulose. Glucose and cellobiose did not affect significantly its activity against carboxymethyl-cellulose. 21 references.

  6. Utilization of a thermosensitive episome bearing transposon TN10 to isolate Hfr donor strains of Erwinia carotovora subsp. chrysanthemi.

    Science.gov (United States)

    Kotoujansky, A; Lemattre, M; Boistard, P

    1982-04-01

    A thermosensitive episome bearing the transposon Tn10, F(Ts)::Tn10 Lac+, has been successfully transferred from Escherichia coli to several wild strains of the enterobacteria Erwinia carotovora subsp. chrysanthemi, which are pathogenic on Saintpaulia ionantha. In one of these strains, all of the characters controlled by this episome (Lac+, Tetr, Tra+) were expressed, and its replication was stopped at 40 degrees C and above. At 30 degrees C, the episome was easily transferred between strains derived from E. carotovora subsp. chrysanthemi 3937j and to E coli. Hfr donor strains were obtained from a F' strain of 3937j by selecting clones which grew at 40 degrees C on plates containing tetracycline. One of these strains, Hfrq, was examined in more detail: the characters Lac+ and Tetr were stabilized and did not segregate higher than its parental F' strain. The mating was most efficient at 37 degrees C on a membrane. Hfrq transferred its chromosome to recipient strains at high frequency and in a polarized fashion, as evidenced by the gradient of transfer frequencies, the kinetics of marker entry (in interrupted mating experiments), and the analysis of linkage between different markers. The chromosome of Hfrq was most probably transferred in the following sequence: origin...met...xyl...arg...ile...leu...thr...cys...pan...ura...gal...trp...his. ..pur... Moreover, this genetic transfer system proved to be efficient in strain construction.

  7. Analysis of the LacI family regulators of Erwinia chrysanthemi 3937, involvement in the bacterial phytopathogenicity.

    Science.gov (United States)

    Van Gijsegem, Frédérique; Wlodarczyk, Aleksandra; Cornu, Amandine; Reverchon, Sylvie; Hugouvieux-Cotte-Pattat, Nicole

    2008-11-01

    Analysis of the regulators of the LacI family was performed in order to identify those potentially involved in pathogenicity of Erwinia chrysanthemi (Dickeya dadantii). Among the 18 members of the LacI family, the function of 11 members is either known or predicted and only 7 members have, as yet, no proposed function. Inactivation of these seven genes, called lfaR, lfbR, lfcR, lfdR, lfeR, lffR, and lfgR, demonstrated that four of them are important for plant infection. The lfaR and lfcR mutants showed a reduced virulence on chicory, Saintpaulia sp., and Arabidopsis. The lfeR mutant showed a reduced virulence on Arabidopsis. The lfdR mutant was more efficient than the wild-type strain in initiating maceration on Saintpaulia sp. The genetic environment of each regulator was examined to detect adjacent genes potentially involved in a common function. Construction of transcriptional fusions in these neighboring genes demonstrated that five regulators, LfaR, LfcR, LfeR, LffR, and LfgR, act as repressors of adjacent genes. Analysis of these fusions also indicated that the genes controlled by LfaR, LfcR, LfgR, and LffR are expressed during plant infection. Moreover, addition of crude plant extracts to culture medium demonstrated that the expression of the LfaR- and LfgR-controlled genes is specifically induced by plant components.

  8. Transcriptomic responses of the olive fruit fly Bactrocera oleae and its symbiont Candidatus Erwinia dacicola to olive feeding

    Science.gov (United States)

    Pavlidi, Nena; Gioti, Anastasia; Wybouw, Nicky; Dermauw, Wannes; Ben-Yosef, Michael; Yuval, Boaz; Jurkevich, Edouard; Kampouraki, Anastasia; van Leeuwen, Thomas; Vontas, John

    2017-02-01

    The olive fruit fly, Bactrocera oleae, is the most destructive pest of olive orchards worldwide. The monophagous larva has the unique capability of feeding on olive mesocarp, coping with high levels of phenolic compounds and utilizing non-hydrolyzed proteins present, particularly in the unripe, green olives. On the molecular level, the interaction between B. oleae and olives has not been investigated as yet. Nevertheless, it has been associated with the gut obligate symbiotic bacterium Candidatus Erwinia dacicola. Here, we used a B.oleae microarray to analyze the gene expression of larvae during their development in artificial diet, unripe (green) and ripe (black) olives. The expression profiles of Ca. E. dacicola were analyzed in parallel, using the Illumina platform. Several genes were found overexpressed in the olive fly larvae when feeding in green olives. Among these, a number of genes encoding detoxification and digestive enzymes, indicating a potential association with the ability of B. oleae to cope with green olives. In addition, a number of biological processes seem to be activated in Ca. E. dacicola during the development of larvae in olives, with the most notable being the activation of amino-acid metabolism.

  9. Diversity, evolution, and functionality of clustered regularly interspaced short palindromic repeat (CRISPR) regions in the fire blight pathogen Erwinia amylovora.

    Science.gov (United States)

    Rezzonico, Fabio; Smits, Theo H M; Duffy, Brion

    2011-06-01

    The clustered regularly interspaced short palindromic repeat (CRISPR)/Cas system confers acquired heritable immunity against mobile nucleic acid elements in prokaryotes, limiting phage infection and horizontal gene transfer of plasmids. In CRISPR arrays, characteristic repeats are interspersed with similarly sized nonrepetitive spacers derived from transmissible genetic elements and acquired when the cell is challenged with foreign DNA. New spacers are added sequentially and the number and type of CRISPR units can differ among strains, providing a record of phage/plasmid exposure within a species and giving a valuable typing tool. The aim of this work was to investigate CRISPR diversity in the highly homogeneous species Erwinia amylovora, the causal agent of fire blight. A total of 18 CRISPR genotypes were defined within a collection of 37 cosmopolitan strains. Strains from Spiraeoideae plants clustered in three major groups: groups II and III were composed exclusively of bacteria originating from the United States, whereas group I generally contained strains of more recent dissemination obtained in Europe, New Zealand, and the Middle East. Strains from Rosoideae and Indian hawthorn (Rhaphiolepis indica) clustered separately and displayed a higher intrinsic diversity than that of isolates from Spiraeoideae plants. Reciprocal exclusion was generally observed between plasmid content and cognate spacer sequences, supporting the role of the CRISPR/Cas system in protecting against foreign DNA elements. However, in several group III strains, retention of plasmid pEU30 is inconsistent with a functional CRISPR/Cas system.

  10. Podridão bacteriana em ciclâmen causada por Erwinia carotovora subsp. carotovora no Brasil.

    Directory of Open Access Journals (Sweden)

    Valdemar Atílio Malavolta Júnior

    2000-05-01

    Full Text Available Plantas de ciclâmen (Cyclamen sp. coletadas em plantios comerciais conduzidos sob cobertura plástica, nos municípios paulistas de Vargem Grande Paulista e Arujá, apresentavam sintomas caracterizados por podridão mole do bulbo, murcha progressiva e irreversível da planta e podridão do pecíolo foliar, acarretando morte das plantas infectadas. Desses tecidos, isolaram-se bactérias distinguidas por meio de testes bioquímicas, culturais, fisiológicos e de patogenicidade, como Erwinia carotovora subsp. carotovora. Trata-se do primeiro relato desse patógeno em cultura de ciclâmen no Brasil. Isolados bacterianos encontram-se depositados na Coleção de Culturas do Instituto Biológico, Seção de Bacteriologia Fitopatológica (IBSBF, sob os números de acesso 1447 e 1448.

  11. Genome Sequence Analyses of Pseudomonas savastanoi pv. glycinea and Subtractive Hybridization-Based Comparative Genomics with Nine Pseudomonads

    Science.gov (United States)

    Qi, Mingsheng; Wang, Dongping; Bradley, Carl A.; Zhao, Youfu

    2011-01-01

    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 within the two Psg genomes. When compared to each other, 437 and 163 specific genes were identified in B076 and race 4, respectively. Most specific genes are plasmid-borne, indicating that acquisition and maintenance of plasmids may represent a major mechanism to change the genetic composition of the genome and even acquire new virulence factors. Type three secretion gene clusters of Psg strains are near identical with that of P. savastanoi pv. phaseolicola (Pph) strain 1448A and they shared 20 common effector genes. Furthermore, the coronatine biosynthetic cluster is present on a large plasmid in strain B076, but not in race 4. In silico subtractive hybridization-based comparative genomic analyses with nine sequenced phytopathogenic pseudomonads identified dozens of specific islands (SIs), and revealed that the genomes of Psg strains are more similar to those belonging to the same genomospecies such as Pph 1448A than to other phytopathogenic pseudomonads. The number of highly conserved genes (core genome) among them decreased dramatically when more genomes were included in the subtraction, suggesting the diversification of pseudomonads, and further indicating the genome heterogeneity among pseudomonads. However, the number of specific genes did not change significantly, suggesting these genes are indeed specific in Psg genomes. These results reinforce the idea of a species complex of P. syringae and support the reclassification of P. syringae into different species. PMID

  12. Characterization of molecular mechanisms controlling fabAB transcription in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Herbert P Schweizer

    Full Text Available BACKGROUND: The FabAB pathway is one of the unsaturated fatty acid (UFA synthesis pathways for Pseudomonas aeruginosa. It was previously noted that this operon was upregulated in biofilms and repressed by exogenous UFAs. Deletion of a 30 nt fabA upstream sequence, which is conserved in P. aeruginosa, P. putida, and P. syringae, led to a significant decrease in fabA transcription, suggesting positive regulation by an unknown positive regulatory mechanism. METHODS/PRINCIPAL FINDINGS: Here, genetic and biochemical approaches were employed to identify a potential fabAB activator. Deletion of candidate genes such as PA1611 or PA1627 was performed to determine if any of these gene products act as a fabAB activator. However, none of these genes were involved in the regulation of fabAB transcription. Use of mariner-based random mutagenesis to screen for fabA activator(s showed that several genes encoding unknown functions, rpoN and DesA may be involved in fabA regulation, but probably via indirect mechanisms. Biochemical attempts performed did fail to isolate an activator of fabAB operon. CONCLUSION/SIGNIFICANCE: The data suggest that fabA expression might not be regulated by protein-binding, but by a distinct mechanism such as a regulatory RNA-based mechanism.

  13. Plasmid Replicons from Pseudomonas Are Natural Chimeras of Functional, Exchangeable Modules

    Science.gov (United States)

    Bardaji, Leire; Añorga, Maite; Ruiz-Masó, José A.; del Solar, Gloria; Murillo, Jesús

    2017-01-01

    Plasmids are a main factor for the evolution of bacteria through horizontal gene exchange, including the dissemination of pathogenicity genes, resistance to antibiotics and degradation of pollutants. Their capacity to duplicate is dependent on their replication determinants (replicon), which also define their bacterial host range and the inability to coexist with related replicons. We characterize a second replicon from the virulence plasmid pPsv48C, from Pseudomonas syringae pv. savastanoi, which appears to be a natural chimera between the gene encoding a newly described replication protein and a putative replication control region present in the widespread family of PFP virulence plasmids. We present extensive evidence of this type of chimerism in structurally similar replicons from species of Pseudomonas, including environmental bacteria as well as plant, animal and human pathogens. We establish that these replicons consist of two functional modules corresponding to putative control (REx-C module) and replication (REx-R module) regions. These modules are functionally separable, do not show specificity for each other, and are dynamically exchanged among replicons of four distinct plasmid families. Only the REx-C module displays strong incompatibility, which is overcome by a few nucleotide changes clustered in a stem-and-loop structure of a putative antisense RNA. Additionally, a REx-C module from pPsv48C conferred replication ability to a non-replicative chromosomal DNA region containing features associated to replicons. Thus, the organization of plasmid replicons as independent and exchangeable functional modules is likely facilitating rapid replicon evolution, fostering their diversification and survival, besides allowing the potential co-option of appropriate genes into novel replicons and the artificial construction of new replicon specificities. PMID:28243228

  14. Metabolic and transcriptomic changes induced in Arabidopsis by the rhizobacterium Pseudomonas fluorescens SS101.

    Science.gov (United States)

    van de Mortel, Judith E; de Vos, Ric C H; Dekkers, Ester; Pineda, Ana; Guillod, Leandre; Bouwmeester, Klaas; van Loon, Joop J A; Dicke, Marcel; Raaijmakers, Jos M

    2012-12-01

    Systemic resistance induced in plants by nonpathogenic rhizobacteria is typically effective against multiple pathogens. Here, we show that root-colonizing Pseudomonas fluorescens strain SS101 (Pf.SS101) enhanced resistance in Arabidopsis (Arabidopsis thaliana) against several bacterial pathogens, including Pseudomonas syringae pv tomato (Pst) and the insect pest Spodoptera exigua. Transcriptomic analysis and bioassays with specific Arabidopsis mutants revealed that, unlike many other rhizobacteria, the Pf.SS101-induced resistance response to Pst is dependent on salicylic acid signaling and not on jasmonic acid and ethylene signaling. Genome-wide transcriptomic and untargeted metabolomic analyses showed that in roots and leaves of Arabidopsis plants treated with Pf.SS101, approximately 1,910 genes and 50 metabolites were differentially regulated relative to untreated plants. Integration of both sets of "omics" data pointed to a prominent role of camalexin and glucosinolates in the Pf.SS101-induced resistance response. Subsequent bioassays with seven Arabidopsis mutants (myb51, cyp79B2cyp79B3, cyp81F2, pen2, cyp71A12, cyp71A13, and myb28myb29) disrupted in the biosynthesis pathways for these plant secondary metabolites showed that camalexin and glucosinolates are indeed required for the induction of Pst resistance by Pf.SS101. Also for the insect S. exigua, the indolic glucosinolates appeared to play a role in the Pf.SS101-induced resistance response. This study provides, to our knowledge for the first time, insight into the substantial biochemical and temporal transcriptional changes in Arabidopsis associated with the salicylic acid-dependent resistance response induced by specific rhizobacteria.

  15. Asparaginase Erwinia chrysanthemi as a component of a multi-agent chemotherapeutic regimen for the treatment of patients with acute lymphoblastic leukemia who have developed hypersensitivity to E. coli-derived asparaginase.

    Science.gov (United States)

    Figueiredo, Lisa; Cole, Peter D; Drachtman, Richard A

    2016-03-01

    Asparaginase has been a mainstay of therapy in the treatment of acute lymphoblastic leukemia since the 1970s. There are two major preparations available and FDA approved in the United States today, one derived from Escherichia coli and the other from Erwinia chrysanthemi. Erwinia asparaginase is antigenically distinct from and has a considerably shorter biological half-life than E coli asparaginase. Erwinia asparaginase has been used in cases of hypersensitivity to E. coli-derived asparaginases, which has been reported in up to 30% of patients. While PEG asparaginase is increasingly used in front-line therapy for ALL, hypersensitivity still occurs with this preparation, and a change to a non-cross-reactive preparation may be necessary.

  16. Seca dos ponteiros da goiabeira causada por Erwinia psidii: níveis de incidência e aspectos epidemiológicos Guava bacterial blight due to Erwinia psidii: incidence levels and epidemiological aspects

    Directory of Open Access Journals (Sweden)

    Abi Soares Anjos Marques

    2007-01-01

    Full Text Available Um dos fatores limitantes ao cultivo da goiabeira no Brasil é a 'seca dos ponteiros', causada por Erwinia psidii, presente nas regiões Sudeste e Centro-Oeste, onde se concentram grandes áreas produtoras. Considerando a pequena disponibilidade de informações sobre a epidemiologia e níveis de incidência dessa bacteriose, este estudo teve como objetivos: confirmar a distribuição e verificar a dispersão da seca dos ponteiros da goiabeira no Distrito Federal; investigar o efeito da temperatura sobre a multiplicação in vitro de E. psidii; desenvolver um teste de patogenicidade prático e eficiente e avaliar a sobrevivência in vitro da bactéria em diferentes substratos. A doença foi identificada em 56% das propriedades produtoras avaliadas no DF, com 81,9% de correlação entre a presença de sintomas e o diagnóstico laboratorial. A melhor faixa de temperatura para multiplicação de E. psidii foi de 24 a 33 ºC, e a bactéria permaneceu viável por até 120 dias em suspensão em água. A inoculação da bactéria em folhas ou hastes destacadas levou ao aparecimento de sintomas a partir do sétimo dia e mostrou-se eficiente como um teste rápido para se avaliar a patogenicidade de isolados.A major disease that affects guava is 'bacterial blight', caused by Erwinia psidii, which has been reported in Southeastern and Central Regions of Brazil where the major producing areas are located. Considering the lack of information on epidemiology and incidence levels of this disease, the objectives of this study were to confirm the presence and to verify the spread of the disease in Distrito Federal (DF; to determine optimal temperature for in vitro multiplication of E. psidii; to develop a simple and effective method for pathogenicity testing and to evaluate in vitro bacterial survival on different substrates. The disease was detected in 56% of producing orchards evaluated in DF, with a correlation of 81, 9% between presence of symptoms and

  17. An AlgU-regulated antisense transcript encoded within the Pseudomonas syringae fleQ gene has a positive effect on motility

    Science.gov (United States)

    Bacterial flagella production is controlled by a multi-tiered regulatory system that coordinates expression of 40-50 subunits and correct assembly of these complicated structures. Flagellar expression is environmentally controlled, presumably to optimize the benefits and liabilities of flagellar ex...

  18. Phylogenomics and systematics in Pseudomonas

    Directory of Open Access Journals (Sweden)

    Margarita eGomila

    2015-03-01

    Full Text Available The genus Pseudomonas currently contains 144 species, making it the genus of Gram-negative bacteria that contains the largest number of species. Currently, multilocus sequence analysis (MLSA is the preferred method for establishing the phylogeny between species and genera. Four partial gene sequences of housekeeping genes (16S rRNA, gyrB, rpoB and rpoD were obtained from 112 complete or draft genomes of strains related to the genus Pseudomonas that were available in databases. These genes were analyzed together with the corresponding sequences of 133 Pseudomonas type strains of validly published species to assess their correct phylogenetic assignations. We confirmed that 30% of the sequenced genomes of non-type strains were not correctly assigned at the species level in the accepted taxonomy of the genus and that 20% of the strains were not identified at the species level. Most of these strains had been isolated and classified several years ago, and their taxonomic status has not been updated by modern techniques. MLSA was also compared with indices based on the analysis of whole-genome sequences that have been proposed for species delineation, such as tetranucleotide usage patterns (TETRA, average nucleotide identity (ANIm, based on MUMmer and ANIb, based on BLAST and genome-to-genome distance (GGDC. TETRA was useful for discriminating Pseudomonas from other genera, whereas ANIb and GGDC clearly separated strains of different species. ANIb showed the strongest correlation with MLSA. The correct species classification is a prerequisite for most diversity and evolutionary studies. This work highlights the necessity for complete genomic sequences of type strains to build a phylogenomic taxonomy and that all new genome sequences submitted to databases should be correctly assigned to species to avoid taxonomic inconsistencies.

  19. Determination of Quantities of Host Protein after Infection with Erwinia amylovora of Apple, Pear And Quince Cultivars

    Directory of Open Access Journals (Sweden)

    Şerife Çetin

    2014-10-01

    Full Text Available Fire blight disease caused by Erwinia amylovora is a destructive bacterial pathogen mainly on pears, apples and quinces from Rosaceae family. In this study, it was aimed determination of total protein amounts in different apple cultivars (Braeburn, Fuji, Gala and Golden, pear cultivars (Santa Maria and Williams and quince cultivars (Eşme and Ekmek in the infections of two virulent E. amylovora strains (Ea234-1 and Ea240-3 according as the time. It was taken leaf samples after leaf inoculation with E. amylovora (108 CFU ml-1 at 24th, 36th and 72nd hours. For verification of the infections, re-isolations were made from bacteria inoculated plants and the agent was identified as E. amylovora by biochemical, physiological and molecular tests. In determining the amounts of total protein and in the SDS-PAGE analyses were used Bradford and Laemmli methods, respectively, and absorbance values of protein extracts derived from the leaf samples taken, were obtained at 595 nm wavelength. According to the findings obtained; after infection of E. amylovora in the apple varieties comparing to controls, total protein concentrations at 24th hours increased and a decrease in the amount of 36th to 72nd hours and Braeburn has the highest protein content was determined. In the pear varieties, while total protein concentrations at 24th and 36th hours increased, a decrease in the amount of 72nd hour, and Santa Maria variety has the highest protein content was detected. In the quince varieties, total protein concentrations at 72th hour increased and Eşme variety has the highest protein content was identified. As a result of SDS-PAGE analysis, protein fractions which have different molecular weights were obtained. The protein bands were defined approximately 55-70 kDa and 35-55 kDa molecule weight on apple and quince varieties, respectively and also approx. 55-70 kDa in pear varieties.

  20. Identification of genes differentially expressed during interaction of resistant and susceptible apple cultivars (Malus x domestica) with Erwinia amylovora.

    Science.gov (United States)

    Baldo, Angela; Norelli, Jay L; Farrell, Robert E; Bassett, Carole L; Aldwinckle, Herb S; Malnoy, Malnoy

    2010-01-04

    The necrogenic enterobacterium, Erwinia amylovora is the causal agent of the fire blight (FB) disease in many Rosaceae species, including apple and pear. During the infection process, the bacteria induce an oxidative stress response with kinetics similar to those induced in an incompatible bacteria-plant interaction. No resistance mechanism to E. amylovora in host plants has yet been characterized, recent work has identified some molecular events which occur in resistant and/or susceptible host interaction with E. amylovora: In order to understand the mechanisms that characterize responses to FB, differentially expressed genes were identified by cDNA-AFLP analysis in resistant and susceptible apple genotypes after inoculation with E. amylovora. cDNA were isolated from M.26 (susceptible) and G.41 (resistant) apple tissues collected 2 h and 48 h after challenge with a virulent E. amylovora strain or mock (buffer) inoculated. To identify differentially expressed transcripts, electrophoretic banding patterns were obtained from cDNAs. In the AFLP experiments, M.26 and G.41 showed different patterns of expression, including genes specifically induced, not induced, or repressed by E. amylovora. In total, 190 ESTs differentially expressed between M.26 and G.41 were identified using 42 pairs of AFLP primers. cDNA-AFLP analysis of global EST expression in a resistant and a susceptible apple genotype identified different major classes of genes. EST sequencing data showed that genes linked to resistance, encoding proteins involved in recognition, signaling, defense and apoptosis, were modulated by E. amylovora in its host plant. The expression time course of some of these ESTs selected via a bioinformatic analysis has been characterized. These data are being used to develop hypotheses of resistance or susceptibility mechanisms in Malus to E. amylovora and provide an initial categorization of genes possibly involved in recognition events, early signaling responses the

  1. Enhancement of expression and apparent secretion of Erwinia chrysanthemi endoglucanase (encoded by celZ) in Escherichia coli B

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, S.; Yomano, L.P.; Saleh, A.Z.; Davis, F.C.; Aldrich, H.C.; Ingram, L.O. [Univ. of Florida, Gainesville, FL (United States)

    1999-06-01

    Escherichia coli B has been engineered as a biocatalyst for the conversion of lignocellulose into ethanol. Previous research has demonstrated that derivatives of E. coli B can produce high levels of Erwinia chrysanthemi endoglucanase (encoded by celZ) as a periplasmic product and that this enzyme can function with commercial fungal cellulase to increase ethanol production. In this study, the authors have demonstrated two methods that improve celZ expression in E. coli B. Initially, with a low-copy-number vector, two E. coli glycolytic gene promoters (gap and eno) were tested and found to be less effective than the original celZ promoter. By screening 18,000 random fragments of Zymomonas mobilis DNA, a surrogate promoter was identified which increased celZ expression up to sixfold. With this promoter, large polar inclusion bodies were clearly evident in the periplasmic space. Sequencing revealed that the most active surrogate promoter is derived from five Sau3A1 fragments, one of which was previously sequenced in Z. mobilis. Visual inspection indicated that this DNA fragment contains at least five putative promoter regions, two of which were confirmed by primer extension analysis. Addition of the out genes from E. chrysanthemi EC16 caused a further increase in the production of active enzyme and facilitated secretion or release of over half of the activity into the extracellular environment. With the most active construct, of a total of 13,000 IU of active enzyme per liter of culture, 7,800 IU was in the supernatant. The total active endoglucanase was estimated to represent 4 to 6% of cellular protein.

  2. Global Effect of Indole-3-Acetic Acid Biosynthesis on Multiple Virulence Factors of Erwinia chrysanthemi 3937▿

    Science.gov (United States)

    Yang, Shihui; Zhang, Qiu; Guo, Jianhua; Charkowski, Amy O.; Glick, Bernard R.; Ibekwe, A. Mark; Cooksey, Donald A.; Yang, Ching-Hong

    2007-01-01

    Production of the plant hormone indole-3-acetic acid (IAA) is widespread among plant-associated microorganisms. The non-gall-forming phytopathogen Erwinia chrysanthemi 3937 (strain Ech3937) possesses iaaM (ASAP16562) and iaaH (ASAP16563) gene homologues. In this work, the null knockout iaaM mutant strain Ech138 was constructed. The IAA production by Ech138 was reduced in M9 minimal medium supplemented with l-tryptophan. Compared with wild-type Ech3937, Ech138 exhibited reduced ability to produce local maceration, but its multiplication in Saintpaulia ionantha was unaffected. The pectate lyase production of Ech138 was diminished. Compared with wild-type Ech3937, the expression levels of an oligogalacturonate lyase gene, ogl, and three endopectate lyase genes, pelD, pelI, and pelL, were reduced in Ech138 as determined by a green fluorescent protein-based fluorescence-activated cell sorting promoter activity assay. In addition, the transcription of type III secretion system (T3SS) genes, dspE (a putative T3SS effector) and hrpN (T3SS harpin), was found to be diminished in the iaaM mutant Ech138. Compared with Ech3937, reduced expression of hrpL (a T3SS alternative sigma factor) and gacA but increased expression of rsmA in Ech138 was also observed, suggesting that the regulation of T3SS and pectate lyase genes by IAA biosynthesis might be partially due to the posttranscriptional regulation of the Gac-Rsm regulatory pathway. PMID:17189441

  3. Pseudomonas-follikulitis efter badning i spabad

    DEFF Research Database (Denmark)

    Uldall Pallesen, Kristine Appel; Andersen, Klaus Ejner; Mørtz, Charlotte Gotthard

    2012-01-01

    Pseudomonas aeruginosa is a rare cause of folliculitis. Pseudomonas folliculitis can develop after contact with contaminated water from swimming pools, hot tubs and spa baths. Systemic therapy may be indicated in patients with widespread lesions, systemic symptoms or in immunosuppressed patients....... We describe a 23-year-old healthy woman who developed a pustular rash and general malaise after using a spa bath contaminated with Pseudomonas aeruginosa. Bacterial culture from a pustule confirmed Pseudomonas folliculitis and the patient was treated with ciprofloxacin with rapid good effect....

  4. Analysis of conductance responses during depolymerization of pectate by soft rot Erwinia spp. and other pectolytic bacteria isolated from potato tubers.

    Science.gov (United States)

    Fraaije, B A; Bosveld, M; Van den Bulk, R W; Rombouts, F M

    1997-07-01

    Different bacteria isolated from potato tubers were screened for their pectolytic properties by examining pitting in polypectate agar, recording conductance responses in polypectate medium and performing potato tuber soft rot tests. For bacteria found positive in conductimetry, the role of polygalacturonase (PG) and pectate lyase (PL) in the generation of conductance changes in a polygalacturonic acid (PGA) medium was further analysed using enzyme activity staining after gel electrophoresis and high-performance anion exchange chromatography. The extent of the conductance changes during depolymerization of PGA was dependent on the amounts of galacturonate monomers and oligomers accumulated in the medium. In comparison with an unidentified saprophyte and a Klebsiella strain, both mainly having PL activity, soft rot Erwinia spp. rapidly produced larger conductance responses, due to a combined action of multiple forms of PG and PL. The responses of Erwinia spp. were initially associated with the accumulation of large amounts of monomers and saturated dimers to heptamers, due to PG activity. Subsequently, as well as monomers and saturated dimers, large amounts of unsaturated dimers were also detected, due to PL activity. The role of PG as an important conductimetric factor was also demonstrated for a pectinase preparation derived from Aspergillus niger. Besides detection, automated conductimetric assays in pectate media may also be useful for monitoring of pectolytic activity in pectinase preparations and for screening of pectolytic activity of microorganisms under different media and growth conditions.

  5. Signalling requirements for Erwinia amylovora-induced disease resistance, callose deposition and cell growth in the non-host Arabidopsis thaliana.

    Science.gov (United States)

    Hamdoun, Safae; Gao, Min; Gill, Manroop; Kwon, Ashley; Norelli, John L; Lu, Hua

    2017-07-29

    Erwinia amylovora is the causal agent of the fire blight disease in some plants of the Rosaceae family. The non-host plant Arabidopsis serves as a powerful system for the dissection of mechanisms of resistance to E. amylovora. Although not yet known to mount gene-for-gene resistance to E. amylovora, we found that Arabidopsis activated strong defence signalling mediated by salicylic acid (SA), with kinetics and amplitude similar to that induced by the recognition of the bacterial effector avrRpm1 by the resistance protein RPM1. Genetic analysis further revealed that SA signalling, but not signalling mediated by ethylene (ET) and jasmonic acid (JA), is required for E. amylovora resistance. Erwinia amylovora induces massive callose deposition on infected leaves, which is independent of SA, ET and JA signalling and is necessary for E. amylovora resistance in Arabidopsis. We also observed tumour-like growths on E. amylovora-infected Arabidopsis leaves, which contain enlarged mesophyll cells with increased DNA content and are probably a result of endoreplication. The formation of such growths is largely independent of SA signalling and some E. amylovora effectors. Together, our data reveal signalling requirements for E. amylovora-induced disease resistance, callose deposition and cell fate change in the non-host plant Arabidopsis. Knowledge from this study could facilitate a better understanding of the mechanisms of host defence against E. amylovora and eventually improve host resistance to the pathogen. © 2017 BSPP AND JOHN WILEY & SONS LTD.

  6. Petroleum-hydrocarbons biodegradation by Pseudomonas strains ...

    African Journals Online (AJOL)

    Many indigenous microorganisms in water and soil are capable of degrading hydrocarbon contaminants. In this study, two bacterial strains were isolated from a contaminated soil of a refinery of Arzew (Oran). The isolated strains were identified as Pseudomonas aeruginosa (P3) and Pseudomonas fluoresens (P4).

  7. Optimization of alkaline protease production from Pseudomonas ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... A protease producing bacteria was isolated from meat waste contaminated soil and identified as. Pseudomonas ... Key words: Alkaline protease, casein agar, meat waste contaminated soil, Pseudomonas fluorescens. INTRODUCTION ... advent of new frontiers in biotechnology, the spectrum of protease ...

  8. Erwinia amylovora expresses fast and simultaneously hrp/dsp virulence genes during flower infection on apple trees.

    Directory of Open Access Journals (Sweden)

    Doris Pester

    Full Text Available BACKGROUND: Pathogen entry through host blossoms is the predominant infection pathway of the gram-negative bacterium Erwinia amylovora leading to manifestation of the disease fire blight. Like in other economically important plant pathogens, E. amylovora pathogenicity depends on a type III secretion system encoded by hrp genes. However, timing and transcriptional order of hrp gene expression during flower infections are unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using quantitative real-time PCR analyses, we addressed the questions of how fast, strong and uniform key hrp virulence genes and the effector dspA/E are expressed when bacteria enter flowers provided with the full defense mechanism of the apple plant. In non-invasive bacterial inoculations of apple flowers still attached to the tree, E. amylovora activated expression of key type III secretion genes in a narrow time window, mounting in a single expression peak of all investigated hrp/dspA/E genes around 24-48 h post inoculation (hpi. This single expression peak coincided with a single depression in the plant PR-1 expression at 24 hpi indicating transient manipulation of the salicylic acid pathway as one target of E. amylovora type III effectors. Expression of hrp/dspA/E genes was highly correlated to expression of the regulator hrpL and relative transcript abundances followed the ratio: hrpA>hrpN>hrpL>dspA/E. Acidic conditions (pH 4 in flower infections led to reduced virulence/effector gene expression without the typical expression peak observed under natural conditions (pH 7. CONCLUSION/SIGNIFICANCE: The simultaneous expression of hrpL, hrpA, hrpN, and the effector dspA/E during early floral infection indicates that speed and immediate effector transmission is important for successful plant invasion. When this delicate balance is disturbed, e.g., by acidic pH during infection, virulence gene expression is reduced, thus partly explaining the efficacy of acidification in fire blight

  9. Identification of genes differentially expressed during interaction of resistant and susceptible apple cultivars (Malus × domestica) with Erwinia amylovora

    Science.gov (United States)

    2010-01-01

    Background The necrogenic enterobacterium, Erwinia amylovora is the causal agent of the fire blight (FB) disease in many Rosaceaespecies, including apple and pear. During the infection process, the bacteria induce an oxidative stress response with kinetics similar to those induced in an incompatible bacteria-plant interaction. No resistance mechanism to E. amylovora in host plants has yet been characterized, recent work has identified some molecular events which occur in resistant and/or susceptible host interaction with E. amylovora: In order to understand the mechanisms that characterize responses to FB, differentially expressed genes were identified by cDNA-AFLP analysis in resistant and susceptible apple genotypes after inoculation with E. amylovora. Results cDNA were isolated from M.26 (susceptible) and G.41 (resistant) apple tissues collected 2 h and 48 h after challenge with a virulent E. amylovora strain or mock (buffer) inoculated. To identify differentially expressed transcripts, electrophoretic banding patterns were obtained from cDNAs. In the AFLP experiments, M.26 and G.41 showed different patterns of expression, including genes specifically induced, not induced, or repressed by E. amylovora. In total, 190 ESTs differentially expressed between M.26 and G.41 were identified using 42 pairs of AFLP primers. cDNA-AFLP analysis of global EST expression in a resistant and a susceptible apple genotype identified different major classes of genes. EST sequencing data showed that genes linked to resistance, encoding proteins involved in recognition, signaling, defense and apoptosis, were modulated by E. amylovora in its host plant. The expression time course of some of these ESTs selected via a bioinformatic analysis has been characterized. Conclusion These data are being used to develop hypotheses of resistance or susceptibility mechanisms in Malus to E. amylovora and provide an initial categorization of genes possibly involved in recognition events, early

  10. Mutation of the Erwinia amylovora argD gene causes arginine auxotrophy, nonpathogenicity in apples, and reduced virulence in pears.

    Science.gov (United States)

    Ramos, Laura S; Lehman, Brian L; Peter, Kari A; McNellis, Timothy W

    2014-11-01

    Fire blight is caused by Erwinia amylovora and is the most destructive bacterial disease of apples and pears worldwide. In this study, we found that E. amylovora argD(1000)::Tn5, an argD Tn5 transposon mutant that has the Tn5 transposon inserted after nucleotide 999 in the argD gene-coding region, was an arginine auxotroph that did not cause fire blight in apple and had reduced virulence in immature pear fruits. The E. amylovora argD gene encodes a predicted N-acetylornithine aminotransferase enzyme, which is involved in the production of the amino acid arginine. A plasmid-borne copy of the wild-type argD gene complemented both the nonpathogenic and the arginine auxotrophic phenotypes of the argD(1000)::Tn5 mutant. However, even when mixed with virulent E. amylovora cells and inoculated onto immature apple fruit, the argD(1000)::Tn5 mutant still failed to grow, while the virulent strain grew and caused disease. Furthermore, the pCR2.1-argD complementation plasmid was stably maintained in the argD(1000)::Tn5 mutant growing in host tissues without any antibiotic selection. Therefore, the pCR2.1-argD complementation plasmid could be useful for the expression of genes, markers, and reporters in E. amylovora growing in planta, without concern about losing the plasmid over time. The ArgD protein cannot be considered an E. amylovora virulence factor because the argD(1000)::Tn5 mutant was auxotrophic and had a primary metabolism defect. Nevertheless, these results are informative about the parasitic nature of the fire blight disease interaction, since they indicate that E. amylovora cannot obtain sufficient arginine from apple and pear fruit tissues or from apple vegetative tissues, either at the beginning of the infection process or after the infection has progressed to an advanced state. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  11. Toprak Solucanlarından Elde Edilen Vermikompostun Bazı Bitki Patojenleri Üzerindeki Antimikrobiyal Aktivitelerinin Araştırılması

    Directory of Open Access Journals (Sweden)

    Uğur Tutar

    2012-12-01

    Full Text Available Toprak solucanlarının, organik atıkları biyolojik olarak parçalayarak ayrıştırmaları ile oluşturdukları “vemikompost” un, bazı patojen bakteri ve funguslara karşı etkili oldukları yapılan çeşitli araştırmalarla saptanmıştır. Bu çalışmada, Eisenia fetida türü toprak solucanlarından elde edilen vermikompostun; etanol ve kloroform solventleri kullanılarak elde edilen ekstrelerinin, bitkilerde hastalıklara neden olan toprak kaynaklı patojen 9 adet bakteri ve 9 adet fungusa karşı etkinliklerinin belirlenmesi amacıyla “disk difüzyon” ve “MIC” testleri uygulanmıştır. Çalışma sonuçlarına göre, toprak solucanlarından elde edilen vermikompostun kloroform ile elde edilen ekstrelerinin Pseudomonas syringae, Xhantomonas carotae, Sclerotinia sclerotiorum, Fusarim oxysporum, Aspergillus humicola ve Aspergillus fumigatus’ a karşı etkileri güçlü olurken Erwinia chrysanthemi, Pseudomonas fluorescens, ve Penicillium brevicompactum’ a karşı etkilerinin daha zayıf olduğu görülmüştür. Vermikompostun etanol ile elde edilen ekstrelerinin ise Pseudomonas syringae, Xhantomonas campestris ve Aspergillus fumigatus’ a karşı etkilerinin güçlü olduğu, Erwinia herbicola, Erwinia chrysanthemi ve Sclerotinia sclerotiorum’ a  karşı ise daha zayıf bir etki gösterdiği saptanmıştır.

  12. Pseudomonas savastanoi pv. savastanoi Contains Two iaaL Paralogs, One of Which Exhibits a Variable Number of a Trinucleotide (TAC) Tandem Repeat▿ †

    Science.gov (United States)

    Matas, Isabel M.; Pérez-Martínez, Isabel; Quesada, José M.; Rodríguez-Herva, José J.; Penyalver, Ramón; Ramos, Cayo

    2009-01-01

    In this study, Pseudomonas savastanoi pv. savastanoi isolates were demonstrated to contain two iaaL paralogs, which are both chromosomally located in most strains. Comparative analysis of iaaL nucleotide sequences amplified from these two paralogs revealed that one paralog, iaaLPsn, is 100% identical to iaaL from P. savastanoi pv. nerii, while the other paralog, iaaLPsv, exhibited 93% identity to iaaL from Pseudomonas syringae pv. tomato (iaaLPto). A 3-nucleotide motif (TAC) comprised of 3 to 15 repeats, which remained stable after propagation of the strains in olive plants, was found in iaaLPsv. Based on the observed nucleotide sequence variations, a restriction fragment length polymorphism assay was developed that allowed differentiation among iaaLPsn, iaaLPsv, and iaaLPto. In addition, reverse transcriptase PCR on total RNA from P. savastanoi pv. savastanoi strains demonstrated that both iaaLPsv and iaaLPsn containing 14 or fewer TAC repeats are transcribed. Capillary electrophoresis analysis of PCR-amplified DNA fragments containing the TAC repeats from iaaLPsv allowed the differentiation of P. savastanoi pv. savastanoi isolates. PMID:19098222

  13. Studies on the O-specific polysaccharide of the lipopolysaccharide from the Pseudomonas mediterranea strain C5P1rad1, a bacterium pathogenic of tomato and chrysanthemum.

    Science.gov (United States)

    Zdorovenko, Evelina L; Cimmino, Alessio; Marchi, Guido; Shashkov, Alexander S; Fiori, Mario; Knirel, Yuriy A; Evidente, Antonio

    2017-08-07

    An O-specific polysaccharide (OPS) was isolated from the lipopolysaccharide of Pseudomonas mediterranea strain C5P1rad1, the causal agents of tomato pith necrosis and Chrysanthemum stem rot, and studied by one- and two-dimensional (1)H and (13)C NMR spectroscopy. The following structure of the trisaccharide repeating unit of the OPS was established, which, to our knowledge, is unique among the known bacterial polysaccharide structures: →4)-β-d-ManpNAc3NAcA-(1 → 4)-β-d-ManpNAc3NAcA-(1 → 3)-α-d-QuipNAc4NAc-(1→ where QuiNAc4NAc and ManNAc3NAcA indicate 2,4-diacetamido-2,4,6-trideoxyglucose and 2,3-diacetamido-2,3-dideoxymannuronic acid, respectively. Pre-treatment of leaves with LPS or OPS preparations at 250 and 50 μg mL(-1) did not inhibit development of a hypersensitivity reaction induced by P. mediterranea C5P1rad1 on tobacco, tomato and chrysanthemum plants. The same preparations at 250 μg mL(-1) partially prevented elicitation of the hypersensitivity reaction by Pseudomonas syringae KVPT7RC on chrysanthemum but not tobacco and tomato. Copyright © 2017. Published by Elsevier Ltd.

  14. NCBI nr-aa BLAST: CBRC-EEUR-01-1199 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-EEUR-01-1199 ref|YP_236375.1| Glycosyl transferase, group 1 [Pseudomonas syringae pv. syr...ingae B728a] gb|AAY38337.1| Glycosyl transferase, group 1 [Pseudomonas syringae pv. syringae B728a] YP_236375.1 6.1 32% ...

  15. NCBI nr-aa BLAST: CBRC-AGAM-07-0018 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-AGAM-07-0018 ref|YP_234515.1| hypothetical protein Psyr_1426 [Pseudomonas syringae pv. syr...ingae B728a] gb|AAY36477.1| conserved hypothetical protein [Pseudomonas syringae pv. syringae B728a] YP_234515.1 4e-23 23% ...

  16. NCBI nr-aa BLAST: CBRC-CREM-01-1302 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CREM-01-1302 ref|YP_238152.1| Acyltransferase 3 [Pseudomonas syringae pv. syri...ngae B728a] gb|AAY40114.1| Acyltransferase 3 [Pseudomonas syringae pv. syringae B728a] YP_238152.1 1e-75 48% ...

  17. NCBI nr-aa BLAST: CBRC-CBRE-01-0002 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CBRE-01-0002 ref|YP_234791.1| Amino acid adenylation [Pseudomonas syringae pv. syr...ingae B728a] gb|AAY36753.1| Amino acid adenylation [Pseudomonas syringae pv. syringae B728a] YP_234791.1 1e-99 29% ...

  18. NCBI nr-aa BLAST: CBRC-XTRO-01-0909 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-XTRO-01-0909 ref|YP_234237.1| protoheme IX farnesyltransferase [Pseudomonas syringae pv. syr...ingae B728a] gb|AAY36199.1| Protoheme IX farnesyltransferase [Pseudomonas syringae pv. syringae B728a] YP_234237.1 1e-143 87% ...

  19. NCBI nr-aa BLAST: CBRC-PCAP-01-0324 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PCAP-01-0324 ref|YP_237870.1| YD repeat-containing protein [Pseudomonas syringae pv. syr...ingae B728a] gb|AAY39832.1| YD repeat [Pseudomonas syringae pv. syringae B728a] YP_237870.1 0.74 33% ...

  20. NCBI nr-aa BLAST: CBRC-DYAK-04-0067 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-DYAK-04-0067 ref|YP_234516.1| hypothetical protein Psyr_1427 [Pseudomonas syringae pv. syr...ingae B728a] gb|AAY36478.1| conserved hypothetical protein [Pseudomonas syringae pv. syringae B728a] YP_234516.1 2.8 27% ...

  1. NCBI nr-aa BLAST: CBRC-PHAM-01-0525 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PHAM-01-0525 ref|YP_234694.1| hypothetical protein Psyr_1608 [Pseudomonas syringae pv. syr...ingae B728a] gb|AAY36656.1| ice-nucleation proteins octamer repeat [Pseudomonas syringae pv. syringae B728a] YP_234694.1 1e-12 26% ...

  2. NCBI nr-aa BLAST: CBRC-AGAM-07-0023 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-AGAM-07-0023 ref|YP_234795.1| Major facilitator superfamily [Pseudomonas syringae pv. syr...ingae B728a] gb|AAY36757.1| Major facilitator superfamily [Pseudomonas syringae pv. syringae B728a] YP_234795.1 1e-147 93% ...

  3. NCBI nr-aa BLAST: CBRC-AGAM-04-0109 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-AGAM-04-0109 ref|YP_236998.1| quinoprotein [Pseudomonas syringae pv. syringae ...B728a] gb|AAY38960.1| quinoprotein [Pseudomonas syringae pv. syringae B728a] YP_236998.1 1.2 29% ...

  4. Pseudomonas fluorescens induces strain-dependent and strain-independent host plant responses in defense networks, primary metabolism and photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Pelletier, Dale A [ORNL; Morrell-Falvey, Jennifer L [ORNL; Karve, Abhijit A [ORNL; Lu, Tse-Yuan S [ORNL; Tschaplinski, Timothy J [ORNL; Tuskan, Gerald A [ORNL; Chen, Jay [ORNL; Martin, Madhavi Z [ORNL; Jawdy, Sara [ORNL; Weston, David [ORNL; Doktycz, Mitchel John [ORNL; Schadt, Christopher Warren [ORNL

    2012-01-01

    Colonization of plants by nonpathogenic Pseudomonas fluorescens strains can confer enhanced defense capacity against a broad spectrum of pathogens. Few studies, however, have linked defense pathway regulation to primary metabolism and physiology. In this study, physiological data, metabolites, and transcript profiles are integrated to elucidate how molecular networks initiated at the root-microbe interface influence shoot metabolism and whole-plant performance. Experiments with Arabidopsis thaliana were performed using the newly identified P. fluorescens GM30 or P. fluorescens Pf-5 strains. Co-expression networks indicated that Pf-5 and GM30 induced a subnetwork specific to roots enriched for genes participating in RNA regulation, protein degradation, and hormonal metabolism. In contrast, only GM30 induced a subnetwork enriched for calcium signaling, sugar and nutrient signaling, and auxin metabolism, suggesting strain dependence in network architecture. In addition, one subnetwork present in shoots was enriched for genes in secondary metabolism, photosynthetic light reactions, and hormone metabolism. Metabolite analysis indicated that this network initiated changes in carbohydrate and amino acid metabolism. Consistent with this, we observed strain-specific responses in tryptophan and phenylalanine abundance. Both strains reduced host plant carbon gain and fitness, yet provided a clear fitness benefit when plants were challenged with the pathogen P. syringae DC3000.

  5. Metabolic and Transcriptomic Changes Induced in Arabidopsis by the Rhizobacterium Pseudomonas fluorescens SS1011[W][OA

    Science.gov (United States)

    van de Mortel, Judith E.; de Vos, Ric C.H.; Dekkers, Ester; Pineda, Ana; Guillod, Leandre; Bouwmeester, Klaas; van Loon, Joop J.A.; Dicke, Marcel; Raaijmakers, Jos M.

    2012-01-01

    Systemic resistance induced in plants by nonpathogenic rhizobacteria is typically effective against multiple pathogens. Here, we show that root-colonizing Pseudomonas fluorescens strain SS101 (Pf.SS101) enhanced resistance in Arabidopsis (Arabidopsis thaliana) against several bacterial pathogens, including Pseudomonas syringae pv tomato (Pst) and the insect pest Spodoptera exigua. Transcriptomic analysis and bioassays with specific Arabidopsis mutants revealed that, unlike many other rhizobacteria, the Pf.SS101-induced resistance response to Pst is dependent on salicylic acid signaling and not on jasmonic acid and ethylene signaling. Genome-wide transcriptomic and untargeted metabolomic analyses showed that in roots and leaves of Arabidopsis plants treated with Pf.SS101, approximately 1,910 genes and 50 metabolites were differentially regulated relative to untreated plants. Integration of both sets of “omics” data pointed to a prominent role of camalexin and glucosinolates in the Pf.SS101-induced resistance response. Subsequent bioassays with seven Arabidopsis mutants (myb51, cyp79B2cyp79B3, cyp81F2, pen2, cyp71A12, cyp71A13, and myb28myb29) disrupted in the biosynthesis pathways for these plant secondary metabolites showed that camalexin and glucosinolates are indeed required for the induction of Pst resistance by Pf.SS101. Also for the insect S. exigua, the indolic glucosinolates appeared to play a role in the Pf.SS101-induced resistance response. This study provides, to our knowledge for the first time, insight into the substantial biochemical and temporal transcriptional changes in Arabidopsis associated with the salicylic acid-dependent resistance response induced by specific rhizobacteria. PMID:23073694

  6. Multilocus sequence typing of carbapenem resistant Pseudomonas ...

    African Journals Online (AJOL)

    Background: Pseudomonas aeruginosa is an important nosocomial pathogen that exhibits multiple drug resistance with increasing frequency, especially to carbapenems making patient treatment difficult. Carbapenem-resistance may be caused by porin gene mutations, active drug efflux, and carbapenemase production.

  7. Dynamics of Pseudomonas aeruginosa Genome Evolution

    National Research Council Canada - National Science Library

    Kalai Mathee; Giri Narasimhan; Camilo Valdes; Xiaoyun Qiu; Jody M. Matewish; Michael Koehrsen; Antonis Rokas; Chandri N. Yandava; Reinhard Engels; Erliang Zeng; Raquel Olavarietta; Melissa Doud; Roger S. Smith; Philip Montgomery; Jared R. White; Paul A. Godfrey; Chinnappa Kodira; Bruce Birren; James E. Galagan; Stephen Lory

    2008-01-01

    One of the hallmarks of the Gram-negative bacterium Pseudomonas aeruginosa is its ability to thrive in diverse environments that includes humans with a variety of debilitating diseases or immune deficiencies...

  8. Pseudomonas aeruginosa: resistance to the max

    National Research Council Canada - National Science Library

    Poole, Keith

    2011-01-01

    Pseudomonas aeruginosa is intrinsically resistant to a variety of antimicrobials and can develop resistance during anti-pseudomonal chemotherapy both of which compromise treatment of infections caused by this organism...

  9. Antibiotic Conditioned Growth Medium of Pseudomonas Aeruginosa

    Science.gov (United States)

    Benathen, Isaiah A.; Cazeau, Barbara; Joseph, Njeri

    2004-01-01

    A simple method to study the consequences of bacterial antibiosis after interspecific competition between microorganisms is presented. Common microorganisms are used as the test organisms and Pseudomonas aeruginosa are used as the source of the inhibitor agents.

  10. Pseudomonas aeruginosa (Family Pseudomonadaceae) is an ...

    African Journals Online (AJOL)

    Pseudomonas aeruginosa (Family Pseudomonadaceae) is an obligate aerobic, motile, gram negative bacillus.which is able to grow and survive in almost any environment and resistant to temperature extremes. It is involved in the etiology of several diseases i.

  11. Systems level analysis of two-component signal transduction systems in Erwinia amylovora: Role in virulence, regulation of amylovoran biosynthesis and swarming motility

    Directory of Open Access Journals (Sweden)

    Sundin George W

    2009-05-01

    Full Text Available Abstract Background Two-component signal transduction systems (TCSTs, consisting of a histidine kinase (HK and a response regulator (RR, represent a major paradigm for signal transduction in prokaryotes. TCSTs play critical roles in sensing and responding to environmental conditions, and in bacterial pathogenesis. Most TCSTs in Erwinia amylovora have either not been identified or have not yet been studied. Results We used a systems approach to identify TCST and related signal transduction genes in the genome of E. amylovora. Comparative genomic analysis of TCSTs indicated that E. amylovora TCSTs were closely related to those of Erwinia tasmaniensis, a saprophytic enterobacterium isolated from apple flowers, and to other enterobacteria. Forty-six TCST genes in E. amylovora including 17 sensor kinases, three hybrid kinases, 20 DNA- or ligand-binding RRs, four RRs with enzymatic output domain (EAL-GGDEF proteins, and two kinases were characterized in this study. A systematic TCST gene-knockout experiment was conducted, generating a total of 59 single-, double-, and triple-mutants. Virulence assays revealed that five of these mutants were non-pathogenic on immature pear fruits. Results from phenotypic characterization and gene expression experiments indicated that several groups of TCST systems in E. amylovora control amylovoran biosynthesis, one of two major virulence factors in E. amylovora. Both negative and positive regulators of amylovoran biosynthesis were identified, indicating a complex network may control this important feature of pathogenesis. Positive (non-motile, EnvZ/OmpR, negative (hypermotile, GrrS/GrrA, and intermediate regulators for swarming motility in E. amylovora were also identified. Conclusion Our results demonstrated that TCSTs in E. amylovora played major roles in virulence on immature pear fruit and in regulating amylovoran biosynthesis and swarming motility. This suggested presence of regulatory networks governing

  12. Lon protease modulates virulence traits in Erwinia amylovora by direct monitoring of major regulators and indirectly through the Rcs and Gac-Csr regulatory systems.

    Science.gov (United States)

    Lee, Jae Hoon; Ancona, Veronica; Zhao, Youfu

    2017-05-16

    Lon, an ATP-dependent protease in bacteria, influences diverse cellular processes by degrading damaged, misfolded and short-lived regulatory proteins. In this study, we characterized the effects of lon mutation and determined the molecular mechanisms underlying Lon-mediated virulence regulation in Erwinia amylovora, an enterobacterial pathogen of apple. Erwinia amylovora depends on the type III secretion system (T3SS) and the exopolysaccharide (EPS) amylovoran to cause disease. Our results showed that mutation of the lon gene led to the overproduction of amylovoran, increased T3SS gene expression and the non-motile phenotype. Western blot analyses showed that mutation in lon directly affected the accumulation and stability of HrpS/HrpA and RcsA. Mutation in lon also indirectly influenced the expression of flhD, hrpS and csrB through the accumulation of the RcsA/RcsB proteins, which bind to the promoter of these genes. In addition, lon expression is under the control of CsrA, possibly at both the transcriptional and post-transcriptional levels. Although mutation in csrA abolished both T3SS and amylovoran production, deletion of the lon gene in the csrA mutant only rescued amylovoran production, but not T3SS. These results suggest that CsrA might positively control both T3SS and amylovoran production partly by suppressing Lon, whereas CsrA may also play a critical role in T3SS by affecting unknown targets. © 2017 BSPP AND JOHN WILEY & SONS LTD.

  13. HPLC-NNE13CNMR coupling fingerprint analysis technology and its application in a study of Syringa pubescens Turcz and its activity against hepatic fibrosis

    Directory of Open Access Journals (Sweden)

    Zhang ZX

    2013-07-01

    Full Text Available Zhixin Zhang,1 Weiping Yin,1 Pu Liu,1 Tianzeng Zhao2 1School of Chemical Engineering and Pharmaceutics, Henan University of Science and Technology, Luoyang, People’s Republic of China; 2Key Laboratory of Natural Products, Henan Academy of Sciences, Zhengzhou, People's Republic of China Abstract: This study describes the active ingredients of Syringa pubescens Turcz which has been identified as being able to protect against hepatic fibrosis. Here we report the characteristics of high performance liquid chromatography and non-nuclear overhauser effect carbon-13 nuclear magnetic resonance (HPLC-NNE13CNMR technology developed for coupling fingerprint analysis. The major contribution of this new method is the development of an efficient technology and a useful tool for analysis of a traditional Chinese herbal medicine using chromatography and spectral coupling fingerprint technology. Isolation of secoiridoid glycosides and investigation of their structure-activity relationship showed that these derivatives are the active ingredients of Syringa pubescens Turcz, and account for the activity of this plant against hepatic fibrosis. The active compounds were identified as oleuropein, 10-hydroxyoleuropein, oleoside-11-methylester, (8Z-ligstroside, and echinacoside by HPLC-NNE13CNMR coupling fingerprint analysis. A concentration-response relationship was also demonstrated for the HPLC-NNE13CNMR coupling fingerprint method. Keywords: HPLC-NNE13CNMR, coupling fingerprint, hepatic fibrosis, Syringa pubescens Turcz, analysis technology

  14. Gama de hospedeiros e reação de genótipos de tomateiro a Pseudomonas cichorii Host range and genotypes reaction to Pseudomonas cichorii

    Directory of Open Access Journals (Sweden)

    Tadeu Antônio Fernandes da Silva Júnior

    2009-06-01

    Full Text Available Em 2005, foi constatada em dois campos comerciais de tomate no Estado de São Paulo, a ocorrência da queima bacteriana, causada por Pseudomonas cichorii. Em vista disso, foram desenvolvidos estudos visando a determinação da gama de hospedeiros de isolados de Pseudomonas cichorii (IBSBF 2309 e IBSBF 2323, obtidos de tomateiro, provenientes de campos comerciais localizados nos municípios de Bragança Paulista e Mogi Guaçú, SP. Plantas de abobrinha, alface, beldroega, berinjela, beterraba, cenoura, couvebrócolo, datura, fumo, girassol, jiló, melão, pepino, petúnia, pimentão, rabanete, repolho, rúcula, salsa e tomateiro foram inoculadas por pulverização, separadamente, com os dois isolados de P. cichorii de tomateiro e um isolado de girassol (GIR-1. Os isolados IBSBF 2309 e IBSBF 2323 foram patogênicos à beldroega, datura, girassol, pimentão e tomate; GIR-1 foi patogênico apenas à beldroega, datura e girassol, não sendo patogênico ao pimentão e ao tomateiro. No Brasil não se conhecem fontes de resistência dentro do gênero Lycopersicon ou a reação de cultivares de tomateiros a esta bactéria. Vinte e oito genótipos de tomateiro provenientes do Banco de Germoplasma da empresa Sakata Seed Sudamerica Ltda., foram avaliados quanto a reação aos isolados IBSBF 2309 e IBSBF 2323 de P. cichorii, pelo método de inoculação nas folhas. Os maiores níveis de resistência foram observados em AF 11768, AF 2521, AF 11766, AF 11772, AF 229, AF 5719-1 e AF 8162. O genótipo AF 5719-1, que possui o gene Pto, que confere resistência a P. syringae pv. tomato, apresentou um bom nível de resistência a P. cichorii. A identificação de genótipos que apresentem bons níveis de resistência a este patógeno é importante para utilização em programas de melhoramento genético do tomateiro, visando a incorporação de genes de resistência a P. cichorii.The occurrence of the bacterial blight, caused by Pseudomonas cichorii, was observed

  15. Active Immunization with Lipopolysaccharide Pseudomonas Antigen for Chronic Pseudomonas Bronchopneumonia in Guinea Pigs

    OpenAIRE

    Pennington, James E.; Hickey, William F.; Blackwood, Linda L.; Arnaut, M. Amin

    1981-01-01

    Chronic respiratory infection with Pseudomonas aeruginosa is a leading clinical problem among patients with cystic fibrosis. Because antimicrobial agents are usually ineffective in eradicating these infections, additional therapeutic or prophylactic measures should be considered. In this study, an experimental guinea pig model of chronic Pseudomonas aeruginosa bronchopneumonia was utilized to determine whether active immunization with lipopolysaccharide (LPS) P. aeruginosa antigen may favorab...

  16. Effects of stomatal development on stomatal conductance and on stomatal limitation of photosynthesis in Syringa oblata and Euonymus japonicus Thunb.

    Science.gov (United States)

    Wu, Bing-Jie; Chow, Wah Soon; Liu, Yu-Jun; Shi, Lei; Jiang, Chuang-Dao

    2014-12-01

    During leaf development, the increase in stomatal conductance cannot meet photosynthetic demand for CO2, thus leading to stomatal limitation of photosynthesis (Ls). Considering the crucial influences of stomatal development on stomatal conductance, we speculated whether stomatal development limits photosynthesis to some extent. To test this hypothesis, stomatal development, stomatal conductance and photosynthesis were carefully studied in both Syringa oblata (normal greening species) and Euonymus japonicus Thunb (delayed greening species). Our results show that the size of stomata increased gradually with leaf expansion, resulting in increased stomatal conductance up to the time of full leaf expansion. During this process, photosynthesis also increased steadily. Compared to that in S. oblata, the development of chloroplasts in E. japonicus Thunb was obviously delayed, leading to a delay in the improvement of photosynthetic capacity. Further analysis revealed that before full leaf expansion, stomatal limitation increased rapidly in both S. oblata and E. japonicus Thunb; after full leaf expansion, stomatal limitation continually increased in E. japonicus Thunb. Accordingly, we suggested that the enhancement of photosynthetic capacity is the main factor leading to stomatal limitation during leaf development but that stomatal development can alleviate stomatal limitation with the increase of photosynthesis by controlling gas exchange. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  17. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2013-01-01

    Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed.......Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed....

  18. Airway epithelial cell tolerance to Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Verghese Margrith W

    2005-04-01

    Full Text Available Abstract Background The respiratory tract epithelium is a critical environmental interface that regulates inflammation. In chronic infectious airway diseases, pathogens may permanently colonize normally sterile luminal environments. Host-pathogen interactions determine the intensity of inflammation and thus, rates of tissue injury. Although many cells become refractory to stimulation by pathogen products, it is unknown whether the airway epithelium becomes either tolerant or hypersensitive in the setting of chronic infection. Our goals were to characterize the response of well-differentiated primary human tracheobronchial epithelial cells to Pseudomonas aeruginosa, to understand whether repeated exposure induced tolerance and, if so, to explore the mechanism(s. Methods The apical surface of well-differentiated primary human tracheobronchial epithelial cell cultures was repetitively challenged with Pseudomonas aeruginosa culture filtrates or the bacterial media control. Toxicity, cytokine production, signal transduction events and specific effects of dominant negative forms of signaling molecules were examined. Additional experiments included using IL-1β and TNFα as challenge agents, and performing comparative studies with a novel airway epithelial cell line. Results An initial challenge of the apical surface of polarized human airway epithelial cells with Pseudomonas aeruginosa culture filtrates induced phosphorylation of IRAK1, JNK, p38, and ERK, caused degradation of IκBα, generation of NF-κB and AP-1 transcription factor activity, and resulted in IL-8 secretion, consistent with activation of the Toll-like receptor signal transduction pathway. These responses were strongly attenuated following a second Pseudomonas aeruginosa, or IL-1β, but not TNFα, challenge. Tolerance was associated with decreased IRAK1 protein content and kinase activity and dominant negative IRAK1 inhibited Pseudomonas aeruginosa -stimulated NF-κB transcriptional

  19. 21 CFR 866.3415 - Pseudomonas spp. serological reagents.

    Science.gov (United States)

    2010-04-01

    ... genus Pseudomonas. Pseudomonas aeruginosa is a major cause of hospital-acquired infections, and has been..., abscesses, and meningitis (inflammation of brain membranes). Pseudomonas pseudomallei causes melioidosis, a chronic pneumonia. (b) Classification. Class II (special controls). The device is exempt from the...

  20. Growth of Pseudomonas spp. in cottage cheese

    DEFF Research Database (Denmark)

    Østergaard, Nina Bjerre; Dalgaard, Paw

    of spoilage microorganisms in cottage cheese can cause undesirable alterations in flavour, odour, appearance and texture. Contamination and growth of psychrotolerant pseudomonads including Pseudomonas fragi and Pseudomonas putida has been reported for cottage cheese but the influence of these bacteria...... on product spoilage and shelf-life remains poorly described. The present study used a quantitative microbial ecology approach to model and predict the effect of product characteristics and storage conditions on growth of psychrotolerant pseudomonads in cottage cheese. The effect of temperature (5-15˚C) and p...

  1. Produção de isomaltulose a partir da transformação enzimática da sacarose, utilizando-se Erwinia sp D12 imobilizada com alginato de cálcio Production of isomaltulose from enzymatic transformation of sucrose, using Erwinia sp D12 immobilized with calcium alginate

    Directory of Open Access Journals (Sweden)

    Ana Lúcia Leite Moraes

    2005-03-01

    Full Text Available A glicosiltransferase de Erwinia sp D12 é capaz de converter a sacarose em isomaltulose (6-o-alfa-glicopiranosil D-frutofuranose, um açúcar alternativo que apresenta baixo potencial cariogênico, e que pode ser utilizado em chocolates, gomas de mascar e balas. A isomaltulose é também utilizada na produção de isomalte, uma mistura de açúcar álcool, de baixo valor calórico e baixo potencial cariogênico. No estudo da influência dos componentes do meio de cultivo, na produção de glicosiltransferase, em frascos agitados, foi obtido maior atividade da enzima (12,8 unidades de atividade/mL do meio de cultura em meio de cultura A constituído de melaço 12% (p/v de sólidos solúveis totais, peptona 4% (p/v e extrato de carne 0,4% (p/v. No estudo do efeito do tempo e da temperatura na fermentação da linhagem de Erwinia sp D12, em fermentador New Brunswick de 3L, contendo meio de cultura A, foi obtida maior atividade de glicosiltransferase (15,6 unidades de atividade/ mL de meio de cultura na fase exponencial de crescimento após 8 horas de fermentação a 30ºC. Na produção de isomaltulose a partir da sacarose utilizando-se células de Erwinia sp D12 imobilizadas em alginato de cálcio, estudou-se o efeito da temperatura (25 - 35ºC e da concentração de substrato (12,5 - 60% p/v. Foi obtido um rendimento em torno de 50% de isomaltulose, com soluções de sacarose entre 20-30% (p/v a 35ºC. Concentrações em excesso de sacarose (ao redor de 40% p/v afetaram a atividade da célula imobilizada, diminuindo a conversão de sacarose em isomaltulose. O xarope de isomaltulose foi purificado através de cromatografia de troca iônica e o eluato cristalizado por abaixamento de temperatura. Os cristais apresentaram 91,39% de isomaltulose.The glucosyltransferase of Erwinia sp D12 is able to convert sucrose into isomaltulose (6-0-alpha-D-glucopyranosyl-D-fructofuranose, an alternative sugar which presents low cariogenic potential, and can be

  2. Plant growth promotion by Pseudomonas fluorescens

    NARCIS (Netherlands)

    Cheng, X.

    2016-01-01

    Pseudomonas fluorescens is a Gram-negative rod shaped bacterium that has a versatile metabolism and is widely spread in soil and water. P. fluorescens strain SBW25 (Pf.SBW25) is a well-known model strain to study bacterial evolution, plant colonization and biocontrol of plant diseases. It produces

  3. Antibiograms of Staphylococcus Aureus and Pseudomonas ...

    African Journals Online (AJOL)

    While there was no bacterial growth after 48hrs incubation recorded for group one, only 5(13.9%) samples yielded growth of Staphylococcus aureus for group two with 31(86.1%) yielding no bacterial growth. All group three samples yielded profuse growth of which 11(36.7%) yielded Pseudomonas aeruginosa and ...

  4. Transesterification of Jatropha oil using immobilized Pseudomonas ...

    African Journals Online (AJOL)

    mild transesterification has become of much current interest for alternative fuel production. In the present study the ability of a commercial immobilized Pseudomonas fluorescens MTCC 103 to catalyze the transesterification of Jatropha oil and methanol was investigated. The cell of P. fluorescens was easily immobilized ...

  5. Behavioral response of resistant and sensitive Pseudomonas ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... Key words: Pseudomonas aeruginosa, cadmium stress, heavy metal resistance. INTRODUCTION. The release of .... plasmids located in the bacterial strains isolated from agricultural and industrial soils ..... esteraromaticum S51 with other strains of non-flocculating sludge bacteria. IWA's Water Environ.

  6. Evaluation of gamma irradiation effect and Pseudomonas ...

    African Journals Online (AJOL)

    Antagonistic effect of Pseudomonas fluorescens and influence of gamma irradiation on the development of Penicillium expansum, the causal agent of postharvest disease on apple fruit was studied. P. fluorescens was originally isolated from rhizosphere of the apple trees. Suspension of P. fluorescens and P. expansum ...

  7. Bacteriocinogenicity and production of pyocins from Pseudomonas ...

    African Journals Online (AJOL)

    The susceptible organisms include Bacillus cereus, Listeria monocytogenes, Klebsiella spp., Staphylococcus aureus, S. epidermidis, Proteus spp. and Vibrio parahaemolyticus. The results of this study have provided evidence for broadspectrum antibacterial activity of pyocins elicited by Pseudomonas species from Nigeria ...

  8. Isolation and characterization of arsenite oxidizing Pseudomonas ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-08

    Mar 8, 2010 ... indicates its potential application in biological treatment of wastewaters contaminated with arsenic. Key words: Arsenic, wastewater, Pseudomonas lubricans, bioremediation. INTRODUCTION. Arsenic is the most prevalent environmental toxic metal and is first on the superfund list of hazardous substances.

  9. Antibiotics Susceptibility Pattern of Pseudomonas aeruginosa ...

    African Journals Online (AJOL)

    ABSTRACT: This work investigated the prevalence and antibiotics sensitivity of Pseudomonas aeruginosa isolated from wounds of patients attending Ahmadu Bello University Teaching Hospital (ABUTH), Zaria-Nigeria. One hundred Isolates were characterized and identified from the specimens using standard ...

  10. Characterization of drug resistant Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Despite the fact that they remain asymptomatic in many cases, they nevertheless play significant roles in the epidemiology of these pathogens through their dissemination to the public, sometimes through the food chain. Four multidrug resistant Gram negative pathogens including: 2 Pseudomonas aeruginosa and 2 Proteus ...

  11. Growth of Pseudomonas fluorescens on Cassava Starch ...

    African Journals Online (AJOL)

    This involved hydrolysis of starch extracted from freshly harvested cassava tubers using enzyme-enzyme method of hydrolysis, followed by aerobic fermentation of Pseudomonas fluorescens on a mixture of the hydrolysate and nutrient media in a fermentor in batch cultures. The reducing sugar hydrolysate served as the ...

  12. Characterization of rhodanese produced by Pseudomonas ...

    African Journals Online (AJOL)

    Enzymatic remediation of polluted environment presents advantages over traditional technologies and also over microbial remediation. Extracellular rhodanese of strains of Pseudomonas aerugionosa and Bacillus brevis isolated from soil of cassava processing site were studied. Biochemical characteristics of the purified ...

  13. Production and characterization of biosurfactant from Pseudomonas ...

    African Journals Online (AJOL)

    In this present study, biosurfactant-producing microorganisms Pseudomonas aeruginosa PBSC1, was isolated from mangrove ecosystem in Pichavaram (Boat house), Tamil Nadu, India. The biosurfactant production was done using a minimal salt medium (MSM) with crude oil as the hydrocarbon. The microbial growths ...

  14. Optimization of alkaline protease production from Pseudomonas ...

    African Journals Online (AJOL)

    A protease producing bacteria was isolated from meat waste contaminated soil and identified as Pseudomonas fluorescens. Optimization of the fermentation medium for maximum protease production was carried out. The culture conditions like inoculum concentration, incubation time, pH, temperature, carbon sources, ...

  15. "Hot Tub Rash" and "Swimmer's Ear" (Pseudomonas)

    Science.gov (United States)

    ... Hot Tub Rash > Remove swimsuits and shower with soap after getting out of the water. > Clean swimsuits after getting out of the water. ... in locations that have been closed because of pollution. Pseudomonas can multiply quickly when water disinfectant levels drop, so testing your pool or ...

  16. Occurrence of Fusarium Oxysporum and Ralstonia (Pseudomonas ...

    African Journals Online (AJOL)

    The microflora associated with the root-surface of five tomato cultivars commonly cultivated in Edo State Nigeria, was investigated by inoculating serially washed 5 mm tomato root segments on potato dextrose agar (PDA) incubated at room temperature (28-30oC). Fusarium oxysporum and Ralstonia (pseudomonas) ...

  17. High pressure inactivation of Pseudomonas in black truffle - comparison with Pseudomonas fluorescens in tryptone soya broth

    Science.gov (United States)

    Ballestra, Patricia; Verret, Catherine; Cruz, Christian; Largeteau, Alain; Demazeau, Gerard; El Moueffak, Abdelhamid

    2010-03-01

    Pseudomonas is one of the most common genera in black Perigord truffle. Its inactivation by high pressure (100-500 MPa/10 min) applied on truffles at sub-zero or low temperatures was studied and compared with those of Pseudomonas fluorescens in tryptone soya broth. Pressurization of truffles at 300 MPa/4 °C reduced the bacterial count of Pseudomonas by 5.3 log cycles. Higher pressures of 400 or 500 MPa, at 4 °C or 20 °C, allowed us to slightly increase the level of destruction to the value of ca. 6.5 log cycles but did not permit us to completely inactivate Pseudomonas. The results showed a residual charge of about 10 CFU/g. Pressure-shift freezing of truffles, which consists in applying a pressure of 200 MPa/-18 °C for 10 min and then quickly releasing this pressure to induce freezing, reduced the population of Pseudomonas by 3.3 log cycles. The level of inactivation was higher than those obtained with conventional freezing. Endogenous Pseudomonas in truffle was shown to be more resistant to high pressure treatments than P. fluorescens used for inoculation of broths.

  18. Molecular characterization and functional analysis of chalcone synthase from Syringa oblata Lindl. in the flavonoid biosynthetic pathway.

    Science.gov (United States)

    Wang, Yu; Dou, Ying; Wang, Rui; Guan, Xuelian; Hu, Zenghui; Zheng, Jian

    2017-11-30

    The flower color of Syringa oblata Lindl., which is often modulated by the flavonoid content, varies and is an important ornamental feature. Chalcone synthase (CHS) catalyzes the first key step in the flavonoid biosynthetic pathway. However, little is known about the role of S. oblata CHS (SoCHS) in flavonoid biosynthesis in this species. Here, we isolate and analyze the cDNA (SoCHS1) that encodes CHS in S. oblata. We also sought to analyzed the molecular characteristics and function of flavonoid metabolism by SoCHS1. We successfully isolated the CHS-encoding genomic DNA (gDNA) in S. oblata (SoCHS1), and the gene structural analysis indicated it had no intron. The opening reading frame (ORF) sequence of SoCHS1 was 1170bp long and encoded a 389-amino acid polypeptide. Multiple sequence alignment revealed that both the conserved CHS active site residues and CHS signature sequence were in the deduced amino acid sequence of SoCHS1. Crystallographic analysis revealed that the protein structure of SoCHS1 is highly similar to that of FnCHS1 in Freesia hybrida. The quantitative real-time polymerase chain reaction (PCR) performed to detect the SoCHS1 transcript expression levels in flowers, and other tissues revealed the expression was significantly correlated with anthocyanin accumulation during flower development. The ectopic expression results of Nicotiana tabacum showed that SoCHS1 overexpression in transgenic tobacco changed the flower color from pale pink to pink. In conclusion, these results suggest that SoCHS1 plays an essential role in flavonoid biosynthesis in S. oblata, and could be used to modify flavonoid components in other plant species. Copyright © 2017. Published by Elsevier B.V.

  19. Carotenoid biosynthesis in bacteria: In vitro studies of a crt/bch transcription factor from Rhodobacter capsulatus and carotenoid enzymes from Erwinia herbicola

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, David Allen [Univ. of California, Berkeley, CA (United States)

    1992-11-01

    A putative transcription factor in Rhodobactor capsulatus which binds upstream of the crt and bch pigment biosynthesis operons and appears to play a role in the adaptation of the organism from the aerobic to the anaerobic-photosynthetic growth mode was characterized. Chapter 2 describes the identification of this factor through an in vitro mobility shift assay, as well as the determination of its binding properties and sequence specificity. Chapter 3 focuses on the isolation of this factor. Biochemistry of later carotenoid biosynthesis enzymes derived from the non-photosynthetic bacterium, Erwinia herbicola. Chapter 4 describes the separate overexpression and in vitro analysis of two enzymes involved in the main sequence of the carotenoid biosynthesis pathway, lycopene cyclase and 5-carotene hydroxylase. Chapter 5 examines the overexpression and enzymology of functionally active zeaxanthin glucosyltransferase, an enzyme which carries out a more unusual transformation, converting a carotenoid into its more hydrophilic mono- and diglucoside derivatives. In addition, amino acid homology with other glucosyltransferases suggests a putative binding site for the UDP-activated glucose substrate.

  20. HopX1 in Erwinia amylovora functions as an avirulence protein in apple and is regulated by HrpL.

    Science.gov (United States)

    Bocsanczy, A M; Schneider, D J; DeClerck, G A; Cartinhour, S; Beer, S V

    2012-02-01

    Fire blight is a devastating disease of rosaceous plants caused by the Gram-negative bacterium Erwinia amylovora. This pathogen delivers virulence proteins into host cells utilizing the type III secretion system (T3SS). Expression of the T3SS and of translocated and secreted substrates is activated by the alternative sigma factor HrpL, which recognizes hrp box promoters upstream of regulated genes. A collection of hidden Markov model (HMM) profiles was used to identify putative hrp boxes in the genome sequence of Ea273, a highly virulent strain of E. amylovora. Among potential virulence factors preceded by putative hrp boxes, two genes previously known as Eop3 and Eop2 were characterized. The presence of functionally active hrp boxes upstream of these two genes was confirmed by β-glucuronidase (GUS) assays. Deletion mutants of the latter candidate genes, renamed hopX1(Ea) and hopAK1(Ea), respectively, did not differ in virulence from the wild-type strain when assayed in pear fruit and apple shoots. The hopX1(Ea) deletion mutant of Ea273, complemented with a plasmid overexpressing hopX1(E)(a), suppressed the development of the hypersensitivity response (HR) when inoculated into Nicotiana benthamiana; however, it contributed to HR in Nicotiana tabacum and significantly reduced the progress of disease in apple shoots, suggesting that HopX1(Ea) may act as an avirulence protein in apple shoots.

  1. T3SS-dependent differential modulations of the jasmonic acid pathway in susceptible and resistant genotypes of Malus spp. challenged with Erwinia amylovora.

    Science.gov (United States)

    Dugé De Bernonville, Thomas; Gaucher, Matthieu; Flors, Victor; Gaillard, Sylvain; Paulin, Jean-Pierre; Dat, James F; Brisset, Marie-Noëlle

    2012-06-01

    Fire blight is a bacterial disease of Maloideae caused by Erwinia amylovora (Ea). This necrogenic enterobacterium uses a type III secretion system (T3SS) to inject type III effectors into the plant cells to cause disease on its susceptible hosts, including economically important crops like apple and pear. The expressions of marker genes of the salicylic acid (SA) and jasmonic acid (JA) defense regulation pathways were monitored by RT-qPCR in leaves of two apple genotypes, one susceptible and one resistant, challenged with a wild type strain, a T3SS-deficient strain or water. The transcriptional data taken together with hormone level measurements indicated that the SA pathway was similarly induced in both apple genotypes during infection by Ea. On the contrary, the data clearly showed a strong T3SS-dependent down-regulation of the JA pathway in leaves of the susceptible genotype but not in those of the resistant one. Accordingly, methyl-jasmonate treated susceptible plants displayed an increased resistance to Ea. Bacterial mutant analysis indicated that JA manipulation by Ea mainly relies on the type III effector DspA/E. Taken together, our data suggest that the T3SS-dependent down-regulation of the JA pathway is a critical step in the infection process of Malus spp. by Ea. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Phylogenetic analysis of PR genes in some pome fruit species with the emphasis on transcriptional analysis and ROS response under Erwinia amylovora inoculation in apple.

    Science.gov (United States)

    Hassani, Maryam; Salami, Seyed Alireza; Nasiri, Jaber; Abdollahi, Hamid; Ghahremani, Zahra

    2016-02-01

    Attempts were made to identify eight pathogenesis related (PR) genes (i.e., PR-1a, PR3-ch1, PR3-Ch2, PR3-Ch3, PR3-Ch4, PR3-Ch5, PR-5 and PR-8) from 27 genotypes of apple, quince and pear, which are induced in response to inoculation with the pathogen Erwinia amylovora, the causal agent of fire blight. Totally, 32 PR genes of different families were obtained, excepting PR3-Ch2 (amplified only in apple) and PR3-Ch4 (amplified only in apple and pear), the others were successfully amplified in all the genotypes of apple, quince and pear. Evolutionary, the genes of each family exhibited significant homology with each other, as the corresponded phylogenetic neighbor-joining-based dendrograms were taken into consideration. Meanwhile, according to the expression assay, it was deduced that the pathogen activity can significantly affect the expression levels of some selected PR genes of PR3-Ch2, PR3-Ch4, PR3-Ch5 and particularly Cat I in both resistant (MM-111) and semi-susceptible (MM-106) apple rootstocks. Lastly, it was concluded that the pathogen E. amylovora is able to stimulate ROS response, particularly using generation of hydrogen peroxide (H2O2) in both aforementioned apple rootstock.

  3. {open_quotes}Horizontal{close_quotes} gene transfer from a transgenic potato line to a bacterial pathogen (Erwinia chrysanthemi) occurs - if at all - at an extremely low frequency

    Energy Technology Data Exchange (ETDEWEB)

    Schlueter, K.; Fuetterer, J.; Potrykus, I. [Institute of Plant Sciences, Zuerich (Switzerland)

    1995-10-01

    The frequency of possible {open_quotes}horizontal{close_quotes} gene transfer between a plant and a tightly associated bacterial pathogen was studied in a model system consisting of transgenic Solanum tuberosum, containing a {beta}-lactamase gene linked to a pBR322 origin of replication, and Erwinia chrysanthemi. This experimental system offers optimal conditions for the detection of possible horizontal gene transfer events, even when they occur at very low frequency. Horizontal gene transfer was not detected under conditions mimicking a {open_quotes}natural{close_quotes} infection. The gradual, stepwise alteration of artificial, positive control conditions to idealized natural conditions, however, allowed the characterization of factors that affected gene transfer, and revealed a gradual decrease of the gene transfer frequency from 6.3 x 10{sup -2} under optimal control conditions to a calculated 2.0 x 10{sub -17} under idealized natural conditions. These data, in combination with other published studies, argue that horizontal gene transfer is so rare as to be essentially irrelevant to any realistic assessment of the risk involved in release experiments involving transgenic plants. 22 refs., 3 figs., 2 tabs.

  4. Virulence of Erwinia amylovora, a prevalent apple pathogen: Outer membrane proteins and type III secreted effectors increase fitness and compromise plant defenses.

    Science.gov (United States)

    Holtappels, Michelle; Noben, Jean-Paul; Valcke, Roland

    2016-09-01

    Until now, no data are available on the outer membrane (OM) proteome of Erwinia amylovora, a Gram-negative plant pathogen, causing fire blight in most of the members of the Rosaceae family. Since the OM forms the interface between the bacterial cell and its environment it is in direct contact with the host. Additionally, the type III secretion system, embedded in the OM, is a pathogenicity factor of E. amylovora. To assess the influence of the OM composition and the secretion behavior on virulence, a 2D-DIGE analysis and gene expression profiling were performed on a high and lower virulent strain, both in vitro and in planta. Proteome data showed an increase in flagellin for the lower virulent strain in vitro, whereas, in planta several interesting proteins were identified as being differently expressed between both the strains. Further, gene expression of nearly all type III secreted effectors was elevated for the higher virulent strain, both in vitro and in planta. As a first, we report that several characteristics of virulence can be assigned to the OM proteome. Moreover, we demonstrate that secreted proteins prove to be the important factors determining differences in virulence between the strains, otherwise regarded as homogeneous on a genome level. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Characterization of a tonB mutation in Erwinia chrysanthemi 3937: TonB(Ech) is a member of the enterobacterial TonB family.

    Science.gov (United States)

    Enard, C; Expert, D

    2000-08-01

    The pectinolytic enterobacterium Erwinia chrysanthemi 3937 causes a systemic disease in its natural host, the African violet (Saintpaulia: ionantha). It produces two structurally unrelated siderophores, chrysobactin and achromobactin. Chrysobactin makes a large contribution to invasive growth of the bacterium in its host. Insertion mutants of a chrysobactin-defective strain were constructed and screened on the universal CAS-agar medium used for siderophore detection. A set of mutants affected in the production of achromobactin were identified. This paper describes a mutant affected in the transport of all the ferrisiderophores used by the bacterium as iron sources. Molecular analysis revealed that the insertion mutation disrupts the tonB gene. The predicted Er. chrysanthemi TonB protein has a molecular mass of 27600 Da and shares 20-58% identity with the TonB proteins from 20 other bacterial species. The pathogenicity of the tonB mutant was assessed by inoculation of African violets. The impairment in the spread of symptoms was similar in the tonB mutant to that in chrysobactin-defective mutants. However, the pectinolytic activity, the major pathogenicity determinant in Er. chrysanthemi, appeared to be stimulated twofold in the tonB mutant.

  6. The minimal gene set member msrA, encoding peptide methionine sulfoxide reductase, is a virulence determinant of the plant pathogen Erwinia chrysanthemi.

    Science.gov (United States)

    Hassouni, M E; Chambost, J P; Expert, D; Van Gijsegem, F; Barras, F

    1999-02-02

    Peptide methionine sulfoxide reductase (MsrA), which repairs oxidized proteins, is present in most living organisms, and the cognate structural gene belongs to the so-called minimum gene set [Mushegian, A. R. & Koonin, E. V., (1996) Proc. Natl. Acad. Sci. USA 93, 10268-10273]. In this work, we report that MsrA is required for full virulence of the plant pathogen Erwinia chrysanthemi. The following differences were observed between the wild-type and a MsrA- mutant: (i) the MsrA- mutant was more sensitive to oxidative stress; (ii) the MsrA- mutant was less motile on solid surface; (iii) the MsrA- mutant exhibited reduced virulence on chicory leaves; and (iv) no systemic invasion was observed when the MsrA- mutant was inoculated into whole Saintpaulia ionantha plants. These results suggest that plants respond to virulent pathogens by producing active oxygen species, and that enzymes repairing oxidative damage allow virulent pathogens to survive the host environment, thereby supporting the theory that active oxygen species play a key role in plant defense.

  7. Biogenesis of Fe/S proteins and pathogenicity: IscR plays a key role in allowing Erwinia chrysanthemi to adapt to hostile conditions.

    Science.gov (United States)

    Rincon-Enriquez, Gabriel; Crété, Patrice; Barras, Frédéric; Py, Béatrice

    2008-03-01

    The Erwinia chrysanthemi genome is predicted to encode three systems, Nif, Isc and Suf, known to assist Fe/S cluster biogenesis and the CsdAE cysteine desulphurase. Single iscU, hscA and fdx mutants were found sensitive to paraquat and exhibited reduced virulence on both chicory leaves and Arabidopsis thaliana. Depletion of the whole Isc system led to a pleiotropic phenotype, including sensitivity to both paraquat and 2,2'-dipyridyl, auxotrophies for branched-chain amino acids, thiamine, nicotinic acid, and drastic alteration in virulence. IscR was able to suppress all of the phenotypes listed above in a sufC-dependent manner while depletion of the Isc system led to IscR-dependent activation of the suf operon. No virulence defects were found associated with csdA or nifS mutations. Surprisingly, we found that the sufC mutant was virulent against A. thaliana, whereas its virulence had been found altered in Saintpaulia. Collectively, these results lead us to propose that E. chrysanthemi possess the Fe/S biogenesis strategy suited to the physico-chemical conditions encountered in its host upon infection. In this view, the IscR regulator, which controls both Isc and Suf, is predicted to play a major role in the ability of E. chrysanthemi to colonize a wide array of different plants.

  8. Following spread of fire blight in Western, Central and Southern Europe by molecular differentiation of Erwinia amylovora strains with PFGE analysis.

    Science.gov (United States)

    Jock, Susanne; Donat, Victoria; López, Maria M; Bazzi, Carlo; Geider, Klaus

    2002-02-01

    Fire blight has been detected recently in several areas of northern Spain and north-eastern Italy. To follow spread of the disease within Europe, more than 120 Erwinia amylovora strains isolated from 1957-1900 in England, France, Germany, The Netherlands, Belgium, Poland, Italy and Spain were assayed using pulsed-field gel electrophoresis (PFGE) analysis of genomic DNA after XbaI digestion. Pattern types Pt1 and Pt4 were found for strains from England. Pt1 was also found in central Europe and eastern France, Pt4 in western France. Pt2 appeared first in Egypt, from where strains with this pattern disseminated northwards as far as into the Balkans. Pt3 was typical for northern France and Belgium. Strains from Spain displayed the pattern types Pt3 and Pt4. In Italy, Pt2 was found in the south-eastern areas, Pt3 in the north-eastern areas, and Pt1 was found very recently in orchards adjacent to the Austrian border, together with Pt3. Despite barely controlled trade with fire blight host plants and associated plant products within Europe, the PFGE patterns of the E. amylovora isolates were ordered indicating sequential spread. On the other hand, the appearance of Pt3 in northern Italy and central Spain can be explained by the import of contaminated plants by nurseries.

  9. Biodegradation Of 4-Chlorobiphenyl By Pseudomonas synxantha

    Directory of Open Access Journals (Sweden)

    Dhanjal Noorpreet Inder Kaur

    2014-10-01

    Full Text Available The stabilization and disposal of polychlorinated biphenyls (PCBs from soil environment and wetland areas is of great concern for health and safety. Wetland remediation with microorganisms is an approach for treating PCBs. A bacterial strain was isolated from hydrocarbon contaminated soil of Ropar, Punjab, able to degrade PCBs under aerobic conditions. The percentage of degradation with 100 mM/ml of 4-chlorobiphenyl was up to 90%. Degradation was monitored by mass spectrometry, high performance liquid chromatography and spectrophotometrically, showing that 4-chlorobiphenyl was degraded almost completely. The bacterial strain was identified as Pseudomonas synxantha by 16sRNA sequencing method. This is the first report of 4-chlorobiphenyl degradation by Pseudomonas synxantha.

  10. Pseudomonas spp. convert metmyoglobin into deoxymyoglobin.

    Science.gov (United States)

    Motoyama, Michiyo; Kobayashi, Miho; Sasaki, Keisuke; Nomura, Masaru; Mitsumoto, Mitsuru

    2010-01-01

    Meat 'reddening' by bacteria was observed in chilled beef. To identify the reddening bacteria, isolates were inoculated onto beef and the changes in CIE L*a*b* values monitored. As a result, two Pseudomonas spp., including Pseudomonas fragi which is commonly observed in raw meat, were selected and identified as reddening bacteria. The reddening was coincidentally occurred with the appearance of slime, and the increase in thiobarbituric acid-reactive substances (TBARS) was simultaneously suppressed. In myoglobin-containing nutrient broth, it is shown spectroscopically that P. fragi converted metmyoglobin into deoxymyoglobin. It was concluded that the meat reddening was due to the formation of deoxymyoglobin, induced by the very-low-oxygen tension brought about by Pseudomonad's oxygen consumption: This oxygen depletion simultaneously suppressed TBARS increase.

  11. The immune system vs. Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, Peter Østrup; Givskov, Michael; Bjarnsholt, Thomas

    2010-01-01

    Ilya Metchnikoff and Paul Ehrlich were awarded the Nobel price in 1908. Since then, numerous studies have unraveled a multitude of mechanistically different immune responses to intruding microorganisms. However, in the vast majority of these studies, the underlying infectious agents have appeared...... the present review on the immune system vs. biofilm bacteria is focused on Pseudomonas aeruginosa (mainly because this is the most thoroughly studied), many of the same mechanisms are also seen with biofilm infections generated by other microorganisms....

  12. Isolation and characterization of arsenite oxidizing Pseudomonas ...

    African Journals Online (AJOL)

    A bacterium, Pseudomonas lubricans, isolated from heavy metal laden industrial wastewater, has been shown to tolerate multiple heavy metals suggesting its importance in bioremediation of industrial effluents. P. lubricans tolerated As(III) up to 3 mg ml-1, Cu2+ up to 0.7 mg ml-1, Hg2+ up to 0.4 mg ml-1, Ni2+ up to 0.4 mg ...

  13. Nosocomial outbreak of Pseudomonas aeruginosa endophthalmitis.

    Science.gov (United States)

    Mateos, I; Valencia, R; Torres, M J; Cantos, A; Conde, M; Aznar, J

    2006-11-01

    We describe an outbreak of nosocomial endophthalmitis due to a common source, which was determined to be trypan blue solution prepared in the hospital's pharmacy service. We assume that viable bacteria probably gained access to the trypan blue stock solution during cooling after autoclaving. The temporal cluster of Pseudomonas aeruginosa endophthalmitis was readily perceived on the basis of clinical and microbiological findings, and an exogenous source of contamination was unequivocally identified by means of DNA fingerprinting.

  14. Pyoverdine synthesis by the Mn(II-oxidizing bacterium Pseudomonas putida GB-1

    Directory of Open Access Journals (Sweden)

    Dorothy Lundquist Parker

    2014-05-01

    Full Text Available When iron-starved, the Mn(II-oxidizing bacteria Pseudomonas putida strains GB-1 and MnB1 produce pyoverdines (PVDGB-1 and PVDMnB1, siderophores that both influence iron uptake and inhibit manganese(II oxidation by these strains. To explore the properties and genetics of a PVD that can affect manganese oxidation, LC-MS/MS and various siderotyping techniques were used to identify the peptides of PVDGB-1 and PVDMnB1 as being (for both PVDs: chromophore-Asp-Lys-OHAsp-Ser-Gly-aThr-Lys-cOHOrn, resembling a structure previously reported for P. putida CFML 90-51, which does not oxidize Mn. All three strains also produced an azotobactin and a sulfonated PVD, each with the peptide sequence above, but with unknown regulatory or metabolic effects. Bioinformatic analysis of the sequenced genome of P. putida GB-1 suggested that a particular non-ribosomal peptide synthetase, coded by the operon PputGB1_4083-4086, could produce the peptide backbone of PVDGB-1. To verify this prediction, plasmid integration disruption of PputGB1_4083 was performed and the resulting mutant failed to produce detectable PVD. In silico analysis of the modules in PputGB1_4083-4086 predicted a peptide sequence of Asp-Lys-Asp-Ser-Ala-Thr-Lsy-Orn, which closely matches the peptide determined by MS/MS. To extend these studies to other organisms, various Mn(II-oxidizing and non-oxidizing isolates of P. putida, P. fluorescens, P. marincola, P. fluorescens-syringae group, P. mendocina-resinovorans group and P. stutzerii group were screened for PVD synthesis. The PVD producers (12 out of 16 tested strains were siderotyped and placed into four sets of differing PVD structures, some corresponding to previously characterized PVDs and some to novel PVDs. These results combined with previous studies suggested that the presence of OHAsp or the flexibility of the pyoverdine polypeptide may enable efficient binding of Mn(III.

  15. Surface survival and internalization of salmonella through natural cracks on developing cantaloupe fruits, alone or in the presence of the melon wilt pathogen Erwinia tracheiphila.

    Science.gov (United States)

    Gautam, Dhiraj; Dobhal, Shefali; Payton, Mark E; Fletcher, Jacqueline; Ma, Li Maria

    2014-01-01

    Outbreaks of foodborne illness attributed to the consumption of Salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of Salmonella on cantaloupe fruit surfaces is limited. We investigated the interactions between Salmonella enterica Poona, the plant pathogenic bacterium Erwinia tracheiphila, and cantaloupe fruit. Fruit surfaces were inoculated at the natural cracking stage by spreading S. enterica and E. tracheiphila, 20 µl at 107 cfu/ml, independently or together, over a 2×2 cm rind area containing a crack. Microbial and microscopic analyses were performed at 0, 9 and 24 days post inoculation (DPI). Even at 24 DPI (fruit maturity) S. enterica was detected on 14% and 40% of the fruit inoculated with S. enterica alone and the two-pathogen mixture, respectively. However, the population of S. enterica declined gradually after initial inoculation. E. tracheiphila, inoculated alone or together with Salmonella, caused watersoaked lesions on cantaloupe fruit; but we could not conclude in this study that S. enterica survival on the fruit surface was enhanced by the presence of those lesions. Of fruit inoculated with E. tracheiphila alone and sampled at 24 DPI, 61% had watersoaked lesions on the surface. In nearly half of those symptomatic fruits the watersoaking extended into the sub-rind mesocarp, and E. tracheiphila was recovered from that tissue in 50% of the symptomatic fruit. In this work, E. tracheiphila internalized through natural cracks on developing fruits. S. enterica was never detected in the fruit interior (ca. 2-3 mm below rind surface) under the limited conditions of our experiments, but the possibility that it, or other human pathogens that contaminate fresh produce, might also do so should be investigated under a wider range of conditions and produce types.

  16. Surface survival and internalization of salmonella through natural cracks on developing cantaloupe fruits, alone or in the presence of the melon wilt pathogen Erwinia tracheiphila.

    Directory of Open Access Journals (Sweden)

    Dhiraj Gautam

    Full Text Available Outbreaks of foodborne illness attributed to the consumption of Salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of Salmonella on cantaloupe fruit surfaces is limited. We investigated the interactions between Salmonella enterica Poona, the plant pathogenic bacterium Erwinia tracheiphila, and cantaloupe fruit. Fruit surfaces were inoculated at the natural cracking stage by spreading S. enterica and E. tracheiphila, 20 µl at 107 cfu/ml, independently or together, over a 2×2 cm rind area containing a crack. Microbial and microscopic analyses were performed at 0, 9 and 24 days post inoculation (DPI. Even at 24 DPI (fruit maturity S. enterica was detected on 14% and 40% of the fruit inoculated with S. enterica alone and the two-pathogen mixture, respectively. However, the population of S. enterica declined gradually after initial inoculation. E. tracheiphila, inoculated alone or together with Salmonella, caused watersoaked lesions on cantaloupe fruit; but we could not conclude in this study that S. enterica survival on the fruit surface was enhanced by the presence of those lesions. Of fruit inoculated with E. tracheiphila alone and sampled at 24 DPI, 61% had watersoaked lesions on the surface. In nearly half of those symptomatic fruits the watersoaking extended into the sub-rind mesocarp, and E. tracheiphila was recovered from that tissue in 50% of the symptomatic fruit. In this work, E. tracheiphila internalized through natural cracks on developing fruits. S. enterica was never detected in the fruit interior (ca. 2-3 mm below rind surface under the limited conditions of our experiments, but the possibility that it, or other human pathogens that contaminate fresh produce, might also do so should be investigated under a wider range of conditions and produce types.

  17. Control of fire blight (Erwinia amylovora on apple trees with trunk-injected plant resistance inducers and antibiotics and assessment of induction of pathogenesis-related protein genes

    Directory of Open Access Journals (Sweden)

    Srđan G. Aćimović

    2015-02-01

    Full Text Available Management of fire blight is complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. Even though successful in control, preventive antibiotic sprays also affect non-target bacteria, aiding the selection for resistance which could ultimately be transferred to the pathogen Erwinia amylovora. Trunk injection is a target-precise pesticide delivery method that utilizes tree xylem to distribute injected compounds. Trunk injection could decrease antibiotic usage in the open environment and increase the effectiveness of compounds in fire blight control. In field experiments, after 1-2 apple tree injections of either streptomycin, potassium phosphites (PH or acibenzolar-S-methyl (ASM, significant reduction of blossom and shoot blight symptoms was observed compared to water- or non-injected control trees. Overall disease suppression with streptomycin was lower than typically observed following spray applications to flowers. Trunk injection of oxytetracycline resulted in excellent control of shoot blight severity, suggesting that injection is a superior delivery method for this antibiotic. Injection of both ASM and PH resulted in the significant induction of PR-1, PR-2 and PR-8 protein genes in apple leaves indicating induction of systemic acquired resistance (SAR under field conditions. The time separating SAR induction and fire blight symptom suppression indicated that various defensive compounds within the SAR response were synthesized and accumulated in the canopy. ASM and PH suppressed fire blight even after cessation of induced gene expression. With the development of injectable formulations and optimization of doses and injection schedules, the injection of protective compounds could serve as an effective option for fire blight control.

  18. Criteria for efficient prevention of dissemination and successful eradication of Erwinia amylovora (the cause of fire blight in Aragón, Spain

    Directory of Open Access Journals (Sweden)

    Ana PALACIO-BIELSA

    2013-01-01

    Full Text Available Erwinia amylovora was detected on pome fruits in the Aragón region (North-Eastern Spain, in a ca. 5 km radius area located in the mid Jalón river (mid Ebro Valley in the province of Zaragoza, during 2000‒2003. Eight years have now passed since this pathogen was last detected, without new infections being reported in the same area. The bases for surveys and rapid eradication performed have been analyzed in detail to understand the reasons for the success in removing fireblight. The results demonstrate that intensive surveillance, risk assessment, plant analyses using accurate identification methods, and, especially, rapid total or selective eradication of infected trees in the plots have been very effective in preventing the generalized spread of fireblight and in delaying economic losses associated with this disease. Eradication and compensation to growers, estimated to cost approx. € 467,000, were clearly counterbalanced by the economic value of apple and pear production in the 2000‒2003 period (approx. € 368 million. Fire blight risk-assessment, using the MARYBLYT system, showed that climatic conditions in the studied area were favourable to infections during the analyzed period (1997‒2006. Molecular characterization of E. amylovora strains had revealed their homogeneity, suggesting that these fire blight episodes could have been caused by just one inoculum source, supporting the hypothesis that there was a unique introduction of E. amylovora in the studied area. Spatial spread of E. amylovora to trees was analyzed within six orchards, indicating an aggregated distribution model. This Spanish experience demonstrates the success of scientifically-based prevention methods that lead to the deployment of a fast and strict containment strategy, useful for other Mediterranean areas.

  19. Same ammo, different weapons: enzymatic extracts from two apple genotypes with contrasted susceptibilities to fire blight (Erwinia amylovora) differentially convert phloridzin and phloretin in vitro.

    Science.gov (United States)

    Gaucher, Matthieu; Dugé de Bernonville, Thomas; Guyot, Sylvain; Dat, James F; Brisset, Marie-Noëlle

    2013-11-01

    The necrogenic bacterium Erwinia amylovora responsible for the fire blight disease causes cell death in apple tissues to enrich intercellular spaces with nutrients. Apple leaves contain large amounts of dihydrochalcones (DHCs), including phloridzin and its aglycone phloretin. Previous work showed an important decrease in the constitutive DHCs stock in infected leaves, probably caused by transformation reactions during the infection process. At least two flavonoid transformation pathways have been described so far: deglucosylation and oxidation. The aim of the present study was to determine whether DHCs are differentially converted in two apple genotypes displaying contrasted susceptibilities to the disease. Different analyses were performed: i) enzymatic activity assays in infected leaves, ii) identification/quantification of end-products obtained after in vitro enzymatic reactions with DHCs, iii) evaluation of the bactericidal activity of end-products. The results of the enzymatic assays showed that deglucosylation was dominant over oxidation in the susceptible genotype MM106 while the opposite was observed in the resistant genotype Evereste. These data were confirmed by LC-UV/Vis-MS analysis of in vitro reaction mixtures, especially because higher levels of o-quinoid oxidation products of phloretin were measured by using the enzymatic extracts of Evereste infected leaves. Their presence correlated well with a strong bactericidal activity of the reaction mixtures. Thus, our results suggest that a differential transformation of DHCs occur in apple genotypes with a potential involvement in the establishment of the susceptibility or the resistance to fire blight, through the release of glucose or of highly bactericidal compounds respectively. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  20. AraC/XylS family stress response regulators Rob, SoxS, PliA, and OpiA in the fire blight pathogen Erwinia amylovora.

    Science.gov (United States)

    Pletzer, Daniel; Schweizer, Gabriel; Weingart, Helge

    2014-09-01

    Transcriptional regulators of the AraC/XylS family have been associated with multidrug resistance, organic solvent tolerance, oxidative stress, and virulence in clinically relevant enterobacteria. In the present study, we identified four homologous AraC/XylS regulators, Rob, SoxS, PliA, and OpiA, from the fire blight pathogen Erwinia amylovora Ea1189. Previous studies have shown that the regulators MarA, Rob, and SoxS from Escherichia coli mediate multiple-antibiotic resistance, primarily by upregulating the AcrAB-TolC efflux system. However, none of the four AraC/XylS regulators from E. amylovora was able to induce a multidrug resistance phenotype in the plant pathogen. Overexpression of rob led to a 2-fold increased expression of the acrA gene. However, the rob-overexpressing strain showed increased resistance to only a limited number of antibiotics. Furthermore, Rob was able to induce tolerance to organic solvents in E. amylovora by mechanisms other than efflux. We demonstrated that SoxS from E. amylovora is involved in superoxide resistance. A soxS-deficient mutant of Ea1189 was not able to grow on agar plates supplemented with the superoxide-generating agent paraquat. Furthermore, expression of soxS was induced by redox cycling agents. We identified two novel members of the AraC/XylS family in E. amylovora. PliA was highly upregulated during the early infection phase in apple rootstock and immature pear fruits. Multiple compounds were able to induce the expression of pliA, including apple leaf extracts, phenolic compounds, redox cycling agents, heavy metals, and decanoate. OpiA was shown to play a role in the regulation of osmotic and alkaline pH stress responses. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  1. Functional implications of the beta-helical protein fold: differences in chemical and thermal stabilities of Erwinia chrysanthemi EC16 pectate lyases B, C, and E.

    Science.gov (United States)

    Hurlbert, J C; Preston, J F

    2000-09-15

    Colonization of plant tissue by the phytopathogen Erwinia chrysanthemi EC16 is aided by the activities of the pectate lyase isozymes (PLs), which depolymerize the polygalacturonic acid component (PGA) of plant cell walls. The bacterium secretes four pectate lyases (PLa, PLb, PLc, and PLe), two of which, PLc and PLe, have been shown to fold into a similar domain motif, the beta-helix. To understand the rationale behind the evolution and retention of these isoforms, the susceptibilities of pectate lyases B, C, and E to chemical and thermal denaturation and the resulting enzymatic inactivation were examined. With guanidine hydrochloride used as a denaturant, all three pectate lyases denatured with transition midpoint guanidine hydrochloride concentrations (Cm) of 1.3, 1.1, and 1.8 M for PLb, PLc, and PLe, respectively. Lyase activity decreased in direct response to loss of secondary structure in all enzymes. Pectate lyases B and C demonstrated increased enzymatic activity at temperatures above 30 degrees C, with maximal activity observed at 40 degrees C for PLb and 35 degrees C for PLc. Transition midpoints (Tm) as measured by circular dichroism were at 46.9 degrees C for PLb and 44.3 degrees C for PLc, indicating detectable conformational changes accompanying thermal inactivation. Decreased enzymatic activity of PLe was observed at all temperatures above 30 degrees C, and the enzyme was found to possess a Tm at 38.9 degrees C. The data demonstrate structural differences among these enzymes that may be the basis for different enzymatic efficiencies under the potential array of environmental conditions experienced by the bacterium. These differences, in turn, may play a part in the retention of these isozymes as virulence factors, allowing the successful colonization of susceptible plant hosts.

  2. Control of postharvest soft rot caused by Erwinia carotovora of vegetables by a strain of Bacillus amyloliquefaciens and its potential modes of action.

    Science.gov (United States)

    Zhao, Yancun; Li, Pengxia; Huang, Kaihong; Wang, Yuning; Hu, Huali; Sun, Ya

    2013-03-01

    Erwinia carotovora subsp. carotovora (Ecc), the causal agent of bacterial soft rot, is one of the destructive pathogens of postharvest vegetables. In this study, a bacterial isolate (BGP20) from the vegetable farm soil showed strong antagonistic activity against Ecc in vitro, and its twofold cell-free culture filtrate showed excellent biocontrol effect in controlling the postharvest bacterial soft rot of potatoes at 25 °C. The anti-Ecc metabolites produced by the isolate BGP20 had a high resistance to high temperature, UV-light and protease K. Based on the colonial morphology, cellular morphology, sporulation, and partial nucleotide sequences of 16S rRNA and gyrB gene, the isolate BGP20 was identified as Bacillus amyloliquefaciens subsp. plantarum. Further in vivo assays showed that the BGP20 cell culture was more effective in controlling the postharvest bacterial soft rot of green peppers and Chinese cabbages than its twofold cell-free culture filtrate. In contrast, the biocontrol effect and safety of the BGP20 cell culture were very poor on potatoes. In the wounds of potatoes treated with both the antagonist BGP20 and the pathogen Ecc, the viable count of Ecc was 31,746 times that of BGP20 at 48 h of incubation at 25 °C. But in the wounds of green peppers, the viable count of BGP20 increased 182.3 times within 48 h, and that of Ecc increased only 51.3 %. In addition, the treatment with both BGP20 and Ecc induced higher activity of phenylalanine ammonia-lyase (PAL) than others in potatoes. But the same treatment did not induce an increase of PAL activity in green peppers. In conclusion, the present study demonstrated that the isolate BGP20 is a promising candidate in biological control of postharvest bacterial soft rot of vegetables, but its main mode of action is different among various vegetables.

  3. High quality draft genome sequences of Pseudomonas fulva DSM 17717(T), Pseudomonas parafulva DSM 17004(T) and Pseudomonas cremoricolorata DSM 17059(T) type strains.

    Science.gov (United States)

    Peña, Arantxa; Busquets, Antonio; Gomila, Margarita; Mulet, Magdalena; Gomila, Rosa M; Reddy, T B K; Huntemann, Marcel; Pati, Amrita; Ivanova, Natalia; Markowitz, Victor; García-Valdés, Elena; Göker, Markus; Woyke, Tanja; Klenk, Hans-Peter; Kyrpides, Nikos; Lalucat, Jorge

    2016-01-01

    Pseudomonas has the highest number of species out of any genus of Gram-negative bacteria and is phylogenetically divided into several groups. The Pseudomonas putida phylogenetic branch includes at least 13 species of environmental and industrial interest, plant-associated bacteria, insect pathogens, and even some members that have been found in clinical specimens. In the context of the Genomic Encyclopedia of Bacteria and Archaea project, we present the permanent, high-quality draft genomes of the type strains of 3 taxonomically and ecologically closely related species in the Pseudomonas putida phylogenetic branch: Pseudomonas fulva DSM 17717(T), Pseudomonas parafulva DSM 17004(T) and Pseudomonas cremoricolorata DSM 17059(T). All three genomes are comparable in size (4.6-4.9 Mb), with 4,119-4,459 protein-coding genes. Average nucleotide identity based on BLAST comparisons and digital genome-to-genome distance calculations are in good agreement with experimental DNA-DNA hybridization results. The genome sequences presented here will be very helpful in elucidating the taxonomy, phylogeny and evolution of the Pseudomonas putida species complex.

  4. The effect of pseudomonas exotoxin A on cytokine production in whole blood exposed to Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Schultz, M. J.; Speelman, P.; Zaat, S. A.; Hack, C. E.; van Deventer, S. J.; van der Poll, T.

    2000-01-01

    To determine the effect of Pseudomonas aeruginosa exotoxin A (P-ExA) on cytokine production, we studied cytokine release induced by heat-killed P. aeruginosa (HKPA) in human whole blood in the presence or absence of P-ExA. P-ExA (0.01-1 microgram ml(-1)) caused a dose-dependent decrease in

  5. Stratified growth in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Werner, E.; Roe, F.; Bugnicourt, A.

    2004-01-01

    In this study, stratified patterns of protein synthesis and growth were demonstrated in Pseudomonas aeruginosa biofilms. Spatial patterns of protein synthetic activity inside biofilms were characterized by the use of two green fluorescent protein (GFP) reporter gene constructs. One construct...... of oxygen limitation in the biofilm. Oxygen microelectrode measurements showed that oxygen only penetrated approximately 50 mum into the biofilm. P. aeruginosa was incapable of anaerobic growth in the medium used for this investigation. These results show that while mature P. aeruginosa biofilms contain...

  6. Pseudomonas salegens sp. nov., a halophilic member of the genus Pseudomonas isolated from a wetland.

    Science.gov (United States)

    Amoozegar, Mohammad Ali; Shahinpei, Azadeh; Sepahy, Abbas Akhavan; Makhdoumi-Kakhki, Ali; Seyedmahdi, Shima Sadat; Schumann, Peter; Ventosa, Antonio

    2014-10-01

    A novel Gram-stain-negative, aerobic, non-endospore-forming, non-pigmented, rod-shaped, slightly halophilic bacterium, designated GBPy5(T), was isolated from aquatic plants of the Gomishan wetland, Iran. Cells of strain GBPy5(T) were motile. Growth occurred with between 1 and 10% (w/v) NaCl and the isolate grew optimally with 3% (w/v) NaCl. The optimum pH and temperature for growth of the strain were pH 8.0 and 30 °C, respectively, while it was able to grow over a pH range of 6.5-9.0 and a temperature range of 4-35 °C. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain GBPy5(T) is a member of the genus Pseudomonas forming a monophyletic branch. The novel strain exhibited 16S rRNA gene sequence similarity of 95.4% with type strains of Pseudomonas guariconensis PCAVU11(T) and Pseudomonas sabulinigri J64(T), respectively. The major cellular fatty acids of the isolate were C18:1ω7c (37.8%), C16:0 (14.9%), C16:1ω7c (12.9%), C12:0 3-OH (7.1%) and C12:0 (7.0%). The polar lipid pattern of strain GBPy5(T) comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and one phospholipid. Ubiquinone 9 (Q-9) was the predominant lipoquinone. The G+C content of the genomic DNA of strain GBPy5(T) was 59.2 mol%. On the basis of the phenotypic and phylogenetic data, strain GBPY5(T) represents a novel species of the genus Pseudomonas, for which the name Pseudomonas salegens sp. nov. is proposed. The type strain is GBPy5(T) ( = IBRC-M 10762(T) = CECT 8338(T)). IUMS.

  7. Antagonistic potential of fluorescent Pseudomonas and its impact on ...

    African Journals Online (AJOL)

    This study focused on the antagonistic potential of fluorescent Pseudomonas in vitro, and its inoculation effect on growth performance of Lycopersicon esculentum in Fusarium oxysporum and Rhizoctonia solani infested soil. Biochemical characteristics of fluorescent Pseudomonas showed that all ten isolates were positive ...

  8. Genetic detection of Pseudomonas spp. in commercial Amazonian fish.

    Science.gov (United States)

    Ardura, Alba; Linde, Ana R; Garcia-Vazquez, Eva

    2013-08-29

    Brazilian freshwater fish caught from large drainages like the River Amazon represent a million ton market in expansion, which is of enormous importance for export to other continents as exotic seafood. A guarantee of bacteriological safety is required for international exports that comprise a set of different bacteria but not any Pseudomonas. However, diarrhoea, infections and even septicaemia caused by some Pseudomonas species have been reported, especially in immune-depressed patients. In this work we have employed PCR-based methodology for identifying Pseudomonas species in commercial fish caught from two different areas within the Amazon basin. Most fish caught from the downstream tributary River Tapajòs were contaminated by five different Pseudomonas species. All fish samples obtained from the River Negro tributary (Manaus markets) contained Pseudomonas, but a less diverse community with only two species. The most dangerous Pseudomonas species for human health, P. aeruginosa, was not found and consumption of these fish (from their Pseudomonas content) can be considered safe for healthy consumers. As a precautionary approach we suggest considering Pseudomonas in routine bacteriological surveys of imported seafood.

  9. Novel Targets for Treatment of Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Morten; Alhede, Maria; Bjarnsholt, Thomas

    2014-01-01

    Pseudomonas aeruginosa causes infection in all parts of the human body. The bacterium is naturally resistant to a wide range of antibiotics. In addition to resistance mechanisms such as efflux pumps, the ability to form aggregates, known as biofilm, further reduces Pseudomonas aeruginosa’s...

  10. Interleukin-18 impairs the pulmonary host response to Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Schultz, Marc J.; Knapp, Sylvia; Florquin, Sandrine; Pater, Jennie; Takeda, Kiyoshi; Akira, Shizuo; van der Poll, Tom

    2003-01-01

    Interleukin-18 (IL-18) is a potent cytokine with many different proinflammatory activities. To study the role of IL-18 in the pathogenesis of Pseudomonas pneumonia, IL-18-deficient (IL-18(-/-)) and wild-type mice were intranasally inoculated with Pseudomonas aeruginosa. IL-18 deficiency was

  11. Interactions between biosurfactant-producing Pseudomonas and Phytophthora species

    NARCIS (Netherlands)

    Tran, H.

    2007-01-01

    Fluorescent Pseudomonas bacteria produce a wide variety of antimicrobial metabolites, including soap-like compounds referred to as biosurfactants. The results of this thesis showed that biosurfactant-producing Pseudomonas bacteria are effective in controlling Phytophthora foot rot disease of black

  12. Biosynthesis and regulation of cyclic lipopeptides in Pseudomonas fluorescens

    NARCIS (Netherlands)

    Bruijn, de I.

    2009-01-01

    Cyclic lipopeptides (CLPs) are surfactant and antibiotic metabolites produced by a variety of bacterial genera. For the genus Pseudomonas, many structurally different CLPs have been identified. CLPs play an important role in surface motility of Pseudomonas strains, but also in virulence and

  13. Typing of Pseudomonas aeruginosa strains in Norwegian cystic fibrosis patients

    DEFF Research Database (Denmark)

    Fluge, G; Ojeniyi, B; Høiby, N

    2001-01-01

    OBJECTIVES: Typing of Pseudomonas aeruginosa isolates from Norwegian cystic fibrosis (CF) patients with chronic Pseudomonas lung infection in order to see whether cross-infection might have occurred. METHODS: Isolates from 60 patients were collected during the years 1994-98, and typed by pulsed...... between cystic fibrosis patients has occurred....

  14. Energetics of binary mixed culture of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Bioenergetic analysis of the growth of the binary mixed culture (Pseudomonas aeruginosa and Pseudomonas fluorescence) on phenol chemostat culture was carried out. The data were checked for consistency using carbon and available electron balances. When more than the minimum number of variables are measured, ...

  15. Energetics of binary mixed culture of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Jane

    2010-12-20

    Dec 20, 2010 ... Bioenergetic analysis of the growth of the binary mixed culture (Pseudomonas aeruginosa and. Pseudomonas fluorescence) on ... biological system is widely gaining recognition (Yang et al., 1984; Solomon et al., .... Thus, by application of the covariate adjustment technique. (Solomon et al., 1985, 1994) in ...

  16. Pseudomonas Exotoxin A: optimized by evolution for effective killing

    Directory of Open Access Journals (Sweden)

    Marta eMichalska

    2015-09-01

    Full Text Available Pseudomonas Exotoxin A (PE is the most toxic virulence factor of the pathogenic bacterium Pseudomonas aeruginosa. This review describes current knowledge about the intoxication pathways of PE. Moreover, PE represents a remarkable example for pathoadaptive evolution, how bacterial molecules have been structurally and functionally optimized under evolutionary pressure to effectively impair and kill their host cells.

  17. 33 original article infections a pseudomonas aeruginosa dans un ...

    African Journals Online (AJOL)

    boaz

    institution of effective resistance surveillance and infection control measures. . Keywords: Pseudomonas aeruginosa, National Hospital Abuja, Susceptibility. INFECTIONS A PSEUDOMONAS AERUGINOSA DANS UN HOPITAL TERTIAIRE. AU NIGERIA. *Iregbu KC, Eze SO,. Département de Microbiologie Médicale and ...

  18. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, H.K.; Gøtzsche, Peter C.; Johansen, Helle Krogh

    2008-01-01

    BACKGROUND: Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed. OBJECTIVES......: To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search May 2008) and PubMed using the terms vaccin* AND cystic...... fibrosis (last search May 2008). SELECTION CRITERIA: Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic fibrosis. DATA COLLECTION AND ANALYSIS: The authors independently selected trials...

  19. SoxR-dependent response to oxidative stress and virulence of Erwinia chrysanthemi: the key role of SufC, an orphan ABC ATPase.

    Science.gov (United States)

    Nachin, L; El Hassouni, M; Loiseau, L; Expert, D; Barras, F

    2001-02-01

    Erwinia chrysanthemi causes soft-rot disease in a great variety of plants. In addition to the depolymerizing activity of plant cell wall-degrading enzymes, iron acquisition and resistance to oxidative stress contribute greatly to the virulence of this pathogen. Here, we studied the pin10 locus originally thought to encode new virulence factors. The sequence analysis revealed six open reading frames that were homologous to the Escherichia coli sufA, sufB, sufC, sufD, sufS and sufE genes. Sequence similarity searching predicted that (i) SufA, SufB, SufD, SufS and SufE proteins are involved in iron metabolism and possibly in Fe-S cluster assembly; and (ii) SufC is an ATPase of an ABC transporter. The reverse transcription-polymerase chain reaction procedure showed that the sufABCDSE genes constitute an operon. Expression of a sufB:uidA fusion was found to be induced in iron-deficient growth conditions and to be repressed by the iron-sensing Fur repressor. Each of the six suf genes was inactivated by the insertion of a cassette generating a non-polar mutation. The intracellular iron level in the sufA, sufB, sufC, sufS and sufE mutants was higher than in the wild type, as assessed by increased sensitivity to the iron-activated antibiotic streptonigrin. In addition, inactivation of sufC and sufD led to increased sensitivity to paraquat. Virulence tests showed that sufA and sufC mutants exhibited reduced ability to cause maceration of chicory leaves, whereas a functional sufC gene was necessary for the bacteria to cause systemic invasion of Saintpaulia ionantha. The E. coli sufC homologue was inactivated by reverse genetic. This mutation was found to modify the soxR-dependent induction of soxS gene expression. We discuss the possibility that SufC is a versatile ATPase that can associate either with the other Suf proteins to form a Fe-S cluster-assembling machinery or with membrane proteins encoded elsewhere in the chromosome to form an Fe-S ABC exporter. Overall, these

  20. Potential application of Northern Argentine propolis to control some phytopathogenic bacteria.

    Science.gov (United States)

    Ordóñez, R M; Zampini, I C; Moreno, M I Nieva; Isla, M I

    2011-10-20

    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 Xanthomonas campestris pvar vesicatoria CECT 792. The most active propolis extract (Tucumán, T1) was selected to bioguide isolation and identified for antimicrobial compound (2',4'-dihydroxychalcone). The antibacterial chalcone was more active than the propolis ethanolic extract (MIC values of 0.5-1 μg ml(-1) and 9.5-15 μg ml(-1), respectively). Phytotoxicity assays were realized and the propolis extracts did not retard germination of lettuce seeds or the growth of onion roots. Propolis solutions applied as sprays on tomato fruits infected with P. syringae reduced the severity of disease. Application of the Argentine propolis extracts diluted with water may be promising for the management of post harvest diseases of fruits. Copyright © 2010 Elsevier GmbH. All rights reserved.

  1. Biotransformation of myrcene by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hashemi Elham

    2011-05-01

    Full Text Available Abstract Background Dihydrolinalool and terpineol are sources of fragrances that provide a unique volatile terpenoid alcohol of low toxicity and thus are widely used in the perfumery industry, in folk medicine, and in aromatherapy. They are important chemical constituents of the essential oil of many plants. Previous studies have concerned the biotransformation of limonene by Pseudomonas putida. The objective of this research was to study biotransformation of myrcene by Pseudomonas aeruginosa. The culture preparation was done using such variables as different microbial methods and incubation periods to obtain maximum cells of P. aeruginosa for myrcene biotransformation. Results It was found that myrcene was converted to dihydrolinalool and 2,6-dimethyloctane in high percentages. The biotransformation products were identified by Fourier-transform infrared spectroscopy (FT-IR, ultraviolet (UV analysis, gas chromatography (GC, and gas chromatography-mass spectroscopy (GC-MS. Comparison of the different incubation times showed that 3 days was more effective, the major products being 2,6-dimethyloctane (90.0% and α-terpineol (7.7% and comprising 97.7%. In contrast, the main compounds derived for an incubation time of 1.5 days were dihydrolinalool (79.5% and 2,6-dimethyloctane (9.3%, with a total yield of 88.8%.

  2. Pseudomonas spp.: contamination sources in bulk tanks of dairy farms

    Directory of Open Access Journals (Sweden)

    Ana M.C. Vidal

    Full Text Available ABSTRACT: This study focused on isolating Pseudomonas spp. during milking process in ten dairy farms with manual and mechanical milking systems during dry and rainy seasons, and evaluating DNA homology and patterns of distribution between isolates, in order to identify main sources of milk contamination by Pseudomonas spp. A total of 167 isolates of Pseudomonas spp. were obtained from water, milkers’ hands, cows’ teats, teat cups, cooling tanks and raw milk. Bacteria of Pseudomonas spp. genus were isolated from 85 and 82 sampling points in dairy farms with manual and mechanical milking system, respectively. A significant difference (p=0.02 on Pseudomonas spp. isolation was observed among samples of surface of cows’ teats before and after pre-dipping, but no significant difference (p>0.05 was observed among milking systems or seasons. The possibility of the same Pseudomonas spp. patterns are distributed in different farms and seasons using Amplified Fragment Length Polymorphism (AFLP technique was demonstrated. Milkers’ hands, surface of cows’ teats, teat cups and cooling tanks were associated with raw milk contamination with Pseudomonas spp. on farms with manual and mechanical milking system, showing that regardless of the type of milking system and season, proper hygiene procedures of equipment, utensils and workers’ hands are essential to avoid contamination of the milk and, therefore, improve milk quality.

  3. Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

    DEFF Research Database (Denmark)

    Johansen, Helle Krogh; Gøtzsche, Peter C

    2015-01-01

    BACKGROUND: Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed. This is a......BACKGROUND: Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed....... This is an update of a previously published review. OBJECTIVES: To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search 30...... March 2015). We previously searched PubMed using the terms vaccin* AND cystic fibrosis (last search 30 May 2013). SELECTION CRITERIA: Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic...

  4. Management and treatment of contact lens-related Pseudomonas keratitis

    Directory of Open Access Journals (Sweden)

    Willcox MD

    2012-06-01

    Full Text Available Mark DP WillcoxSchool of Optometry and Vision Science, University of New South Wales, Sydney, AustraliaAbstract: Pubmed and Medline were searched for articles referring to Pseudomonas keratitis between the years 2007 and 2012 to obtain an overview of the current state of this disease. Keyword searches used the terms "Pseudomonas" + "Keratitis" limit to "2007–2012", and ["Ulcerative" or "Microbial"] + "Keratitis" + "Contact lenses" limit to "2007–2012". These articles were then reviewed for information on the percentage of microbial keratitis cases associated with contact lens wear, the frequency of Pseudomonas sp. as a causative agent of microbial keratitis around the world, the most common therapies to treat Pseudomonas keratitis, and the sensitivity of isolates of Pseudomonas to commonly prescribed antibiotics. The percentage of microbial keratitis associated with contact lens wear ranged from 0% in a study from Nepal to 54.5% from Japan. These differences may be due in part to different frequencies of contact lens wear. The frequency of Pseudomonas sp. as a causative agent of keratitis ranged from 1% in Japan to over 50% in studies from India, Malaysia, and Thailand. The most commonly reported agents used to treat Pseudomonas keratitis were either aminoglycoside (usually gentamicin fortified with a cephalosporin, or monotherapy with a fluoroquinolone (usually ciprofloxacin. In most geographical areas, most strains of Pseudomonas sp. (≥95% were sensitive to ciprofloxacin, but reports from India, Nigeria, and Thailand reported sensitivity to this antibiotic and similar fluoroquinolones of between 76% and 90%.Keywords: Pseudomonas, keratitis, contact lens

  5. The pseudomonas quinolone signal (PQS balances life and death in Pseudomonas aeruginosa populations.

    Directory of Open Access Journals (Sweden)

    Susanne Häussler

    Full Text Available When environmental conditions deteriorate and become inhospitable, generic survival strategies for populations of bacteria may be to enter a dormant state that slows down metabolism, to develop a general tolerance to hostile parameters that characterize the habitat, and to impose a regime to eliminate damaged members. Here, we provide evidence that the pseudomonas quinolone signal (PQS mediates induction of all of these phenotypes. For individual cells, PQS, an interbacterial signaling molecule of Pseudomonas aeruginosa, has both deleterious and beneficial activities: on the one hand, it acts as a pro-oxidant and sensitizes the bacteria towards oxidative and other stresses and, on the other, it efficiently induces a protective anti-oxidative stress response. We propose that this dual function fragments populations into less and more stress tolerant members which respond differentially to developing stresses in deteriorating habitats. This suggests that a little poison may be generically beneficial to populations, in promoting survival of the fittest, and in contributing to bacterial multi-cellular behavior. It further identifies PQS as an essential mediator of the shaping of the population structure of Pseudomonas and of its response to and survival in hostile environmental conditions.

  6. Análisis genético de la resistencia razaespecífica a Pseudomonas syringae pv. phaseolicola (Psp) y Xanthomonas campestris pv. phaseoli (Xcp) agentes causales de bacteriosis de halo y común en Phaseolus vulgaris

    OpenAIRE

    Godoy Montiel, Luis Alberto

    2017-01-01

    La judía común es uno de los cultivos de leguminosas de grano para consumo humano de mayor importancia a nivel mundial. Enfermedades bacterianas, como bacteriosis de halo y común, afectan de manera importante la producción y calidad del cultivo, siendo la incorporación de resistencia el único método eficiente y sostenible para su control. La variación en la respuesta a la interacción planta – patógeno, y la herencia de la resistencia, dificultan piramidar diferentes genes de resistencia dentr...

  7. Pseudomonas-induced corneal ulcers associated with contaminated eye mascaras.

    Science.gov (United States)

    Wilson, L A; Ahearn, D G

    1977-07-01

    Seven Pseudomonas-induced corneal ulcers were associated with the use of four brands of mascara contaminated with P. aeruginosa. In laboratory studies, preservative systems of three of the four brands were inadequate in comparison with a control mascara of known antimicrobial activity. If the corneal epithelium is scratched during the application of mascara, particularly if the applicator is old, the cornea should be treated immediately and the mascara cultured to detect Pseudomonas. The high incidence of recurrent corneal ulceration in cases of Pseudomonas-induced keratitis indicates that initial chemotherapy should be intensive and maintained until the lesion stabilizes.

  8. Targeting quorum sensing in Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jakobsen, Tim Holm; Bjarnsholt, Thomas; Jensen, Peter Østrup

    2013-01-01

    Bacterial resistance to conventional antibiotics combined with an increasing acknowledgement of the role of biofilms in chronic infections has led to a growing interest in new antimicrobial strategies that target the biofilm mode of growth. In the aggregated biofilm mode, cell-to-cell communication...... systems involved in the process known as quorum sensing regulate coordinated expression of virulence with immune shielding mechanisms and antibiotic resistance. For two decades, the potential of interference with quorum sensing by small chemical compounds has been investigated with the aim of developing...... alternative antibacterial strategies. Here, we review state of the art research of quorum sensing inhibitors against the opportunistic human pathogen Pseudomonas aeruginosa, which is found in a number of biofilm-associated infections and identified as the predominant organism infecting the lungs of cystic...

  9. Complement activation by Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Jensen, E T; Kharazmi, A; Garred, P

    1993-01-01

    In chronic infections, such as the bronchopulmonary Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients, bacteria persist despite an intact host immune defense and frequent antibiotic treatment. An important reason for the persistence of the bacteria is their capacity for the biofilm...... mode of growth. In this study we investigated the role of biofilms in activation of complement, a major contributor to the inflammatory process. Complement activation by P. aeruginosa was examined in a complement consumption assay, production of C3 and factor B conversion products assessed by crossed...... immuno-electrophoresis, C5a generation tested by a PMN chemotactic assay, and terminal complement complex formation measured by ELISA. Two of the four assays showed that P. aeruginosa grown in biofilm activated complement less than planktonic bacteria, and all assays showed that activation by intact...

  10. Rhamnolipid Biosurfactants Produced by Pseudomonas Species

    Directory of Open Access Journals (Sweden)

    Banu Kaskatepe

    Full Text Available ABSTRACT: Surfactants are chemical products widely used in our daily life in toothpaste and other personal hygiene and cosmetic products, and in several industries. Biosurfactants are surfactants of biological origin that can be produced by microorganisms and have many advantages, such as low toxicity and high biodegradability, compared to synthetic counterparts. Unfortunately, high production costs limit the use of biosurfactants. Low-cost production is the most important factor for biosurfactants to be able to compete in the global market place. This review presents general information on rhamnolipid biosurfactant produced by Pseudomonas species, as well as on their production and applications. In addition, industrial products and their wastes used for rhamnolipid production are reviewed in detail based on recent studies.

  11. Cell death in Pseudomonas aeruginosa biofilm development

    DEFF Research Database (Denmark)

    Webb, J.S.; Thompson, L.S.; James, S.

    2003-01-01

    Bacteria growing in biofilms often develop multicellular, three-dimensional structures known as microcolonies. Complex differentiation within biofilms of Pseudomonas aeruginosa occurs, leading to the creation of voids inside microcolonies and to the dispersal of cells from within these voids....... However, key developmental processes regulating these events are poorly understood. A normal component of multicellular development is cell death. Here we report that a repeatable pattern of cell death and lysis occurs in biofilms of P. aeruginosa during the normal course of development. Cell death...... occurred with temporal and spatial organization within biofilms, inside microcolonies, when the biofilms were allowed to develop in continuous-culture flow cells. A subpopulation of viable cells was always observed in these regions. During the onset of biofilm killing and during biofilm development...

  12. Cooperative production of siderophores by Pseudomonas aeruginosa.

    Science.gov (United States)

    Harrison, Freya; Buckling, Angus

    2009-01-01

    The production of iron-scavenging siderophores by the opportunistic animal pathogen Pseudomonas aeruginosa is a textbook example of public goods cooperation. This trait provides an excellent model system with which to study cooperation. Further, the links between siderophore production and P. aeruginosa virulence allow us to investigate how pathogen ecology, social behaviour and pathology might be connected. We present here the results of basic research on the evolution and ecology of siderophore cooperation in this species. In particular, we explore the effects of population and community structure, iron regime and genomic mutation rate on the relative success of siderophore cooperators and cheats. We also present preliminary data on the links between siderophore production and another clinically-relevant social trait, biofilm formation. It is our hope that more realistic laboratory studies of siderophore cooperation in P. aeruginosa will eventually cast light on the roles played by social traits in long-term microbial infections.

  13. Pseudomonas aeruginosa endophthalmitis masquerading as chronic uveitis

    Directory of Open Access Journals (Sweden)

    Kalpana Badami Nagaraj

    2013-01-01

    Full Text Available A 65-year-old male presented with decreased vision in the left eye of 15-day duration after having undergone an uneventful cataract surgery 10 months back. He had been previously treated with systemic steroids for recurrent uveitis postoperatively on three occasions in the same eye. B-scan ultrasonography showed multiple clumplike echoes suggestive of vitreous inflammation. Aqueous tap revealed Pseudomonas aeruginosa sensitive to ciprofloxacin. The patient was treated with intravitreal ciprofloxacin and vancomycin along with systemic ciprofloxacin with good clinical response. Even a virulent organism such as P.aeruginosa can present as a chronic uveitis, which, if missed, can lead to a delay in accurate diagnosis and appropriate management.

  14. Pseudomonas aeruginosa biofilms in cystic fibrosis

    DEFF Research Database (Denmark)

    Høiby, Niels; Ciofu, Oana; Bjarnsholt, Thomas

    2010-01-01

    of mutations, slow growth and adaptation of the bacteria to the conditions in the lungs, and to antibiotic therapy. Low bacterial metabolic activity and increase of doubling times of the bacterial cells in CF lungs are responsible for some of the tolerance to antibiotics. Conventional resistance mechanisms......, such as chromosomal ß-lactamase, upregulated efflux pumps, and mutations of antibiotic target molecules in the bacteria, also contribute to the survival of P. aeruginosa biofilms. Biofilms can be prevented by early aggressive antibiotic prophylaxis or therapy, and they can be treated by chronic suppressive therapy.......The persistence of chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) patients is due to biofilm-growing mucoid (alginate-producing) strains. A biofilm is a structured consortium of bacteria, embedded in a self-produced polymer matrix consisting of polysaccharide, protein...

  15. Biosynthesis of pyocyanin pigment by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    M.Z. El-Fouly

    2015-01-01

    Full Text Available Sixty-three isolates belonging to the genus Pseudomonas were isolated from different environmental sources including; soil, water and clinical specimens. Twenty out of them were identified as Pseudomonas aeruginosa and individually screened for pyocyanin production. P. aeruginosa R1; isolated from rice-cultivated soil and P. aeruginosa U3 selected from clinical specimen (Urinary tract infection were the highest pyocyanin producers; pyocyanin production reached 9.3 and 5.9 μg/ml, respectively on synthetic glucose supplemented nutrient medium (GSNB. The identification of both selected strains (P. aeruginosa R1 and P. aeruginosa U3 was confirmed by 16S rRNA, the similarity with other strains available in database was 97% (with P. aeruginosa FPVC 14 and 94% (with P. aeruginosa 13.A, respectively. P. aeruginosa R1 and P. aeruginosa U3 are accessed at gene bank with accession numbers KM924432 and KM603511, in the same order. Pyocyanin was extracted by standard methods, purified by column chromatography and characterized by UV-Vis absorption, mass spectrometry and nuclear magnetic resonance. The antimicrobial activity of purified pyocyanin against multi-drug resistant microbes was investigated; the efficiency of pyocyanin was more obvious in Gram +ve bacteria than Gram−ve bacteria and yeast. To reduce the cost of pyocyanin production, a new conventional medium based on cotton seed meal supplemented with peptone was designed. The pyocyanin production of both selected strains P. aeruginosa R1 and P. aeruginosa U3 using the new medium is increased by 30.1% and 17.2%, respectively in comparison with synthetic GSNB medium, while the cost of production process is reduced by 56.7%.

  16. Direct detection of the plant pathogens Burkholderia glumae, Burkholderia gladioli pv. gladioli, and Erwinia chrysanthemi pv. zeae in infected rice seedlings using matrix assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Kajiwara, Hideyuki

    2016-01-01

    The plant pathogens Burkholderia glumae, Burkholderia gladioli pv. gladioli, and Erwinia chrysanthemi pv. zeae were directly detected in extracts from infected rice seedlings by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This method did not require culturing of the pathogens on artificial medium. In the MALDI-TOF MS analysis, peaks originating from bacteria were found in extracts from infected rice seedlings. The spectral peaks showed significantly high scores, in spite of minor differences in spectra. The spectral peaks originating from host plant tissues did not affect this direct MALDI-TOF MS analysis for the rapid identification of plant pathogens. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Improvement of the Efficacy of Linear Undecapeptides against Plant-Pathogenic Bacteria by Incorporation of d-Amino Acids ▿

    Science.gov (United States)

    Güell, Imma; Cabrefiga, Jordi; Badosa, Esther; Ferre, Rafael; Talleda, Montserrat; Bardají, Eduard; Planas, Marta; Feliu, Lidia; Montesinos, Emilio

    2011-01-01

    A set of 31 undecapeptides, incorporating 1 to 11 d-amino acids and derived from the antimicrobial peptide BP100 (KKLFKKILKYL-NH2), was designed and synthesized. This set was evaluated for inhibition of growth of the plant-pathogenic bacteria Erwinia amylovora, Pseudomonas syringae pv. syringae, and Xanthomonas axonopodis pv. vesicatoria, hemolysis, and protease degradation. Two derivatives were as active as BP100, and 10 peptides displayed improved activity, with the all-d isomer being the most active. Twenty-six peptides were less hemolytic than BP100, and all peptides were more stable against protease degradation. Plant extracts inhibited the activity of BP100 as well as that of the d-isomers. Ten derivatives incorporating one d-amino acid each were tested in an infectivity inhibition assay with the three plant-pathogenic bacteria by using detached pear and pepper leaves and pear fruits. All 10 peptides studied were active against E. amylovora, 6 displayed activity against P. syringae pv. syringae, and 2 displayed activity against X. axonopodis pv. vesicatoria. Peptides BP143 (KKLFKKILKYL-NH2) and BP145 (KKLFKKILKYL-NH2), containing one d-amino acid at positions 4 and 2 (underlined), respectively, were evaluated in whole-plant assays for the control of bacterial blight of pepper and pear and fire blight of pear. Peptide BP143 was as effective as streptomycin in the three pathosystems, was more effective than BP100 against bacterial blight of pepper and pear, and equally effective against fire blight of pear. PMID:21335383

  18. Dynamic regulation of GacA in type III secretion, pectinase gene expression, pellicle formation, and pathogenicity of Dickeya dadantii (Erwinia chrysanthemi 3937).

    Science.gov (United States)

    Yang, Shihui; Peng, Quan; Zhang, Qiu; Yi, Xuan; Choi, Chang Jae; Reedy, Ralph M; Charkowski, Amy O; Yang, Ching-Hong

    2008-01-01

    Dickeya dadantii (Erwinia chrysanthemi 3937) secretes exoenzymes, including pectin-degrading enzymes, leading to the loss of structural integrity of plant cell walls. A type III secretion system (T3SS) is essential for full virulence of this bacterium within plant hosts. The GacS/GacA two-component signal transduction system participates in important biological roles in several gram-negative bacteria. In this study, a gacA deletion mutant (Ech137) of D. dadantii was constructed to investigate the effect of this mutation on pathogenesis and other phenotypes. Compared with wild-type D. dadantii, Ech137 had a delayed biofilm-pellicle formation. The production of pectate lyase (Pel), protease, and cellulase was diminished in Ech137 compared with the wild-type cells. Reduced transcription of two endo-Pel genes, pelD and pelL, was found in Ech137 using a green fluorescence protein-based fluorescence-activated cell sorter promoter activity assay. In addition, the transcription of T3SS genes dspE (an effector), hrpA (a structural protein of the T3SS pilus), and hrpN (a T3SS harpin) was reduced in Ech137. A lower amount of rsmB regulatory RNA was found in gacA mutant Ech137 compared with the wild-type bacterium by quantitative reverse-transcription polymerase chain reaction. Compared with wild-type D. dadantii, a lower amount of hrpL mRNA was observed in Ech137 at 12 h grown in medium. Although the role of RsmA, rsmB, and RsmC in D. dadantii is not clear, from the regulatory pathway revealed in E. carotovora, the lower expression of dspE, hrpA, and hrpN in Ech137 may be due to a post-transcriptional regulation of hrpL through the Gac-Rsm regulatory pathway. Consequently, the reduced exoenzyme production and Pel gene expression in the mutant may be sue partially to the regulatory role of rsmB-RsmA on exoenzyme expression. Similar to in vitro results, a lower expression of T3SS and pectinase genes of Ech137 also was observed in bacterial cells inoculated into Saintpaulia

  19. Characterization of Pseudomonas aeruginosa PB112 (JN996498 ...

    African Journals Online (AJOL)

    Characterization of Pseudomonas aeruginosa PB112 (JN996498) isolated from infected Labeo bata (Hamilton) by 16S rRNA gene sequence analysis and fatty acid methyl ester (FAME) analysis. Somerita Panda, PK Bandyopadhyay, SN Chatterjee ...

  20. The Enzymes of the Ammonia Assimilation in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Janssen, Dick B.; Camp, Huub J.M. op den; Leenen, Pieter J.M.; Drift, Chris van der

    1980-01-01

    Glutamine synthetase from Pseudomonas aeruginosa is regulated by repression/derepression of enzyme synthesis and by adenylylation/deadenylylation control. High levels of deadenylylated biosynthetically active glutamine synthetase were observed in cultures growing with limiting amounts of nitrogen