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Sample records for pseudomonas syringae strain

  1. 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.

  2. 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.

  3. 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...

  4. 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...

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

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    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

  6. 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.

  7. 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.

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

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    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.;

  9. 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...

  10. 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....

  11. 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

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

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    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

  13. 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

  14. 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.

  15. 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

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    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

  16. 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.

  17. 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...

  18. 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...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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. ...

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

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    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...

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

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    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

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

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    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.

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

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    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.

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

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    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.

  9. 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.

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    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.

  10. 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

  11. HOPM1 mediated disease resistance to Pseudomonas syringae in Arabidopsis

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    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.

  12. 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

  13. 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.

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

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    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.

  15. 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.

  16. 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.

  17. 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

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

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    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.

  19. 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.

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

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    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.

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

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    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

  2. 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.

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

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    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.

  4. 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...

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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 ...

  10. 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).

  11. 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...

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

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    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

  15. 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)

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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

  5. 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

  6. 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.

  7. 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.

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

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    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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

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

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    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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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...

  8. 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.

  9. 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.

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

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    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.

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

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    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.

  12. 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.

  13. 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.

  14. 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...

  15. 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

  16. 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

  17. 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

  18. 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

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

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    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.

  20. 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

  1. 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...

  2. 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.

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

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    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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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).

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

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    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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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....

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

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    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.

  5. 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.

  6. 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.

  7. 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

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

    Directory of Open Access Journals (Sweden)

    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

  9. 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...

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. 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

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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...

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

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    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.

  9. 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.

  10. 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.

  11. 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.

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    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.

  12. 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

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

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    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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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...

  3. Effect of biosurfactant from two strains of Pseudomonas on ...

    African Journals Online (AJOL)

    Two Pseudomonas strains isolated from oil-contaminated soil which produce biosurfactant were studied. The biosurfactant containing broth formed stable emulsions with liquid light paraffin, cooking medium vegetable oil and toluene. The strains under study produce extra cellular biosurfactant in the culture media.

  4. Degradation of polynuclear aromatic hydrocarbons by two strains of Pseudomonas

    Directory of Open Access Journals (Sweden)

    Obinna C. Nwinyi

    Full Text Available ABSTRACT The goal of this investigation was to isolate competent polynuclear aromatic hydrocarbons degraders that can utilize polynuclear aromatic hydrocarbons of former industrial sites at McDoel Switchyard in Bloomington, Indiana. Using conventional enrichment method based on soil slurry, we isolated, screened and purified two bacterial species strains PB1 and PB2. Applying the ribotyping technique using the 16S rRNA gene analysis, the strains were assigned to the genus Pseudomonas (Pseudomonas plecoglossicida strain PB1 and Pseudomonas sp. PB2. Both isolates showed promising metabolic capacity on pyrene sprayed MS agar plates during the preliminary investigations. Using time course studies in the liquid cultures at calculated concentrations 123, 64, 97 and 94 ppm for naphthalene, chrysene, fluroanthene and pyrene, P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 showed partial utilization of the polynuclear aromatic hydrocarbons. Naphthalene was degraded between 26% and 40%, chrysene 14% and 16%, fluroanthene 5% and 7%; pyrene 8% and 13% by P. plecoglossicida strain PB1 and Pseudomonas sp. PB2 respectively. Based on their growth profile, we developed a model R2 = 1 to predict the degradation rate of slow polynuclear aromatic hydrocarbon-degraders where all the necessary parameters are constant. From this investigation, we confirm that the former industrial site soil microbial communities may be explored for the biorestoration of the industrial site.

  5. 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

  6. 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

  7. 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.

  8. [Mechanism of cyanide and thiocyanate decomposition by an association of Pseudomonas putida and Pseudomonas stutzeri strains].

    Science.gov (United States)

    Grigor'eva, N V; Kondrat'eva, T F; Krasil'nikova, E N; Karavaĭko, G I

    2006-01-01

    The intermediate and terminal products of cyanide and thiocyanate decomposition by individual strains of the genus Pseudomonas, P. putida strain 21 and P. stutzeri strain 18, and by their association were analyzed. The activity of the enzymes of nitrogen and sulfur metabolism in these strains was compared with that of the collection strains P. putida VKM B-2187T and P. stutzeri VKM B-975T. Upon the introduction of CN- and SCN- into cell suspensions of strains 18 and 21 in phosphate buffer (pH 8.8), the production of NH4+ was observed. Due to the high rate of their utilization, NH3, NH4+, and CNO- were absent from the culture liquids of P. putida strain 21 and P. stutzeri strain 18 grown with CN- or SCN-. Both Pseudomonas strains decomposed SCN- via cyanate production. The cyanase activity was 0.75 micromol/(min mg protein) for P. putida strain 21 and 1.26 micromol/(min mg protein) for P. stutzeri strain 18. The cyanase activity was present in the cells grown with SCN- but absent in cells grown with NH4+. Strain 21 of P. putida was a more active CN- decomposer than strain 18 of P. stutzeri. Ammonium and CO2 were the terminal nitrogen and carbon products of CN- and SCN- decomposition. The terminal sulfur products of SCN- decomposition by P. stutzeri strain 18 and P. putida strain 21 were thiosulfate and tetrathionate, respectively. The strains utilized the toxic compounds in the anabolism only, as sources of nitrogen (CN- and SCN-) and sulfur (SCN-). The pathway of thiocyanate decomposition by the association of bacteria of the genus Pseudomonas is proposed based on the results obtained.

  9. 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.

  10. 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.

  11. Aflatoxin B₁ degradation by a Pseudomonas strain.

    Science.gov (United States)

    Sangare, Lancine; Zhao, Yueju; Folly, Yawa Minnie Elodie; Chang, Jinghua; Li, Jinhan; Selvaraj, Jonathan Nimal; Xing, Fuguo; Zhou, Lu; Wang, Yan; Liu, Yang

    2014-10-23

    Aflatoxin B1 (AFB1), one of the most potent naturally occurring mutagens and carcinogens, causes significant threats to the food industry and animal production. In this study, 25 bacteria isolates were collected from grain kernels and soils displaying AFB1 reduction activity. Based on its degradation effectiveness, isolate N17-1 was selected for further characterization and identified as Pseudomonas aeruginosa. P. aeruginosa N17-1 could degrade AFB₁, AFB₂ and AFM₁ by 82.8%, 46.8% and 31.9% after incubation in Nutrient Broth (NB) medium at 37 °C for 72 h, respectively. The culture supernatant of isolate N17-1 degraded AFB₁ effectively, whereas the viable cells and intra cell extracts were far less effective. Factors influencing AFB1 degradation by the culture supernatant were investigated. Maximum degradation was observed at 55 °C. Ions Mn²⁺ and Cu²⁺ were activators for AFB1 degradation, however, ions Mg²⁺, Li⁺, Zn²⁺, Se²⁺, Fe³⁺ were strong inhibitors. Treatments with proteinase K and proteinase K plus SDS significantly reduced the degradation activity of the culture supernatant. No degradation products were observed based on preliminary LC-QTOF/MS analysis, indicating AFB₁ was metabolized to degradation products with chemical properties different from that of AFB₁. The results indicated that the degradation of AFB₁ by P. aeruginosa N17-1 was enzymatic and could have a great potential in industrial applications. This is the first report indicating that the isolate of P. aeruginosa possesses the ability to degrade aflatoxin.

  12. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  14. 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.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Specific Genomic Fingerprints of Phosphate Solubilizing Pseudomonas Strains Generated by Box Elements

    Science.gov (United States)

    Javadi Nobandegani, Mohammad Bagher; Saud, Halimi Mohd; Yun, Wong Mui

    2014-01-01

    Primers corresponding to conserved bacterial repetitive of BOX elements were used to show that BOX-DNA sequences are widely distributed in phosphate solubilizing Pseudomonas strains. Phosphate solubilizing Pseudomonas was isolated from oil palm fields (tropical soil) in Malaysia. BOX elements were used to generate genomic fingerprints of a variety of Pseudomonas isolates to identify strains that were not distinguishable by other classification methods. BOX-PCR, that derived genomic fingerprints, was generated from whole purified genomic DNA by liquid culture of phosphate solubilizing Pseudomonas. BOX-PCR generated the phosphate solubilizing Pseudomonas specific fingerprints to identify the relationship between these strains. This suggests that distribution of BOX elements' sequences in phosphate solubilizing Pseudomonas strains is the mirror image of their genomic structure. Therefore, this method appears to be a rapid, simple, and reproducible method to identify and classify phosphate solubilizing Pseudomonas strains and it may be useful tool for fast identification of potential biofertilizer strains. PMID:25580434

  19. Effect of green manure on the incidence of cyanogenic Pseudomonas strains in hop garden soils.

    Science.gov (United States)

    Paszkowski, Wojciech L; Dwornikiewicz, Jerzy

    2003-05-01

    Incidence of cyanogenic Pseudomonas strains in hop garden soils in relation to the kind of fertilization was studied. Incidence differed with respect to the fertilization treatment and the age of the plantation. Amendment of soil with rye and with white mustard as green manures limited the number of cyanogenic Pseudomonas strains relative to farmyard manures and NPK fertilization. Among all fertilization treatments, cyanogenic Pseudomonas spp. strains had lowest populations in soils amended with white mustard.

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

    Directory of Open Access Journals (Sweden)

    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

  1. Biodegradation of acetochlor by a newly isolated Pseudomonas strain.

    Science.gov (United States)

    Luo, Wei; Gu, Qiuya; Chen, Wenting; Zhu, Xiangcheng; Duan, Zhibing; Yu, Xiaobin

    2015-05-01

    A novel microbial strain JD115 capable of degrading acetochlor was isolated from the sludge of acetochlor manufacture and was identified as Pseudomonas aeruginosa species. This strain was able to grow on acetochlor as the sole source of both carbon and nitrogen. The biodegradation of acetochlor by strain JD115 could be described either by the pseudo-first-order or by the second-order kinetics models, while the latter gave a better performance. The strain optimally degraded acetochlor at a pH value of 7.0 and a temperature of 37 °C. Additional nutriments could greatly enhance the degradation rate of acetochlor up to 95.4% in the presence of 50 mg acetochlor l(-1). The metabolite analyses by GC-MS presumed that catechol was an intermediate product of acetochlor, which was finally degraded for 5 days of incubation. This study highlights the potential use of this strain for the bioremediation of an acetochlor-polluted environment.

  2. 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...

  3. Resistance of Animal Strains of Pseudomonas aeruginosa to Carbapenems

    Directory of Open Access Journals (Sweden)

    Marisa Haenni

    2017-09-01

    Full Text Available Carbapenems are major antibiotics reserved to human medicine. This study aimed to investigate the mechanisms of carbapenem resistance of a selection of Pseudomonas aeruginosa veterinary strains from the French network Resapath. Thirty (5.7% imipenem and/or meropenem non-susceptible P. aeruginosa of canine (n = 24, feline (n = 5, or bovine (n = 1 origin were identified in a large collection of 527 veterinary strains gathered by the Resapath. These resistant isolates belonged to 25 MultiLocus Sequence Types (MLST, of which 17 (68% are shared with clinical (human strains, such as high risk clones ST233 and ST395. Interestingly, none of the veterinary strains produced a carbapenemase, and only six of them (20% harbored deletions or insertion sequence (IS disrupting the porin OprD gene. The remaining 24 strains contained mutations or IS in various loci resulting in down-regulation of gene oprD coupled with upregulation of efflux system CzcCBA (n = 3; activation of sensor kinase CzcS ± CopS, MexEF-OprN (n = 4; alteration of oxido reductase MexS, MexXY (n = 8; activation of two-component system ParRS, or MexAB-OprM (n = 12; alteration of regulator MexR, NalC ± NalD. Two efflux pumps were co-produced simultaneously in three mutants. Finally, in 11 out of 12 strains displaying an intact porin OprD, derepression of MexAB-OprM accounted for a decreased susceptibility to meropenem relative to imipenem. Though not treated by carbapenems, animals thus represent a reservoir of multidrug resistant P. aeruginosa strains potentially able to contaminate fragile outpatients.

  4. Identification of pesticide-degrading Pseudomonas strains as poly-β ...

    African Journals Online (AJOL)

    . 14 strains of pesticide-degrading Pseudomonas isolated from subtropical lowland soil in southern Brazil were analyzed using optical microscopy. Lipid inclusions were identified in four strains, and three of them, which degraded the pesticide ...

  5. 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

    Directory of Open Access Journals (Sweden)

    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

  6. Comparative genomic analysis of multiple strains of two unusual plant pathogens: Pseudomonas corrugata and Pseudomonas mediterranea

    Directory of Open Access Journals (Sweden)

    Emmanouil A Trantas

    2015-08-01

    Full Text Available The non-fluorescent pseudomonads, Pseudomonas corrugata (Pcor and P. mediterranea (Pmed, are closely related species that cause pith necrosis, a disease of tomato that causes severe crop losses. However, they also show strong antagonistic effects against economically important pathogens, demonstrating their potential for utilization as biological control agents. In addition, their metabolic versatility makes them attractive for the production of commercial biomolecules and bioremediation. An extensive comparative genomics study is required to dissect the mechanisms that Pcor and Pmed employ to cause disease, prevent disease caused by other pathogens, and to mine their genomes for commercially significant chemical pathways. Here, we present the draft genomes of nine Pcor and Pmed strains from different geographical locations. This analysis covered significant genetic heterogeneity and allowed in-depth genomic comparison. All examined strains were able to trigger symptoms in tomato plants but not all induced a hypersensitive-like response in Nicotiana benthamiana. Genome-mining revealed the absence of a type III secretion system and of known type III effectors from all examined Pcor and Pmed strains. The lack of a type III secretion system appears to be unique among the plant pathogenic pseudomonads. Several gene clusters coding for type VI secretion system were detected in all genomes.

  7. Genome diversity of Pseudomonas aeruginosa PAO1 laboratory strains.

    Science.gov (United States)

    Klockgether, Jens; Munder, Antje; Neugebauer, Jens; Davenport, Colin F; Stanke, Frauke; Larbig, Karen D; Heeb, Stephan; Schöck, Ulrike; Pohl, Thomas M; Wiehlmann, Lutz; Tümmler, Burkhard

    2010-02-01

    Pseudomonas aeruginosa PAO1 is the most commonly used strain for research on this ubiquitous and metabolically versatile opportunistic pathogen. Strain PAO1, a derivative of the original Australian PAO isolate, has been distributed worldwide to laboratories and strain collections. Over decades discordant phenotypes of PAO1 sublines have emerged. Taking the existing PAO1-UW genome sequence (named after the University of Washington, which led the sequencing project) as a blueprint, the genome sequences of reference strains MPAO1 and PAO1-DSM (stored at the German Collection for Microorganisms and Cell Cultures [DSMZ]) were resolved by physical mapping and deep short read sequencing-by-synthesis. MPAO1 has been the source of near-saturation libraries of transposon insertion mutants, and PAO1-DSM is identical in its SpeI-DpnI restriction map with the original isolate. The major genomic differences of MPAO1 and PAO1-DSM in comparison to PAO1-UW are the lack of a large inversion, a duplication of a mobile 12-kb prophage region carrying a distinct integrase and protein phosphatases or kinases, deletions of 3 to 1,006 bp in size, and at least 39 single-nucleotide substitutions, 17 of which affect protein sequences. The PAO1 sublines differed in their ability to cope with nutrient limitation and their virulence in an acute murine airway infection model. Subline PAO1-DSM outnumbered the two other sublines in late stationary growth phase. In conclusion, P. aeruginosa PAO1 shows an ongoing microevolution of genotype and phenotype that jeopardizes the reproducibility of research. High-throughput genome resequencing will resolve more cases and could become a proper quality control for strain collections.

  8. Comparative genomic analysis of multiple strains of two unusual plant pathogens: Pseudomonas corrugata and Pseudomonas mediterranea.

    Science.gov (United States)

    Trantas, Emmanouil A; Licciardello, Grazia; Almeida, Nalvo F; Witek, Kamil; Strano, Cinzia P; Duxbury, Zane; Ververidis, Filippos; Goumas, Dimitrios E; Jones, Jonathan D G; Guttman, David S; Catara, Vittoria; Sarris, Panagiotis F

    2015-01-01

    The non-fluorescent pseudomonads, Pseudomonas corrugata (Pcor) and P. mediterranea (Pmed), are closely related species that cause pith necrosis, a disease of tomato that causes severe crop losses. However, they also show strong antagonistic effects against economically important pathogens, demonstrating their potential for utilization as biological control agents. In addition, their metabolic versatility makes them attractive for the production of commercial biomolecules and bioremediation. An extensive comparative genomics study is required to dissect the mechanisms that Pcor and Pmed employ to cause disease, prevent disease caused by other pathogens, and to mine their genomes for genes that encode proteins involved in commercially important chemical pathways. Here, we present the draft genomes of nine Pcor and Pmed strains from different geographical locations. This analysis covered significant genetic heterogeneity and allowed in-depth genomic comparison. All examined strains were able to trigger symptoms in tomato plants but not all induced a hypersensitive-like response in Nicotiana benthamiana. Genome-mining revealed the absence of type III secretion system and known type III effector-encoding genes from all examined Pcor and Pmed strains. The lack of a type III secretion system appears to be unique among the plant pathogenic pseudomonads. Several gene clusters coding for type VI secretion system were detected in all genomes. Genome-mining also revealed the presence of gene clusters for biosynthesis of siderophores, polyketides, non-ribosomal peptides, and hydrogen cyanide. A highly conserved quorum sensing system was detected in all strains, although species specific differences were observed. Our study provides the basis for in-depth investigations regarding the molecular mechanisms underlying virulence strategies in the battle between plants and microbes.

  9. 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.

  10. Genome sequence of Pseudomonas sp. strain PAMC 25886, isolated from alpine glacial cryoconite.

    Science.gov (United States)

    Shin, Seung Chul; Kim, Su Jin; Hong, Soon Gyu; Ahn, Do Hwan; Lee, Yung Mi; Lee, Hyoungseok; Lee, Jungeun; Park, Hyun

    2012-04-01

    Pseudomonas spp. have shown characteristics of efficiently metabolizing environmental pollutants and also producing exopolysaccharides known as biofilms. Here we present the draft genome sequence of Pseudomonas sp. strain PAMC 25886, which was isolated from glacier cryoconite in the Alps mountain permafrost region and which may provide further insight into biodegradative and/or biofilm-producing mechanisms in a cold environment.

  11. TSCA Experimental Release Application Approved for Pseudomonas putida Strains (fact sheet)

    Science.gov (United States)

    In 1998, EPA approved the TERAs R98-0004/5 submitted by the National Explosives Waste Technology & Evaluation Center (NEWTEC) and the Oak Ridge National Laboratory for field trials of two modified strains of Pseudomonas putida (P.putida).

  12. 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....

  13. ANOMALOUS BLUE COLOURING OF MOZZARELLA CHEESE INTENTIONALLY CONTAMINATED WITH PIGMENT PRODUCING STRAINS OF PSEUDOMONAS FLUORESCENS

    Directory of Open Access Journals (Sweden)

    P. Sechi

    2011-04-01

    Full Text Available In summer 2010 a large outbreak of anomalous blue coloration of mozzarella cheese was recorded in Italy and some northern European countries. Official laboratory analysis and health authorities linked the outbreak to the contamination of processing water with strains of Pseudomonas fluorescens, although several expert raised the question of how to unequivocally link the blue coloring to the presence of the micro-organism. In an attempt to set-up a method to determine whether a given Pseudomonas spp. strain is responsible of the defect, an in vitro system for the evaluation of blue colouring of mozzarella cheese intentionally contaminated with strains of Pseudomonas fluorescens. was developed The system is aimed to ascertain whether P. fluorescens strains, isolated from mozzarella cheese with anomalous blue coloration, are able to reproduce the blue coloration under controlled experimental condition. 96 trials of experimental inoculation of mozzarella cheese in different preservation liquids, were conducted using various suspension of Pseudomonas spp. (P. fluorescens ATCC 13525, P. fluorescens CFBP 3150, one P. fluorescens field strain isolated from blue-colored mozzarella cheese and P. aeruginosa ATCC 10145 as positive control at different concentrations and incubated at different temperatures. Growth curve of all Pseudomonas spp. strains tested demonstrated that after three days of incubation the concentration was generally higher than 106 CFU/g of mozzarella cheese incubated in Tryptic Soy Broth (TSB, and higher than 105 CFU/g of mozzarella cheese incubated in preservation liquid. All mozzarella cheeses inoculated with the field strain of Pseudomonas fluorescens showed the characteristic anomalous blue coloration, which is often associated with Pseudomonas fluorescens contamination of water used during mozzarella cheesemaking. With the proposed system, which enabled a considerable amount of samples to be analysed under controlled experimental

  14. 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.

  15. Virulence Attributes and Host Response Assays for Determining Pathogenic Potential of Pseudomonas Strains Used in Biotechnology.

    Directory of Open Access Journals (Sweden)

    Azam F Tayabali

    Full Text Available Pseudomonas species are opportunistically pathogenic to humans, yet closely related species are used in biotechnology applications. In order to screen for the pathogenic potential of strains considered for biotechnology applications, several Pseudomonas strains (P.aeruginosa (Pa, P.fluorescens (Pf, P.putida (Pp, P.stutzeri (Ps were compared using functional virulence and toxicity assays. Most Pa strains and Ps grew at temperatures between 28°C and 42°C. However, Pf and Pp strains were the most antibiotic resistant, with ciprofloxacin and colistin being the most effective of those tested. No strain was haemolytic on sheep blood agar. Almost all Pa, but not other test strains, produced a pyocyanin-like chromophore, and caused cytotoxicity towards cultured human HT29 cells. Murine endotracheal exposures indicated that the laboratory reference strain, PAO1, was most persistent in the lungs. Only Pa strains induced pro-inflammatory and inflammatory responses, as measured by elevated cytokines and pulmonary Gr-1 -positive cells. Serum amyloid A was elevated at ≥ 48 h post-exposure by only some Pa strains. No relationship was observed between strains and levels of peripheral leukocytes. The species designation or isolation source may not accurately reflect pathogenic potential, since the clinical strain Pa10752 was relatively nonvirulent, but the industrial strain Pa31480 showed comparable virulence to PAO1. Functional assays involving microbial growth, cytotoxicity and murine immunological responses may be most useful for identifying problematic Pseudomonas strains being considered for biotechnology applications.

  16. Resistance to a polyquaternium-1 lens care solution and isoelectric points of Pseudomonas aeruginosa strains

    NARCIS (Netherlands)

    Bruinsma, GM; Rustema-Abbing, M; van der Mei, HC; Lakkis, C; Busscher, HJ

    Objectives: The aim of this study was to correlate the cell surface hydrophobicity and charge of various strains of Pseudomonas aeruginosa with their resistance to a polyquaternium-1 lens care solution. Methods: The 11 P. aeruginosa strains included were isolated from eyes, contact lenses, lens

  17. Influence of volatile organic compounds emitted by Pseudomonas and Serratia strains on Agrobacterium tumefaciens biofilms.

    Science.gov (United States)

    Plyuta, Vladimir; Lipasova, Valentina; Popova, Alexandra; Koksharova, Olga; Kuznetsov, Alexander; Szegedi, Erno; Chernin, Leonid; Khmel, Inessa

    2016-07-01

    The ability to form biofilms plays an important role in bacteria-host interactions, including plant pathogenicity. In this work, we investigated the action of volatile organic compounds (VOCs) produced by rhizospheric strains of Pseudomonas chlororaphis 449, Pseudomonas fluorescens B-4117, Serratia plymuthica IC1270, as well as Serratia proteamaculans strain 94, isolated from spoiled meat, on biofilms formation by three strains of Agrobacterium tumefaciens which are causative agents of crown-gall disease in a wide range of plants. In dual culture assays, the pool of volatiles emitted by the tested Pseudomonas and Serratia strains suppressed the formation of biofilms of A. tumefaciens strains grown on polycarbonate membrane filters and killed Agrobacterium cells in mature biofilms. The individual VOCs produced by the tested Pseudomonas strains, that is, ketones (2-nonanone, 2-heptanone, 2-undecanone), and dimethyl disulfide (DMDS) produced by Serratia strains, were shown to kill A. tumefaciens cells in mature biofilms and suppress their formation. The data obtained in this study suggest an additional potential of some ketones and DMDS as protectors of plants against A. tumefaciens strains, whose virulence is associated with the formation of biofilms on the infected plants. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  18. Lethality and Developmental Delay of Drosophila melanogaster Following Ingestion of Selected Pseudomonas fluorescens Strains

    Science.gov (United States)

    Pseudomonas fluorescens secretes antimicrobial compounds that promote plant health and provide protection from pathogens. We used a non-invasive feeding assay to study the toxicity of P. fluorescens strains Pf0-1, SBW25, and Pf-5 to Drosophila melanogaster. The three strains of P. fluorescens varie...

  19. Dynamics of sodium dodecyl sulfate utilization andantibiotic susceptibility of strain Pseudomonas sp. ATCC19151

    Directory of Open Access Journals (Sweden)

    Jovčić B.

    2009-01-01

    Full Text Available Pseudomonas sp. ATCC19151 harbors a gene encoding a putative alkylsulfatase (sdsA. Here we report a growth ability of this strain in minimal media containing 0.5, 0.75, and 1% sodium dodecyl sulfate as the sole carbon source. The most prominent growth was detected for the minimal medium with 0.5% SDS, so this concentration of SDS was used to monitor Pseudomonas sp. ATCC19151 SDS biodegradation dynamics. Bacterial growth coincided with the disappearance of SDS. Antibiotic susceptibility was tested as well. Pseudomonas sp. ATCC19151 was resistant to six out of nine tested antibiotics, including ampicillin, tetracycline, chloramphenicol, tobramycin, nalidixic acid, and gentamycin.

  20. A novel nicotine catabolic plasmid pMH1 in Pseudomonas sp. strain HF-1.

    Science.gov (United States)

    Wang, Meizhen; Yang, Guiqin; Min, Hang; Lv, Zhenmei

    2009-03-01

    Attempts were made to acquire a plasmid-loss mutant via various methods (spontaneous mutation, SDS, and mitomycin C), among which the method involving mitomycin C (10 microg/mL) has been proven successful. Concomitant with the loss of the plasmid in Pseudomonas sp. strain HF-1, the cured derivative was identified as having a nicotine-negative (Nic-) phenotype, named mutant strain 6-13 (Nic-). After plasmids were transferred from strain HF-1 (named plasmid pMH1) to the mutant strain 6-13, the mutant strain acquired nicotine-degrading ability, called 6-13 transformant (Nic+). There were no differences in growth or nicotine-degrading efficiency between strain HF-1 (wild-type strain) and strain 6-13 transformant. After pMH1 was transferred to Escherichia coli strain Top10 (Nic-), a distant relative of Pseudomonas, it also gained nicotine-degrading ability, showing the highest nicotine degradation efficiency at pH 7.0, the optimal pH for growth of E. coli. The hsp gene, which encodes 6-hydroxy-3-succinoylpyridine hydroxylase, is involved in nicotine degradation in Pseudomonas putida strain S16 and was present in pMH1 but not in pAO1, the well-known nicotine degradation plasmid in Arthrobacter nicotinovorans. It was demonstrated that plasmid pMH1 is a novel nicotine-degrading plasmid.

  1. Isolation and characterization of a fluoranthene-utilizing strain of Pseudomonas paucimobilis.

    OpenAIRE

    Mueller, J G; Chapman, P J; Blattmann, B O; Pritchard, P. H.

    1990-01-01

    A soil bacterium capable of utilizing fluoranthene as the sole source of carbon and energy for growth was purified from a seven-member bacterial community previously isolated from a creosote waste site for its ability to degrade polycyclic aromatic hydrocarbons. By standard bacteriological methods, this bacterium was characterized taxonomically as a strain of Pseudomonas paucimobilis and was designated strain EPA505. Utilization of fluoranthene by strain EPA 505 was demonstrated by increase i...

  2. 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...

  3. 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.

  4. Draft Genome Sequence of a Kale (Brassica oleracea L.) Root Endophyte, Pseudomonas sp. Strain C9.

    Science.gov (United States)

    Laugraud, Aurelie; Young, Sandra; Gerard, Emily; O'Callaghan, Maureen; Wakelin, Steven

    2017-04-13

    Pseudomonas sp. strain C9 is a plant growth-promoting bacterium isolated from the root tissue of Brassica oleracea L. grown in soil from Marlborough, New Zealand. Its draft genome of 6,350,161 bp contains genes associated with plant growth promotion and biological control. Copyright © 2017 Laugraud et al.

  5. Galacto-oligosaccharide hydrolysis by genetically-engineered alpha-galactosidase-producing Pseudomonas chlororaphis strains

    Science.gov (United States)

    Various Pseudomonas chlororaphis strains have been shown to produce rhamnolipid (a biosurfactant), poly(hydroxyalkanoate) (PHA; a biopolymer), and/or antifungal compounds for plants. An ability to metabolize galacto-oligosaccharides in soy molasses would allow P. chlororaphis to use the byproduct as...

  6. Three Strains of Pseudomonas fluorescens Exhibit Differential Toxicity Against Drosophila melanogaster

    Science.gov (United States)

    Three strains of Pseudomonas fluorescens were tested for toxicity to Drosophila melanogaster in an insect feeding assay. Insect eggs were placed on the surface of a non-nutritive agar plate supplemented with a food source that was non-inoculated or inoculated with P. fluorescens Pf0-1, SBW25, or Pf-...

  7. OXIDATION OF BIPHENYL BY A MULTICOMPONENT ENZYME SYSTEM FROM PSEUDOMONAS SP. STRAIN LB400

    Science.gov (United States)

    Pseudomonas sp. strain LB400 grows on biphenyl as the sole carbon and energy source. This organism also cooxidizes several chlorinated biphenyl congeners. Biphenyl dioxygenase activity in cell extract required addition of NAD(P)H as an electron donor for the conversion of bipheny...

  8. Synthesis of poly(3-hydroxyalkanoates) by mutant and recombinant Pseudomonas strains

    NARCIS (Netherlands)

    Huisman, Gjalt W.; WONINK, E; DEKONING, G; Preusting, Hans; Witholt, Bernard

    1992-01-01

    We have studied the accumulation kinetics and physical characteristics of the poly(3-hydroxyalkanoates) (PHAs) formed by several Pseudomonas strains, mutants and recombinants. Although PHA synthesis generally begins only after an essential nutrient such as N, P, S or Mg becomes limiting, we have

  9. A Novel Caffeine Dehydrogenase in Pseudomonas sp. Strain CBB1 Oxidizes Caffeine to Trimethyluric Acid▿

    Science.gov (United States)

    Yu, Chi Li; Kale, Yogesh; Gopishetty, Sridhar; Louie, Tai Man; Subramanian, Mani

    2008-01-01

    A unique heterotrimeric caffeine dehydrogenase was purified from Pseudomonas sp. strain CBB1. This enzyme oxidized caffeine to trimethyluric acid stoichiometrically and hydrolytically, without producing hydrogen peroxide. The enzyme was not NAD(P)+ dependent; coenzyme Q0 was the preferred electron acceptor. The enzyme was specific for caffeine and theobromine and showed no activity with xanthine. PMID:17981969

  10. Ni 2-uptake in Pseudomonas putida strain S4: a possible role of Mg ...

    Indian Academy of Sciences (India)

    Essential metal ion homeostasis is based on regulated uptake of metal ions, both during its scarcity and abundance. Pseudomonas putida strain S4, a multimetal resistant bacterium, was employed to investigate Ni2+ entry into cells. It was observed that Mg2+ regulates the entry of Ni2+ and by this plays a protective role to ...

  11. Study on Antibiotic compounds from Pseudomonas aeruginosa NO4 Strain

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Ji Young; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2011-05-15

    As important human and veterinary medicines, antibiotics are being produced and consumed in large quantities around the world. For example, more than 50 million pounds (22,000 tons) of antibiotics are produced in the U.S. each year and annual production in Germany is about 2,000 tons. Antibiotics are low molecular weight microbial metabolites that at low concentrations inhibit the growth of other microorganisms. Resistant bacteria may also spread and become broader infection-control problems, not only within health care institutions, but in communities as well. Clinically important bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a common cause of infection among hospitalized patients. Pseudomonas aeruginosa is a major cause of opportunistic infections among immunocompromised individuals. The spread of this organism in health care settings is often difficult to control due to the presence of multiple intrinsic and acquired mechanisms of antimicrobial resistance. In this study, we isolated novel bacterium which had strong antagonistic activity and separated antibiotic compounds from Pseudomonas sp., and analyzed characteristics and molecular weight of the antibiotic compound

  12. Gentamicin Delivery to Burkholderia cepacia Group IIIa Strains via Membrane Vesicles from Pseudomonas aeruginosa PAO1

    OpenAIRE

    Allan, Nick D.; Beveridge, Terry J.

    2003-01-01

    When Pseudomonas aeruginosa PAO1 is treated with gentamicin, it releases membrane vesicles containing gentamicin (g-MVs) and peptidoglycan hydrolase, which makes the MVs bactericidal. We evaluate the ability of g-MVs to deliver gentamicin past the intrinsic permeability barrier of group IIIa Burkholderia cepacia and show that strain CEP0248 with low resistance to gentamicin is killed but the highly resistant strain C5424 is not. Immunoelectron microscopy revealed that gentamicin was delivered...

  13. 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.

  14. 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.

  15. 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.

  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

    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.

  17. 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

  18. Efficacy of selected Pseudomonas strains for biocontrol of Rhizoctonia solani in potato

    Directory of Open Access Journals (Sweden)

    Moncef MRABET

    2014-01-01

    Full Text Available Thirty seven bacterial isolates from faba bean (Vicia faba L. root-nodules were screened for their antagonistic activity against eight Rhizoctonia solani strains isolated from infected potato (Solanum tuberosum L. tubers. Two bacterial strains (designated as Kl.Fb14 and S8.Fb11 gave 50% in vitro inhibition of R. solani mycelial growth. 16S rDNA sequence analysis indicated that strain Kl.Fb14 exhibited 99.5% identity with Pseudomonas moraviensis, and that S8.Fb11 exhibited 99.8% identity with Pseudomonas reinekei. Greenhouse trials in soil showed that strain S8.Fb11 reduced the percentage of sclerotia on potato tubers and amounts of tuber infection for the potato cultivars Spunta and Nicola. In a field trial conducted in South Tunisia, infection with R. solani reduced potato yield by approximately 40% for ‘Spunta’ and 17% for ‘Nicola’; about 20% of the total tuber production was severely infected. However, when potato tubers were treated with strain S8.Fb11 prior to sowing, disease incidence was reduced to 6% of total production with low infection levels; potato yield was enhanced by about 6 kg per 10 m row in comparison to R. solani infected plants. The second selected Pseudomonas sp. (strain Kl.Fb14 did not affect either the levels of sclerotia on tubers or potato yield.

  19. A genetically engineered Pseudomonas fluorescens strain possesses the dual activity against phytopathogenic fungi and insects.

    Science.gov (United States)

    Lu, Wenwei; Zhang, Weiqiong; Bai, Yan; Fu, Yingying; Chen, Jun; Geng, Xiaolu; Wang, Yujing; Xiao, Ming

    2010-02-01

    A Pseudomonas fluorescens strain was isolated and showed antagonistic activity against phytopathogenic fungi and found to possess a gene responsible for production of antibiotic 2, 4-diacetylphloroglucinol. For the extension of biocontrol range, a gene for an Androctonus australis Hector insect toxin 1 (AaHIT1), one of the most toxic known insect-selective peptides, was designed and synthesized according to the preferred codon usage of Pseudomonas fluorescens, cloned and transformed into the strain by pSUP106 vector, a broad-host-range plasmid. Bioassays indicated that the engineered strain was able to produce AaHIT1 with insecticidal activity, in the same time retained the activity against plant pathogen. The experiments for nonplanted soil and rhizosphere colonization showed that, similar to the population of the wild-type strain, that of the engineered strain remained relatively constant in the first 10 d, and the subsequent 50 d, suggesting that AaHIT expression in the bacterial cell does not substantially impair its long-term colonization. It is first reported that a Pseudomonas fluorescens strain expressing an active scorpion neurotoxin has dual activity against phytopathogenic fungi and insects, attractive for agronomic applications.

  20. Construction of a Pseudomonas hybrid strain that mineralizes 2,4,6-trinitrotoluene.

    Science.gov (United States)

    Duque, E; Haidour, A; Godoy, F; Ramos, J L

    1993-01-01

    A bacterium, Pseudomonas sp. strain C1S1, able to grow on 2,4,6-trinitrotoluene (TNT), 2,4- and 2,6-dinitrotoluene, and 2-nitrotoluene as N sources, was isolated. The bacterium grew at 30 degrees C with fructose as a C source and accumulated nitrite. Through batch culture enrichment, we isolated a derivative strain, called Pseudomonas sp. clone A, which grew faster on TNT and did not accumulate nitrite in the culture medium. Use of TNT by these two strains as an N source involved the successive removal of nitro groups to yield 2,4- and 2,6-dinitrotoluene, 2-nitrotoluene, and toluene. Transfer of the Pseudomonas putida TOL plasmid pWW0-Km to Pseudomonas sp. clone A allowed the transconjugant bacteria to grow on TNT as the sole C and N source. All bacteria in this study, in addition to removing nitro groups from TNT, reduced nitro groups on the aromatic ring via hydroxylamine to amino derivatives. Azoxy dimers probably resulting from the condensation of partially reduced TNT derivatives were also found. PMID:8468288

  1. [Multicenter surveillance of Pseudomonas aeruginosa strains for antimicrobials in Aichi prefecture in 2009].

    Science.gov (United States)

    Iguchi, Mitsutaka; Mochizuki, Mariko; Yagi, Tetsuya; Ookawa, Hironaga; Shimazaki, Yutaka; Ootsuka, Yumiko; Sato, Kazuya; Shiota, Arufumi; Wakiyama, Naoki; Nakamura, Atsushi; Kidono, Mariko; Hara, Yuki; Asai, Sachie; Kawashima, Makoto; Sakuragi, Kazuko; Asahi, Jitsuko; Murase, Hitoshi; Nishio, Mitsuru; Miyaki, Yuki; Funahashi, Keiji; Mouri, Tetsuo; Sugiura, Yasuyuki; Yamada, Takako; Kondo, Konomi; Sahara, Kaori; Sugaki, Yoshiko; Kawabata, Atsushi; Itou, Yumi; Yamamoto, Yu; Kinoshita, Keiko; Yamaguchi, Ikuo; Sasano, Masaaki; Inukai, Tomomi; Matsui, Natsuko; Kuramae, Hitoshi; Okugawa, Masaru; Kawai, Hiroki; Shibata, Motohiro; Inuzuka, Kazuhisa; Yamada, Atsuko; Koita, Isao; Suematsu, Hiroyuki; Sawamura, Haruki; Yamagishi, Yuka; Mikamo, Hiroshige

    2013-08-01

    We investigated the susceptibility to antimicrobials of 204 Pseudomonas aeruginosa strains isolated from 21 hospitals in Aichi prefecture from September to November 2009. MIC distributions of various antimicrobials were analyzed in terms of geographic region of isolation, patient status (outpatient or inpatient), and type of specimens that the strain was isolated from. The results were as follows. 1. Although more than 90% of strains were susceptible to all aminoglycosides and colistin, 80-90% of them were susceptible to beta-lactams and fluoroquinolones. MIC distributions of all antimicrobials measured were not significantly different between regions. 2. Only 1 strain (0.5%) was multi-drug resistant Pseudomonas aeruginosa (MDRP). Thirteen strains (6.4%) showed imipenem MIC > or = 16 microg/mL, and 16 strains (7.8%) showed ciprofloxacin MIC > or = 4 microg/mL. These strains tended to be more isolated from urine, respiratory tract specimens, or surgical specimens. 3. The MICs of tazobactam/piperacillin, panipenem, meropenem, doripenem, biapenem, sulbactam/cefoperazone, cefepime, and aztreonam were significantly higher in strains isolated from inpatients than in those from outpatients. MIC distributions of antimicrobials other than beta-lactams were not significantly different between situations where strains were isolated. 4. MIC distributions of piperacillin, all carbapenems, cefepime, gentamicin, and all fluoroquinolones were significantly different among samples from which strains were isolated. The strains isolated from blood showed lower MICs against all antimicrobials than those from other samples. No difference was found in MIC distributions when categorized according to bacteremic origin. The MICs were apparently elevated against beta-lactams, fluoroquinolones, and gentamicin in strains isolated from respiratory tract specimens, and against beta-lactams, and fluoroquinolones in strains isolated from urine. It was suggested that in P. aeruginosa surveillance

  2. Influence of twitching and swarming motilities on biofilm formation in Pseudomonas strains.

    Science.gov (United States)

    Otton, Letícia Muner; da Silva Campos, Marina; Meneghetti, Karine Lena; Corção, Gertrudes

    2017-07-01

    The genus Pseudomonas mainly includes opportunistic pathogens that rely on type IV pili as an important virulence factor, which is associated with adherence and biofilm formation. Pseudomonas infections are well known to be persistent and resilient in nature largely because of the tendency of the species to form biofilms. This study aimed at analyzing environmental strains of Pseudomonas genus with respect to their ability to execute twitching and swarming motilities as well as with respect to their ability to form biofilms both in the presence as well as in the absence of furanone, a substance that has the potential to prevent the formation of biofilms. Strains of Pseudomonas aeruginosa and strains belonging to other species of the genus were analyzed. Twitching and swarming motility assays and biofilm-formation assays, both in the presence as well as in the absence of furanone, were performed. In twitching assay strains belonging to P. aeruginosa outperformed those belonging to other species. Interestingly, it was seen that the presence of furanone had a negative impact on formation of twitching and swarming motility zones. In the case of biofilm assays, it was observed that the presence of furanone resulted in an observable decrease in the degree of adhesion in 30% of the analyzed strains. Thus, from our results, it can be concluded that, as compared to other species, the strains belonging to P. aeruginosa exhibit a higher potential for twitching motility and similar performance in swarming motility and biofilm formation. It can also be concluded that furanone has the potential to interfere with both motilities as well as with biofilm formation.

  3. methoxyethanol by a new bacterium isolate Pseudomonas sp. Strain ...

    African Journals Online (AJOL)

    Michael Horsfall

    at room temperature by using a Clark - Type electrode Model 10 Ranke Brothers, Birmingham,. Great Britain) ... strain VB was determined with Clarke-Type electrode. Briefly, 3ml of 50mM phosphate buffer. (pH 7.2) was ... Aerobic transformation of 2 – methoxyethanol and hypothetical pathways intermediates: Studies of the.

  4. Isolation and characterization of a new Pseudomonas- related strain ...

    African Journals Online (AJOL)

    SAM

    2014-04-02

    Apr 2, 2014 ... bacterial strains from phenol-formaldehyde resin manufacturing industrial wastewater. J. Hazard. Mater. B127:238-243. Ausubel FM , Brent R, Kingston RE, Moore DD, Seidman JG, Smith JA,. Struhl K(1995). Current Protocols in Molecular Biology. Greene. Publishing Associates/Wiley Interscience, New ...

  5. 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

    producing avariety of different symptoms depending on the host species and site ofinfection. For example, it causes leaf spot diseases that defoliateplants such as tomato, bean, soybean, trunk cankers, and so-called"blast" diseases on fruit, nut and ornamental species. Considerablevariation occurs both between and within different pathovars of P.syringae (1). Because of its importance as a plant pathogen, it has beenthe subject of much research, especially of its epidemiology andvirulence mechanisms (2). Pseudomonas syringae pv. syringae (Pss) strainB728a is typical of most strains of this pathovar in that it exhibits avery pronounced epiphytic phase on plants. Such strains achieve andmaintain large populations on healthy plants, where they are exposed tostressful conditions such as dryness and sunlight that are hostile tobacterial growth(2). Epiphytic Pss populations serve as inocula that cansubsequently invade plants and initiate disease. Pss strains are distinctfrom many P. syringae strains, such as P. syringae pv. tomato (Pst)strain DC3000, that poorly colonize the exterior of plants; these strainsmay be considered "endophytes" based on their ability to multiply mostlywithin the plant (3). True epiphytes such as Pss B728a often reachsurface populations of over 107 cells/g while strains such as Pst DC3000seldom exceed 105 cells/g (2, 3). Thus, these strains might be consideredto occupy different ends of the epiphytic/endophytic spectrum of plantcolonization as described by Beattie and Lindow (4). As a pathogen and anepiphyte, Pss B728a has evolved to exploit at least two distincthabitats: the leaf surface and apoplast. Because rapid changes intemperature, low water content, and incident solar radiation occur onleaf surfaces, it has been hypothesized that the epiphyte Pss B728aposseses more genes conferring environmental stress tolerance than theendophyte Pst DC3000 (4). Pss B728a also exhibits several traits such asice nucleation activity and SR production (2) that are

  6. Characterization of CMR5c and CMR12a, novel fluorescent Pseudomonas strains from the cocoyam rhizosphere with biocontrol activity

    NARCIS (Netherlands)

    Perneel, M.; Heyrman, J.; Adiobo, A.; Maeyer, de K.; Raaijmakers, J.M.; Vos, de P.; Höfte, M.

    2007-01-01

    Aim: To screen for novel antagonistic Pseudomonas strains producing both phenazines and biosurfactants that are as effective as Pseudomonas aeruginosa PNA1 in the biocontrol of cocoyam root rot caused by Pythium myriotylum. Material and Results: Forty pseudomonads were isolated from the rhizosphere

  7. Aflatoxin B1 Degradation by a Pseudomonas Strain

    Directory of Open Access Journals (Sweden)

    Lancine Sangare

    2014-10-01

    Full Text Available Aflatoxin B1 (AFB1, one of the most potent naturally occurring mutagens and carcinogens, causes significant threats to the food industry and animal production. In this study, 25 bacteria isolates were collected from grain kernels and soils displaying AFB1 reduction activity. Based on its degradation effectiveness, isolate N17-1 was selected for further characterization and identified as Pseudomonas aeruginosa. P. aeruginosa N17-1 could degrade AFB1, AFB2 and AFM1 by 82.8%, 46.8% and 31.9% after incubation in Nutrient Broth (NB medium at 37 °C for 72 h, respectively. The culture supernatant of isolate N17-1 degraded AFB1 effectively, whereas the viable cells and intra cell extracts were far less effective. Factors influencing AFB1 degradation by the culture supernatant were investigated. Maximum degradation was observed at 55 °C. Ions Mn2+ and Cu2+ were activators for AFB1 degradation, however, ions Mg2+, Li+, Zn2+, Se2+, Fe3+ were strong inhibitors. Treatments with proteinase K and proteinase K plus SDS significantly reduced the degradation activity of the culture supernatant. No degradation products were observed based on preliminary LC-QTOF/MS analysis, indicating AFB1 was metabolized to degradation products with chemical properties different from that of AFB1. The results indicated that the degradation of AFB1 by P. aeruginosa N17-1 was enzymatic and could have a great potential in industrial applications. This is the first report indicating that the isolate of P. aeruginosa possesses the ability to degrade aflatoxin.

  8. 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.

  9. Pseudomonas cremoricolorata Strain ND07 Produces N-acyl Homoserine Lactones as Quorum Sensing Molecules

    Directory of Open Access Journals (Sweden)

    Nina Yusrina Muhamad Yunos

    2014-06-01

    Full Text Available Quorum sensing (QS is a bacterial cell-to-cell communication system controlling QS-mediated genes which is synchronized with the population density. The regulation of specific gene activity is dependent on the signaling molecules produced, namely N-acyl homoserine lactones (AHLs. We report here the identification and characterization of AHLs produced by bacterial strain ND07 isolated from a Malaysian fresh water sample. Molecular identification showed that strain ND07 is clustered closely to Pseudomonas cremoricolorata. Spent culture supernatant extract of P. cremoricolorata strain ND07 activated the AHL biosensor Chromobacterium violaceum CV026. Using high resolution triple quadrupole liquid chromatography-mass spectrometry, it was confirmed that P. cremoricolorata strain ND07 produced N-octanoyl-l-homoserine lactone (C8-HSL and N-decanoyl-l-homoserine lactone (C10-HSL. To the best of our knowledge, this is the first documentation on the production of C10-HSL in P. cremoricolorata strain ND07.

  10. Mechanisms of plant growth promotion and disease suppression by Pseudomonas aeruginosa strain 2apa.

    Science.gov (United States)

    Hariprasad, P; Chandrashekar, S; Singh, S Brijesh; Niranjana, S R

    2014-08-01

    A new Pseudomonas strain, designated as 2apa was isolated from tomato rhizosphere and identified as a member of species Pseudomonas aeruginosa based on its morphology, conventional, biochemical, cell wall fatty acid methyl ester analysis, and 16S rRNA gene sequence analysis. The strain 2apa was positive for root colonization, indole acetic acid (IAA), salicylic acid and siderophore production and inhibited the growth of wide range of microorganisms. Antimicrobial substances produced by this strain with further purification and structure elucidation proved to be phenazine. Under laboratory and greenhouse conditions the strain promoted plant growth and suppressed a wide range of foliar and root pathogens in tomato. The protection offered by strain 2apa to foliar pathogens is considered as induced systemic resistance and was further confirmed by enhanced accumulation of phenolics, elicitation of lipoxygenas activity, and jasmonic acid levels. The broad-spectrum antimicrobial and induced systemic resistance exhibiting strain P. aeruginosa 2apa can be used as an effective biological control candidate against devastating fungal and bacterial pathogens, which attack both root and foliar portions of tomato plant. Production of other functional traits such as IAA and siderophore may enhance its potential as biofertilizer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Desulfurization activity evaluation of native strains of pseudomonas spp. in the presence of hydrocarbon

    OpenAIRE

    Alméciga-Díaz, Carlos Javier; Sánchez Medina, Óscar Fernando; Silva Gómez, Edelberto

    2007-01-01

    The main difficulty with fossil fuel combustión lies in sulphur and nitrogen becoming converted to their respective oxides, forming part of the acid rain which deteriorates the environment and infrastructure. Removing sulphur from organo-sulfur compounds by using micro-organisms has become an alternative to hydrodesulphurisation (HDS). Twenty-three Pseudomonas spp. native strains' desulphurisation activity on dibenzothiophene (DBT) was evaluated by using a fermentation system having equal pro...

  12. Anaerobic toluene oxidation to benzyl alcohol and benzaldehyde in a denitrifying Pseudomonas strain.

    Science.gov (United States)

    Altenschmidt, U; Fuchs, G

    1992-07-01

    The denitrifying Pseudomonas strain K172 was grown with a generation time of 6 h to a cell density of 0.4 g (dry weight) per liter with toluene and nitrate as substrates. We found that anaerobic cell suspensions oxidize [14C]toluene first to [14C]benzyl alcohol and subsequently to [14C]benzaldehyde. This proves that the methyl group of toluene is oxidized without molecular oxygen to a hydroxymethyl group.

  13. Anaerobic toluene oxidation to benzyl alcohol and benzaldehyde in a denitrifying Pseudomonas strain.

    OpenAIRE

    Altenschmidt, U; Fuchs, G

    1992-01-01

    The denitrifying Pseudomonas strain K172 was grown with a generation time of 6 h to a cell density of 0.4 g (dry weight) per liter with toluene and nitrate as substrates. We found that anaerobic cell suspensions oxidize [14C]toluene first to [14C]benzyl alcohol and subsequently to [14C]benzaldehyde. This proves that the methyl group of toluene is oxidized without molecular oxygen to a hydroxymethyl group.

  14. Coregulation of the cyclic lipopeptides orfamide and sessilin in the biocontrol strain Pseudomonas sp. CMR12a

    National Research Council Canada - National Science Library

    Olorunleke, Feyisara E; Kieu, Nam P; De Waele, Evelien; Timmerman, Marc; Ongena, Marc; Höfte, Monica

    2017-01-01

    ... ), which are often flanked by LuxR‐type transcriptional regulators. Pseudomonas sp. CMR 12a, an effective biocontrol strain, produces two different classes of CLP s namely sessilins and orfamides...

  15. Silver Nanocomposite Biosynthesis: Antibacterial Activity against Multidrug-Resistant Strains of Pseudomonas aeruginosa and Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Klebson Silva Santos

    2016-09-01

    Full Text Available Bacterial resistance is an emerging public health issue that is disseminated worldwide. Silver nanocomposite can be an alternative strategy to avoid Gram-positive and Gram-negative bacteria growth, including multidrug-resistant strains. In the present study a silver nanocomposite was synthesized, using a new green chemistry process, by the addition of silver nitrate (1.10−3 mol·L−1 into a fermentative medium of Xanthomonas spp. to produce a xanthan gum polymer. Transmission electron microscopy (TEM was used to evaluate the shape and size of the silver nanoparticles obtained. The silver ions in the nanocomposite were quantified by flame atomic absorption spectrometry (FAAS. The antibacterial activity of the nanomaterial against Escherichia coli (ATCC 22652, Enterococcus faecalis (ATCC 29282, Pseudomonas aeruginosa (ATCC 27853 and Staphylococcus aureus (ATCC 25923 was carried out using 500 mg of silver nanocomposite. Pseudomonas aeruginosa and Acinetobacter baumannii multidrug-resistant strains, isolated from hospitalized patients were also included in the study. The biosynthesized silver nanocomposite showed spherical nanoparticles with sizes smaller than 10 nm; 1 g of nanocomposite contained 49.24 µg of silver. Multidrug-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii, and the other Gram-positive and Gram-negative bacteria tested, were sensitive to the silver nanocomposite (10–12.9 mm of inhibition zone. The biosynthesized silver nanocomposite seems to be a promising antibacterial agent for different applications, namely biomedical devices or topical wound coatings.

  16. Biodegradation of Methyl tert-Butyl Ether by Co-Metabolism with a Pseudomonas sp. Strain

    Directory of Open Access Journals (Sweden)

    Shanshan Li

    2016-09-01

    Full Text Available Co-metabolic bioremediation is supposed to be an impressive and promising approach in the elimination technology of methyl tert-butyl ether (MTBE, which was found to be a common pollutant worldwide in the ground or underground water in recent years. In this paper, bacterial strain DZ13 (which can co-metabolically degrade MTBE was isolated and named as Pseudomonas sp. DZ13 based on the result of 16S rRNA gene sequencing analysis. Strain DZ13 could grow on n-alkanes (C5-C8, accompanied with the co-metabolic degradation of MTBE. Diverse n-alkanes with different carbon number showed a significant influence on the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA. When Pseudomonas sp. DZ13 co-metabolically degraded MTBE with n-pentane as the growth substrate, a higher MTBE-degrading rate (Vmax = 38.1 nmol/min/mgprotein, Ks = 6.8 mmol/L and lower TBA-accumulation was observed. In the continuous degradation experiment, the removal efficiency of MTBE by Pseudomonas sp. Strain DZ13 did not show an obvious decrease after five times of continuous addition.

  17. 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.

  18. Effects of ambroxol on biofilm adhesion and viability of Pseudomonas aeruginosa quorum sensing defective strain

    OpenAIRE

    Lu, Qi; Hai-ying ZHONG; Lin, Li-Hua; Ya-yin LIN; Xi-qiang YANG; Yu, Jia-Lin

    2013-01-01

    Objective To investigate the effects of ambroxol on the biofilm viability and pristine adhesion of Pseudomonas aeruginosa wild (PAO1) and quorum sensing defective strain (QS, gene deletion of ∆lasI and ∆rhlI). Methods The biofilm was treated by different concentrations (0, 1.875, 3.75mg/ml) of ambroxol. The number of colony was measured with agar plate, multifunction fluorometer was used to measure the fluorescence intensity of PAO1 and QS strains at the bottom of 96-well plate. The adhesion ...

  19. ANTIMICROBIAL, ENTOMOPATHOGENIC AND ANTIVIRAL ACTIVITY OF GAUPSIN BIOPREPARATION CREATED ON THE BASIS OF Pseudomonas chlororaphis STRAINS

    Directory of Open Access Journals (Sweden)

    E. A. Kiprianova

    2017-02-01

    Full Text Available The aim of this review was to present the results of more than ten-year study of gaupsin biopreparation created on the basis of two strains Pseudomonas chlororaphis subsp. aureofaciens UCM В-111 and UCM В-306 with antifungal, entomopathogenic and antiviral activities. Data about antibiotic substances produced by these strains — phenazine and phenylpyrrole derivatives — are presented. Entomocidal properties against the wide spectrum of insect pests have been found out in the strains-producers. Antiviral activity of gaupsin due to the production of thermostable exopolymers containing neutral monosaccharides has been shown using the tobacco mosaic virus as a model. Lipopolysaccharides of the strains В-111 and В-306 also appeared to be highly active antiviral agents. Structure of their O-specific polysaccharides has been established. The last one are structurally heterogenic, presented by linear tri-and tetrasaccharide repeated links and have specific structure that has not been described previously.

  20. Pseudomonas aeruginosa ATCC 9027 is a non-virulent strain suitable for mono-rhamnolipids production.

    Science.gov (United States)

    Grosso-Becerra, María-Victoria; González-Valdez, Abigail; Granados-Martínez, María-Jessica; Morales, Estefanía; Servín-González, Luis; Méndez, José-Luis; Delgado, Gabriela; Morales-Espinosa, Rosario; Ponce-Soto, Gabriel-Yaxal; Cocotl-Yañez, Miguel; Soberón-Chávez, Gloria

    2016-12-01

    Rhamnolipids produced by Pseudomonas aeruginosa are biosurfactants with a high biotechnological potential, but their extensive commercialization is limited by the potential virulence of P. aeruginosa and by restrictions in producing these surfactants in heterologous hosts. In this work, we report the characterization of P. aeruginosa strain ATCC 9027 in terms of its genome-sequence, virulence, antibiotic resistance, and its ability to produce mono-rhamnolipids when carrying plasmids with different cloned genes from the type strain PAO1. The genes that were expressed from the plasmids are those coding for enzymes involved in the synthesis of this biosurfactant (rhlA and rhlB), as well as the gene that codes for the RhlR transcriptional regulator. We confirm that strain ATCC 9027 forms part of the PA7 clade, but contrary to strain PA7, it is sensitive to antibiotics and is completely avirulent in a mouse model. We also report that strain ATCC 9027 mono-rhamnolipid synthesis is limited by the expression of the rhlAB-R operon. Thus, this strain carrying the rhlAB-R operon produces similar rhamnolipids levels as PAO1 strain. We determined that strain ATCC 9027 with rhlAB-R operon was not virulent to mice. These results show that strain ATCC 9027, expressing PAO1 rhlAB-R operon, has a high biotechnological potential for industrial mono-rhamnolipid production.

  1. 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.

  2. Photodynamic therapy for the eradication of biofilms formed by catheter associated Pseudomonas aeruginosa strains

    Directory of Open Access Journals (Sweden)

    Viviana Teresa Orlandi

    2011-06-01

    Full Text Available Pseudomonas aeruginosa has emerged as a major opportunistic pathogen causing catheter-associated urinary tract infections (CA-UTIs associated with high mortality and morbidity. In this study 18 P. aeruginosa isolates from urine of catheterized patients were evaluated for in vitro biofilm formation.All the tested strains showed the ability to form biofilm more thicker than those formed by a cohort of 29 blood culture strains belonging to the same species. Photodynamic antimicrobial chemotherapy (PACT is a novel antimicrobial treatment that exploits a photosensitizer (PS and visible light to induce lethal oxidative damages in bacterial cells and could be used as local antimicrobial approach in CA-UTIs. Here we tested the susceptibility of planktonic and sessile cultures of P. aeruginosa strains, the model strain PAO1 and CA-UTI isolates, to photodynamic inactivation with a di cationic porphyrinic photosensitizer, the 5, 15-di (N-benzyl-4-pyridynium-porphyrin di chloride.Although Pseudomonas aeruginosa is regarded as a difficult target for antimicrobial chemotherapy, satisfactory bactericidal activities on both planktonic and biofilm cultures were observed.

  3. [Incidence of alginate-coding gene in carbapenem-resistant Pseudomonas aeruginosa strains].

    Science.gov (United States)

    Bogiel, Tomasz; Kwiecińska-Piróg, Joanna; Kozuszko, Sylwia; Gospodarek, Eugenia

    2011-01-01

    Pseudomonas aeruginosa rods are one of the most common isolated opportunistic nosocomial pathogens. Strains usually are capable to secret a capsule-like polysaccharide called alginate important for evasion of host defenses, especially during chronic pulmonary disease of patients with cystic fibrosis. Most genes for alginate biosynthesis and lysis are encoded by the operon. The aim of our study was to evaluate the incidence of algD sequence, generally use for alginate-coding gene detection, in 120 P. aeruginosa strains resistant to carbapenems. All isolates were obtained in the Department of Clinical Microbiology University Hospital no. 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń. Examined strains demonstrated resistance to carbenicillin (90,0%), ticarcillin (89,2%) and ticarcillin clavulanate (86,7%). All strains were susceptible to colistin. The majority of examined strains was susceptible to ceftazidime and cefepime (40,8% each) and norfloxacin (37,5%). Presence of algD gene - noted in 112 (93,3%) strains proves that not every strain is capable to produce alginate. It was also found out that differences in algD genes incidence in case of different clinical material that strains were isolated from were not statistically important.

  4. Strain-dependent induction of neutrophil histamine production and cell death by Pseudomonas aeruginosa

    Science.gov (United States)

    Xu, Xiang; Zhang, Hong; Song, Yuanlin; Lynch, Susan V.; Lowell, Clifford A.; Wiener-Kronish, Jeanine P.; Caughey, George H.

    2012-01-01

    Airway diseases often feature persistent neutrophilic inflammation and infection. In cystic fibrosis bronchitis, for example, Pseudomonas aeruginosa is isolated frequently. Previously, this laboratory revealed that neutrophils become major sources of histamine in mice with tracheobronchitis caused by the wall-less bacterium Mycoplasma pulmonis. To test the hypothesis that more-broadly pathogenic P. aeruginosa (which expresses cell wall-associated LPS and novel toxins) has similar effects, we incubated naïve mouse neutrophils with two strains of P. aeruginosa. Strain PAO1 greatly increased neutrophil histamine content and secretion, whereas strain PA103 depressed histamine production by killing neutrophils. The histamine-stimulating capacity of PAO1, but not PA103-mediated toxicity, persisted in heat-killed organisms. In PAO1-infected mice, lung and neutrophil histamine content increased. However, PAO1 did not alter production by mast cells (classical histamine reservoirs), which also resisted PA103 toxicity. To explore mechanisms of neutrophil-selective induction, we measured changes in mRNA encoding histidine decarboxylase (rate-limiting for histamine synthesis), probed involvement of endotoxin-TLR pathways in Myd88-deficient neutrophils, and examined contributions of pyocyanin and exotoxins. Results revealed that PAO1 increased histamine production by up-regulating histidine decarboxylase mRNA via pathways largely independent of TLR, pyocyanin, and type III secretion system exotoxins. PAO1 also increased histidine decarboxylase mRNA in neutrophils purified from infected lung. Stimulation required direct contact with neutrophils and was blocked by phagocytosis inhibitor cytochalasin D. In summary, Pseudomonas-augmented histamine production by neutrophils is strain-dependent in vitro and likely mediated by up-regulation of histidine decarboxylase. These findings raise the possibility that Pseudomonas-stimulated neutrophils can enhance airway inflammation by

  5. Survival of a Rifampicin-Resistant Pseudomonas fluorescens Strain in Nine Mollisols

    Directory of Open Access Journals (Sweden)

    Tami L. Stubbs

    2014-01-01

    Full Text Available Pseudomonas fluorescens strain D7 (P.f. D7 is a naturally occurring soil bacterium that shows promise as a biological herbicide to inhibit growth of annual grass weeds, including downy brome (Bromus tectorum L., in crop- and rangelands. Pseudomonas fluorescens strain D7rif (P.f. D7rif is a rifampicin-resistant strain of P.f. D7. One of the greatest obstacles to successful biological weed control is survival of the organism under field conditions. Nine soils in the taxonomic order of Mollisols, collected from downy brome-infested areas of the Western and Central United States, were inoculated with P.f. D7rif and incubated in the laboratory to determine the effects of soil type, soil properties, incubation temperature, and soil water potential on survival of P.f. D7rif over 63 days. Silt loam soils from Lind, Washington, and Moro, Oregon, sustained the highest P.f. D7rif populations, and recovery was the lowest from Pendleton, Oregon soil. Survival and recovery of P.f. D7rif varied with soil type and temperature but not with the two soil water potentials tested. After 63 days, P.f. D7rif was recovered at levels greater than log 5.5 colony forming units (CFU g−1 soil from five of the nine test soils, a level adequate to suppress downy brome under field or range conditions.

  6. Antifungal activity of plant essential oils and selected Pseudomonas strains against Phomopsis theicola

    Directory of Open Access Journals (Sweden)

    Starović Mira

    2017-01-01

    Full Text Available Development of natural plant protection products as an alternative to synthetic fungicides is of significant importance regarding the environment. This study was carried out with an objective to investigate in vitro antifungal activities of several essential oils extracted from oregano, basil, myrtle and Turkish pickling herb, and the plant growth-promoting rhizobacteria in the genus Pseudomonas, against the phytopathogenic fungus Phomopsis theicola. Microdilution methods were used to determine the minimum inhibitory concentrations (MIC of selected antimicrobial essential oils (EOs. All EOs exhibited significant levels of antifungal activity against the tested fungal isolates. The oregano EO was found the most potent one (MIC - 5.5 µg/mL, followed by basil (MIC - 75.0µg/mL, myrtle (MIC - 775 µg/mL and Turkish pickling herb (MIC - 7750 µg/mL. Inhibition of Ph. theicola mycelial growth was observed for all tested Pseudomonas spp. strains. K113 and L1 strains were highly effective and achieved more than 60% of fungal growth inhibition using the overnight culture and more than 57% inhibition by applying cell-free supernatants of both strains. A future field trial with K113 and L1 cultures and cell-free supernatants, containing extracellular metabolites toward Ph. theicola, will estimate their effectiveness and applicability as an alternative to chemical protection of apple trees.

  7. RESEARCH IN SENSITIVITY TO ANTIBIOTICS, ANTISEPTICS IN PSEUDOMONAS AERUGINOSA STRAINS ISOLATED FROM PATIENTS WITH INFECTIOUS COMPLICATIONS

    Directory of Open Access Journals (Sweden)

    O. A. Nazarchuk

    2017-07-01

    Full Text Available Background. Infections caused by Pseudomonas are one of the topical issues of medicine. Objective. The aim of the research was to study sensityvity to antibiotics, antiseptics of P. aeruginosa clinical strains that cause infectious complications in patients with burns. Methods. Microbiological study of biological material, received from 435 patients with burns of the 3rd-4th stages (2011-2015 years. In early terms of burn disease 127 clinical strains of P. aeruginosa were isolated from patients. Standard methods were used to identify clinical isolates of P. aeruginosa by their morphological, tinctirial, culture and biochemical properties. The research of antimicrobial action of antiseptics, antibiotics against Pseudomonas were carried out by means of standard methods according to the Directive of the Ministry of Health of Ukraine (No. 167 from 05.04.2007 р. and guidelines of National Committee of Clinical and Laboratory Study (NCCLS, 2002. Results. It was established that P. aeruginosa caused infectious complications in 23.9% of patients among other pathogens. Clinical isolates of P. aeruginosa were found to be low sensitive to amoxicillin/clavulanate (30.76%, ceftazidime (25.92%, cefoperazonum/sulbactam (46.15%, aztreonam (51.85%, tobramycin (38.46%, amicacin (70.34%, doxiciclini (26.92%, fluoroquinolones (59.26%. The analitical progistic criteria of decrease of sensitivity to ceftazidime, cefepim, meropenem and gatifloxacin were found in P. aeruginosa. This pathogen was determined to be sensitive to decasan ®, antimicrobial composition of decamethoxine ®, iodine pvidone. Conclusions. Clinical strains of Pseudomonas aeruginosa, being highly resistant to antibiotics, are also very sensitive to antiseptics decasan ®, antimicrobial of decamethoxine®, povidone iodine.

  8. Metabolic engineering of bacteria for environmental applications: construction of Pseudomonas strains for biodegradation of 2-chlorotoluene.

    Science.gov (United States)

    Haro, M A; de Lorenzo, V

    2001-02-13

    In this article, we illustrate the challenges and bottlenecks in the metabolic engineering of bacteria destined for environmental bioremediation, by reporting current efforts to construct Pseudomonas strains genetically designed for degradation of the recalcitrant compound 2-chlorotoluene. The assembled pathway includes one catabolic segment encoding the toluene dioxygenase of the TOD system of Pseudomonas putida F1 (todC1C2BA), which affords the bioconversion of 2-chlorotoluene into 2-chlorobenzaldehyde by virtue of its residual methyl-monooxygenase activity on o-substituted substrates. A second catabolic segment encoded the entire upper TOL pathway from pWW0 plasmid of P. putida mt-2. The enzymes, benzyl alcohol dehydrogenase (encoded by xylB) and benzaldehyde dehydrogenase (xylC) of this segment accept o-chloro-substituted substrates all the way down to 2-chlorobenzoate. These TOL and TOD segments were assembled in separate mini-Tn5 transposon vectors, such that expression of the encoded genes was dependent on the toluene-responsive Pu promoter of the TOL plasmid and the cognate XylR regulator. Such gene cassettes (mini-Tn5 [UPP2] and mini-Tn5 [TOD2]) were inserted in the chromosome of the 2-chlorobenzoate degraders Pseudomonas aeruginosa PA142 and P. aeruginosa JB2. GC-MS analysis of the metabolic intermediates present in the culture media of the resulting strains verified that these possessed, not only the genetic information, but also the functional ability to mineralise 2-chlorotoluene. However, although these strains did convert the substrate into 2-chlorobenzoate, they failed to grow on 2-chlorotoluene as the only carbon source. These results pinpoint the rate of the metabolic fluxes, the non-productive spill of side-metabolites and the physiological control of degradative pathways as the real bottlenecks for degradation of certain pollutants, rather than the theoretical enzymatic and genetic fitness of the recombinant bacteria to the process. Choices to

  9. Construction of an efficient biologically contained Pseudomonas putida strain and its survival in outdoor assays

    DEFF Research Database (Denmark)

    Molina, Lazaro; Rodriguez, Cayo Juan Ramos; Ronchel, Maria C.

    1998-01-01

    Active biological containment systems consist of two components, a killing element designed to induce cell death and a control element which modulates the expression of the killing function. We constructed a mini-Tn5 transposon bearing a fusion of the P(lac) promoter to the gef killing gene...... and a fusion of the Pm promoter to the lad gene plus the positive regulator of the Pm promoter, the xylS gene. This mini-Tn5 transposon was transferred to the chromosome of Pseudomonas putida CMC4, and in culture this strain survived in the presence of 3-methylbenzoate (an XylS effector) and committed suicide...

  10. Effects of ambroxol on biofilm adhesion and viability of Pseudomonas aeruginosa quorum sensing defective strain

    Directory of Open Access Journals (Sweden)

    Qi LU

    2013-07-01

    Full Text Available Objective To investigate the effects of ambroxol on the biofilm viability and pristine adhesion of Pseudomonas aeruginosa wild (PAO1 and quorum sensing defective strain (QS, gene deletion of ∆lasI and ∆rhlI. Methods The biofilm was treated by different concentrations (0, 1.875, 3.75mg/ml of ambroxol. The number of colony was measured with agar plate, multifunction fluorometer was used to measure the fluorescence intensity of PAO1 and QS strains at the bottom of 96-well plate. The adhesion ratio (% was calculated to determine the effects of ambroxol on bacterial biofilm adhesion. Results Ambroxol treatment reduced the survival rate of the mutant strains compared to that of wild strain, even though the QS strain had increased the adhesion in the presence of ambroxol compared to that of wild strain (P<0.05. Conclusion Ambroxol has a property of significantly antagonizing quorum-sensing system, suggesting that it might be of importance in treatment against chronic Pseudomonasaeruginosainfections.

  11. Organic-solvent stability of elastase strain K overexpressed in an Escherichia-Pseudomonas expression system.

    Science.gov (United States)

    Wong, Chee Fah; Salleh, Abu Bakar; Basri, Mahiran; Abd Rahman, Raja Noor Zaliha Raja

    2010-09-01

    The structural gene of elastase strain K (elastase from Pseudomonas aeruginosa strain K), namely HindIII1500PstI, was successfully sequenced to contain 1497 bp. The amino acid sequence, deduced from the nucleotide sequence, revealed that the mature elastase consists of 301 amino acids, with a molecular mass of 33.1 kDa, and contains a conserved motif HEXXH, zinc ligands and residues involved in the catalysis of elastase strain K. The structural gene was successfully cloned to a shuttle vector, pUCP19, and transformed into Escherichia coli strains TOP10, KRX, JM109 and Tuner™ pLacI as well as P. aeruginosa strains PA01 (A.T.C.C. 47085) and S5, with detection of significant protein expression. Overexpression was detected from transformants KRX/pUCP19/HindIII1500PstI of E. coli and PA01/pUCP19/HindIII1500PstI of P. aeruginosa, with increases in elastolytic activity to 13.83- and 5.04-fold respectively relative to their controls. In addition, recombinant elastase strain K showed considerable stability towards numerous organic solvents such as methanol, ethanol, acetone, toluene, undecan-1-ol and n-dodecane, which typically pose a detrimental effect on enzymes; our finding provides further information to support the potential application of the enzyme in synthetic industries, particularly peptide synthesis.

  12. 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 ...

  13. Diverse effects of Galleria mellonella infection with entomopathogenic and clinical strains of Pseudomonas aeruginosa.

    Science.gov (United States)

    Andrejko, Mariola; Zdybicka-Barabas, Agnieszka; Cytryńska, Małgorzata

    2014-01-01

    In numerous studies, the greater wax moth Galleria mellonella has been exploited as an alternative model host for investigating virulence factors of different pathogenic bacteria. In the present paper, we provide evidence that G. mellonella constitutes a useful and convenient model for analysis of the pathogenicity of Pseudomonas aeruginosa clinical strains. In this in vivo study on the G. mellonella–P. aeruginosa interaction, a bidirectional analysis comprising evaluation of humoral immune response of the bacteria-infected larvae and determination of P. aeruginosa proteinases synthesized during the infection was performed. The effects of G. mellonella infection by two clinical strains (PA C124/9 and PA 02/18) and one entomopathogenic strain (ATCC 27853) cultured in a rich LB and minimal M9 medium, known to induce synthesis of different sets of extracellular proteinases, were evaluated. Both clinical isolates were able to establish infection in G. mellonella caterpillars after intrahemocelic injection. However, although the final effect of the larvae infection by each P. aeruginosa strain was their death within ca. 48 h, considerable strain and medium-dependent differences in the immune response of the insects were detected. The results indicated that G. mellonella larvae distinguished between the three P. aeruginosa strains, which was well reflected by the diverse humoral immune response. The significant differences concerned, among others, the level of phenoloxidase, lysozyme, and antibacterial activity in the hemolymph of the infected insects. An analysis of proteinases performed using specific activity tests, zymography and immunoblotting, revealed that elastase B and alkaline protease were synthesized by each P. aeruginosa strain during the infection. In contrast, a high level of elastase A activity was detected only in the larvae infected by the P. aeruginosa ATCC 27853 strain. It can be postulated that the three P. aeruginosa strains exploit different

  14. Small RNAs regulate the biocontrol property of fluorescent Pseudomonas strain Psd.

    Science.gov (United States)

    Upadhyay, Anamika; Kochar, Mandira; Upadhyay, Ashutosh; Tripathy, Soumya; Rajam, Manchikatla Venkat; Srivastava, Sheela

    2017-03-01

    The production of biocontrol factors by Pseudomonads is reported to be controlled at the post-transcriptional level by the GacS/GacA signal transduction pathway. This involves RNA-binding translational repressor proteins, RsmA and RsmE, and the small regulatory RNAs (sRNAs) RsmX, RsmY, and RsmZ. While the former represses genes involved in secondary metabolite production, the latter relieves this repression at the end of exponential growth. We have studied the fluorescent Pseudomonas strain Psd, possessing good biocontrol potential, and confirmed the presence of rsmY and rsmZ by PCR amplification. Gene constructs for all the three small RNAs (RsmX, RsmY and RsmZ) carried on broad host-range plasmid, pME6032 were mobilized into strain Psd. Expression analysis of gacA in the recombinant strains over-expressing rsmX (Psd-pME7320), rsmY (Psd-pME6359) and rsmZ (Psd-pME6918) revealed a significant upregulation of the response regulator. Besides, a remarkable down-regulation of rsmA was also reported in all the strains. The variant strains were found to produce comparatively higher levels of phenazines. Indole acetic acid levels were higher to some extent, and strain Psd-pME6918 also showed elevated production of HCN. The tomato seedlings infected with Fusarium oxysporum and Verticillium dahliae in the presence of culture filtrate of the recombinant strains showed better plant protection response in comparison to the wild-type strain Psd. These results suggest that small RNAs are important determinants in regulation of the biocontrol property of strain Psd. Copyright © 2016 Elsevier GmbH. All rights reserved.

  15. [Degradation characteristics of naphthalene with a Pseudomonas aeruginosa strain isolated from soil contaminated by diesel].

    Science.gov (United States)

    Liu, Wen-Chao; Wu, Bin-Bin; Li, Xiao-Sen; Lu, Dian-Nan; Liu, Yong-Min

    2015-02-01

    Abstract: A naphthalene-degrading bacterium (referred as HD-5) was isolated from the diesel-contaminated soil and was assigned to Pseudomonas aeruginosa according to 16S rDNA sequences analysis. Gene nah, which encodes naphthalene dioxygenase, was identified from strain HD-5 by PCR amplification. Different bioremediation approaches, including nature attenuation, bioaugmentation with strain Pseudomonas aeruginosa, biostimulation, and an integrated degradation by bioaugmentation and biostimulation, were evaluated for their effectiveness in the remediating soil containing 5% naphthalene. The degradation rates of naphthalene in the soil were compared among the different bioremediation approaches, the FDA and dehydrogenase activity in bioremediation process were measured, and the gene copy number of 16S rRNA and nah in soil were dynamically monitored using real-time PCR. It was shown that the naphthalene removal rate reached 71.94%, 62.22% and 83.14% in approaches of bioaugmentation (B), biostimulation(S) and integrated degradation composed of bioaugmentation and biostimulation (BS), respectively. The highest removal rate of naphthalene was achieved by using BS protocol, which also gives the highest FDA and dehydrogenase activity. The gene copy number of 16S rRNA and nah in soil increased by about 2.67 x 10(11) g(-1) and 8.67 x 10(8) g(-1) after 31 days treatment using BS protocol. Above-mentioned results also demonstrated that the screened bacterium, Pseudomonas aeruginosa, could grow well in naphthalene-contaminated soil and effectively degrade naphthalene, which is of fundamental importance for bioremediation of naphthalene-contaminated soil.

  16. Enhancement of the potential to utilize octopine in the nonfluorescent Pseudomonas sp. strain 92

    Energy Technology Data Exchange (ETDEWEB)

    Gill, S.S.; Boivin, R.; Dion, P. (Univ. Laval, Quebec City, Quebec (Canada))

    1991-08-01

    The nonfluorescent Pseudomonas sp. strain 92 requires the presence of a supplementary carbon source for growth on octopine, whereas the spontaneous mutant RB100 has acquired the capacity to utilize this opine as the sole carbon and nitrogen source. Insertional mutagenesis of RB100 with transposon Tn5 generated mutants which were unable to grow on octopine and others which grew slowly on this substrate. Both types of mutants yielded revertants that had regained the ability to utilize octopine. Some of the revertants had lost the transposon, whereas in others the transposon was retained but with rearrangements of the insertion site. Genes of octopine catabolism from strain 92 were cloned on a cosmid vector to generate pK3. The clone pK3 conferred the ability to utilize octopine as the sole carbon and nitrogen source on the host Pseudomonas putida KT2440. Although they conferred an equivalent growth phenotype, the mutant genes carried by RB100 and the cloned genes on pK3 differed in their regulation. Utilization of ({sup 14}C)octopine was inducible by octopine in RB100 and was constitutive in KT2440(pK3).

  17. Antibacterial properties of Chinese herbal medicines against nosocomial antibiotic resistant strains of Pseudomonas aeruginosa in Taiwan.

    Science.gov (United States)

    Liu, Ching-Shen; Cham, Thau-Ming; Yang, Cheng-Hong; Chang, Hsueh-Wei; Chen, Chia-Hong; Chuang, Li-Yeh

    2007-01-01

    Pseudomonas aeruginosa is well-recognized as a nosocomial pathogen, which exhibits inherent drug resistance. In this study, the antibacterial activity of ethanol extracts of 58 Chinese herbal medicines used in Taiwan were tested against 89 nosocomial antibiotic resistant strains of Pseudomonas aeruginosa. The results gathered by the disc diffusion method showed that 26 out of the 58 herbal extracts exhibited antibacterial activity. Among the 26 herbal extracts, 10 extracts showed broad-spectrum antibacterial activities and were selected for further antibacterial property assay. The minimum inhibitory concentrations (MIC) of the active partition fractions ranged from 0.25 to 11.0 mg/L. The presence of flavonoid compounds in the active fractions of test herbal extracts was observed by the TLC-bioautography. The results from the time-kill assay revealed that most of the herbal extracts completely killed the test organisms within 4 hours. Exposure of the test strains to a sub-MIC level of the herbal extracts for 10 consecutive subcultures did not induce resistance to the active components. A combination of the active herbal fractions with antibiotics showed that one of the herbal medicines, the hexane fraction of Ramulus Cinnamomi, possessed a synergistic effect with tetracycline, gentamycin, and streptomycin. In conclusion, the tested Chinese medical herbs have the potential to be developed into natural antibiotics. This is the first evaluation for screening large amounts of medical plants against nosocomial antibiotic resistant bacteria in Taiwan.

  18. Isolation of the Autoinducer-Quenching Strain that Inhibits LasR in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Lixing Weng

    2014-04-01

    Full Text Available Quorum sensing (QS has been recognized as a general phenomenon in microorganisms and plays an important role in many pathogenic bacteria. In this report, we used the Agrobacterium tumefaciens biosensor strain NT1 to rapidly screen for autoinducer-quenching inhibitors from bacteria. After initial screening 5389 isolates obtained from land and beach soil, 53 putative positive strains were identified. A confirmatory bioassay was carried out after concentrating the putative positive culture supernatant, and 22 strains were confirmed to have anti-LasR activity. Finally, we determined the strain JM2, which could completely inhibit biofilm formation of Pseudomonas aeruginosa PAO1, belonged to the genus Pseudomonas by analysis of 16S rDNA. Partially purified inhibitor factor(s F5 derived from culture supernatants specifically inhibited LasR-controlled elastase and protease in wild type P. aeruginosa PAO1 by 68% and 73%, respectively, without significantly affecting growth; the rhl-controlled pyocyanin and rhamnolipids were inhibited by 54% and 52% in the presence of 100 µg/mL of F5. The swarming motility and biofilm of PAO1 were also inhibited by F5. Real time RT-PCR on samples from 100 µg/mL F5-treated P. aeruginosa showed downregulation of autoinducer synthase (LasRI and rhlI and cognate receptor (lasR and rhlR genes by 50%, 28%, 48%, and 29%, respectively. These results provide compelling evidence that the F5 inhibitor(s interferes with the las system and significantly inhibits biofilm formation.

  19. Degradation of ethyl mercaptan and its major intermediate diethyl disulfide by Pseudomonas sp. strain WL2.

    Science.gov (United States)

    Wang, Xiangqian; Wu, Chao; Liu, Nan; Li, Sujing; Li, Wei; Chen, Jianmeng; Chen, Dongzhi

    2015-04-01

    A Pseudomonas sp. strain WL2 that is able to efficiently metabolize ethyl mercaptan (EM) into diethyl disulfide (DEDS) through enzymatic oxidation was isolated from the activated sludge of a pharmaceutical wastewater plant. One hundred percent removal of 113.5 mg L(-1) EM and 110.3 mg L(-1) DEDS were obtained within 14 and 32 h, respectively. A putative EM degradation pathway that involved the catabolism via DEDS was proposed, which indicated DEDS were further mineralized into carbon dioxide (CO2), bacterial cells, and sulfate (SO4 (2-)) through the transformation of element sulfur and ethyl aldehyde. Degradation kinetics for EM and DEDS with different initial concentrations by strain WL2 were evaluated using Haldane-Andrews model with maximum specific degradation rates of 3.13 and 1.33 g g(-1) h(-1), respectively, and maximum degradation rate constants of 0.522 and 0.175 h(-1) using pseudo-first-order kinetic model were obtained. Results obtained that aerobic degradation of EM by strain WL2 was more efficient than those from previous studies. Substrate range studies of strain WL2 demonstrated its ability to degrade several mercaptans, disulfides, aldehydes, and methanol. All the results obtained highlight the potential of strain WL2 for the use in the biodegradation of volatile organic sulfur compounds (VOSCs).

  20. Antibiotic resistance determinants in a Pseudomonas putida strain isolated from a hospital.

    Directory of Open Access Journals (Sweden)

    Lázaro Molina

    Full Text Available Environmental microbes harbor an enormous pool of antibiotic and biocide resistance genes that can impact the resistance profiles of animal and human pathogens via horizontal gene transfer. Pseudomonas putida strains are ubiquitous in soil and water but have been seldom isolated from humans. We have established a collection of P. putida strains isolated from in-patients in different hospitals in France. One of the isolated strains (HB3267 kills insects and is resistant to the majority of the antibiotics used in laboratories and hospitals, including aminoglycosides, ß-lactams, cationic peptides, chromoprotein enediyne antibiotics, dihydrofolate reductase inhibitors, fluoroquinolones and quinolones, glycopeptide antibiotics, macrolides, polyketides and sulfonamides. Similar to other P. putida clinical isolates the strain was sensitive to amikacin. To shed light on the broad pattern of antibiotic resistance, which is rarely found in clinical isolates of this species, the genome of this strain was sequenced and analysed. The study revealed that the determinants of multiple resistance are both chromosomally-borne as well as located on the pPC9 plasmid. Further analysis indicated that pPC9 has recruited antibiotic and biocide resistance genes from environmental microorganisms as well as from opportunistic and true human pathogens. The pPC9 plasmid is not self-transmissible, but can be mobilized by other bacterial plasmids making it capable of spreading antibiotic resistant determinants to new hosts.

  1. A diagnostic PCR assay for the detection of an Australian epidemic strain of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Murphy Anna

    2010-07-01

    Full Text Available Abstract Background Chronic lung infection with the bacterium Pseudomonas aeruginosa is one of the hallmarks of cystic fibrosis (CF and is associated with worsening lung function, increased hospitalisation and reduced life expectancy. A virulent clonal strain of P. aeruginosa (Australian epidemic strain I; AES-I has been found to be widespread in CF patients in eastern Australia. Methods Suppression subtractive hybridization (SSH was employed to identify genetic sequences that are present in the AES-I strain but absent from the sequenced reference strain PAO1. We used PCR to evaluate the distribution of several of the AES-I loci amongst a collection of 188 P. aeruginosa isolates which was comprised of 35 AES-I isolates (as determined by PFGE, 78 non-AES-I CF isolates including other epidemic CF strains as well as 69 P. aeruginosa isolates from other clinical and environmental sources. Results We have identified a unique AES-I genetic locus that is present in all 35 AES-I isolates tested and not present in any of the other 153 P. aeruginosa strains examined. We have used this unique AES-I locus to develop a diagnostic PCR and a real-time PCR assay to detect the presence of P. aeruginosa and AES-I in patient sputum samples. Conclusions We have developed diagnostic PCR assays that are 100% sensitive and 100% specific for the P. aeruginosa strain AES-I. We have also shown that Whatman FTA® Elute cards may be used with PCR-based assays to rapidly detect the presence of P. aeruginosa strains in CF sputum.

  2. Prevalence of extended spectrum beta lactamases among strains of Pseudomonas aeruginosa isolated from burn patients

    Directory of Open Access Journals (Sweden)

    Mirsalehian

    2008-08-01

    Full Text Available Background: The resistance of Pseudomonas aeruginosa strains to broad spectrum cephalosporins may be mediated by extended spectrum b-lactamases (ESBLs. These enzymes are encoded by different genes located either on chromosome or plasmids. In this study, we determined the antimicrobial resistance patterns of P. aeruginosa isolates and screened for ESBL production. Methods: After isolation from burn patients in Tehran Hospital, identification of P. aeruginosa isolates were assessed using biochemical tests. We then performed disk agar diffusion (DAD according to CLSI guidelines to determine the pattern of antimicrobial resistance. The frequency of ESBLs and prevalence of the OXA-10 and PER-1 genes were determined with combined disk and polymerase chain reaction (PCR methods, respectively. Results: One hundred strains of P. aeruginosa were isolated. The resistance of these strains to cephpodoxime, aztreonam, ciprofloxacin, ofloxacin, ceftazidime, cefepime, imipenem, meropenem, cefotaxime, levofloxacin, piperacilin- tazobactam and ceftriaxon was 100%, 90%, 83%, 92%, 85%, 88%, 63%, 66%, 98%, 89%, 70% and 91%, respectively. Of these, 40 strains (40% were ESBL positive, 29 strains (29% were OXA-10 positive and 18 strains (18% were PER-1 positive. Conclusion: Our results confirm the need for proper antimicrobial therapy in burn hospitals, considering the resistance pattern and frequency of strains producing ESBLs and the presence of the OXA-10 and PER-1 genes. Since an increase in the prevalence of ESBL in P. aeruginosa strains might lead to the transfer of these ESBL genes to other gram-negative bacteria, we recommend the use of appropriate drugs, especially cephalosporins, in burn hospitals.

  3. Specific genomic fingerprints of phytopathogenic Xanthomonas and Pseudomonas pathovars and strains generated with repetitive sequences and PCR

    Energy Technology Data Exchange (ETDEWEB)

    Louws, F.J.; Stephens, C.T.; Fulbright, D.W. [Michigan State Univ., East Lansing, MI (United States)] [and others

    1994-07-01

    DNA primers corresponding to conserved motifs in bacterial repetitive (REP, ERIC, and BOX) elements and PCR were used to show that REP-, ERIC-, and BOX-like DNA sequences are widely distributed in phytopathogenic Xanthomonas and Pseudomonas strains. REP-, ERIC-, and BOX-PCR (collectively known as rep-PCR) were used to generate genomic fingerprints of a variety of Xanthomonas and Pseudomonas isolates and to to identify pathovars and strains that were previously not distinguishable by other classification methods. Analogous rep-PCR-derived genomic fingerprints were generated from purified genomic DNA, colonies on agar plates, liquid cultures, and directly from lesions on infected plants. REP-, ERIC-, and BOX-PCR-generated fingerprints of specific Xanthomonas and Pseudomonas strains were found to yield similar conclusions with regard to the identity of and relationship between these strains. This suggests that the distribution of REP-, ERIC-, and BOX-like sequences in these strains is a reflection of their genomic structure. Thus, the rep-PCR technique appears to be a rapid, simple, and reproducible method to identify and classify Xanthomonas and Pseudomonas strains, and it may be a useful diagnostic tool for these important plant pathogens. 70 refs., 5 figs., 1 tab.

  4. Players over the Surface: Unraveling the Role of Exopolysaccharides in Zinc Biosorption by Fluorescent Pseudomonas Strain Psd.

    Science.gov (United States)

    Upadhyay, Anamika; Kochar, Mandira; Rajam, Manchikatla V; Srivastava, Sheela

    2017-01-01

    Fluorescent Pseudomonas strain Psd is a soil isolate, possessing multiple plant growth promoting (PGP) properties and biocontrol potential. In addition, the strain also possesses high Zn2+ biosorption capability. In this study, we have investigated the role exopolysaccharides (EPS) play in Zn2+ biosorption. We have identified that alginates are the prime components contributing to Zn2+ biosorption. Deletion of the alg8 gene, which codes for a sub-unit of alginate polymerase, led to a significant reduction in EPS production by the organism. We have also demonstrated that the increased alginate production in response to Zn2+ exposure leads to improved biofilm formation by the strain. In the alg8 deletion mutant, however, biofilm formation was severely compromised. Further, we have studied the functional implications of Zn2+ biosorption by Pseudomonas strain Psd by demonstrating the effect on the PGP and biocontrol potential of the strain.

  5. Whole-Genome Sequence of Pseudomonas putida Strain UASWS0946, a Highly Ammonia-Tolerant Nitrifying Bacterium Isolated from Sewage Sludge Aerobic Granules

    OpenAIRE

    Crovadore, Julien; Calmin, Gautier; Cochard, Bastien; Chablais, Romain; Grizard, Damien; Berthon, Jean-Yves; Lefort, François

    2015-01-01

    We report here the genome of Pseudomonas putida strain UASWS0946, a highly ammonia-tolerant nitrifying strain isolated from sewage sludge aerobic granules, which displays adequate genetic equipment for soil depollution, sludge treatment, and biological fertilization in agriculture.

  6. Potato seed dressing with Pseudomonas aeruginosa strain RZ9 enhances yield and reduces black scurf

    Directory of Open Access Journals (Sweden)

    Moncef MRABET

    2015-09-01

    Full Text Available A rhizospheric strain RZ9 of Pseudomonas aeruginosa was assessed for in-vitro growth inhibition of Rhizoctonia solani and effectiveness to control black scurf on potatoes (Solanum tuberosum L. of the cultivars Spunta and Nicola, in greenhouse and field experiments. The strain RZ9 inhibited R. solani mycelial growth by more than 60% and completely inhibited the germination of sclerotia from infested potato tubers in in-vitro tests. In greenhouse assays, seed potato treatment with RZ9 cell suspension increased stem length, decreased the relative weight of infected potato tubers (by 67%, and increased the potato yield (by 16% compared to pathogen-inoculated plants for both potato cultivars. In field trials conducted on sandy soils during 2012 and 2013, strain RZ9 reduced black scurf incidence and increased potato yield by an average of 5.3 t ha-1 for ′Spunta′ and 5 t ha-1 for ′Nicola′. This study showed that the selected strain of P. aeruginosa is an efficient bacterium for enhancing yield and reducing black scurf of field-grown potatoes.

  7. Dataset of proteomics analysis of aging C. elegans exposed to Pseudomonas aeruginosa strain PA01

    Directory of Open Access Journals (Sweden)

    Christina D. King

    2017-04-01

    Full Text Available Here, we present the proteomics dataset of young and middle-aged Caenorhabditis elegans (C. elegans exposed to Pseudomonas aeruginosa (P. aeruginosa strain PA01, which is related to the article "Proteomic Identification of Virulence-Related Factors in Young and Aging C. elegans infected with Pseudomonas aeruginosa" (C. D. King et. al, in-revisions. This dataset was generated to better understand the effects of aging on molecular mechanisms involved in host response to pathogen exposure. Protein from C. elegans of different age and exposure to P. aeruginosa PA01 or control E. coli OP50 were extracted and tryptically digested. Peptides were labeled with the reagents tandem mass tag (TMT6-plex, separated, and detected by using offline strong-cation exchange and online liquid chromatography – mass spectrometry (SCX – LC – MS/MS & MS3. A separate mixture of peptides were labeled on N-terminal amines and lysines with dimethylation. Dimethylated peptides were analyzed using LC – MS/MS and a portion of the results were used to verify fold-change direction for TMT6-plex experiments. Raw data can be found online at www.CHORUSproject.org, a cloud-based data repository (see specifications table for details.

  8. Biodegradation of hexavalent chromium (Cr+6) in wastewater using Pseudomonas sp. and Bacillus sp. bacterial strains

    Energy Technology Data Exchange (ETDEWEB)

    Qasim, Muhammad [Department of Chemical Engineering, American University of Sharjah (United Arab Emirates)

    2013-07-01

    The recovery of toxic metal compounds is a deep concern in all industries. Hexavalent chromium is particularly worrying because of its toxic influence on human health. In this paper, biodegradation of hexavalent chromium (Cr+6) present in wastewater has been studied using two different bacterial strains; Pseudomonas sp. and Bacillus sp. A chemostat (with and without recycle of cells) with 10 L liquid culture volume was used to study the substrate and the biomass cell concentrations with time. Also, the degree of substrate conversion was studied by the varying the dilution rate as an independent parameter. The dilution rate (ratio of feed flow rate to the culture volume) was varied by varying the feed volumetric rate from 110-170 mL/h for inlet hexavalent chromium concentrations of 70 mg/dm3. The results show that a chemostat with recycle gives a better performance in terms of substrate conversion than a chemostat without a recycle. Moreover, the degree of substrate conversion decreases as the dilution rate is increased. Also, Bacillus sp. was found to give higher conversions compared to pseudomonas sp.

  9. Transcriptomic Analyses Elucidate Adaptive Differences of Closely Related Strains of Pseudomonas aeruginosa in Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Gunasekera, Thusitha S.; Bowen, Loryn L.; Zhou, Carol E.; Howard-Byerly, Susan C.; Foley, William S.; Striebich, Richard C.; Dugan, Larry C.; Ruiz, Oscar N.; Stams, Alfons J. M.

    2017-03-17

    Pseudomonas aeruginosacan utilize hydrocarbons, but different strains have various degrees of adaptation despite their highly conserved genome.P. aeruginosaATCC 33988 is highly adapted to hydrocarbons, whileP. aeruginosastrain PAO1, a human pathogen, is less adapted and degrades jet fuel at a lower rate than does ATCC 33988. We investigated fuel-specific transcriptomic differences between these strains in order to ascertain the underlying mechanisms utilized by the adapted strain to proliferate in fuel. During growth in fuel, the genes related to alkane degradation, heat shock response, membrane proteins, efflux pumps, and several novel genes were upregulated in ATCC 33988. Overexpression ofalkgenes in PAO1 provided some improvement in growth, but it was not as robust as that of ATCC 33988, suggesting the role of other genes in adaptation. Expression of the function unknown gene PA5359 from ATCC 33988 in PAO1 increased the growth in fuel. Bioinformatic analysis revealed that PA5359 is a predicted lipoprotein with a conserved Yx(FWY)xxD motif, which is shared among bacterial adhesins. Overexpression of the putative resistance-nodulation-division (RND) efflux pump PA3521 to PA3523 increased the growth of the ATCC 33988 strain, suggesting a possible role in fuel tolerance. Interestingly, the PAO1 strain cannot utilizen-C8andn-C10. The expression of green fluorescent protein (GFP) under the control ofalkBpromoters confirmed thatalkgene promoter polymorphism affects the expression ofalkgenes. Promoter fusion assays further confirmed that the regulation ofalkgenes was different in the two strains. Protein sequence analysis

  10. Transcriptomic Analyses Elucidate Adaptive Differences of Closely Related Strains of Pseudomonas aeruginosa in Fuel.

    Science.gov (United States)

    Gunasekera, Thusitha S; Bowen, Loryn L; Zhou, Carol E; Howard-Byerly, Susan C; Foley, William S; Striebich, Richard C; Dugan, Larry C; Ruiz, Oscar N

    2017-05-15

    Pseudomonas aeruginosa can utilize hydrocarbons, but different strains have various degrees of adaptation despite their highly conserved genome. P. aeruginosa ATCC 33988 is highly adapted to hydrocarbons, while P. aeruginosa strain PAO1, a human pathogen, is less adapted and degrades jet fuel at a lower rate than does ATCC 33988. We investigated fuel-specific transcriptomic differences between these strains in order to ascertain the underlying mechanisms utilized by the adapted strain to proliferate in fuel. During growth in fuel, the genes related to alkane degradation, heat shock response, membrane proteins, efflux pumps, and several novel genes were upregulated in ATCC 33988. Overexpression of alk genes in PAO1 provided some improvement in growth, but it was not as robust as that of ATCC 33988, suggesting the role of other genes in adaptation. Expression of the function unknown gene PA5359 from ATCC 33988 in PAO1 increased the growth in fuel. Bioinformatic analysis revealed that PA5359 is a predicted lipoprotein with a conserved Yx(FWY)xxD motif, which is shared among bacterial adhesins. Overexpression of the putative resistance-nodulation-division (RND) efflux pump PA3521 to PA3523 increased the growth of the ATCC 33988 strain, suggesting a possible role in fuel tolerance. Interestingly, the PAO1 strain cannot utilize n -C 8 and n -C 10 The expression of green fluorescent protein (GFP) under the control of alkB promoters confirmed that alk gene promoter polymorphism affects the expression of alk genes. Promoter fusion assays further confirmed that the regulation of alk genes was different in the two strains. Protein sequence analysis showed low amino acid differences for many of the upregulated genes, further supporting transcriptional control as the main mechanism for enhanced adaptation. IMPORTANCE These results support that specific signal transduction, gene regulation, and coordination of multiple biological responses are required to improve the survival

  11. [The antibacterial activity of oregano essential oil (Origanum heracleoticum L.) against clinical strains of Escherichia coli and Pseudomonas aeruginosa].

    Science.gov (United States)

    Sienkiewicz, Monika; Wasiela, Małgorzata; Głowacka, Anna

    2012-01-01

    The aim of this study was to investigate the antibacterial properties of oregano (Origanum heracleoticum L.) essential oil against clinical strains of Escherichia coli and Pseudomonas aeruginosa. The antibacterial activity of oregano essential oil was investigate against 2 tested and 20 clinical bacterial strains of Escherichia coli and 20 clinical strains o Pseudomonas aeruginosa come from patients with different clinical conditions. The agar dilution method was used for microbial growth inhibition at various concentrations ofoil. Susceptibility testing to antibiotics was carried out using disc-diffusion method. The results of experiments showed that the tested oil was active against all of the clinical strains from both genus of bacteria, but strains of Escherichia coli were more sensitive to tested oil. Essential oil from Origanum heracleoticum L. inhibited the growth of Escherichia coli and Pseudomonas aeruginosa clinical strains with different patters of resistance. The obtained outcomes will enable further investigations using oregano essential oil obtained from Origanum heracleoticum L. as alternative antibacterial remedies enhancing healing process in bacterial infections and as an effective means for the prevention of antibiotic-resistant strain development.

  12. Effects of some organic pollutants on the exopolysaccharides (EPSs) produced by some Pseudomonas spp. strains

    Energy Technology Data Exchange (ETDEWEB)

    Onbasli, Dilsad, E-mail: donbasili@kastamonu.edu.tr [Kastamonu University, Faculty of Science and Arts, Department of Biology, 37100 Kastamonu (Turkey); Aslim, Belma [Gazi University, Faculty of Science and Arts, Department of Biology, 06500 Teknikokullar, Ankara (Turkey)

    2009-08-30

    In this study, isolation and characterization of exopolysaccharides produced by Pseudomonas aeruginosa B1, P. fluorescens B5, P. stutzeri B11 and P. putida B15 which had been seen to produce exopolymers of potential interest in biotechnological applications were examined. To initiate the observation of the organic pollutants-polymer interactions, the yield and properties of their extracellular polysaccharide were researched. The exopolysaccharide production by these strains during growth in nutrient broth medium (control) was 41-75 mg L{sup -1}. Also, P. aeruginosa B1, P. fluorescens B5, P. stutzeri B11 and P. putida B15 had exhibited high production of EPSs in presence of various organic pollutants (2,4-D, benzene, BTX and gasoline, respectively) in mineral salt medium (MSM) as a sole carbon source. EPS production by the 4 strains ranged from 40 mg L{sup -1} to 8 mg L{sup -1}. Monosaccharide composition of EPS produced by these cultures were analyzed by HPLC. Results indicated that EPSs of strains contained neutral sugars and acetylated amino sugars. The neutral sugars in the EPS were mainly composed of glucose, arabinose, glycerol, ribose. The presence of galactronic acid, N-acetyl-D-galactosamin and N-acetyl-D-glucosamine indicated the acidic nature of the polysaccharide. Glycerol was the basic structural unit of EPS produced by the strains except P. stutzeri B11 (MSM with 1% BTX). Strain B1 (in NB medium) was found to be composed of neutral sugars (100%) while strain B1 [in MSM medium with 0.2% (v/v) 2.4-D] contained neutral sugars (70.0%), acetylated amino sugars (30.0%). Also, EPS content of strain B5 (in the NB medium) was neutral sugars (99.8%), acetylated amino sugars (0.2%) while the strain B5 [in MSM medium containing the 1% (v/v) benzene] was found to contain neutral sugars (99.9%), acetylated amino sugars (0.1%). However, EPS monomer composition by strain B11 was detected as neutral sugars (99.77%), acetylated amino sugars (0.23%) in NB medium while

  13. Antimicrobial activity of essential oils of Thymus vulgaris and Origanum vulgare on phytopathogenic strains isolated from soybean.

    Science.gov (United States)

    Oliva, M de las M; Carezzano, M E; Giuliano, M; Daghero, J; Zygadlo, J; Bogino, P; Giordano, W; Demo, M

    2015-05-01

    The aim of this work was to study the antimicrobial activity of essential oils obtained from Thymus vulgaris (thyme) and Origanum vulgare (oregano) on phytopathogenic Pseudomonas species isolated from soybean. Strains with characteristics of P. syringae were isolated from leaves of soybean plants with blight symptoms. Ten of these could be identified in Group Ia of LOPAT as P. syringae. Six of these were confirmed as P. syringae using 16S rRNA, indicating the presence of these phytopathogenic bacteria in east and central Argentina. All the phytopathogenic bacteria were re-isolated and identified from the infected plants. MIC values for thyme were 11.5 and 5.7 mg·ml(-1) on P. syringae strains, while oregano showed variability in the inhibitory activity. Both essential oils inhibited all P. syringae strains, with better inhibitory activity than the antibiotic streptomycin. The oils were not bactericidal for all pseudomonads. Both oils contained high carvacrol (29.5% and 19.7%, respectively) and low thymol (1.5%). Natural products obtained from aromatic plants represent potential sources of molecules with biological activity that could be used as new alternatives for the treatment of phytopathogenic bacteria infections. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  14. Draft Genome Sequence of an Invasive Multidrug-Resistant Strain, Pseudomonas aeruginosa BK1, Isolated from a Keratitis Patient

    KAUST Repository

    Jeganathan, Lakshmi Priya

    2014-03-27

    Pseudomonas aeruginosa infections are difficult to treat due to the presence of a multitude of virulence factors and antibiotic resistance. Here, we report the draft genome sequence of P. aeruginosa BK1, an invasive and multidrug-resistant strain, isolated from a bacterial keratitis patient in southern India.

  15. Whole-Genome Sequence of Pseudomonas graminis Strain UASWS1507, a Potential Biological Control Agent and Biofertilizer Isolated in Switzerland.

    Science.gov (United States)

    Crovadore, Julien; Calmin, Gautier; Chablais, Romain; Cochard, Bastien; Schulz, Torsten; Lefort, François

    2016-10-06

    We report here the whole-genome shotgun sequence of the strain UASWS1507 of the species Pseudomonas graminis, isolated in Switzerland from an apple tree. This is the first genome registered for this species, which is considered as a potential and valuable resource of biological control agents and biofertilizers for agriculture. Copyright © 2016 Crovadore et al.

  16. Rhizoxin analogs, orfamide A and chitinase production contribute to the toxicity of Pseudomonas protegens strain Pf-5 to Drosophila melanogaster

    Science.gov (United States)

    Pseudomonas protegens strain Pf-5 is a soil bacterium that was first described for its activity in biological control of plant diseases and has since been shown to be lethal to certain insects. Among these is the fruit fly Drosophila melanogaster, a well-established model organism for studies evalu...

  17. Genome Sequence of Pseudomonas aeruginosa Strain DK1-NH57388A, a Stable Mucoid Cystic Fibrosis Isolate

    DEFF Research Database (Denmark)

    Norman, Anders; Ciofu, Oana; Amador Hierro, Cristina Isabel

    2016-01-01

    Pseudomonas aeruginosa is an important opportunistic pathogen associated with chronic pulmonary infections and mortality in cystic fibrosis (CF) patients. Here, we present the complete genome sequence of stable mucoid P. aeruginosa strain DK1-NH57388A, a CF isolate which has previously been used...

  18. Disruption of narH, narJ, and moaE Inhibits Heterotrophic Nitrification in Pseudomonas Strain M19

    OpenAIRE

    Nemergut, D.R.; Schmidt, S K

    2002-01-01

    Interruptions in three nitrate reductase-related genes, narH, narJ, and moaE, inhibited heterotrophic nitrification in Pseudomonas strain M19. No nitrate was detected in the medium, and nitrification proceeded in the presence of a nitrate reductase inhibitor. Heterotrophic nitrification was greatly stimulated by the addition of nitrate.

  19. Evaluating synergy between marbofloxacin and gentamicin in Pseudomonas aeruginosa strains isolated from dogs with otitis externa.

    Science.gov (United States)

    Jerzsele, Ákos; Pásztiné-Gere, Erzsébet

    2015-03-01

    The aim of this study was to determine antimicrobial susceptibility of Pseudomonas aeruginosa strains to marbofloxacin and gentamicin, and investigate the possible synergistic, additive, indifferent or antagonistic effects between the two agents. P. aeruginosa strains can develop resistance quickly against certain antibiotics if used alone, thus the need emerges to find synergistic combinations. A total of 68 P. aeruginosa strains isolated from dogs were examined. In order to describe interactions between marbofloxacin and gentamicin the checkerboard microdilution method was utilized. The MICs (minimum inhibitory concentrations) for marbofloxacin and gentamicin were in the range 0.25-64 mg/L and 0.25-32 mg/L, respectively. The combination of marbofloxacin and gentamicin was more effective with a MIC range of 0.031-8 mg/L and a MIC90 of 1 mg/L, compared to 16 mg/L for marbofloxacin alone and 8 mg/L for gentamicin alone. The FIC (fractional inhibitory concentration) indices ranged from 0.0945 (pronounced synergy) to 1.0625 (indifference). Synergy between marbofloxacin and gentamicin was found in 33 isolates. The mean FIC index is 0.546, which represents a partial synergistic/additive effect close to the full synergy threshold. In vitro results indicate that marbofloxacin and gentamicin as partially synergistic agents may prove clinically useful in combination therapy against P. aeruginosa infections. Although marbofloxacin is not used in the human practice, the interactions between fluoroquinolones and aminoglycosides may have importance outside the veterinary field.

  20. Isolation and characterization of a fluoranthene-utilizing strain of pseudomonas paucimobilis

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, J.G.; Chapman, P.J.; Pritchard, P.H.; Blattmann, B.O. (Environmental Protection Agency Environmental Research Laboratory, Gulf Breeze, FL (USA))

    1990-04-01

    A soil bacterium capable of utilizing fluoranthene as the sole source of carbon and energy for growth was purified from a seven-member bacterial community previously isolated from a creosote waste site for its ability to degrade polycyclic aromatic hydrocarbons. By standard bacteriological methods, this bacterium was characterized taxonomically as a strain of Pseudomonas paucimobilis and was designated strain EPA505. Utilization of fluoranthene by strain EPA505 was demonstrated by increase in bacterial biomass, decrease in aqueous fluoranthene concentration, and transient formation of transformation products in liquid cultures where fluoranthene was supplied as the sole carbon source. Resting cells grown in complex medium showed activity toward anthraquinone, benzo(b)fluorene, biphenyl, chrysene, and pyrene as demonstrated by the disappearance of parent compounds or changes in their UV absorption spectra. Fluoranthene-grown resting cells were active against these compounds as well as 2,3-dimethylnaphthalene, anthracene, fluoranthene, fluorene, naphthalene, and phenanthrene. These studies demonstrate that organic compounds not previously reported to serve as growth substrates can be utilized by axenic cultures of microorganisms. Such organisms may possess novel degradative systems that are active toward other compounds whose biological degradation has been limited because inherent structural considerations or because of low aqueous solubility.

  1. Rhamnolipids from Pseudomonas aeruginosa strain W10; as antibiofilm/antibiofouling products for metal protection.

    Science.gov (United States)

    Chebbi, Alif; Elshikh, Mohamed; Haque, Farazul; Ahmed, Syed; Dobbin, Sara; Marchant, Roger; Sayadi, Sami; Chamkha, Mohamed; Banat, Ibrahim M

    2017-05-01

    Industrial biofouling-problems associated with the accumulation of microorganisms from flowing water and fluids on processing surfaces can cause severe problems. A Pseudomonas aeruginosa strain W10 was isolated from industrial setting and found to produce predominantly di-rhamnolipids (Rha-Rha-C10-C10) with a yield of around 10 g L-1 and a critical micelle concentration (CMC) of 80 mg L-1 . P. aeruginosa W10 rhamnolipids were able to disrupt up to 99% of 48 h pre-formed biofilms of the Gram-positive organisms Bacillus licheniformis CAN55, Staphylococcus capitis SH6, and a mixed culture (strains CAN55, SH6, and W10), under static conditions, at concentrations of 0.1, 0.5, and 1 mg ml-1 on a stainless steel surface commonly used in industrial process pipelines. CFU measurements and LIVE/DEAD BacLight staining confirmed these observations. Furthermore, a purified di-rhamnolipid fraction was found to be responsible for the microbial inhibition of B. licheniformis strain CAN55. This study provides evidence that rhamnolipids may have valuable applications in preventing biofilms and biofouling in industrial plants and, in a wider context, may also apply to metal medical devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Genotyping of Pseudomonas aeruginosa strains isolated from burn patients by RAPD-PCR.

    Science.gov (United States)

    Nanvazadeh, Fatemeh; Khosravi, Azar Dokht; Zolfaghari, Mohammad Reza; Parhizgari, Najmeh

    2013-11-01

    Pseudomonas aeruginosa is one of the important causes of nosocomial infections that easily gains resistance to many antibiotics. This opportunistic pathogen is a major health hazard particularly in immunodeficient patients, patients in intensive care units (ICU) and burn units with life threatening outcome. The bacterium may be originated from different or common sources, and comprises a high colonization and transmission capacity. The aim of present study was to investigate the genotypic variation of Pseudomonas aeroginosa strains isolated from burn patients by using Random Amplified Polymorphic DNA (RAPD) method. Totally 70 clinical samples were collected from burn patients in Taleghani Burn Hospital of Ahvaz. Fifty out of total samples were positive for P. aeruginosa by application of conventional culture and biochemical identification tests. DNA was extracted from the isolates and the RAPD-PCR method was applied to the DNA extracts according to standard method using a short single primer of 272. The technique created repetitive electrophoresis patterns which was used for genotypic differentiation. RAPD-PCR, created 9 genotypic profiles designated as I-IX with base pair length ranging from 180 to 2700. Each genotype showed between 3 and 6 different weight DNA bands. Genotype I was the most prevalent, identified in 10 bacterial isolates (20%). Genotypes I, II and VI were mostly common in patients with more severe burn, and were mainly isolated from wound and blood samples obtained from the same patients. In present study, we found RAPD-PCR technique as a useful tool for investigation of the genetic variation among P. aeruginosa strains. This is a rapid, low cost, genotypic method with high discriminatory power. The results could assist to screen for the original of infection caused by this organism with subsequent control of colonization and transmission. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

  3. Regulation of GacA in Pseudomonas chlororaphis Strains Shows a Niche Specificity.

    Directory of Open Access Journals (Sweden)

    Jun Li

    Full Text Available The GacS/GacA two-component system plays a central role in the regulation of a broad range of biological functions in many bacteria. In the biocontrol organism Pseudomonas chlororaphis, the Gac system has been shown to positively control quorum sensing, biofilm formation, and phenazine production, but has an overall negative impact on motility. These studies have been performed with strains originated from the rhizosphere predominantly. To investigate the level of conservation between the GacA regulation of biocontrol-related traits in P. chlororaphis isolates from different habitats, the studies presented here focused on the endophytic isolate G5 of P. chlororaphis subsp. aurantiaca. A gacA mutant deficient in the production of N-acylhomoserine lactones (AHLs and phenazine was isolated through transposon mutagenesis. Further phenotypic characterization revealed that in strain G5, similar to other P. chlororaphis strains, a gacA mutation caused inability to produce biocontrol factors such as phenazine, HCN and proteases responsible for antifungal activity, but overproduced siderophores. LC-MS/MS analysis revealed that AHL production was also practically abolished in this mutant. However, the wild type exhibited an extremely diverse AHL pattern which has never been identified in P. chlororaphis. In contrast to other isolates of this organism, GacA in strain G5 was shown to negatively regulate biofilm formation and oxidative stress response whilst positively regulating cell motility and biosynthesis of indole-3-acetic acid (IAA. To gain a better understanding of the overall impact of GacA in G5, a comparative proteomic analysis was performed revealing that, in addition to some of the traits like phenazine mentioned above, GacA also negatively regulated lipopolysaccharide (LPS and trehalose biosynthesis whilst having a positive impact on energy metabolism, an effect not previously described in P. chlororaphis. Consequently, GacA regulation shows a

  4. Exploring the In Vitro Thrombolytic Activity of Nattokinase From a New Strain Pseudomonas aeruginosa CMSS.

    Science.gov (United States)

    Chandrasekaran, Subathra Devi; Vaithilingam, Mohanasrinivasan; Shanker, Ravi; Kumar, Sanjeev; Thiyur, Swathi; Babu, Vaishnavi; Selvakumar, Jemimah Naine; Prakash, Suyash

    2015-10-01

    Thrombolytic therapy has become a conventional treatment for acute myocardial infarction (AMI), yet currently, clinically prescribed thrombolytic drugs have problems such as delayed action and other side effects. Fibrinolytic enzymes have attracted interest as thrombolytic agents because of their efficiency in the fibrinolytic process, including plasmin activation. Nattokinase (NK) is a potent fibrinolytic agent for thrombosis therapy. The aim of this study was to enhance the production of NK from Pseudomonas aeruginosa CMSS by media optimization and strain improvement. In the present study, a potent NK-producing strain was isolated from cow milk and identified. To enhance the yield of NK, effect of various parameters such as pH, temperature, carbon source, nitrogen source and inoculum size were optimized. Strain improvement of P. aeruginosa CMSS was done by random UV-mutagenesis. Nattokinase was partially purified and the activity was determined by the casein digestion method, blood clot lysis and fibrin degradation assay. Based on morphological, biochemical and molecular characterization, the strain was confirmed as P. aeruginosa (GenBank accession number: JX112657), designated as P. aeruginosa CMSS. The optimum condition at pH 7 and temperature at 25˚C showed activity of NK as 1514 U mL(-1) and 1532 U mL(-1), respectively. Sucrose as the carbon source and shrimp shell powder (SSP) as the nitrogen source expressed NK activity of 1721 U mL(-1) and 2524 U mL(-1), respectively. At 1% inoculum size, the maximum rate of enzyme production was achieved with 2581 U mL(-1). The NK activity of the mutant strain UV60 was 4263 U mL(-1), indicating a two-fold increase in activity compared to the wild strain (2581 UmL(-1)). Nattokinase produced from mutant strain P. aeruginosa CMSS UV60 showed 94% blood clot lysis at ten minutes. The degradation of fibrin clot by the produced NK was observed after two hours of incubation. Sodium dodecyl sulfate polyacrylamide gel

  5. Ageing of atrazine in manure amended soils assessed by bioavailability to Pseudomonas sp. strain ADP

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Bælum, Jacob; Strobel, Bjarne W.

    2014-01-01

    Animal manure is applied to agricultural land in areas of high livestock production. In the present study, we evaluated ageing of atrazine in two topsoils with and without addition of manure and in one subsoil. Ageing was assessed as the bioavailability of atrazine to the atrazine mineralizing ba......-treated and untreated soil. The present study illustrates that not simply the organic carbon content influences adsorption and ageing of atrazine in soil but the origin and composition of organic matter plays an important role....... bacteria Pseudomonas sp. strain ADP. Throughout an ageing period of 90 days bioavailability was investigated at days 1, 10, 32, 60 and 90, where ~108 cells g−1 of the ADP strain was inoculated to the 14C-atrazine exposed soil and 14CO2 was collected over 7 days as a measure of mineralized atrazine. Even...... though the bioavailable residue decreased in all of the three soils as time proceeded, we found that ageing occurred faster in the topsoils rich in organic carbon than in subsoil. For one topsoil rich in organic carbon content, Simmelkær, we observed a higher degree of ageing when treated with manure...

  6. Australian epidemic strain pseudomonas (AES-1) declines further in a cohort segregated cystic fibrosis clinic.

    Science.gov (United States)

    Griffiths, Amanda L; Wurzel, Danielle F; Robinson, Phil J; Carzino, Rosemary; Massie, John

    2012-01-01

    To evaluate changes in prevalence of an epidemic strain of Pseudomonas aeruginosa (AES-1, Australian epidemic strain, type 1) in a paediatric cystic fibrosis (CF) centre practising cohort segregation, to describe the patients' clinical characteristics at acquisition and observe mortality rates. Cohort segregation was introduced in our paediatric CF clinic January 2000. The prevalence of AES-1 was analysed in 1999, 2002 and 2007. Age at acquisition, lung function, presence of bronchiectasis, hospitalisations, prior P. aeruginosa infection and mortality rates were collected. AES-1 infection was determined by pulse-field-gel-electrophoresis (PFGE) on airway specimen cultures taken three monthly. The prevalence of AES-1 declined from 21% in 1999 to 14% in 2002 (risk difference 7% (95% CI 1,13) p=0.0256) and to 6% in 2007 (risk difference 8% (95% CI 3,13) p=0.0018). New acquisitions after the introduction of cohort segregation were uncommon (10 by 2002 and another 7 by 2007) with a declining incidence of 3.3 cases/year (1999 to 2002) compared to 1.4 cases/year (2002 to 2007). Twenty-two of 32 (69%) deaths between 1999 and 2007 occurred in patients infected with AES-1. Cohort segregation has been associated with reductions in the prevalence of AES-1 in our CF clinic. Mortality was higher in patients infected with AES-1 than other organisms. Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  7. Thiamethoxam degradation by Pseudomonas and Bacillus strains isolated from agricultural soils.

    Science.gov (United States)

    Rana, Shivnam; Jindal, Vikas; Mandal, Kousik; Kaur, Gurpreet; Gupta, V K

    2015-05-01

    Twelve bacterial species were evaluated to know the degradation pattern of thiamethoxam in liquid medium. All the bacterial species could actively degrade phorate in a mineral salt medium containing phorate (50 μg ml(-1)) as sole carbon source. As these species have ability to degrade, we used these for the degradation of thiamethoxam--a neonicoitinoids. Screening of 12 active phorate-metabolizing bacterial species resulted in selection of Bacillus aeromonas strain IMBL 4.1 and Pseudomonas putida strain IMBL 5.2 causing 45.28 and 38.23 % thiamethoxam (50 μg ml(-1)) reduction, respectively, in 15 days as potential thiamethoxam degrading species. These two bacterial species grew optimally at 37 °C under shake culture conditions in MSMT medium raised with initial pH of 6.0-6.5 and use of these optimum cultural conditions resulted in improved thiamethoxam degradation by these bacterial species. These species caused maximum thiamethoxam degradation only in the presence of thiamethoxam as sole source of carbon and energy and the same was reduced in the presence of easily metabolize able carbon (C₀ and C₁) and nitrogen ((N₀, N₁ and N₂) sources. This could be attributed to involvement of repressible metabolic pathways, reactions of which are inhibited by the presence of easily available nutrients for growth. Besides above, qualitative analysis of thiamethoxam residues by gas liquid chromatography revealed complete metabolization of thiamethoxam without detectable accumulation of any known thiamethoxam metabolites.

  8. Phosphatidylcholine affects the secretion of the alkaline phosphatase PhoA in Pseudomonas strains.

    Science.gov (United States)

    Liu, Xin; Long, Deliang; You, Heng; Yang, Dingpeng; Zhou, Shuang; Zhang, Shuting; Li, Mengqiu; He, Miao; Xiong, Min; Wang, Xingguo

    2016-11-01

    Pseudomonas aeruginosa ATCC 27853 and Pseudomonas sp. 593 use the phosphatidylcholine synthase pathway (Pcs-pathway) for the biosynthesis of phosphatidylcholine (PC). Both bacterial strains contain the phoA and lapA genes encoding alkaline phosphatases (ALP) and display strong ALP activities. The PhoA and LapA enzymes are thought to be independently secreted via the Xcp and Hxc type II secretion system (T2SS) subtypes, in which the Hxc system may act as a complementary mechanism when the Xcp pathway becomes limiting. Inactivation of the pcs gene in both bacteria abolished PC synthesis and resulted in approximately 50% less ALP activity in the cell-free culture. Analysis by western blotting showed that LapA protein content in the wild type and the pcs- mutant was unchanged in the cytoplasmic, periplasmic or extracellular protein fractions. In contrast, the PhoA protein in the pcs- mutant was less prevalent among extracellular proteins but was more abundant in the periplasmic protein fraction compared to the wild type. Semi- quantitative reverse transcriptase PCR showed that phoA, lapA and 12 xcp genes were equally expressed at the transcriptional level in both the wild types and the pcs- mutants. Our results demonstrate that the absence of PC in bacterial membrane phospholipids does not interfere with the transcription of the phoA and lapA genes but primarily affects the export of PhoA from the cytoplasm to the extracellular environment via the Xcp T2SS. Copyright © 2016 Elsevier GmbH. All rights reserved.

  9. Impact on Arbuscular Mycorrhiza Formation of Pseudomonas Strains Used as Inoculants for Biocontrol of Soil-Borne Fungal Plant Pathogens

    Science.gov (United States)

    Barea, J. M.; Andrade, G.; Bianciotto, V.; Dowling, D.; Lohrke, S.; Bonfante, P.; O’Gara, F.; Azcon-Aguilar, C.

    1998-01-01

    The arbuscular mycorrhizal symbiosis, a key component of agroecosystems, was assayed as a rhizosphere biosensor for evaluation of the impact of certain antifungal Pseudomonas inoculants used to control soil-borne plant pathogens. The following three Pseudomonas strains were tested: wild-type strain F113, which produces the antifungal compound 2,4-diacetylphloroglucinol (DAPG); strain F113G22, a DAPG-negative mutant of F113; and strain F113(pCU203), a DAPG overproducer. Wild-type strain F113 and mutant strain F113G22 stimulated both mycelial development from Glomus mosseae spores germinating in soil and tomato root colonization. Strain F113(pCU203) did not adversely affect G. mosseae performance. Mycelial development, but not spore germination, is sensitive to 10 μM DAPG, a concentration that might be present in the rhizosphere. The results of scanning electron and confocal microscopy demonstrated that strain F113 and its derivatives adhered to G. mosseae spores independent of the ability to produce DAPG. PMID:9603857

  10. Selection of a new Pseudomonas chlororaphis strain for the biological control of Fusarium oxysporum f. sp. radicis-lycopersici

    Directory of Open Access Journals (Sweden)

    Gerardo PUOPOLO

    2011-09-01

    Full Text Available Fluorescent pseudomonads possess several physiological characteristics exploitable for the biological control of phytopathogenic fungi. A group of 11 pseudomonads able to inhibit tomato pathogenic fungi in vitro were identified using the Biolog test and the phylogenetic analysis of recA. Strain M71 of Pseudomonas chlororaphis was selected as a new potential biocontrol agent. This strain drastically reduced Fusarium oxysporum f. sp. radicis-lycopersici pathogenicity on tomato plantlets in seed assays and greenhouse trials. Moreover, the strain produced several important secondary metabolites, including proteases, siderophores and antibiotics. The presence of a region involved in phenazine production and the biosynthesis of N-acyl homoserine lactones were also assessed.

  11. Isolation of a strain of Pseudomonas putida capable of metabolizing anionic detergent sodium dodecyl sulfate (SDS).

    Science.gov (United States)

    Chaturvedi, V; Kumar, A

    2011-03-01

    Sodium Dodecyl Sulfate (SDS) is one of the most widely used anionic detergents. The present study deals with isolation and identification of SDS-degrading bacteria from a detergent contaminated pond situated in Varanasi city, India. Employing enrichment technique in minimal medium (PBM), SDS-degrading bacteria were isolated from pond water sample. Rate of degradation of SDS was studied in liquid PBM and also degradation of different concentrations of SDS was also studied to find out maximum concentration of SDS degraded by the potent isolates. Alkyl sulfatase activity (key enzyme in SDS degradation) was estimated in crude cell extracts and multiplicity of alkyl sulfatase was studied by Native PAGE Zymography. The potent isolate was identified by 16S rRNA sequence analysis. Using enrichment technique in minimal medium containing SDS as a sole carbon source, initially three SDS degrading isolates were recovered. However, only one isolate, SP3, was found to be an efficient degrader of SDS. It was observed that this strain could completely metabolize 0.1% SDS in 16 h, 0.2% SDS in 20 h and 0.3% SDS in 24 h of incubation. Specific activity of alkyl sulfatase was 0.087±0.004 µmol SDS/mg protein/min and Native PAGE Zymography showed presence of alkyl sulfatase of Rf value of 0.21. This isolate was identified as Pseudomonas putida strain SP3. This is the report of isolation of SDS-degrading strain of P. putida, which shows high rate of SDS degradation and can degrade up to 0.3% SDS. It appears that this isolate can be exploited for bioremediation of this detergent from water systems.

  12. The Survey of Withani somnifera Extraction against Resistant Strains of Pseudomonas aeruginosa Bacteria to Selective Antibiotics

    Directory of Open Access Journals (Sweden)

    Mohammad Bokaeian

    2015-11-01

    Full Text Available Introduction:  Due  to  more  resistance  of  pathogenic  bacteria  to  new  and  current antibiotics  researchers  are  looking  to  find  the  agents  of  herbal  with  antimicrobial activities in order to replace chemical drugs.Methods:   The herbal extract of Withani somnifera was done by using a rotary vacuum,20 strains of Pseudomons aeruginosa were isolated from urinary infections hospitalized patients  in  city of Zabol  hospital.  The  MIC  Withani  somnifera  were  determined  by dilution method in various concentrations. Sensitivity of strains to multiple antibiotics was evaluated by standard disk diffusion Kirby-Bauer.Results:    The  result  showed  that  P.  aeruginosa  were  resistance  to  4  of the  agents including ampicillin  (85%, nitrofurantoin  (65%, nalidixic acid  (65%, ciprofloxacin (15% and for 5 strains of Pseudomonas showed MIC with activity of 100 ppm.Conclusion:   This  study  has  suggested  the  effect  of  winter  cherry  extract  on  P. aeruginosa in the in vitro assay. It s effectiveness of on in vivo system can be examined in future.

  13. Lethality and developmental delay in Drosophila melanogaster larvae after ingestion of selected Pseudomonas fluorescens strains.

    Directory of Open Access Journals (Sweden)

    Marika H Olcott

    2010-09-01

    Full Text Available The fruit fly, Drosophila melanogaster, is a well-established model organism for probing the molecular and cellular basis of physiological and immune system responses of adults or late stage larvae to bacterial challenge. However, very little is known about the consequences of bacterial infections that occur in earlier stages of development. We have infected mid-second instar larvae with strains of Pseudomonas fluorescens to determine how infection alters the ability of larvae to survive and complete development.We mimicked natural routes of infection using a non-invasive feeding procedure to study the toxicity of the three sequenced P. fluorescens strains (Pf0-1, SBW25, and Pf-5 to Drosophila melanogaster. Larvae fed with the three strains of P. fluorescens showed distinct differences in developmental trajectory and survival. Treatment with SBW25 caused a subset of insects to die concomitant with a systemic melanization reaction at larval, pupal or adult stages. Larvae fed with Pf-5 died in a dose-dependent manner with adult survivors showing eye and wing morphological defects. In addition, larvae in the Pf-5 treatment groups showed a dose-dependent delay in the onset of metamorphosis relative to control-, Pf0-1-, and SBW25-treated larvae. A functional gacA gene is required for the toxic properties of wild-type Pf-5 bacteria.These experiments are the first to demonstrate that ingestion of P. fluorescens bacteria by D. melanogaster larvae causes both lethal and non-lethal phenotypes, including delay in the onset of metamorphosis and morphological defects in surviving adult flies, which can be decoupled.

  14. Isolation and Characterization of Pseudomonas spp. Strains That Efficiently Decompose Sodium Dodecyl Sulfate

    Directory of Open Access Journals (Sweden)

    Ewa M. Furmanczyk

    2017-11-01

    Full Text Available Due to their particular properties, detergents are widely used in household cleaning products, cosmetics, pharmaceuticals, and in agriculture as adjuvants tailoring the features of pesticides or other crop protection agents. The continuously growing use of these various products means that water soluble detergents have become one of the most problematic groups of pollutants for the aquatic and terrestrial environments. Thus it is important to identify bacteria having the ability to survive in the presence of large quantities of detergent and efficiently decompose it to non-surface active compounds. In this study, we used peaty soil sampled from a surface flow constructed wetland in a wastewater treatment plant to isolate bacteria that degrade sodium dodecyl sulfate (SDS. We identified and initially characterized 36 Pseudomonas spp. strains that varied significantly in their ability to use SDS as their sole carbon source. Five isolates having the closest taxonomic relationship to the Pseudomonas jessenii subgroup appeared to be the most efficient SDS degraders, decomposing from 80 to 100% of the SDS present in an initial concentration 1 g/L in less than 24 h. These isolates exhibited significant differences in degree of SDS degradation, their resistance to high detergent concentration (ranging from 2.5 g/L up to 10 g/L or higher, and in chemotaxis toward SDS on a plate test. Mass spectrometry revealed several SDS degradation products, 1-dodecanol being dominant; however, traces of dodecanal, 2-dodecanol, and 3-dodecanol were also observed, but no dodecanoic acid. Native polyacrylamide gel electrophoresis zymography revealed that all of the selected isolates possessed alkylsulfatase-like activity. Three isolates, AP3_10, AP3_20, and AP3_22, showed a single band on native PAGE zymography, that could be the result of alkylsulfatase activity, whereas for isolates AP3_16 and AP3_19 two bands were observed. Moreover, the AP3_22 strain exhibited a band

  15. Global transcriptional response of solvent-sensitive and solvent-tolerant Pseudomonas putida strains exposed to toluene.

    Science.gov (United States)

    Molina-Santiago, Carlos; Udaondo, Zulema; Gómez-Lozano, María; Molin, Soren; Ramos, Juan-Luis

    2017-02-01

    Pseudomonas putida strains are generally recognized as solvent tolerant, exhibiting varied sensitivity to organic solvents. Pan-genome analysis has revealed that 30% of genes belong to the core-genome of Pseudomonas. Accessory and unique genes confer high degree of adaptability and capabilities for the degradation and synthesis of a wide range of chemicals. For the use of these microbes in bioremediation and biocatalysis, it is critical to understand the mechanisms underlying these phenotypic differences. In this study, RNA-seq analysis compared the short- and long-term responses of the toluene-sensitive KT2440 strain and the highly tolerant DOT-T1E strain. The sensitive strain activates a larger number of genes in a higher magnitude than DOT-T1E. This is expected because KT2440 bears one toluene tolerant pump, while DOT-T1E encodes three of these pumps. Both strains activate membrane modifications to reduce toluene membrane permeability. The KT2440 strain activates the TCA cycle to generate energy, while avoiding energy-intensive processes such as flagellar biosynthesis. This suggests that KT2440 responds to toluene by focusing on survival mechanisms. The DOT-T1E strain activates toluene degradation pathways, using toluene as source of energy. Among the unique genes encoded by DOT-T1E is a 70 kb island composed of genes of unknown function induced in response to toluene. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  16. Nitrogen Source Stabilization of Quorum Sensing in the Pseudomonas aeruginosa Bioaugmentation Strain SD-1.

    Science.gov (United States)

    Wang, Mei-Zhen; Lai, Bai-Min; Dandekar, Ajai A; Yang, Yu-Sheng; Li, Na; Yin, Jun; Shen, Dong-Sheng

    2017-08-15

    Pseudomonas aeruginosa SD-1 is efficient at degrading aromatic compounds and can therefore contribute to the bioremediation of wastewater. P. aeruginosa uses quorum sensing (QS) to regulate the production of numerous secreted "public goods." In wastewater bioaugmentation applications, there are myriad nitrogen sources, and we queried whether various nitrogen sources impact the stabilities of both QS and the bacterial populations. In a laboratory strain of P. aeruginosa, PAO1, the absence of a nitrogen source has been shown to destabilize these populations through the emergence of QS mutant "cheaters." We tested the ability of SD-1 to grow in casein broth, a condition that requires QS for growth, when the nitrogen source with either NH4Cl, NaNO3, or NaNO2 or with no added nitrogen source. There was great variability in susceptibility to invasion by QS mutant cheaters and, by extension, the stability of the SD-1 population. When grown with NH4Cl as an extra nitrogen source, no population collapse was observed; by contrast, two-thirds of cultures grown in the presence of NaNO2 collapsed. In the populations that collapsed, the frequency of social cheaters exceeded 40%. NaNO3 and NaNO2 directly favor QS mutants of P. aeruginosa SD-1. Although the mechanism by which these nitrogen sources act is not clear, these data indicate that the metabolism of nitrogen can affect the stability of bacterial populations, an important observation for continuing industrial applications with this species.IMPORTANCE Bioaugmentation as a method to help remediate wastewater pollutant streams holds significant potential to enhance traditional methods of treatment. Addition of microbes that can catabolize organic pollutants can be an effective method to remove several toxic compounds. Such bioaugmented strains of bacteria have been shown to be susceptible to competition from the microbiota that are present in wastewater streams, limiting their potential effectiveness. Here, we show that

  17. 13C-NMR studies of acetate and methanol metabolism by methylotrophic Pseudomonas strains.

    Science.gov (United States)

    Narbad, A; Hewlins, M J; Callely, A G

    1989-06-01

    The metabolism of [2-13C]acetate by Pseudomonas M27(Icl-) and Pseudomonas MA(Icl+) was studied in vivo using 13C-NMR spectroscopy. The flux of 13C-label into bicarbonate, glutamate and citrate was observed in both organisms. In addition 13C-labelled alpha, alpha-trehalose was synthesized as a major metabolite by Pseudomonas M27 but not by Pseudomonas MA. The presence of this disaccharide in cell extracts of Pseudomonas AM1(Icl-) grown with [13C]methanol was also observed. The data from analysis of the trehalose multiplet signal observed in the spectra of Pseudomonas M27 cell extracts were consistent with the absence of the glyoxylate cycle in this methylotroph.

  18. Oxidation of gasoline oxygenates by closely related non-haem-iron alkane hydroxylases in Pseudomonas mendocina KR1 and other n-octane-utilizing Pseudomonas strains.

    Science.gov (United States)

    Smith, Christy A; Hyman, Michael R

    2010-06-01

    Pseudomonas mendocina KR1 oxidizes the gasoline oxygenate methyl tertiary butyl ether (MTBE) to tertiary butyl alcohol (TBA) during growth on C5 -C8 n-alkanes. We have further explored oxidation of ether oxygenates by this strain to help identify the enzyme that catalyses these reactions. High levels of MTBE-oxidizing activity occurred in resting cells grown on C5 -C8 n-alkanes. Lower activities occurred in cells grown on longer-chain n-alkanes (C9 -C11 ) and 1°-alcohols (C5 -C10 ). N-octane-grown cells also oxidized tertiary amyl methyl ether (TAME) to tertiary amyl alcohol (TAA), but did not oxidize ethyl tertiary butyl ether (ETBE), TBA or TAA. A 39 kDa polypeptide in whole cell extracts of n-octane-grown cells strongly cross-reacted with an anti-AlkB polyclonal antiserum in an SDS-PAGE/immunoblot. This polypeptide was absent or less abundant in cells grown on dextrose, dextrose plus dicyclopropylketone or 1-octanol. N-octane-grown cells of Pseudomonas aeruginosa strains KSLA-473 and ATCC 17423 oxidized MTBE and TAME but not ETBE. N-hexadecane-grown cells of these strains and strain PAO1 did not oxidize any of the oxygenates tested. Our results indicate ether oxygenate-degrading activity in alkane-utilizing pseudomonads is consistently observed with close homologues of the GPo1 non-haem-iron alkane hydroxylases but is otherwise not a consistent catalytic feature of these diverse enzymes. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  19. Toluene and ethylbenzene oxidation by purified naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4.

    Science.gov (United States)

    Lee, K; Gibson, D T

    1996-01-01

    Purified naphthalene dioxygenase (NDO) from Pseudomonas sp. strain NCIB 9816-4 oxidized toluene to benzyl alcohol and benzaldehyde by reactions involving benzylic monooxygenation and dioxygen-dependent alcohol oxidation, respectively. Xylene and nitrotoluene isomers were also oxidized to substituted benzyl alcohol and benzaldehyde derivatives. NDO oxidized ethylbenzene sequentially through (S)-1-phenethyl alcohol (77% enantiomeric excess) and acetophenone to 2-hydroxyacetophenone. In addition, NDO also oxidized ethylbenzene through styrene to (R)-1-phenyl-1,2-ethanediol (74% enantiomeric excess) by reactions involving desaturation and dihydroxylation, respectively. Isotope experiments with 18O2, H2 18O, and D2O suggest that 1-phenethyl alcohol is oxidized to acetophenone by a minor reaction involving desaturation followed by tautomerization. The major reaction in the conversion of 1-phenethyl alcohol and benzyl alcohol to acetophenone and benzaldehyde, respectively, probably involves monohydroxylation to form a gem-diol intermediate which stereospecifically loses the incoming hydroxyl group to leave the carbonyl product. These results are compared with similar reactions catalyzed by cytochrome P-450. PMID:8795196

  20. Daya Tahan Hidup Pseudomonas putida Strain Pf-20 dalam Beberapa Macam Inokulum

    Directory of Open Access Journals (Sweden)

    Yenny Wuryandari

    2004-07-01

    Full Text Available For any crop-protection agent, an efficient formulation is a necessity to translate laboratory activity into adequate field performance. There are particular challenges to be faced in formulation of biological control agents, because the active ingredient is a living organism that must be kept relatively immobile and inactive while in storage, but quickly resume its  normal metabolic processes once applied to the target site. The objective of the research was  to study survival of Pseudomonas putida strain Pf-20 in various formulations at the storage  time and germination. The twelve formulations include carriers, additives and concentration  of Pf-20. The efficacy of various formulation in maintaining the population of Pf-20 in storage was assessed. The research result showed that population of Pf 20  in the formulation  number seven was the highest, with the combination peat+talc, CMC+arginin and  concentration of Pf[20 10^10 CFU/ml. In peat+talc, CMC+arginin, Pf-20 10^10  CFU/ml based formulation the bacteria survived even up to 84 days of storage although the population declined. In all formulations, population of Pf-20 increased at the time of seed germination. At the time of seed germination, formulation number seven was the highest too.

  1. Enhancement of Rhamnolipid Production in Residual Soybean Oil by an Isolated Strain of Pseudomonas aeruginosa

    Science.gov (United States)

    de Lima, C. J. B.; França, F. P.; Sérvulo, E. F. C.; Resende, M. M.; Cardoso, V. L.

    In the present work, the production of rhamnolipid from residual soybean oil (RSO) from food frying facilities was studied using a strain of Pseudomonas aeruginosa of contaminated lagoon, isolated from a hydrocarbon contaminated soil. The optimization of RSO, amonium nitrate, and brewery residual yeast concentrations was accomplished by a central composite experimental design and surface response analysis. The experiments were performed in 500-mL Erlenmeyer flasks containing 50mL of mineral medium, at 170 rpm and 30±1°C, for a 48-h fermentation period. Rhamnolipid production has been monitored by measurements of surface tension, rhamnose concentration, and emulsifying activity. The best-planned results, located on the central point, have corresponded to 22g/L of RSO, 5.625 g/ L of NH4NO3' and 11.5 g/L of brewery yeast. At the maximum point the values for rhamnose and emulsifying index were 2.2g/L and 100%, respectively.

  2. Toluene and ethylbenzene oxidation by purified naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4.

    Science.gov (United States)

    Lee, K; Gibson, D T

    1996-09-01

    Purified naphthalene dioxygenase (NDO) from Pseudomonas sp. strain NCIB 9816-4 oxidized toluene to benzyl alcohol and benzaldehyde by reactions involving benzylic monooxygenation and dioxygen-dependent alcohol oxidation, respectively. Xylene and nitrotoluene isomers were also oxidized to substituted benzyl alcohol and benzaldehyde derivatives. NDO oxidized ethylbenzene sequentially through (S)-1-phenethyl alcohol (77% enantiomeric excess) and acetophenone to 2-hydroxyacetophenone. In addition, NDO also oxidized ethylbenzene through styrene to (R)-1-phenyl-1,2-ethanediol (74% enantiomeric excess) by reactions involving desaturation and dihydroxylation, respectively. Isotope experiments with 18O2, H2 18O, and D2O suggest that 1-phenethyl alcohol is oxidized to acetophenone by a minor reaction involving desaturation followed by tautomerization. The major reaction in the conversion of 1-phenethyl alcohol and benzyl alcohol to acetophenone and benzaldehyde, respectively, probably involves monohydroxylation to form a gem-diol intermediate which stereospecifically loses the incoming hydroxyl group to leave the carbonyl product. These results are compared with similar reactions catalyzed by cytochrome P-450.

  3. Metabolic functions of Pseudomonas fluorescens strains from Populus deltoides depend on rhizosphere or endosphere isolation compartment.

    Science.gov (United States)

    Timm, Collin M; Campbell, Alisha G; Utturkar, Sagar M; Jun, Se-Ran; Parales, Rebecca E; Tan, Watumesa A; Robeson, Michael S; Lu, Tse-Yuan S; Jawdy, Sara; Brown, Steven D; Ussery, David W; Schadt, Christopher W; Tuskan, Gerald A; Doktycz, Mitchel J; Weston, David J; Pelletier, Dale A

    2015-01-01

    The bacterial microbiota of plants is diverse, with 1000s of operational taxonomic units (OTUs) associated with any individual plant. In this work, we used phenotypic analysis, comparative genomics, and metabolic models to investigate the differences between 19 sequenced Pseudomonas fluorescens strains. These isolates represent a single OTU and were collected from the rhizosphere and endosphere of Populus deltoides. While no traits were exclusive to either endosphere or rhizosphere P. fluorescens isolates, multiple pathways relevant for plant-bacterial interactions are enriched in endosphere isolate genomes. Further, growth phenotypes such as phosphate solubilization, protease activity, denitrification and root growth promotion are biased toward endosphere isolates. Endosphere isolates have significantly more metabolic pathways for plant signaling compounds and an increased metabolic range that includes utilization of energy rich nucleotides and sugars, consistent with endosphere colonization. Rhizosphere P. fluorescens have fewer pathways representative of plant-bacterial interactions but show metabolic bias toward chemical substrates often found in root exudates. This work reveals the diverse functions that may contribute to colonization of the endosphere by bacteria and are enriched among closely related isolates.

  4. Metabolic functions of Pseudomonas fluorescens strains from Populus deltoides depend on rhizosphere or endosphere isolation compartment

    Directory of Open Access Journals (Sweden)

    Collin M Timm

    2015-10-01

    Full Text Available The bacterial microbiota of plants is diverse, with 1,000s of operational taxonomic units (OTUs associated with any individual plant. In this work we investigate the differences between 19 sequenced Pseudomonas fluorescens strains, isolated from Populus deltoides rhizosphere and endosphere and which represent a single OTU, using phenotypic analysis, comparative genomics, and metabolic models. While no traits were exclusive to either endosphere or rhizosphere P. fluorescens isolates, multiple pathways relevant for plant-bacterial interactions are enriched in endosphere isolate genomes. Further, growth phenotypes such as phosphate solubilization, protease activity, denitrification and root growth promotion are biased towards endosphere isolates. Endosphere isolates have significantly more metabolic pathways for plant signaling compounds and an increased metabolic range that includes utilization of energy rich nucleotides and sugars, consistent with endosphere colonization. Rhizosphere P. fluorescens have fewer pathways representative of plant-bacterial interactions but show metabolic bias towards chemical substrates often found in root exudates. This work reveals the diverse functions that may contribute to colonization of the endosphere by bacteria and are enriched among closely related isolates.

  5. Mechanism of biosynthesis of unsaturated fatty acids in Pseudomonas sp. strain E-3, a psychrotrophic bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Wada, M.; Fukunaga, N.; Sasaki, S. (Hokkaido Univ., Sapporo (Japan))

    1989-08-01

    Biosynthesis of palmitic, palmitoleic, and cis-vaccenic acids in Pseudomonas sp. strain E-3 was investigated with in vitro and in vivo systems. (1-{sup 14}C)palmitic acid was aerobically converted to palmitoleate and cis-vaccenate, and the radioactivities on their carboxyl carbons were 100 and 43%, respectively, of the total radioactivity in the fatty acids. Palmitoyl coenzyme A desaturase activity was found in the membrane fraction. (1-{sup 14}C)stearic acid was converted to octadecenoate and C16 fatty acids. The octadecenoate contained oleate and cis-vaccenate, but only oleate was produced in the presence of cerulenin. (1-{sup 14}C)lauric acid was aerobically converted to palmitate, palmitoleate, and cis-vaccenate. Under anaerobic conditions, palmitate (62%), palmitoleate (4%), and cis-vaccenate (34%) were produced from (1-{sup 14}C)acetic acid, while they amounted to 48, 39, and 14%, respectively, under aerobic conditions. In these incorporation experiments, 3 to 19% of the added radioactivity was detected in released {sup 14}CO{sub 2}, indicating that part of the added fatty acids were oxidatively decomposed. Partially purified fatty acid synthetase produced saturated and unsaturated fatty acids with chain lengths of C10 to C18. These results indicated that both aerobic and anaerobic mechanisms for the synthesis of unsaturated fatty acid are operating in this bacterium.

  6. Molecular characterization of carbapenem-resistant Pseudomonas aeruginosa strains isolated from patients with urinary tract infections in Southern Poland.

    Science.gov (United States)

    Pobiega, Monika; Maciąg, Joanna; Chmielarczyk, Agnieszka; Romaniszyn, Dorota; Pomorska-Wesolowska, Monika; Ziolkowski, Grzegorz; Heczko, Piotr B; Bulanda, Malgorzata; Wojkowska-Mach, Jadwiga

    2015-11-01

    Due to the clinical threat posed by multidrug-resistant (MDR) Pseudomonas aeruginosa and importance of virulence factors produced in infection, 21 carbapenem-resistant P. aeruginosa were analyzed. 42.8% metallo-beta-lactamases-positive strains were identified. 85.7% of strains were meropenem resistant. 14.2% of strains were MDR; 38%, extensively drug-resistant (XDR). ExoY was present in all strains; exoT, in 95.2%; exoS, in 90.5%; exoU, in 47.6%. Eight XDR strains were typed using multilocus sequence typing: 4 as ST235, 2 as ST260, 2 as ST654 and ST234. MDR P. aeruginosa were isolated from hospitalized patients and among those from the community. Our study demonstrates the serious clinical issues posed by MDR P. aeruginosa and underscores the need for new treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Complete genome of Pseudomonas sp. strain L10.10, a psychrotolerant biofertilizer that could promote plant growth.

    Science.gov (United States)

    See-Too, Wah Seng; Lim, Yan-Lue; Ee, Robson; Convey, Peter; Pearce, David A; Yin, Wai-Fong; Chan, Kok Gan

    2016-03-20

    Pseudomonas sp. strain L10.10 (=DSM 101070) is a psychrotolerant bacterium which was isolated from Lagoon Island, Antarctica. Analysis of its complete genome sequence indicates its possible role as a plant-growth promoting bacterium, including nitrogen-fixing ability and indole acetic acid (IAA)-producing trait, with additional suggestion of plant disease prevention attributes via hydrogen cyanide production. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Conjugal transfer of R68.45 and FP5 between Pseudomonas aeruginosa strains in a freshwater environment.

    OpenAIRE

    O'Morchoe, S B; Ogunseitan, O; Sayler, G S; Miller, R V

    1988-01-01

    Recent concern over the release of genetically engineered organisms has resulted in a need for information about the potential for gene transfer in the environment. In this study, the conjugal transfer in Pseudomonas aeruginosa of the plasmids R68.45 and FP5 was demonstrated in the freshwater environment of Fort Loudoun Resevoir, Knoxville, Tenn. When genetically well defined plasmid donor and recipient strains were introduced into test chambers suspended in Fort Loudoun Lake, transfer of bot...

  9. Draft Genome Sequence of Pseudomonas mediterranea Strain CFBP 5447T, a Producer of Filmable Medium-Chain-Length Polyhydroxyalkanoates.

    Science.gov (United States)

    Licciardello, G; Bella, P; Devescovi, G; Strano, C P; Sarris, P F; Catara, A F; Venturi, V; Catara, V

    2014-12-24

    Pseudomonas mediterranea strain CFBP 5447(T) is a phytopathogenic bacterium isolated from tomato plants affected by pith necrosis disease. Moreover, its ability to produce medium-chain-length polyhydroxyalkanoates (mcl-PHAs) in culture from different carbon sources and valuable microbial products, such as cyclic lipopeptides, has been well documented. Here, we report the first draft genome sequence of this species. Copyright © 2014 Licciardello et al.

  10. Pseudomonas aeruginosa mucoid strain 8830 binds glycans containing the sialyl-Lewis x epitope.

    Science.gov (United States)

    Xia, Baoyun; Sachdev, Goverdhan P; Cummings, Richard D

    2007-01-01

    Pseudomonas aeruginosa infection of patients with cystic fibrosis (CF) is a leading cause of their morbidity and mortality. Pathogenesis is initiated in part by molecular interactions of P. aeruginosa with carbohydrate residues in airway mucins that accumulate in the lungs of patients with this disease. To explore the nature of the glycans recognized by a stable, mucoid, alginate-producing strain P. aeruginosa 8830 we generated a genetically modified Pa8830 expressing green fluorescent protein (Pa3380-GFP). We tested its binding to a panel of glycolipids and neoglycolipids in which selected glycans were covalently attached to dipalmitoyl phosphatidylethanolamine and analyzed on silica gel surfaces. Among all glycans tested, Pa8830-GFP bound best to sialyl-Le(x)-containing glycan NeuAc(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc-R and bound weakly to H-type blood group Fucalpha1-2Galbeta1-4GlcNAc-R, sialyl-lactose, and Le(x), and exhibited little binding toward non-fucosylated derivatives. Interestingly, while Pa8830-GFP bound to the glycosphingolipid asialoGM1, it did not appear to bind to a wide variety of other glycosphingolipids including GM1, GM2, asialoGM2, and sulfatide. These results indicate that P. aeruginosa 8830 has preferential binding to sialyl-Le(x)-containing glycans and has weak recognition of related fucose- and sialic acid-containing glycans. The finding that Pa8830 binds sialyl-Le(x)-containing glycans, which occur at increased levels in mucins from CF patients, is consistent with studies of other strains of P. aeruginosa and further suggests that such glycans on CF mucins contribute to disease pathogenesis.

  11. 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.

  12. Draft genome sequences of eight bacteria isolated from the indoor environment: Staphylococcus capitis strain H36, S. capitis strain H65, S. cohnii strain H62, S. hominis strain H69, Microbacterium sp. strain H83, Mycobacterium iranicum strain H39, Plantibacter sp. strain H53, and Pseudomonas oryzihabitans strain H72.

    Science.gov (United States)

    Lymperopoulou, Despoina S; Coil, David A; Schichnes, Denise; Lindow, Steven E; Jospin, Guillaume; Eisen, Jonathan A; Adams, Rachel I

    2017-01-01

    We report here the draft genome sequences of eight bacterial strains of the genera Staphylococcus, Microbacterium, Mycobacterium, Plantibacter, and Pseudomonas. These isolates were obtained from aerosol sampling of bathrooms of five residences in the San Francisco Bay area. Taxonomic classifications as well as the genome sequence and gene annotation of the isolates are described. As part of the "Built Environment Reference Genome" project, these isolates and associated genome data provide valuable resources for studying the microbiology of the built environment.

  13. Characterization and Genome Analysis of a Nicotine and Nicotinic Acid-Degrading Strain Pseudomonas putida JQ581 Isolated from Marine

    Directory of Open Access Journals (Sweden)

    Aiwen Li

    2017-05-01

    Full Text Available The presence of nicotine and nicotinic acid (NA in the marine environment has caused great harm to human health and the natural environment. Therefore, there is an urgent need to use efficient and economical methods to remove such pollutants from the environment. In this study, a nicotine and NA-degrading bacterium—strain JQ581—was isolated from sediment from the East China Sea and identified as a member of Pseudomonas putida based on morphology, physio-biochemical characteristics, and 16S rDNA gene analysis. The relationship between growth and nicotine/NA degradation suggested that strain JQ581 was a good candidate for applications in the bioaugmentation treatment of nicotine/NA contamination. The degradation intermediates of nicotine are pseudooxynicotine (PN and 3-succinoyl-pyridine (SP based on UV, high performance liquid chromatography, and liquid chromatography-mass spectrometry analyses. However, 6-hydroxy-3-succinoyl-pyridine (HSP was not detected. NA degradation intermediates were identified as 6-hydroxynicotinic acid (6HNA. The whole genome of strain JQ581 was sequenced and analyzed. Genome sequence analysis revealed that strain JQ581 contained the gene clusters for nicotine and NA degradation. This is the first report where a marine-derived Pseudomonas strain had the ability to degrade nicotine and NA simultaneously.

  14. Phytohormone Production by Strains of Pantoea agglomerans from Knots on Olive Plants Caused by Pseudomonas savastanoi pv. savastanoi

    Directory of Open Access Journals (Sweden)

    A. Cimmino

    2006-12-01

    Full Text Available Pantoea agglomerans is a common epiphyte of many plant species, and it is associated with Pseudomonas savastanoi pv. savastanoi in young and apparently intact olive knots. Strains of P. agglomerans collected from various olive groves in central Italy were studied for their ability to accumulate plant growth substances in culture. All the strains produced indole-3-aldehyde, indole-3-ethanol and indole-3-acetic acid (IAA, this last compound in amounts (average 8.7 mg l-1 comparable to those produced in vitro by virulent strains of P. savastanoi. None of the olive strains produced cytokinins. It is suggested that the IAA produced by P. agglomerans may increase the size of the knots caused on olive by P. savastanoi.

  15. A Pseudomonas aeruginosa strain isolated from a contact lens-induced acute red eye (CLARE) is protease-deficient.

    Science.gov (United States)

    Estrellas, P S; Alionte, L G; Hobden, J A

    2000-03-01

    Pseudomonas aeruginosa proteases are thought to be important virulence factors in the pathogenesis of corneal disease. This study examined protease production from two strains of P. aeruginosa responsible for two very distinct clinical diseases: strain Paer1, isolated from a Contact Lens-induced Acute Red Eye (CLARE), and strain KEI 1025, isolated from a corneal ulcer. Strains were compared to a laboratory strain (ATCC 19660) known to produce severe keratitis in experimentally infected mice for protease production and for ocular virulence. Protease production was examined with colorimetric assays, gelatin zymography and western blots. Elastase A activity was quantitated with a staphylolytic assay. Ocular virulence was examined using a mouse scratch model of keratitis. In contrast to strains KEI 1025 or ATCC 19660, Paer1 was unable to produce enzymatically active elastase A, elastase, and protease IV. All three strains produced active alkaline protease. Strains KEI 1025 and ATCC 19660 produced a fulminant keratitis in mice whereas Paer1 produced a mild transient infection. Restoration of elastase activity in Paer1 via genetic complementation did not result in a virulent phenotype. Co-infection of mouse eyes with strains Paer1 and ATCC 19660 resulted in the eventual loss of Paer1 from corneal tissue. These studies suggest that P. aeruginosa elastase A and/or protease IV, but not alkaline protease or elastase, contribute to the ocular virulence of this organism.

  16. Phenotypic characterization of an international Pseudomonas aeruginosa reference panel: strains of cystic fibrosis (CF) origin show less in vivo virulence than non-CF strains.

    Science.gov (United States)

    Cullen, Louise; Weiser, Rebecca; Olszak, Tomasz; Maldonado, Rita F; Moreira, Ana S; Slachmuylders, Lisa; Brackman, Gilles; Paunova-Krasteva, Tsvetelina S; Zarnowiec, Paulina; Czerwonka, Grzegorz; Reilly, James; Drevinek, Pavel; Kaca, Wieslaw; Melter, Oto; De Soyza, Anthony; Perry, Audrey; Winstanley, Craig; Stoitsova, Stoyanka R; Lavigne, Rob; Mahenthiralingam, Eshwar; Sá-Correia, Isabel; Coenye, Tom; Drulis-Kawa, Zuzanna; Augustyniak, Daria; Valvano, Miguel A; McClean, Siobhán

    2015-10-01

    Pseudomonas aeruginosa causes chronic lung infections in people with cystic fibrosis (CF) and acute opportunistic infections in people without CF. Forty-two P. aeruginosa strains from a range of clinical and environmental sources were collated into a single reference strain panel to harmonise research on this diverse opportunistic pathogen. To facilitate further harmonized and comparable research on P. aeruginosa, we characterized the panel strains for growth rates, motility, virulence in the Galleria mellonella infection model, pyocyanin and alginate production, mucoid phenotype, LPS pattern, biofilm formation, urease activity, and antimicrobial and phage susceptibilities. Phenotypic diversity across the P. aeruginosa panel was apparent for all phenotypes examined, agreeing with the marked variability seen in this species. However, except for growth rate, the phenotypic diversity among strains from CF versus non-CF sources was comparable. CF strains were less virulent in the G. mellonella model than non-CF strains (P = 0.037). Transmissible CF strains generally lacked O-antigen, produced less pyocyanin and had low virulence in G. mellonella. Furthermore, in the three sets of sequential CF strains, virulence, O-antigen expression and pyocyanin production were higher in the earlier isolate compared to the isolate obtained later in infection. Overall, this full phenotypic characterization of the defined panel of P. aeruginosa strains increases our understanding of the virulence and pathogenesis of P. aeruginosa and may provide a valuable resource for the testing of novel therapies against this problematic pathogen.

  17. Interactions of Plutonium with Pseudomonas sp. Strain EPS-1W and Its Extracellular Polymeric Substances.

    Science.gov (United States)

    Boggs, Mark A; Jiao, Yongqin; Dai, Zurong; Zavarin, Mavrik; Kersting, Annie B

    2016-12-15

    Safe and effective nuclear waste disposal, as well as accidental radionuclide releases, necessitates our understanding of the fate of radionuclides in the environment, including their interaction with microorganisms. We examined the sorption of Pu(IV) and Pu(V) to Pseudomonas sp. strain EPS-1W, an aerobic bacterium isolated from plutonium (Pu)-contaminated groundwater collected in the United States at the Nevada National Security Site (NNSS) in Nevada. We compared Pu sorption to cells with and without bound extracellular polymeric substances (EPS). Wild-type cells with intact EPS sorbed Pu(V) more effectively than cells with EPS removed. In contrast, cells with and without EPS showed the same sorption affinity for Pu(IV). In vitro experiments with extracted EPS revealed rapid reduction of Pu(V) to Pu(IV). Transmission electron microscopy indicated that 2- to 3-nm nanocrystalline Pu(IV)O2 formed on cells equilibrated with high concentrations of Pu(IV) but not Pu(V). Thus, EPS, while facilitating Pu(V) reduction, inhibit the formation of nanocrystalline Pu(IV) precipitates. Our results indicate that EPS are an effective reductant for Pu(V) and sorbent for Pu(IV) and may impact Pu redox cycling and mobility in the environment. Additionally, the resulting Pu morphology associated with EPS will depend on the concentration and initial Pu oxidation state. While our results are not directly applicable to the Pu transport situation at the NNSS, the results suggest that, in general, stationary microorganisms and biofilms will tend to limit the migration of Pu and provide an important Pu retardation mechanism in the environment. In a broader sense, our results, along with a growing body of literature, highlight the important role of microorganisms as producers of redox-active organic ligands and therefore as modulators of radionuclide redox transformations and complexation in the subsurface. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  18. Control of foodborne pathogens on fresh-cut fruit by a novel strain of Pseudomonas graminis.

    Science.gov (United States)

    Alegre, Isabel; Viñas, Inmaculada; Usall, Josep; Teixidó, Neus; Figge, Marian J; Abadias, Maribel

    2013-06-01

    The consumption of fresh-cut fruit has substantially risen over the last few years, leading to an increase in the number of outbreaks associated with fruit. Moreover, consumers are currently demanding wholesome, fresh-like, safe foods without added chemicals. As a response, the aim of this study was to determine if the naturally occurring microorganisms on fruit are "competitive with" or "antagonistic to" potentially encountered pathogens. Of the 97 and 107 isolates tested by co-inoculation with Escherichia coli O157:H7, Salmonella and Listeria innocua on fresh-cut apple and peach, respectively, and stored at 20 °C, seven showed a strong antagonistic capacity (more than 1-log unit reduction). One of the isolates, CPA-7, achieved the best reduction values (from 2.8 to 5.9-log units) and was the only isolate able to inhibit E. coli O157:H7 at refrigeration temperatures on both fruits. Therefore, CPA-7 was selected for further assays. Dose-response assays showed that CPA-7 should be present in at least the same amount as the pathogen to adequately reduce the numbers of the pathogen. From the results obtained in in vitro assays, competition seemed to be CPA-7's mode of action against E. coli O157:H7. The CPA-7 strain was identified as Pseudomonas graminis. Thus, the results support the potential use of CPA-7 as a bioprotective agent against foodborne pathogens in minimally processed fruit. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. The MSHA strain of Pseudomonas aeruginosa activated TLR pathway and enhanced HIV-1 DNA vaccine immunoreactivity.

    Directory of Open Access Journals (Sweden)

    Jue Hou

    Full Text Available The mannose-sensitive hemagglutination pilus strain of Pseudomonas aeruginosa (PA-MSHA has been shown to trigger naïve immune responses through the activation of monocytes, macrophages, natural killer cells (NK cells and antigen presenting cells (APCs. Based on the hypothesis that PA-MSHA activates natural immunity through the Toll-like receptor (TLR pathway, we scanned several critical TLR pathway molecules in mouse splenocytes using high-throughput real-time QRT-PCR and co-stimulatory molecule in bone marrow-derived dendritic cells (BMDCs following in vitro stimulation by PA-MSHA. PA-MSHA enabled activation of the TLR pathway mediated by NF-κB and JNK signaling in splenocytes, and the co-stimulatory molecule CD86 was up-regulated in BMDCs. We then assessed the adjuvant effect of PA-MSHA for HIV-1 DNA vaccines. In comparison to DNA inoculation alone, co-inoculation with low dosage of PA-MSHA enhanced specific immunoreactivity against HIV-1 Env in both cellular and humoral responses, and promoted antibody avidity maturation. However, high doses of adjuvant resulted in an immunosuppressive effect; a two- or three-inoculation regimen yielded low antibody responses and the two-inoculation regimen exhibited only a slight cellular immunity response. To our knowledge, this is the first report demonstrating the utility of PA-MSHA as an adjuvant to a DNA vaccine. Further research is needed to investigate the exact mechanisms through which PA-MSHA achieves its adjuvant effects on innate immune responses, especially on dendritic cells.

  20. Pseudomonas putida Strain FStm2 Isolated from Shark Skin: A Potential Source of Bacteriocin.

    Science.gov (United States)

    Ahmad, Asmat; Hamid, Rahimi; Dada, Ayokunle Christopher; Usup, Gires

    2013-09-01

    Bacteriocin-producing Pseudomonas putida strain FStm2 isolated from shark showed broad range of antibacterial activity against all pathogens tested except Bacillus subtilis ATCC11774, MRSA N32064, Proteus mirabilis ATCC12453, Enterococcus faecalis ATCC14506, Salmonella typhimurium ATCC51312, Salmonella mutan ATCC25175, and Aeromonas hydrophila Wbf314. Of the three growth media tested in this study, TSB was observed to support the bacteriocin activity the most. While the highest bacteriocin activity was observed for media supplemented with 1 % NaCl, there was an observed reduction in bacteriocin activity with increasing salt concentration. Although the least bacteriocin activity was observed for marine broth, addition of increasing amounts of tryptone, glucose, or yeast extract increased bacteriocin activity. This was, however, contrary to the effect observed when MgSO4 and MnSO4 were added as supplements. In the presence of α-amylase, lipase, DNase, and RNase, a positive effect on bacteriocin production was observed. Proteinase K strongly inhibited bacteriocin production. Furthermore, the bacteriocins produced were heat stable within the temperature range of 30-70 °C. Bacteriocin activity also was not affected within a wide pH range of 3-9. Exposure to detergents did not inhibit the activity of the bacteriocin at the concentrations tested. Instead, a positive effect on the relative activity of produced bacteriocin was observed as sodium dodecyl sulfate (SDS), EDTA, and Tween 20 at 1 % concentration all improved bacteriocin activity when the cell-free supernatant was tested against Serratia marcescens ATCC 13880. The bacteriocin was purified by ammonium sulfate precipitation and gel filtration on a Superdex-200 column. SDS-PAGE analysis of the partially purified bacteriocin revealed an apparent molecular weight of ~32 kDa.

  1. Effects of heavy metals on aerobic denitrification by strain Pseudomonas stutzeri PCN-1.

    Science.gov (United States)

    Gui, Mengyao; Chen, Qian; Ma, Tao; Zheng, Maosheng; Ni, Jinren

    2017-02-01

    Effects of heavy metals on aerobic denitrification have been poorly understood compared with their impacts on anaerobic denitrification. This paper presented effects of four heavy metals (Cd(II), Cu(II), Ni(II), and Zn(II)) on aerobic denitrification by a novel aerobic denitrifying strain Pseudomonas stutzeri PCN-1. Results indicated that aerobic denitrifying activity decreased with increasing heavy metal concentrations due to their corresponding inhibition on the denitrifying gene expression characterized by a time lapse between the expression of the nosZ gene and that of the cnorB gene by PCN-1, which led to lower nitrate removal rate (1.67∼6.67 mg L(-1) h(-1)), higher nitrite accumulation (47.3∼99.8 mg L(-1)), and higher N2O emission ratios (5∼283 mg L(-1)/mg L(-1)). Specially, promotion of the nosZ gene expression by increasing Cu(II) concentrations (0∼0.05 mg L(-1)) was found, and the absence of Cu resulted in massive N2O emission due to poor synthesis of N2O reductase. The inhibition effect for both aerobic denitrifying activity and denitrifying gene expression was as follows from strongest to least: Cd(II) (0.5∼2.5 mg L(-1)) > Cu(II) (0.5∼5 mg L(-1)) > Ni(II) (2∼10 mg L(-1)) > Zn(II) (25∼50 mg L(-1)). Furthermore, sensitivity of denitrifying gene to heavy metals was similar in order of nosZ > nirS ≈ cnorB > napA. This study is of significance in understanding the potential application of aerobic denitrifying bacteria in practical wastewater treatment.

  2. Intracellular excision and reintegration dynamics of the ICEclc genomic island of Pseudomonas knackmussii sp. strain B13.

    Science.gov (United States)

    Sentchilo, Vladimir; Czechowska, Kamila; Pradervand, Nicolas; Minoia, Marco; Miyazaki, Ryo; van der Meer, Jan Roelof

    2009-06-01

    Genomic islands are DNA elements acquired by horizontal gene transfer that are common to a large number of bacterial genomes, which can contribute specific adaptive functions, e.g. virulence, metabolic capacities or antibiotic resistances. Some genomic islands are still self-transferable and display an intricate life-style, reminiscent of both bacteriophages and conjugative plasmids. Here we studied the dynamical process of genomic island excision and intracellular reintegration using the integrative and conjugative element ICEclc from Pseudomonas knackmussii B13 as model. By using self-transfer of ICEclc from strain B13 to Pseudomonas putida and Cupriavidus necator as recipients, we show that ICEclc can target a number of different tRNA(Gly) genes in a bacterial genome, but only those which carry the GCC anticodon. Two conditional traps were designed for ICEclc based on the attR sequence, and we could show that ICEclc will insert with different frequencies in such traps producing brightly fluorescent cells. Starting from clonal primary transconjugants we demonstrate that ICEclc is excising and reintegrating at detectable frequencies, even in the absence of recipient. Recombination site analysis provided evidence to explain the characteristics of a larger number of genomic island insertions observed in a variety of strains, including Bordetella petri, Pseudomonas aeruginosa and Burkholderia.

  3. Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.).

    Science.gov (United States)

    Ahmad, Maqshoof; Zahir, Zahir A; Nazli, Farheen; Akram, Fareeha; Arshad, Muhammad; Khalid, Muhammad

    2013-12-01

    Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m(-1) under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

  4. Antimicrobial activities of Rhizobium sp. strains against Pseudomonas savastanoi, the agent responsible for the olive knot disease in Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Mourad, K.; Fadhila, K.; Chahinez, M.; Merien, R.; Philippe, L. de; Abdelkader, B.

    2009-07-01

    In the present investigation, six Rhizobium strains isolated from Algerian soil were checked for their antimicrobial activity against Pseudomonas savastanoi, the agent responsible for olive knot disease. Rhizobium sp. ORN 24 and ORN 83 were found to produce antimicrobial activities against Pseudomonas savastanoi. The antimicrobial activity produced by Rhizobium sp. ORN24 was precipitable with ammonium sulfate, between 1,000 and 10,000 KDa molecular weight, heat resistant but sensitive to proteases and detergents. These characteristics suggest the bacteriocin nature of the antimicrobial substance produced by Rhizobium sp. ORN24, named rhizobiocin 24. In contrast, the antimicrobial activity produced by Rhizobium sp. ORN83 was not precipitable with ammonium sulfate; it was smaller than 1,000 KDa molecular weight, heat labile, and protease and detergent resistant. These characteristics could indicate the relationship between the antimicrobial substance produced by Rhizobium sp. ORN 83 and the small bacteriocins described in other rhizobia. (Author) 51 refs.

  5. Promotion of plant growth by Pseudomonas fluorescens strain SS101 via novel volatile organic compounds

    NARCIS (Netherlands)

    Park, Yong-Soon; Dutta, Swarnalee; Ann, Mina; Raaijmakers, Jos M.; Park, Kyungseok

    2015-01-01

    Abstract Volatile organic compounds (VOCs) from plant growth-promoting rhizobacteria (PGPR) play key roles in modulating plant growth and induced systemic resistance (ISR) to pathogens. Despite their significance, the physiological functions of the specific VOCs produced by Pseudomonas fluorescens

  6. ANTIBACTERIAL ACTIVITY EVALUATION OF ALLIUM SATIVUM ESSENTIAL OIL COMPARED TO DIFFERENT PSEUDOMONAS AERUGINOSA STRAINS IN EASTERN ALGERIA

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    Mazzouz Dekhil

    2010-12-01

    Full Text Available The chemical composition of essential oil extracted from Allium sativum bulbs harvested in the region of El Harrouch in Skikda was studied by gas chromatography coupled with mass spectrometry; six compounds were identified which predominant materials are: methyl allyl trisulfide (34.61�20and diallyl disulfide (31.65� The antibacterial activity was tested on 52 clinical strains and one reference strain of Pseudomonas aeruginosa by both variants of the dilution method, the dilution method in liquid medium and the dilution method in solid medium. The results showed that the essential oil of Allium sativum has an inhibitory activity of growth compared to over 50�0of strains tested with MICs relatively averages between 32 and 128 μg•mL-1.

  7. Antibacterial activity of wild Xylaria sp. strain R005 (Ascomycetes) against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa.

    Science.gov (United States)

    Ramesh, Veluchamy; Arivudainambi, U; Thalavaipandian, Annamalai; Karunakaran, Chandran; Rajendran, Ayyappan

    2012-01-01

    There is a growing need for new and effective antibiotic agents due to the recent emergence of life-threatening, multidrug-resistant bacterial infections such as methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. In the present study, the antimicrobial potential of mushroom was investigated against multidrug-resistant bacterial strains. The mushroom was identified as Xylaria sp. strain R005 based on the morphological characteristics and confirmed by 18S ribosomal RNA sequence comparisons. The crude ethyl acetate extracts of culture filtrate and fruiting bodies of Xylaria sp. showed significant antibacterial activity against multidrug-resistant S. aureus strains (1-10) and P. aeruginosa strains (1-8). The minimum inhibitory concentration of the ethyl acetate extracts of culture filtrate and fruiting bodies ranged from 225 µg/mL to 625 µg/mL, and 120 µg/mL to 625 µg/mL, respectively, against clinical strains of S. aurues and P. aeruginosa. The synergistic action of extracts of Xylaria sp. with vancomycin and ciprofloxacin was observed against S. aureus strain 6 and P. aeruginosa strain 3, respectively. The fractional inhibitory concentration indices (FICIs) of culture filtrate extract with vancomycin and ciprofloxacin were 0.5 and 0.18, respectively. The FICI of fruiting body extract with vancomycin and ciprofloxacin were 0.5 and 0.375, respectively. These results clearly indicate that the metabolites of culture filtrate and fruiting bodies of Xylaria sp. are the potential source for production of new antimicrobial compounds.

  8. Characterization of a Pseudomonas fluorescens strain from tomato rhizosphere and its use for integrated management of tomato damping-off

    Energy Technology Data Exchange (ETDEWEB)

    Jayaraj, J; Parthasarathi, T.; Radhakrishnan, N.V. [Annamalai University, Annamalainagar (India). Faculty of Agriculture

    2007-10-15

    A highly antagonistic Pseudomonas fluorescens strain was isolated from tomato rhizosphere and characterized for its in vitro and in vivo biocontrol potential against Pythium aphanidermatum. The identified Pseudomonas fluorescens strain (PfT-8) was capable of producing high levels of chitinase, beta-1,3-glucanase, cellulase, fungitoxic metabolites and siderophores. Seven different carrier formulations including a talc-based powder, lignite-based powder, peat-based powder, lignite + fly ash-based powder, wettable powder, bentonite-paste and polyethylene glycol (PEG) paste were prepared utilizing PfT-8. Shelf life was evaluated for up to 6 months of storage at ambient room temperature (28{sup o}C). Biocontrol efficacy of formulations was studied under greenhouse and field conditions. Among the formulations, peat, lignite, lignite+fly-ash and bentonite paste based formulations maintained higher propagule number than others and also showed greater biocontrol potential. However, propagule number gradually decreased with time. Soil incorporation of organic amendments and specifically poultry manure and FYM, significantly reduced damping-off incidence and also augmented the rhizosphere population of the marked P. fluorescens strain that was resistant to streptomycin and rifampicin.

  9. Whole-Genome Sequence of Pseudomonas putida Strain UASWS0946, a Highly Ammonia-Tolerant Nitrifying Bacterium Isolated from Sewage Sludge Aerobic Granules.

    Science.gov (United States)

    Crovadore, Julien; Calmin, Gautier; Cochard, Bastien; Chablais, Romain; Grizard, Damien; Berthon, Jean-Yves; Lefort, François

    2015-10-08

    We report here the genome of Pseudomonas putida strain UASWS0946, a highly ammonia-tolerant nitrifying strain isolated from sewage sludge aerobic granules, which displays adequate genetic equipment for soil depollution, sludge treatment, and biological fertilization in agriculture. Copyright © 2015 Crovadore et al.

  10. Draft Genome Sequence of the Plant Growth–Promoting Pseudomonas punonensis Strain D1-6 Isolated from the Desert Plant Erodium hirtum in Jordan

    KAUST Repository

    Lafi, Feras Fawzi

    2017-01-13

    Pseudomonas punonensis strain D1-6 was isolated from roots of the desert plant Erodium hirtum, near the Dead Sea in Jordan. The genome of strain D1-6 reveals several key plant growth-promoting and herbicide-resistance genes, indicating a possible specialized role for this endophyte.

  11. Factors influencing the ability of Pseudomonas putida strains epI and II to degrade the organophosphate ethoprophos.

    Science.gov (United States)

    Karpouzas, D G; Walker, A

    2000-07-01

    Two strains of Pseudomonas putida (epI and epII), isolated previously from ethoprophos-treated soil, were able to degrade ethoprophos (10 mg 1(-1)) in a mineral salts medium plus nitrogen (MSMN) in less than 50 h with a concurrent population growth. Addition of glucose or succinate to MSMN did not influence the degrading ability of Ps. putida epI, but increased the lag phase before rapid degradation commenced with Ps. putida epII. The degrading ability of the two isolates was lost when the pesticide provided the sole source of phosphorus. Degradation of ethoprophos was most rapid when bacterial cultures were incubated at 25 and 37 degrees C. Pseudomonas putida epI was capable of completely degrading ethoprophos at a slow rate at 5 degrees C, compared with Ps. putida epII which could not completely degrade ethoprophos at the same time. Pseudomonas putida epI was capable of degrading ethoprophos when only 60 cells ml(-1) were used as initial inoculum. In contrast, Ps. putida epII was able to totally degrade ethoprophos when inoculum densities of 600 cells ml(-1) or higher were used. In general, longer lag phases accompanied the lower inoculum levels. Both isolates rapidly degraded ethoprophos in MSMN at pHs ranging from 5.5 to 7.6, but not at pH 5 or below.

  12. Overexpression of the (R)-specific enoyl-CoA hydratase gene from Pseudomonas chlororaphis HS21 in Pseudomonas strains for the biosynthesis of polyhydroxyalkanoates of altered monomer composition.

    Science.gov (United States)

    Chung, Moon Gyu; Rhee, Young Ha

    2012-01-01

    The (R)-specific enoyl-CoA hydratase gene (phaJ(HS21)) from Pseudomonas chlororaphis HS21 was overexpressed in various Pseudomonas strains, alone and in combination with the polyhydroxyalkanoate synthase gene (phaC(HS21)), for the biosynthesis of polyhydroxyalkanoates (PHAs) of altered monomer composition. Recombinant Pseudomonas strains harboring phaC(HS21) and phaJ(HS21) generated saturated and unsaturated monomers of C12-C14 in their PHAs. In particular, the level of the 3-hydroxytetradecenoate monomer in recombinant P. chlororaphis HS21 increased by approximately 260%. PhaJ(HS21) is expected to be useful in the biosynthesis of PHAs consisting of unusual monomer units.

  13. Development of a lipase fermentation process that uses a recombinant Pseudomonas alcaligenes strain

    NARCIS (Netherlands)

    Gerritse, G; Hommes, R.W J; Quax, Wim

    Pseudomonas alcaligenes M-l secretes an alkaline lipase, which has excellent characteristics for the removal of fatty stains under modern washing conditions. A fed-batch fermentation process based on the secretion of the alkaline lipase from P. alcaligenes was developed. Due to the inability of P.

  14. Pesticide tolerant and phosphorus solubilizing Pseudomonas sp. strain SGRAJ09 isolated from pesticides treated Achillea clavennae rhizosphere soil.

    Science.gov (United States)

    Rajasankar, R; Manju Gayathry, G; Sathiavelu, A; Ramalingam, C; Saravanan, V S

    2013-05-01

    In this study, an attempt was made to identify an effective phosphate solubilizing bacteria from pesticide polluted field soil. Based on the formation of solubilization halo on Pikovskaya's agar, six isolates were selected and screened for pesticide tolerance and phosphate (P) solubilization ability through liquid assay. The results showed that only one strain (SGRAJ09) obtained from Achillea clavennae was found to tolerate maximum level of the pesticides tested and it was phylogenetically identified as Pseudomonas sp. It possessed a wide range of pesticide tolerance, ranging from 117 μg mL(-1) for alphamethrin to 2,600 μg mL(-1) for endosulfan. The available P concentrations increased with the maximum and double the maximum dose of monocrotophos and imidacloprid, respectively. On subjected to FT-IR and HPLC analysis, the presence of organic acids functional group in the culture broth and the production of gluconic acid as dominant acid aiding the P solubilization were identified. On comparison with control broth, monocrotophos and imidacloprid added culture broth showed quantitatively high organic acids production. In addition to gluconic acid production, citric and acetic acids were also observed in the pesticide amended broth. Furthermore, the Pseudomonas sp. strain SGRAJ09 possessed all the plant growth promoting traits tested. In presence of monocrotophos and imidacloprid, its plant growth promoting activities were lower than that of the pesticides unamended treatment.

  15. Lead-enhanced siderophore production and alteration in cell morphology in a Pb-resistant Pseudomonas aeruginosa strain 4EA.

    Science.gov (United States)

    Naik, Milind Mohan; Dubey, Santosh Kumar

    2011-02-01

    A lead-resistant bacterial strain 4EA from soil contaminated with car battery waste from Goa, India was isolated and identified as Pseudomonas aeruginosa. This lead-resistant bacterial isolate interestingly revealed lead-enhanced siderophore (pyochelin and pyoverdine) production up to 0.5 mM lead nitrate whereas cells exhibit a significant decline in siderophore production above 0.5 mM lead nitrate. The bacterial cells also revealed significant alteration in cell morphology as size reduction when exposed to 0.8 mM lead nitrate. Enhanced production of siderophore was evidently detected by chrome azurol S agar diffusion (CASAD) assay as increase in diameter of orange halo, and reduction in bacterial size along with significant biosorption of lead was recorded by scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDX). Pseudomonas aeruginosa strain 4EA also exhibits cross tolerance to other toxic metals viz. cadmium, mercury, and zinc besides resistance to multiple antibiotics such as ampicillin, erythromycin, amikacin, cephalexin, co-trimoxazole, mecillinam, lincomycin, ciphaloridine, oleondamycin, and nalidixic acid.

  16. The Prevalence of Exoenzyme S Gene in Multidrug-Sensitive and Multidrug-Resistant Pseudomonas aeruginosa Clinical Strains.

    Science.gov (United States)

    Bogiel, Tomasz; Deptuła, Aleksander; Kwiecińska-Piróg, Joanna; Prażyńska, Małgorzata; Mikucka, Agnieszka; Gospodarek-Komkowska, Eugenia

    2017-12-04

    Pseudomonas aeruginosa rods are one of the most commonly isolated microorganisms from clinical specimens, usually responsible for nosocomial infections. Antibiotic-resistant P. aeruginosa strains may present reduced expression of virulence factors. This fact may be caused by appropriate genome management to adapt to changing conditions of the hospital environment. Virulence factors genes may be replaced by those crucial to survive, like antimicrobial resistance genes. The aim of this study was to evaluate, using PCR, the occurrence of exoenzyme S-coding gene (exoS) in two distinct groups of P. aeruginosa strains: 83 multidrug-sensitive (MDS) and 65 multidrug-resistant (MDR) isolates. ExoS gene was noted in 72 (48.7%) of the examined strains: 44 (53.0%) MDS and 28 (43.1%) MDR. The observed differences were not statistically significant (p = 0.1505). P. aeruginosa strains virulence is rather determined by the expression regulation of the possessed genes than the difference in genes frequency amongst strains with different antimicrobial susceptibility patterns.

  17. THE FORMATION OF BIOFILMS BY PSEUDOMONAS AERUGINOSA STRAINS, AND METHODS OF ITS CONTROL (REVIEW

    Directory of Open Access Journals (Sweden)

    Sarkis-Ivanova VV

    2017-03-01

    fission; development of preparations that block intercellular signaling (quorum sensing, and cause disconnection of cells from biofilm and their transition into plankton existence or resist pathogenicity factor expression. Nowadays the influence of certain physical factors on biological properties of biofilms is studied as well. At the present time the new technology that is photodynamic therapy is in intensive progress. Low intensity electromagnetic radiation has widespread application practically in all areas of medicine. In fact, under the influence of light emitting diode radiation metabolic and functional properties of biological system variety can be significantly changed. According to a number of investigators a direct method of light emitting diode radiation effect provides direct influence on cellular structure elements, moreover it has been proved that membrane structures of cell are the most sensitive to optical radiation effect. It was found that under influence of light emitting diode radiation a breakdown of daily biofilms with inhibition of plankton cells production capacity was observed. All the above allows to assess current problem of medical science and practice that is process of biofilm formation in microorganisms particularly in Pseudomonas aeruginosa strains. Analysis of literature sources shows practicability of research line of specific subject that is proved by crisis of antibiotic therapy observed for now and characterized not only by multitude of resistant microorganisms but also by absence of preparations and infection pathology therapeutic regimen that have assuring effectiveness and therefore search for alternative control methods is critical and challenging.

  18. Complete genome sequence of the biocontrol strain Pseudomonas protegens Cab57 discovered in Japan reveals strain-specific diversity of this species.

    Science.gov (United States)

    Takeuchi, Kasumi; Noda, Naomi; Someya, Nobutaka

    2014-01-01

    The biocontrol strain Pseudomonas sp. Cab57 was isolated from the rhizosphere of shepherd's purse growing in a field in Hokkaido by screening the antibiotic producers. The whole genome sequence of this strain was obtained by paired-end and whole-genome shotgun sequencing, and the gaps between the contigs were closed using gap-spanning PCR products. The P. sp. Cab57 genome is organized into a single circular chromosome with 6,827,892 bp, 63.3% G+C content, and 6,186 predicted protein-coding sequences. Based on 16S rRNA gene analysis and whole genome analysis, strain Cab57 was identified as P. protegens. As reported in P. protegens CHA0 and Pf-5, four gene clusters (phl, prn, plt, and hcn) encoding the typical antibiotic metabolites and the reported genes associated with Gac/Rsm signal transduction pathway of these strains are fully conserved in the Cab57 genome. Actually strain Cab57 exhibited typical Gac/Rsm activities and antibiotic production, and these activities were enhanced by knocking out the retS gene (for a sensor kinase acting as an antagonist of GacS). Two large segments (79 and 115 kb) lacking in the Cab57 genome, as compared with the Pf-5 genome, accounted for the majority of the difference (247 kb) between these genomes. One of these segments was the complete rhizoxin analog biosynthesis gene cluster (ca. 79 kb) and another one was the 115-kb mobile genomic island. A whole genome comparison of those relative strains revealed that each strain has unique gene clusters involved in metabolism such as nitrite/nitrate assimilation, which was identified in the Cab57 genome. These findings suggest that P. protegens is a ubiquitous bacterium that controls its biocontrol traits while building up strain-specific genomic repertoires for the biosynthesis of secondary metabolites and niche adaptation.

  19. Isolation and characterization of Pseudomonas aeruginosa strain SJTD-2 for degrading long-chain n-alkanes and crude oil.

    Science.gov (United States)

    Xu, Jing; Liu, Huan; Liu, Jianhua; Liang, Rubing

    2015-06-04

    Oil pollution poses a severe threat to ecosystems, and bioremediation is considered as a safe and efficient alternative to physicochemical. for eliminating this contaminant. In this study, a gram-negative bacteria strain SJTD-2 isolated from oil-contaminated soil was found capable of utilizing n-alkanes and crude oil as sole energy sources. The efficiency of this strain in degrading these pollutants was analyzed. Strain SJTD-2 was identified on the basis of its phenotype, its physiological features, and a comparative genetic analysis using 16S rRNA sequence. Growth of strain SJTD-2 with different carbon sources (n-alkanes of different lengths and crude oil) was assessed, and the gas chromatography-mass spectrometry method was used to analyze the degradation efficiency of strain SJTD-2 for n-alkanes and petroleum by detecting the residual n-alkane concentrations. Strain SJTD-2 was identified as Pseudomonas aeruginosa based on the phenotype, physiological features, and 16S rRNA sequence analysis. This strain can efficiently decompose medium-chain and long-chain n-alkanes (C10-C26), and petroleum as its sole carbon sources. It preferred the long-chain n-alkanes (C18-C22), and n-docosane was considered as the best carbon source for its growth. In 48 h, 500 mg/L n-docosane could be degraded completely, and 2 g/L n-docosane was decomposed to undetectable levels within 72 h. Moreover, strain SJTD-2 could utilize about 88% of 2 g/L crude oil in 7days. Compared with other alkane-utilizing strains, strain SJTD-2 showed outstanding degradation efficiency for long-chain n-alkanes and high tolerance to petroleum at elevated concentrations. The isolation and characterization of strain SJTD-2 would help researchers study the mechanisms underlying the biodegradation of n-alkanes, and this strain could be used as a potential strain for environmental governance and soil bioremediation.

  20. Characterization of Pseudomonas Aeruginosa Strains Isolated from Burned Patients Hospitalized in A Major Burn Center in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Arjomandzadegan

    2011-10-01

    Full Text Available Pseudomonas aeruginosa is an important life-threatening nosocomial pathogen and plays a prominent role in serious infections in burned patients. The current study was undertaken to characterize P. aeruginosa strains isolated from burned patients in Tehran, Iran. The study was conducted in a major burn center in Tehran, Iran in 2007. A total of seventy specimens obtained from different clinical origin with positive culture results for P. aeruginosa were included in the study. Antimicrobial susceptibility test was performed according to the standard CLSI guideline. The relationship between the strains was also determined using antimicrobial drug resistance pattern analysis and plasmid profiling. All strains were multi drug resistant. The percentage of resistance to tested antibiotics was: imipenem 97.5%, amikacin 90%, piperacillin 87.5%, ceftizoxime 72.7%, gentamicin 67.5%, ciprofloxacin 65%, ceftriaxone 60%, and ceftazidime 57.5%. Thirteen resistant phenotypes were recognized, R3 (TET, IPM, AMK, CIP, PIP, GM, CAZ, CRO, CT was the predominant resistance pattern seen in 27.5% of isolates. Results obtained from E-test showed that 100% of P. aeruginosa strains were resistant to cefoxitin, 97% to cefotetan, 93% to ticarcillin, 89% to ticarcillin/clav, 76% to gentamicin and imipenem, 63% to piperacillin, 49% to tetracycline, and 20% to meropenem. Nine different plasmid profiles were observed among the strains. The current study showed an increase rate of resistance for some antibiotics tested among P. aeruginosa strains isolated from burned patients in Tehran. A combination of antibiotic susceptibility testing and profile plasmid analysis, which are relatively cheap and available methods, showed to be useful to characterize the clinical strains of P. aeruginosa isolated from burned patients in Iran.

  1. Occurrence of Ambler Class B Metallo-β-Lactamase Gene in Imipenem-Resistant Pseudomonas Aeruginosa Strains Isolated from Clinical Samples

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    Zeynab Golshani

    2014-02-01

    Full Text Available Background: 5TMetallo-β-lactamase (MBLs can hydrolyze a broad spectrum of beta-lactams, including penicillins, cephalosporins, and carbapenems. Genes encoding these enzymes are located on the plasmid that can easily be transferred to other bacteria. The aim of this study was to isolate and identify the Pseudomonas aeruginosa strains encoding VIM1 gene, in clinical samples, using the PCR technique. Materials and Methods: During a 4 month period, 100 strains of Pseudomonas aeruginosa from clinical specimens were collected. Standard tests were performed to identify strains of Pseudomonas aeruginosa. Resistance to antibiotics was examined and then the PCR was used to detect VIM1gene. Results:In this study, the highest rates of resistance to antibiotics, amikacin and cefotaxime was observed (65% and 62%, the lowest resistance to antibiotics piperacillin (48% and imipenem and cefepime with 55% resistance was reported. DDST method was performed for 37 strains for the MBl detection. Among the 37 isolate, 30 strains were MBL-producing with imipenem-EDTA method. Twelve strains (18% were carriers of VIM1 gene using the PCR method. Conclusion: In the present study, the prevalence of strains producing MBL genes in strains of hospitals is a growing trend; correct prescription of medications can prevent the spread of resistant pathogens. It is suggested that molecular methods for rapid detection of resistance genes can be used to prevent the spread of this genes.

  2. Pseudomonas aeruginosa in cystic fibrosis: pyocyanin negative strains are associated with BPI-ANCA and progressive lung disease.

    Science.gov (United States)

    Carlsson, Malin; Shukla, Swati; Petersson, Ann Cathrine; Segelmark, Mårten; Hellmark, Thomas

    2011-07-01

    The clinical consequence of chronic Pseudomonas aeruginosa colonization in cystic fibrosis (CF) varies between individuals for unknown reasons. Auto-antibodies against bactericidal/permeability increasing protein (BPI-ANCA) are associated with poor prognosis in CF. We hypothesize that there is a correlation between the presence of BPI-ANCA, the properties of the colonizing bacteria and the clinical conditions of the host. We compared isolates of P. aeruginosa from BPI-ANCA positive CF patients who have deteriorating lung disease with BPI-ANCA negative CF patients who are in stable clinical conditions. Epithelial cells (A549) and isolated polymorphonuclear granulocytes (PMNs) were stimulated with the isolates and cell death was analyzed with flow cytometry. We found that the ANCA associated strains in most cases showed pyocyanin negative phenotypes. These strains also induced less inflammatory response than the non-ANCA associated strains as shown by apoptosis and necrosis of epithelial cells and neutrophils. Our results suggest that colonization with strains of P. aeruginosa that induce a weak inflammatory response is associated with unfavorable outcome in CF. We speculate that inadequate control of pathogen proliferation through an insufficient inflammatory response results in a slowly increasing number of bacteria and accumulation of dying PMNs in the airways, contributing to progression in CF lung disease. Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  3. Molecular analysis of exotoxin A associated with antimicrobial resistance of Pseudomonas aeruginosa strains isolated from patients in Tehran hospitals

    Directory of Open Access Journals (Sweden)

    Nour Amirmozafari

    2014-12-01

    Full Text Available Background and Aim:  Pseudomonas aeruginosa is a unique bacteria that in order to survive in different environments by complex adaptation process can make changes in his virulence genes expression and drug resistance. The aim of this research is the investigation of existence of a logical association between toxA gene and antibiotic resistance in strains possess the gene. Materials and Methods: Antibiogram test by disk diffusion method (Kirby Bauer was performed according to CLSI protocols. In this study, the existence of toxA gene with the help of polymerase chain reaction (PCR in 102 clinical isolates from blood samples, wound, urine and trachea was examined. Chi-square test was used to investigate the relationship between exotoxin A and antibiotic resistance. Results: The 81 strains (79.4% had toxA gene. Frequency of toxA genes in isolated strains from different infections were wound (91.4%, blood (85.7%, trachea (72.7%, and urine (42.1%. Multiple resistance index in strains possess the toxA gene was calculated 75%. Chi 2 test to determine the relationship between drug resistance and gene toxA was significant (P<0.05. Conclusions: The significant chi-square test and an increase in multi-resistant strains possessing the toxA gene, can represent a considerable genetic switch between exotoxin A activity and resistance to antibiotics in the blood, urine, tracheal, wound infections Respectively, which lead to turn genes on of drug resistance regulating in bacteria. The results of this study will be verified by southern blot, analysis of the expression of toxA gene and determine the mechanism of resistance in resistant strains Methods.

  4. [Persistence of Pseudomonas aeruginosa strains in patients of Federal Scientific Center of Transplantology and Artificial Organs].

    Science.gov (United States)

    Avetisian, L R; Voronina, O L; Chernukha, M Iu; Kunda, M S; Gabrielian, N I; Lunin, V G; Shaginian, I A

    2012-01-01

    Study genetic diversity of P. aeruginosa strains persisting in patients of Federal Scientific Center of Transplantology and Artificial Organs, and main factors facilitating persistence of strains in the hospital. 136 P. aeruginosa strains isolated from patients of the center for 3 years 6 months were genotyped by RAPD-PCR and MLST methods and studied for antibiotics resistance and presence of integrons. Genetic diversity of strains persisting in hospital was established. Strains of main genotypes ST235, ST446, ST598 were isolated from patients of various surgical departments. Patients were shown to be colonized by these strains during stay in reanimation and intensive therapy department (RITD) of the hospital. Strains of dominant genotype 235 were isolated from 47% of examined patients during more than 3 years. Only genotype 235 strains contained integron with cassettes of antibiotics resistance genes blaGES5 and aadA6 in the genome. The data obtained show that over the period of observation in the center 1 clone of P. aeruginosa that belonged to genotype 235 dominated. This clone was endemic for this hospital and in the process of prolonged persistence became more resistant to antibiotics. Colonization of patients with these strains occurs in RITD. This confirms the necessity of constant monitoring of hospital microflora for advance detection of potentially dangerous epidemic hospital strains able to cause hospital infections.

  5. Antimicrobial activity of Rhizobium sp. strains against Pseudomonas savastanoi, the agent responsible for the olive knot disease in Algeria

    Directory of Open Access Journals (Sweden)

    2009-06-01

    Full Text Available In the present investigation, six Rhizobium strains isolated from Algerian soil were checked for their antimicrobial activity against Pseudomonas savastanoi, the agent responsible for olive knot disease. Rhizobium sp. ORN 24 and ORN 83 were found to produce antimicrobial activities against Pseudomonas savastanoi. The antimicrobial activity produced by Rhizobium sp. ORN24 was precipitable with ammonium sulfate, between 1,000 and 10,000 KDa molecular weight, heat resistant but sensitive to proteases and detergents. These characteristics suggest the bacteriocin nature of the antimicrobial substance produced by Rhizobium sp. ORN24, named rhizobiocin 24. In contrast, the antimicrobial activity produced by Rhizobium sp. ORN83 was not precipitable with ammonium sulfate; it was smaller than 1,000 KDa molecular weight, heat labile, and protease and detergent resistant. These characteristics could indicate the relationship between the antimicrobial substance produced by Rhizobium sp. ORN 83 and the “small” bacteriocins described in other rhizobia.

    En la presente investigación, seis cepas de Rhizobium aisladas de suelos argelinos fueron estudiadas para conocer su actividad antimicrobiana contra Pseudomonas savastanoi, el agente causante de la tuberculosis del olivo. Rhizobium sp. ORN 24 y ORN 83 produjeron actividad antimicrobiana contra Pseudomonas savastanoi. La actividad antimicrobiana producida por Rhizobium sp. ORN 24 precipitó con sulfato amónico, tuvo un peso molecular entre 1000 y 10000 KDa, fue resistente al calor pero sensible a proteasas y detergentes. Estas características sugieren que la sustancia antimicrobial producida por Rhizobium sp. ORN 24 es la bacteriocina natural conocida como rizobiocina 24. Por el contrario, la actividad antimicrobiana producida por Rhizobium sp. ORN83 no fue precipitable con sulfato amónico, y tuvo un peso molecular menor de 1000 KDa, fue lábil al calor y resistente a detergentes y proteasas. Estas

  6. Exposure-related effects of Pseudomonas fluorescens, strain CL145A, on coldwater, coolwater, and warmwater fish

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Denise A. Mayer,

    2015-01-01

    The exposure-related effects of a commercially prepared spray-dried powder (SDP) formulation of Pseudomonas fluorescens, strain CL145A, were evaluated on coldwater, coolwater, and warmwater fish endemic to the Great Lakes and Upper Mississippi River Basins. Nine species of young-of-the-year fish were exposed to SDP for 24 hours by using continuous-flow, serial-dilution exposure systems at temperatures of 12 degrees Celsius (°C; 2 species; Oncorhynchus mykiss [rainbow trout] and Salvelinus fontinalis [brook trout]), 17 °C (3 species; Perca flavescens [yellow perch], Sander vitreus [walleye], and Acipenser fulvescens [lake sturgeon]), or 22 °C (4 species; Micropterus salmoides [largemouth bass], Micropterus dolomieu [smallmouth bass], Lepomis macrochirus [bluegill sunfish], and Ictalurus punctatus [channel catfish]).

  7. Exposure-related effects of formulated Pseudomonas fluorescens strain CL145A to glochidia from seven unionid mussel species

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Severson, Todd J.; Schreier, Theresa M.; Mayer, Denise A.; Aloisi, Douglas B.; Eckert, Nathan L.

    2015-01-01

    The study was completed to evaluate the exposure-related effects of a biopesticide for dreissenid mussel (Dreissena polymorpha, zebra mussel and Dreissena rostriformis bugensis, quagga mussel) control on glochidia from unionid mussels endemic to the Great Lakes and Upper Mississippi River Basins. The commercially prepared biopesticide was either a spray-dried powder (SDP) or freeze-dried powder (FDP) formulation of Pseudomonas fluorescens, strain CL145A. Glochidia of the unionid mussel species Lampsilis cardium, Lampsilis siliquoidea,Lampsilis higginsii, Ligumia recta, Obovaria olivaria, and Actinonaias ligamentina were exposed to SDP-formulated P. fluorescens andLampsilis cardium and Megalonaias nervosa were exposed to FDP-formulated P. fluorescens.

  8. Cow Dung Substrate for the Potential Production of Alkaline Proteases by Pseudomonas putida Strain AT in Solid-State Fermentation

    Directory of Open Access Journals (Sweden)

    Ponnuswamy Vijayaraghavan

    2014-01-01

    Full Text Available Cow dung and agroresidues were used as the substrates for the production of alkaline proteases by Pseudomonas putida strain AT in solid-state fermentation. Among the various substrates evaluated, cow dung supported maximum (1351±217 U/g protease production. The optimum conditions for the production of alkaline proteases were a fermentation period of 48 h, 120% (v/w moisture, pH 9, and the addition of 6% (v/w inoculum, 1.5% (w/w trehalose, and 2.0% (w/w yeast extract to the cow dung substrate. The enzyme was active over a range of temperatures (50–70°C and pHs (8–10, with maximum activity at 60°C and pH 9. These enzymes showed stability towards surfactants, detergents, and solvent and digested various natural proteins.

  9. Two strains of Pseudomonas fluorscens bacteria differentially affect survivorship of waxworm (Galleria mellonella) larvae exposed to an arthropod fungal pathogen, Beauveria bassiana

    Science.gov (United States)

    Two strains of Pseudomonas fluorescens were found contaminating a biopesticide used in a previous study against Varroa destructor infestations in honey bee hives. In the aforementioned study the biopesticide, a formulation of the arthropod pathogen Beauveria bassiana, failed to have any impact on t...

  10. Endophytic Colonization of Potato (Solanum tuberosum L.) by a Novel Competent Bacterial Endophyte, Pseudomonas putida Strain P9, and Its Effect on Associated Bacterial Communities

    NARCIS (Netherlands)

    Andreote, F.D.; Araujo, W.L.; Azevedo, J.L.; Elsas, van J.D.; Rocha, da U.N.; Overbeek, van L.S.

    2009-01-01

    Pseudomonas putida strain P9 is a novel competent endophyte from potato. P9 causes cultivar-dependent suppression of Phytophthora infestans. Colonization of the rhizoplane and endosphere of potato plants by P9 and its rifampin-resistant derivative P9R was studied. The purposes of this work were to

  11. Endophytic colonization of potato (Solanum tuberosum L.) by a novel competent bacterial endophyte, Pseudomonas putida Strain P9, and its effect on associated bacterial communities

    NARCIS (Netherlands)

    Andreote, F.D; De Araujo, W.L.; de Azevedo, J.L.; van Elsas, J.D.; Nunes da Rocha, U.; van Overbeek, L.S.

    2009-01-01

    Pseudomonas putida strain P9 is a novel competent endophyte from potato. P9 causes cultivar-dependent suppression of Phytophthora infestans. Colonization of the rhizoplane and endosphere of potato plants by P9 and its rifampin-resistant derivative P9R was studied. The purposes of this work were to

  12. Genome Sequence of Pseudomonas sp. Strain Chol1, a Model Organism for the Degradation of Bile Salts and Other Steroid Compounds

    KAUST Repository

    Holert, Johannes

    2013-01-15

    Bacterial degradation of steroid compounds is of high ecological and biotechnological relevance. Pseudomonas sp. strain Chol1 is a model organism for studying the degradation of the steroid compound cholate. Its draft genome sequence is presented and reveals one gene cluster responsible for the metabolism of steroid compounds.

  13. Draft Genome Sequence of the Phosphate-Solubilizing Bacterium Pseudomonas argentinensis Strain SA190 Isolated from the Desert Plant Indigofera argentea

    KAUST Repository

    Lafi, Feras Fawzi

    2016-12-23

    Pseudomonas argentinensis strain SA190 is a plant endophytic-inhabiting bacterium that was isolated from root nodules of the desert plant Indigofera argentea collected from the Jizan region of Saudi Arabia. Here, we report the genome sequence of SA190, highlighting several functional genes related to plant growth-promoting activity, environment adaption, and antifungal activity.

  14. Augmented effect of early antibiotic treatment in mice with experimental lung infections due to sequentially adapted mucoid strains of Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    van Gennip, M; Moser, Claus; Christensen, Louise D

    2009-01-01

    Background: Effects of treatment with tobramycin initiated 1 or 24 h post-infection were investigated in a new version of a pulmonary infection model in mice. The model reflects the differentiated behaviour of Pseudomonas aeruginosa mucoid strains isolated from the lungs of one chronically infect...

  15. Bacterial Feeders, the Nematode Caenorhabditis elegans and the Flagellate Cercomonas longicauda, have different Effects on Outcome of Competition among the Pseudomonas Biocontrol Strains CHA0 and DSS73

    DEFF Research Database (Denmark)

    Pedersen, Annette; Nybroe, Ole; Winding, Anne

    2009-01-01

    selective feeding flagellate Cercomonas longicauda versus the non-selective feeding nematode Caenorhabditis elegans) influence the abundance of two bacteria that compete for resources in simple model communities. Microcosms consisted of either one gfp-tagged bacterial strain (Pseudomonas fluorescens DSM...

  16. Bioaugmentation with Pseudomonas sp. strain MHP41 promotes simazine attenuation and bacterial community changes in agricultural soils.

    Science.gov (United States)

    Morgante, Verónica; López-López, Arantxa; Flores, Cecilia; González, Myriam; González, Bernardo; Vásquez, Mónica; Rosselló-Mora, Ramón; Seeger, Michael

    2010-01-01

    Bioremediation is an important technology for the removal of persistent organic pollutants from the environment. Bioaugmentation with the encapsulated Pseudomonas sp. strain MHP41 of agricultural soils contaminated with the herbicide simazine was studied. The experiments were performed in microcosm trials using two soils: soil that had never been previously exposed to s-triazines (NS) and soil that had >20 years of s-triazine application (AS). The efficiency of the bioremediation process was assessed by monitoring simazine removal by HPLC. The simazine-degrading microbiota was estimated using an indicator for respiration combined with most-probable-number enumeration. The soil bacterial community structures and the effect of bioaugmentation on these communities were determined using 16S RNA gene clone libraries and FISH analysis. Bioaugmentation with MHP41 cells enhanced simazine degradation and increased the number of simazine-degrading microorganisms in the two soils. In highly contaminated NS soil, bioaugmentation with strain MHP41 was essential for simazine removal. Comparative analysis of 16S rRNA gene clone libraries from NS and AS soils revealed high bacterial diversity. Bioaugmentation with strain MHP41 promoted soil bacterial community shifts. FISH analysis revealed that bioaugmentation increased the relative abundances of two phylogenetic groups (Acidobacteria and Planctomycetes) in both soils. Although members of the Archaea were metabolically active in these soils, their relative abundance was not altered by bioaugmentation.

  17. Characterization of carbapenem resistance mechanisms and integrons in Pseudomonas aeruginosa strains from blood samples in a French hospital.

    Science.gov (United States)

    Rojo-Bezares, Beatriz; Cavalié, Laurent; Dubois, Damien; Oswald, Eric; Torres, Carmen; Sáenz, Yolanda

    2016-04-01

    Metallo-β-lactamases (MBLs), porin OprD, integrons, virulence factors and the clonal relationships were characterized in imipenem-resistant Pseudomonas aeruginosa (IRPA) isolates. Fifty-six IRPA strains were recovered from blood samples of different patients at a Toulouse teaching hospital from 2011 to 2013. Susceptibility testing of 14 antibiotics was performed by the disc diffusion method. Detection and characterization of MBLs, the oprD gene and integrons were studied by PCR and sequencing. Thirteen genes involved in the virulence of P. aeruginosa were analysed. Molecular typing of IRPA strains was performed by PFGE and multilocus sequence typing. In this study, 61 % of the IRPA isolates showed a multi-resistance phenotype. The MBL phenotype, detected in three isolates (5.4 %), was linked to the blaVIM-2 gene. The oprD gene was amplified in 55 (98.2 %) IRPA strains, and variations were observed in 54 of them. Insertion sequences (IS) truncating oprD were detected in eight IRPA strains, with the novel ISPa56 identified in two strains. Class 1 integrons were detected in 24 (42.9 %) IRPA strains. The blaVIM-2 gene was found inside the class 1 integron arrangements. The new integrons In1054 (intI1-aacA56-qacEΔ1-sul1) and In1160 (intI1-aacA4-aacC1d-ISKpn4-gcuE-qacEΔ1-sul1) have been described for the first time, to the best of our knowledge, in this study. A high clonal diversity was found in our strains. Among the variety of sequence types (STs) found, ST175, ST233, ST235, ST244 and ST654 were noteworthy as epidemic clones. In conclusion, 5.4 % of IRPA strains showed an MBL phenotype linked to the blaVIM-2 gene. The identified oprD high polymorphism could be implicated in the variable resistance to carbapenems in IRPA strains. The dissemination of high-risk clones is a cause of concern.

  18. Toluene-degrading Antarctic Pseudomonas strains from fuel-contaminated soil.

    Science.gov (United States)

    Farrell, Roberta L; Rhodes, Phillippa L; Aislabie, Jackie

    2003-12-05

    Two psychrotolerant toluene-degrading Pseudomonas spp. were isolated from JP8 jet-fuel-contaminated soils, Scott Base, Antarctica. Isolates metabolized meta-toluate as sole carbon source at temperatures ranging from 6 to 30 degrees C. Large plasmids (>64kb) were isolated from both isolates. Sequence analysis of PCR products amplified using xylB (the gene encoding benzyl alcohol dehydrogenase) primers revealed that isolates 7/167 and 8/46 were 100% and 92% homologous, respectively, to the xylB gene of the meta-cleavage toluene degradative pathway encoded by the TOL plasmid (pWWO) of Pseudomonas putida mt-2. Assays of cell-free extracts of 7/167 and 8/46 demonstrated activity of catechol 2,3-dioxygenase, benzyl alcohol dehydrogenase, and benzaldehyde dehydrogenase, indicating that the isolates use the meta-cleavage pathway enzymes of toluene degradation typical of TOL type plasmids. As both isolates are able to grow at 6 degrees C ex situ it is feasible that they would be able to metabolize toluene in the Antarctic soils from where they were originally isolated.

  19. Genome Sequences of Two Naphthalene-Degrading Strains of Pseudomonas balearica, Isolated from Polluted Marine Sediment and from an Oil Refinery Site.

    Science.gov (United States)

    Salvà-Serra, Francisco; Jakobsson, Hedvig E; Busquets, Antonio; Gomila, Margarita; Jaén-Luchoro, Daniel; Seguí, Carolina; Aliaga-Lozano, Francisco; García-Valdés, Elena; Lalucat, Jorge; Moore, Edward R B; Bennasar-Figueras, Antoni

    2017-04-06

    The genome sequences of Pseudomonas balearica strains LS401 (CCUG 66666) and st101 (CCUG 66667) have been determined. The strains were isolated as naphthalene degraders from polluted marine sediment and from a sample from an oil refinery site, respectively. These genomes provide essential data about the biodegradation capabilities and the ecological implications of P. balearica. Copyright © 2017 Salvà-Serra et al.

  20. Screening of strains of soil micromycetes – antagonists of fungal and bacterial plant pathogens

    Directory of Open Access Journals (Sweden)

    O. A. Drehval

    2017-05-01

    Full Text Available The antagonistic activity of 23 strains of micromycetes belonging to different taxonomic groups, against phythopathogenic bacteria and fungi was studied. The antagonistic activity of the micromycetes was tested by agar diffusion (the method of blocks. For the determination of the influence of the micromycetes on plants, spring barley seeds were treated by cultural liquid of fungi (dilution 1 : 10 for 24 hours and germinated in Petri dishes on moist filter paper. Two strains Trichoderma longibrachiatum 17 and T. lignorum 14 showed the highest antagonistic activity against the phytopathogenic bacteria and fungi. T. longibrachiatum 17 actively suppressed the growth of fungi Fusarium oxysporum 54201, F. culmorum 50716, F. oxysporum 12, F. moniliforme 23, Cladosporium herbarum 16878, Alternaria alternata 16, Aspergillus niger 25 and bacteria Agrobacterium tumefaciens 8628, Xanthomonas campestris 8003b, Pectobacterium carotovorum 8982, Pseudomonas syringae pv. atrofaciens 8254, P. syringae pv. lachrymans 7595, zones inhibition of growth were 20.7–38.3 and 14.7–24.7 mm, respectively. The strain of T. lignorum 14 inhibited the growth of fungi F. culmorum 50716, C. herbarum 16878, F. moniliforme 23, A. alternata 16, A. niger 25 and bacteria A. tumefaciens 8628, P. carotovorum 8982, P. syringae pv. atrofaciens 8254, P. syringae pv. lachrymans 7595, zones of inhibition of growth were 14.0–38.7 and 12.3–23.3 mm, respectively. Treatment of spring barley seeds by T. longibrachiatum 17 cultural liquid showed a positive effect on seed germination, both strains T. longibrachiatum 17 and T. lignorum 14 increased the dry weight of the roots (by 17.5% and 22.0%, respectively and the stems (by 8.0% of spring barley plants compared with the water-treated controls. The results presented in this article indicate that the strains T. longibrachiatum 17 and T. lignorum 14 can be recommended as promising microbial agents to protect plants from fungal and

  1. Laboratory-based evaluation of MDR strains of Pseudomonas in patients with acute burn injuries

    Science.gov (United States)

    Zhang, Hong-Tu; Liu, Hui

    2015-01-01

    Localization of burn was variable: head and face in 76 patients (29%), trunk in 58 (49%), upper limb in 37 (52%), lower limbs in 44 (41%), hands in 16 (15%), perinea area in 26 (5.5%) and whole body except perinea area in 10 (9%) patients. Inhalation syndrome was present in 56 (44%) patients. Ninety patients (82%) had indwelling venous catheters, 83 (75.5%) patients’ arterial catheter and 86 (78%) patients’ urinary catheters. By multivariate analysis: age ≤4 years, Garcés 4, colistin use in documented multiresistant infections, and mechanical ventilation were independent variables related with mortality and graft requirement was a protective factor for mortality. Despite advances in care, gram negative bacterial infections and infection with Pseudomonas aeruginosa remain the most common cause of bacteria related mortality early in the hospital course. Viral infections are also associated with mortality and numbers have remained stable when compared to data from prior years. PMID:26629178

  2. Effects of phosphorus fertilizer rate and Pseudomonas fluorescens strain on field pea (Pisum sativum subsp. arvense (L. Asch. growth and yield

    Directory of Open Access Journals (Sweden)

    Bahram SALEHI

    2015-11-01

    Full Text Available A field experiment was conducted at Rezvanshahr, Guilan province, Iran, to evaluate the effects of phosphorus fertilizer rate and Pseudomonas fluorescens strains on growth and yield of field pea (Pisum sativum L.. The experimental design was a randomized complete block in a factorial arrangement with three replicates. Factors were phosphorus fertilizer rates (0, 25, 50, 75, and 100 kg P2O5 ha-1 as triple superphosphate, and seed inoculation with P. florescens strains [control (non-inoculated, inoculated with strain R41, and strain R187. Analysis of variance showed that plant height, seed yield, pod number per m2, 100-seed weight, biological yield, harvest index, and leaf P concentration were significantly influenced by phosphorus fertilizer rate and P. florescens strain. At the same time, phosphorus fertilizer rate × P. fluorescens strain interaction was significant only for 100-seed weight. On the other hand, seed number per pod was significantly affected neither by phosphorus fertilizer rate nor by pseudomonas strains. Result showed that seed yield was significantly increased from 1099 ± 67 to 1898 ± 118 kg ha-1 as P2O5 application rate increased from 0 to 75 kg ha-1, and thereafter relatively remained constant. There was no significant difference in seed yield between plants raised from inoculated seeds with P. fluorescens, strain R187 (1664 ± 97 kg ha-1 and those raised from inoculated seeds with P. fluorescens, strain R41 (1669 ± 104 kg ha-1. At the same time, plants raised from inoculated seeds with P. fluorescens (both strains produced greater grain yield compared to those raised from uninoculated seeds (1370 ± 80 kg ha-1. Based on the results of this study, P2O5 application at the rate of 75 kg ha-1 and inoculation with pseudomonas bacteria are recommended for obtaining the greatest seed yield in field pea.

  3. Colonization and plant growth promoting characterization of endophytic Pseudomonas chlororaphis strain Zong1 isolated from Sophora alopecuroides root nodules

    Directory of Open Access Journals (Sweden)

    Long Fei Zhao

    2013-01-01

    Full Text Available The endophytic strain Zong1 isolated from root nodules of the legume Sophora alopecuroides was characterized by conducting physiological and biochemical tests employing gfp-marking, observing their plant growth promoting characteristics (PGPC and detecting plant growth parameters of inoculation assays under greenhouse conditions. Results showed that strain Zong1 had an effective growth at 28 ºC after placed at 4-60 ºC for 15 min, had a wide range pH tolerance of 6.0-11.0 and salt tolerance up to 5% of NaCl. Zong1 was resistant to the following antibiotics (µg/mL: Phosphonomycin (100, Penicillin (100 and Ampicillin (100. It could grow in the medium supplemented with 1.2 mmol/L Cu, 0.1% (w/v methylene blue and 0.1-0.2% (w/v methyl red, respectively. Zong1 is closely related to Pseudomonas chlororaphis based on analysis the sequence of 16S rRNA gene. Its expression of the gfp gene indicated that strain Zong1 may colonize in root or root nodules and verified by microscopic observation. Furthermore, co-inoculation with Zong1 and SQ1 (Mesorhizobium sp. showed significant effects compared to single inoculation for the following PGPC parameters: siderophore production, phosphate solubilization, organic acid production, IAA production and antifungal activity in vitro. These results suggest strains P. chlororaphi Zong1 and Mesorhizobium sp. SQ1 have better synergistic or addictive effect. It was noteworthy that each growth index of co-inoculated Zong1+SQ1 in growth assays under greenhouse conditions is higher than those of single inoculation, and showed a significant difference (p < 0.05 when compared to a negative control. Therefore, as an endophyte P. chlororaphis Zong1 may play important roles as a potential plantgrowth promoting agent.

  4. [PCR-RAPD typing of carbapenem-resistant Pseudomonas aeruginosa strains].

    Science.gov (United States)

    Bogiel, Tomasz; Gospodarek, Eugenia

    2010-01-01

    P. aeruginosa rods are opportunistic pathogens responsible generally for nosocomial infections. Resistance to carbapenems, observed among them, is a serious threat due to ability to be transmitted between bacterial species. The aim of our study was to evaluate the usefulness of PCR-RAPD technique in typing of 16 carbapenem-resistant P. aeruginosa strains isolated in 2007 from different patients of University HospitalNo. 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń. Study shows increasing frequency of isolation that type of strains when compared to 2006. Percentage of carbapenem-resistant isolates raised from 12,4% in 2006 to 22.9% in 2007. The majority of examined strains were obtained from patients of the Intensive Care Units (25.0%) and were isolated from bronchoalveolar lavage (25.0%), urine (25.0%) and wound swabs (18.8%) samples. Examined P. aeruginosa strains demonstrated resistance to doripenem (81.3%) and piperacillin (75.0%) and susceptibility to colistin (100.0%), amikacin (81.3%), netilmicin and norfloxacin (75.0% each). Using PCR-RAPD amplification with 208 and 272 primers, 14 and 16 DNA patterns were obtained, respectively. Usefulness of PCR-RAPD in carbapenem-resistant P. aeruginosa strains typing was proved in case of strains presenting similar and/or different antimicrobials susceptibility patterns.

  5. [Occurrence and susceptibility to antibiotics of carbapenem-resistant Pseudomonas aeruginosa strains between 1998 and 2009].

    Science.gov (United States)

    Bogiel, Tomasz; Mikucka, Agnieszka; Skalski, Tomasz; Gospodarek, Eugenia

    2010-01-01

    P. aeruginosa rods are dangerous pathogens mainly responsible for nosocomial infections of different localization. Resistance to carbapenems, observed among them, is a serious threat due to ability to be transmitted between bacterial species. The aim of our study was to retrospectively evaluate the frequency of isolation and susceptibility to antibiotics of imipenem- and meropenem-resistant P. aeruginosa strains isolated between 1998 and 2009 from patients of University Hospital No 1 of dr A. Jurasz in Bydgoszcz. Study shows increasing number of isolation that type of strains from 19 in 1998 to 144 in 2009. Among all isolated P. aeruginosa strains majority was obtained from patients of the Intensive Care Units, Rehabilitation and Surgery Clinics. Examined strains of P. aeruginosa rods were mainly isolated from urine (20.5%), bronchoalveolar lavage (17.7%) and wound swabs (14.5%) samples. The isolates demonstrated frequently resistance to carbenicillin (> or 66.7%), ticarcillin (> or = 72.7%) and cefotaxime (> or = 75.6%). The lowest rate of resistant strains was observed in case of ceftazidime (< or = 68.8%), aztreonam (< or = 47.4%) and colistin (< or = 1.7%) suggesting the highest activity of that antimicrobials against infections caused by examined strains.

  6. Analysis of plant growth-promoting effects of fluorescent Pseudomonas strains isolated from Mentha piperita rhizosphere and effects of their volatile organic compounds on essential oil composition

    Directory of Open Access Journals (Sweden)

    Maricel Valeria Santoro

    2016-07-01

    Full Text Available Many species or strains of the genus Pseudomonas have been characterized as plant growth promoting rhizobacteria (PGPR. We used a combination of phenotypic and genotypic techniques to analyze the community of fluorescent Pseudomonas strains in the rhizosphere of commercially grown Mentha piperita (peppermint. Biochemical techniques, Amplified rDNA Restriction Analysis (ARDRA, and 16S rRNA gene sequence analysis revealed that the majority of the isolated native fluorescent strains were P. putida. Use of two Repetitive Sequence-based PCR (rep-PCR techniques, BOX-PCR and ERIC-PCR, allowed us to evaluate diversity among the native strains and to more effectively distinguish among them. PGPR activity was tested for the native strains and reference strain P. fluorescens WCS417r. Micropropagated M. piperita plantlets were exposed to microbial volatile organic compounds (mVOCs emitted by the bacterial strains, and plant biomass parameters and production of essential oils (EOs were measured. mVOCs from 11 of the native strains caused an increase in shoot fresh weight. mVOCs from three native strains (SJ04, SJ25,SJ48 induced changes in M. pierita EO composition. The mVOCs caused a reduction of metabolites in the monoterpene pathway, for example menthofuran, and an increase in menthol production. Menthol production is the primary indicator of EO quality. The mVOCs produced by native strains SJ04, SJ25,SJ48 and strain WCS417r were analyzed. The obtained mVOC chromatographic profiles were unique for each of the three native strains analyzed, containing varying hydrocarbon, aromatic, and alogenic compounds. The differential effects of the strains were most likely due to the specific mixtures of mVOCs emitted by each strain, suggesting a synergistic effect occurs among the compounds present.

  7. Chromosomal insertion of the entire Escherichia coli lactose operon, into two strains of Pseudomonas, using a modified mini-Tn5 delivery system

    DEFF Research Database (Denmark)

    Hansen, L. H.; Sørensen, S. J.; Jensen, Lars Bogø

    1997-01-01

    A 12-kb PstI fragment including the entire E. coli lactose operon (lacIPOZYA) was inserted in one copy into the chromosome of Pseudomonas putida, Pseudomonas fluorescens and an E. coli strain with lac(-) phenotype. This was made possible by improvements of an already existing mini-Tn5 transposon...... flanked by NotI sites needed in the mini-Tn5 delivery system; (b) the generation of E. coli nonlysogenic strains expressing the pi protein thus being capable of maintaining and delivering R6K-based mini-Tn5 vectors to other E. coli strains; (c) the successful insertion of the E. coli lactose operon...... into the P. fluorescens chromosome giving P. fluorescens the ability to grow on lactose; (d) evidence from Southern blotting that contradicts the assumption that the mini-Tn5 delivery system always creates one-copy inserts. These improvements allow insertion of large DNA fragments encoding highly expressed...

  8. Systemic resistance and lipoxygenase-related defence response induced in tomato by Pseudomonas putida strain BTP1

    Directory of Open Access Journals (Sweden)

    Dommes Jacques

    2008-11-01

    Full Text Available Abstract Background Previous studies showed the ability of Pseudomonas putida strain BTP1 to promote induced systemic resistance (ISR in different host plants. Since ISR is long-lasting and not conducive for development of resistance of the targeted pathogen, this phenomenon can take part of disease control strategies. However, in spite of the numerous examples of ISR induced by PGPR in plants, only a few biochemical studies have associated the protective effect with specific host metabolic changes. Results In this study, we showed the protective effect of this bacterium in tomato against Botrytis cinerea. Following treatment by P. putida BTP1, analyses of acid-hydrolyzed leaf extracts showed an accumulation of antifungal material after pathogen infection. The fungitoxic compounds thus mainly accumulate as conjugates from which active aglycones may be liberated through the activity of hydrolytic enzymes. These results suggest that strain BTP1 can elicit systemic phytoalexin accumulation in tomato as one defence mechanism. On another hand, we have shown that key enzymes of the lipoxygenase pathway are stimulated in plants treated with the bacteria as compared with control plants. Interestingly, this stimulation is observed only after pathogen challenge in agreement with the priming concept almost invariably associated with the ISR phenomenon. Conclusion Through the demonstration of phytoalexin accumulation and LOX pathway stimulation in tomato, this work provides new insights into the diversity of defence mechanisms that are inducible by non-pathogenic bacteria in the context of ISR.

  9. Complete Genome Sequence of Pseudomonas Parafulva PRS09-11288, a Biocontrol Strain Produces the Antibiotic Phenazine-1-carboxylic Acid.

    Science.gov (United States)

    Zhang, Yu; Chen, Ping; Ye, Guoyou; Lin, Haiyan; Ren, Deyong; Guo, Longbiao; Zhu, Bo; Wang, Zhongwei

    2018-01-22

    Rhizoctonia solani is a plant pathogenic fungus, which can infect a wide range of economic crops including rice. In this case, biological control of this pathogen is one of the fundmental way to effectively control this pathogen. The Pseudomonas parafulva strain PRS09-11288 was isolated from rice rhizosphere and shows biocontrol ability against R. solani. Here, we analyzed the P. parafulva genome, which is ~ 4.7 Mb, with 4310 coding sequences, 76 tRNAs, and 7 rRNAs. Genome analysis identified a phenazine biosynthetic pathway, which can produce antibiotic phenazine-1-carboxylic acid (PCA). This compound is responsible for biocontrol ability against R. solani Kühn, which is one of the most serious fungus disease on rice. Analysis of the phenazine biosynthesis gene mutant, ΔphzF, which is very important in this pathway, confirmed the relationship between the pathway and PCA production using LC-MS profiles. The annotated full genome sequence of this strain sheds light on the role of P. parafulva PRS09-11288 as a biocontrol bacterium.

  10. Effects of culture conditions of Pseudomonas aeruginosa strain RB on the synthesis of CdSe nanoparticles.

    Science.gov (United States)

    Ayano, Hiroyuki; Kuroda, Masashi; Soda, Satoshi; Ike, Michihiko

    2015-04-01

    Cadmium selenide (CdSe) was synthesized by Pseudomonas aeruginosa strain RB in a culture containing lactic acid as a carbon source, 1 mM selenite, and 1 mM cadmium under various conditions. High purity (1.02-1.16 of the atomic ratio of Se to Cd) and efficient synthesis of biogenic CdSe nanoparticles were observed at 25-30°C, 0.05-10 g L(-1) NaCl, and neutral pH conditions compared with other tested conditions. However, the size and shape of synthesized CdSe nanoparticles were not changed by changing culture conditions. The contents of S and Se in the particles respectively increased under alkaline and weak acidic conditions. Furthermore, high temperature (>37°C), high salinity (>10 g L(-1) NaCl), and alkaline pH affected the CdSe-synthesizing rate by strain RB. This report is the first optimizing the culture conditions for synthesizing biogenic CdSe nanoparticles in a batch processing. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  11. Overexpression of Pseudomonas aeruginosa LpxC with its inhibitors in an acrB-deficient Escherichia coli strain.

    Science.gov (United States)

    Gao, Ning; McLeod, Sarah M; Hajec, Laurel; Olivier, Nelson B; Lahiri, Sushmita D; Bryan Prince, D; Thresher, Jason; Ross, Philip L; Whiteaker, James D; Doig, Peter; Li, Amanda Haixi; Hill, Pamela J; Cornebise, Mark; Reck, Folkert; Hale, Michael R

    2014-12-01

    In Gram-negative bacteria, the cell wall is surrounded by an outer membrane, the outer leaflet of which is comprised of charged lipopolysaccharide (LPS) molecules. Lipid A, a component of LPS, anchors this molecule to the outer membrane. UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a zinc-dependent metalloamidase that catalyzes the first committed step of biosynthesis of Lipid A, making it a promising target for antibiotic therapy. Formation of soluble aggregates of Pseudomonas aeruginosa LpxC protein when overexpressed in Escherichia coli has limited the availability of high quality protein for X-ray crystallography. Expression of LpxC in the presence of an inhibitor dramatically increased protein solubility, shortened crystallization time and led to a high-resolution crystal structure of LpxC bound to the inhibitor. However, this approach required large amounts of compound, restricting its use. To reduce the amount of compound needed, an overexpression strain of E. coli was created lacking acrB, a critical component of the major efflux pump. By overexpressing LpxC in the efflux deficient strain in the presence of LpxC inhibitors, several structures of P. aeruginosa LpxC in complex with different compounds were solved to accelerate structure-based drug design. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Antibacterial compound produced by Pseudomonas aeruginosa strain UICC B-40, an endophytic bacterium isolated from Neesia altissima.

    Science.gov (United States)

    Pratiwi, Rina Hidayati; Hidayat, Iman; Hanafi, Muhammad; Mangunwardoyo, Wibowo

    2017-04-01

    This study's aim was to determine the identity of antibacterial compounds produced by Pseudomonas aeruginosa strain UICC B-40 and describe the antibacterial compounds' mechanisms of action for damaging pathogenic bacteria cells. Isolation and identification of the compounds were carried out using thin layer chromatography (TLC), nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography mass spectrometry (LC-MS) analyses. Antibacterial activity was assayed via minimum inhibitory concentration (MIC) and the antibacterial compound mechanism was observed morphologically through scanning electron microscopy (SEM). This study successfully identified the (2E,5E)-phenyltetradeca-2,5-dienoate antibacterial compound (molecular weight 300 g/mol), composed of a phenolic ester, fatty acid and long chain of aliphatic group structures. MIC values for this compound were determined at 62.5 μg/ml against Staphylococcus aureus strain ATCC 25923. The mechanism of the compound involved breaking down the bacterial cell walls through the lysis process. The (2E,5E)-phenyltetradeca-2,5-dienoate compound exhibited inhibitory activity on the growth of Gram-positive bacteria.

  13. Synthesis of Medium-Chain-Length Polyhydroxyalkanoate Homopolymers, Random Copolymers, and Block Copolymers by an Engineered Strain of Pseudomonas entomophila.

    Science.gov (United States)

    Wang, Ying; Chung, Ahleum; Chen, Guo-Qiang

    2017-04-01

    Medium-chain-length polyhydroxyalkanoates (mcl-PHAs), widely used in medical area, are commonly synthesized by Pseudomonas spp. This study tries to use β-oxidation pathways engineered P. entomophila to achieve single source of a series of mcl-monomers for microbial production of PHA homopolymers. The effort is proven successful for the first time to obtain a wide range of mcl-PHA homopolymers from engineered P. entomophila LAC23 grown on various fatty acids, respectively, ranging from poly(3-hydroxyheptanoate) to poly(3-hydroxytetradecanoate). Effects of a PHA monomer chain length on thermal and crystallization properties including the changes of Tm , Tg , and Td5% are investigated. Additionally, strain LAC23 is used to synthesize random copolymers of 3-hydroxyoctanoate (3HO) and 3-hydroxydodecanoate (3HDD) or 3-hydroxytetradecanoates, their compositions could be controlled by adjusting the ratios of two related fatty acids. Meanwhile, block copolymer P(3HO)-b-P(3HDD) is synthesized by the same strain. It is found for the first time that even- and odd number mcl-PHA homopolymers have different physical properties. When the gene of the PHA synthase in the engineered P. entomophila is replaced by phaC from Aeromonas hydrophila 4AK4, poly(3-hydroxybutyrate-co-30 mol%-3-hydroxyhexanoate) is synthesized. Therefore, P. entomophila can be used to synthesize the whole range of PHA (C7-C14) homopolymers, random- and block copolymers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Rhamnolipid but not motility is associated with the initiation of biofilm seeding dispersal of Pseudomonas aeruginosa strain PA17.

    Science.gov (United States)

    Wang, Jingjing; Yu, Bing; Tian, Deying; Ni, Ming

    2013-03-01

    Seeding dispersal is an active detachment exhibit in aging Pseudomonas aeruginosa biofilm. Yet, effect factors of this process in the biofilm of clinical isolated mucoid P. aeruginosa strain remain to be better characterized. In our previous work, one mucoid P. earuginosa strain PA17 was isolated from a patient with recurrent pulmonary infection. In this study, confocal scanning laser microscope combined with LIVE/DEAD viability staining revealed that PA17 biofilm exhibited earlier seeding dispersal than non-mucoid PAO1. We further compared the motility and the expression of motility-associated gene during biofilm development between PA17 and PAO1. PA17 was found to be impaired in all three kinds of motility compared to PAO1. Moreover, we investigated the expression of rhamnolipid-associated genes in PA17 and PAO1 biofilm. The expression of these genes was in accordance with the process of seeding dispersal. Our results indicated that rhamnolipid but not motility is associated with the initiation of seeding dispersal of PA17 biofilm.

  15. Phenotypic characterization of multidrug-resistant Pseudomonas aeruginosa strains isolated from pediatric patients associated to biofilm formation.

    Science.gov (United States)

    Ochoa, Sara A; Cruz-Córdova, Ariadnna; Rodea, Gerardo E; Cázares-Domínguez, Vicenta; Escalona, Gerardo; Arellano-Galindo, José; Hernández-Castro, Rigoberto; Reyes-López, Alfonso; Xicohtencatl-Cortes, Juan

    2015-03-01

    Pseudomonas aeruginosa is an opportunistic pathogen that has acquired several mechanisms of resistance to multiple groups of antibiotic agents and has been widely employed as a model organism for the study of biofilm formation. Many P. aeruginosa structures embedded in the extracellular matrix, such as exopolysaccharides (EPS), flagella, and type-IV pili (T4P), have been associated with biofilm formation. In this study, we assess biofilm formation by crystal violet quantification in clinical strains of multidrug-resistant (MDR) P. aeruginosa isolated from the Hospital Infantil de México Federico Gómez (HIMFG) associated to total and reducing EPS production (quantification by the anthrone and DNS method, respectively), twitching motility activity by T4P, and flagellar-mediated motility. The determination of Minimum Inhibitory Concentration (MIC) showed that >50% of P. aeruginosa strains were resistant to 12 different antibiotics (TIC, CAZ, CTX, CRO, FEP, AZT, GM, CIP, LEV, PZT, IMP, and MEM). Total and reducing EPS analysis of the 58 biofilm-forming MDR P. aeruginosa strains showed heterogeneous values ranging from OD600 9.06 to 212.33, displaying a linear correlation with the production of total EPS (59.66μg/ml to 6000.33μg/ml; R(2)=0.89), and a higher correlation with reducing EPS (88.33μg/ml to 1100.66μg/ml; R(2)=0.96). T4P twitching motility showed a moderated linear correlation (2.00mm to 28.33mm; R(2)=0.74). Even though it has been demonstrated that flagella contribute to the initial stages of biofilm formation, crystal violet analysis showed a moderate correlation (R(2)=0.49) with flagellar-mediated motility in MDR P. aeruginosa under the tested conditions. In addition, PFGE profiles revealed two subgroups generating profiles group A, consisting of 89.63% (52/58) of the strains, and group B, consisting of 13.09% (6/58) of the strains. Phenotypic analysis showed a correlation among the biofilms developed in the MDR P. aeruginosa strains with EPS (total

  16. Comparing insertion libraries in two Pseudomonas aeruginosa strains to assess gene essentiality.

    Science.gov (United States)

    Liberati, Nicole T; Urbach, Jonathan M; Thurber, Tara K; Wu, Gang; Ausubel, Frederick M

    2008-01-01

    Putative essential genes can be identified by comparing orthologs not disrupted in multiple near-saturated transposon insertion mutation libraries in related strains of the same bacterial species. Methods for identifying all orthologs between two bacterial strains and putative essential orthologs are described. In addition, protocols detailing near-saturation transposon insertion mutagenesis of bacteria are presented, including (1) conjugation-mediated mutagenesis, (2) automated colony picking and liquid handling of mutant cultures, and (3) arbitrary polymerase chain reaction amplification and sequencing of genomic DNA adjacent to transposon insertion sites.

  17. The resistance of pseudomonas aeruginosa strains to fluoroquinolone group of antibiotics

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    Algun U

    2004-01-01

    Full Text Available Fluoroquinolones are antibiotics that are very effective against many gram negative microorganisms, including P. aeruginosa. However, resistance to these antibiotics has been reported in recent years as well. In this study, the sensivity of 136 P. aeruginosa strains, isolated from various clinical materials, to fluoroquinolones has been investigated. The lowest resistance rate was in ciprofloxacin with 12.5%. The resistance rates of the others were as follows: norfloxacin 14.7%, levofloxacin 16.9%, ofloxacin 19.9% and pefloxacin 28.7%. The 88.2% of the resistant strains to all fluoroquinolones were originated from intensive care unit.

  18. Preparation, characterization and in vitro antimicrobial activity of liposomal ceftazidime and cefepime against Pseudomonas aeruginosa strains

    Directory of Open Access Journals (Sweden)

    Ieda Maria Sapateiro Torres

    2012-09-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic microorganism with the ability to respond to a wide variety of environmental changes, exhibiting a high intrinsic resistance to a number of antimicrobial agents. This low susceptibility to antimicrobial substances is primarily due to the low permeability of its outer membrane, efflux mechanisms and the synthesis of enzymes that promote the degradation of these drugs. Cephalosporins, particularty ceftazidime and cefepime are effective against P. aeruginosa, however, its increasing resistance has limited the usage of these antibiotics. Encapsulating antimicrobial drugs into unilamellar liposomes is an approach that has been investigated in order to overcome microorganism resistance. In this study, antimicrobial activity of liposomal ceftazidime and cefepime against P. aeruginosa ATCC 27853 and P. aeruginosa SPM-1 was compared to that of the free drugs. Liposomal characterization included diameter, encapsulation efficiency and stability. Minimum Inhibitory Concentration (MIC was determined for free and liposomal forms of both drugs. Minimum Bactericidal Concentration (MBC was determined at concentrations 1, 2 and 4 times MIC. Average diameter of liposomes was 131.88 nm and encapsulation efficiency for cefepime and ceftazidime were 2.29% end 5.77%, respectively. Improved stability was obtained when liposome formulations were prepared with a 50% molar ratio for cholesterol in relation to the phospholipid. MIC for liposomal antibiotics for both drugs were 50% lower than that of the free drug, demonstrating that liposomal drug delivery systems may contribute to increase the antibacterial activity of these drugs.

  19. Promotion of plant growth by Pseudomonas fluorescens strain SS101 via novel volatile organic compounds.

    Science.gov (United States)

    Park, Yong-Soon; Dutta, Swarnalee; Ann, Mina; Raaijmakers, Jos M; Park, Kyungseok

    2015-05-29

    Volatile organic compounds (VOCs) from plant growth-promoting rhizobacteria (PGPR) play key roles in modulating plant growth and induced systemic resistance (ISR) to pathogens. Despite their significance, the physiological functions of the specific VOCs produced by Pseudomonas fluorescens SS101 (Pf.SS101) have not been precisely elucidated. The effects of Pf.SS101 and its VOCs on augmentation of plant growth promotion were investigated in vitro and in planta. A significant growth promotion was observed in plants exposed Pf.SS101 under both conditions, suggesting that its VOCs play a key role in promoting plant growth. Solid-phase micro-extraction (SPME) and a gas chromatography-mass spectrophotometer (GC-MS) system were used to characterize the VOCs emitted by Pf.SS101 and 11 different compounds were detected in samples inoculated this bacterium, including 13-Tetradecadien-1-ol, 2-butanone and 2-Methyl-n-1-tridecene. Application of these compounds resulted in enhanced plant growth. This study suggests that Pf.SS101 promotes the growth of plants via the release of VOCs including 13-Tetradecadien-1-ol, 2-butanone and 2-Methyl-n-1-tridecene, thus increasing understanding of the role of VOCs in plant-bacterial inter-communication. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Crude petroleum-oil biodegradation efficiency of Bacillus subtilis and Pseudomonas aeruginosa strains isolated from a petroleum-oil contaminated soil from North-East India.

    Science.gov (United States)

    Das, Kishore; Mukherjee, Ashis K

    2007-05-01

    The efficiency of Bacillus subtilis DM-04 and Pseudomonas aeruginosa M and NM strains isolated from a petroleum contaminated soil sample from North-East India was compared for the biodegradation of crude petroleum-oil hydrocarbons in soil and shake flask study. These bacterial strains could utilize crude petroleum-oil hydrocarbons as sole source of carbon and energy. Bioaugmentation of TPH contaminated microcosm with P. aeruginosa M and NM consortia and B. subtilis strain showed a significant reduction of TPH levels in treated soil as compared to control soil at the end of experiment (120 d). P. aeruginosa strains were more efficient than B. subtilis strain in reducing the TPH content from the medium. The plate count technique indicated expressive growth and biosurfactant production by exogenously seeded bacteria in crude petroleum-oil rich soil. The results showed that B. subtilis DM-04 and P. aeruginosa M and NM strains could be effective for in situ bioremediation.

  1. Biological control of wheat root diseases by the CLP-producing strain Pseudomonas fluorescens HC1-07.

    Science.gov (United States)

    Yang, Ming-Ming; Wen, Shan-Shan; Mavrodi, Dmitri V; Mavrodi, Olga V; von Wettstein, Diter; Thomashow, Linda S; Guo, Jian-Hua; Weller, David M

    2014-03-01

    Pseudomonas fluorescens HC1-07, previously isolated from the phyllosphere of wheat grown in Hebei province, China, suppresses the soilborne disease of wheat take-all, caused by Gaeumannomyces graminis var. tritici. We report here that strain HC1-07 also suppresses Rhizoctonia root rot of wheat caused by Rhizoctonia solani AG-8. Strain HC1-07 produced a cyclic lipopeptide (CLP) with a molecular weight of 1,126.42 based on analysis by electrospray ionization mass spectrometry. Extracted CLP inhibited the growth of G. graminis var. tritici and R. solani in vitro. To determine the role of this CLP in biological control, plasposon mutagenesis was used to generate two nonproducing mutants, HC1-07viscB and HC1-07prtR2. Analysis of regions flanking plasposon insertions in HC1-07prtR2 and HC1-07viscB revealed that the inactivated genes were similar to prtR and viscB, respectively, of the well-described biocontrol strain P. fluorescens SBW25 that produces the CLP viscosin. Both genes in HC1-07 were required for the production of the viscosin-like CLP. The two mutants were less inhibitory to G. graminis var. tritici and R. solani in vitro and reduced in ability to suppress take-all. HC1-07viscB but not HC-07prtR2 was reduced in ability to suppress Rhizoctonia root rot. In addition to CLP production, prtR also played a role in protease production.

  2. Colonization Pattern of the Biocontrol Strain Pseudomonas chlororaphis MA 342 on Barley Seeds Visualized by Using Green Fluorescent Protein

    Science.gov (United States)

    Tombolini, Riccardo; van der Gaag, Dirk Jan; Gerhardson, Berndt; Jansson, Janet K.

    1999-01-01

    Pseudomonas chlororaphis MA 342 is a potent biocontrol agent that can be used against several seed-borne diseases of cereal crops, including net blotch of barley caused by the fungus Drechslera teres. In this study, strain MA 342 was tagged with the gfp gene (encoding the green fluorescent protein) in order to study the fate of cells after seed inoculation. The gfp-tagged strain, MA 342G2, had the same biocontrol efficacy as the wild type when it was applied at high cell concentrations to seeds but was less effective at lower cell concentrations. By comparing cell counts determined by microscopy to the number of CFU, we found that the number of culturable cells was significantly lower than the total number of bacteria on seeds which were inoculated and dried for 20 h. Confocal microscopy and epifluorescence stereomicroscopy were used to determine the pattern of MA 342G2 colonization and cell aggregation on barley seeds. Immediately after inoculation of seeds, bacteria were found mainly under the seed glume, and there was no particular aggregation pattern. However, after the seeds were sown, irregularly distributed areas of bacterial aggregation were found, which reflected epiphytic colonization of glume cells. There was a trend towards bacterial aggregation near the embryo but never within the embryo. Bacterial aggregates were regularly found in the groove of each seed formed by the base of the coleoptile and the scutellum. Based on these results, we suggest that MA 342 colocalizes with the pathogen D. teres, which facilitates the action of the fungistatic compound(s) produced by this strain. PMID:10427065

  3. Comparative genomics of isolates of a Pseudomonas aeruginosa epidemic strain associated with chronic lung infections of cystic fibrosis patients.

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    Julie Jeukens

    Full Text Available Pseudomonas aeruginosa is the main cause of fatal chronic lung infections among individuals suffering from cystic fibrosis (CF. During the past 15 years, particularly aggressive strains transmitted among CF patients have been identified, initially in Europe and more recently in Canada. The aim of this study was to generate high-quality genome sequences for 7 isolates of the Liverpool epidemic strain (LES from the United Kingdom and Canada representing different virulence characteristics in order to: (1 associate comparative genomics results with virulence factor variability and (2 identify genomic and/or phenotypic divergence between the two geographical locations. We performed phenotypic characterization of pyoverdine, pyocyanin, motility, biofilm formation, and proteolytic activity. We also assessed the degree of virulence using the Dictyostelium discoideum amoeba model. Comparative genomics analysis revealed at least one large deletion (40-50 kb in 6 out of the 7 isolates compared to the reference genome of LESB58. These deletions correspond to prophages, which are known to increase the competitiveness of LESB58 in chronic lung infection. We also identified 308 non-synonymous polymorphisms, of which 28 were associated with virulence determinants and 52 with regulatory proteins. At the phenotypic level, isolates showed extensive variability in production of pyocyanin, pyoverdine, proteases and biofilm as well as in swimming motility, while being predominantly avirulent in the amoeba model. Isolates from the two continents were phylogenetically and phenotypically undistinguishable. Most regulatory mutations were isolate-specific and 29% of them were predicted to have high functional impact. Therefore, polymorphism in regulatory genes is likely to be an important basis for phenotypic diversity among LES isolates, which in turn might contribute to this strain's adaptability to varying conditions in the CF lung.

  4. Selection and molecular characterization of ceftazidime/avibactam-resistant mutants in Pseudomonas aeruginosa strains containing derepressed AmpC.

    Science.gov (United States)

    Lahiri, Sushmita D; Walkup, Grant K; Whiteaker, James D; Palmer, Tiffany; McCormack, Kathy; Tanudra, M Angela; Nash, Tory J; Thresher, Jason; Johnstone, Michele R; Hajec, Laurie; Livchak, Stephania; McLaughlin, Robert E; Alm, Richard A

    2015-01-01

    Pseudomonas aeruginosa is an important nosocomial pathogen that can cause a wide range of infections resulting in significant morbidity and mortality. Avibactam, a novel non-β-lactam β-lactamase inhibitor, is being developed in combination with ceftazidime and has the potential to be a valuable addition to the treatment options for the infectious diseases practitioner. We compared the frequency of resistance development to ceftazidime/avibactam in three P. aeruginosa strains that carried derepressed ampC alleles. The strains were incubated in the presence of increasing concentrations of ceftazidime with a fixed concentration (4 mg/L) of avibactam to calculate the frequency of spontaneous resistance. The mutants were characterized by WGS to identify the underlying mechanism of resistance. A representative mutant protein was characterized biochemically. The resistance frequency was very low in all strains. The resistant variants isolated exhibited ceftazidime/avibactam MIC values that ranged from 64 to 256 mg/L. All of the mutants exhibited changes in the chromosomal ampC gene, the majority of which were deletions of various sizes in the Ω-loop region of AmpC. The mutant enzyme that carried the smallest Ω-loop deletion, which formed a part of the avibactam-binding pocket, was characterized biochemically and found to be less effectively inhibited by avibactam as well as exhibiting increased hydrolysis of ceftazidime. The development of high-level resistance to ceftazidime/avibactam appears to occur at low frequency, but structural modifications in AmpC can occur that impact the ability of avibactam to inhibit the enzyme and thereby protect ceftazidime from hydrolysis. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  5. Divergence of a strain of Pseudomonas aeruginosa during an outbreak of ovine mastitis.

    Science.gov (United States)

    Wright, Elli A; Di Lorenzo, Valeria; Trappetti, Claudia; Liciardi, Manuele; Orru, Germano; Viti, Carlo; Bronowski, Christina; Hall, Amanda J; Darby, Alistair C; Oggioni, Marco R; Winstanley, Craig

    2015-01-30

    Bacterial infections causing mastitis in sheep can result in severe economic losses for farmers. A large survey of milk samples from ewes with mastitis in Sardinia, Italy, indicated an increasing prevalence of Pseudomonas aeruginosa infections. It has been shown previously that during chronic, biofilm-associated infections P. aeruginosa populations diversify. We report the phenotypic and genomic characterisation of two clonal P. aeruginosa isolates (PSE305 and PSE306) from a mastitis infection outbreak, representing distinct colony morphology variants. In addition to pigment production, PSE305 and PSE306 differed in phenotypic characteristics including biofilm formation, utilisation of various carbon and nitrogen sources, twitching motility. We found higher levels of expression of genes associated with biofilm formation (pelB) and twitching motility (flgD) in PSE305, compared to the biofilm and twitching-defective PSE306. Comparative genomics analysis revealed single nucleotide polymorphisms (SNPs) and minor insertion/deletion variations between PSE305 and PSE306, including a SNP mutation in the pilP gene of PSE306. By introducing a wild-type pilP gene we were able to partially complement the defective twitching motility of PSE306. There were also three larger regions of difference between the two genomes, indicating genomic instability. Hence, we have demonstrated that P. aeruginosa population divergence can occur during an outbreak of mastitis, leading to significant variations in phenotype and genotype, and resembling the behaviour of P. aeruginosa during chronic biofilm-associated infections. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Structural basis for effectiveness of siderophore-conjugated monocarbams against clinically relevant strains of Pseudomonas aeruginosa

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    Han, Seungil; Zaniewski, Richard P.; Marr, Eric S.; Lacey, Brian M.; Tomaras, Andrew P.; Evdokimov, Artem; Miller, J. Richard; Shanmugasundaram, Veerabahu (Pfizer)

    2012-02-08

    Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that causes nosocomial infections for which there are limited treatment options. Penicillin-binding protein PBP3, a key therapeutic target, is an essential enzyme responsible for the final steps of peptidoglycan synthesis and is covalently inactivated by {beta}-lactam antibiotics. Here we disclose the first high resolution cocrystal structures of the P. aeruginosa PBP3 with both novel and marketed {beta}-lactams. These structures reveal a conformational rearrangement of Tyr532 and Phe533 and a ligand-induced conformational change of Tyr409 and Arg489. The well-known affinity of the monobactam aztreonam for P. aeruginosa PBP3 is due to a distinct hydrophobic aromatic wall composed of Tyr503, Tyr532, and Phe533 interacting with the gem-dimethyl group. The structure of MC-1, a new siderophore-conjugated monocarbam complexed with PBP3 provides molecular insights for lead optimization. Importantly, we have identified a novel conformation that is distinct to the high-molecular-weight class B PBP subfamily, which is identifiable by common features such as a hydrophobic aromatic wall formed by Tyr503, Tyr532, and Phe533 and the structural flexibility of Tyr409 flanked by two glycine residues. This is also the first example of a siderophore-conjugated triazolone-linked monocarbam complexed with any PBP. Energetic analysis of tightly and loosely held computed hydration sites indicates protein desolvation effects contribute significantly to PBP3 binding, and analysis of hydration site energies allows rank ordering of the second-order acylation rate constants. Taken together, these structural, biochemical, and computational studies provide a molecular basis for recognition of P. aeruginosa PBP3 and open avenues for future design of inhibitors of this class of PBPs.

  7. Characterization of chromosomal mediated cadmium resistance in Pseudomonas aeruginosa strain BC15.

    Science.gov (United States)

    Raja, Chellaiah Edward; Selvam, Govindan Sadasivam

    2012-04-01

    Cadmium (Cd) has been used extensively in metal plating, mining, paints and plastic generation etc. In this study, Cd resistance (cadR) gene was characterized from the environmental isolate Pseudomonas aeruginosa BC15. The cadR sequences showed high homology with P. aeruginosa FLH033011 (100%), P. aeruginosa PAO1 (99%), and P. aeruginosa UCBPP-PA14 (98%) respectively. Homology modeling of cadR was carried out by using swiss-prot server. Crystal structures of E. coli CueR for Cu (1q05) and ZntR (1q08) for Zn have been used as a template. The sequence identity of P. aeruginosa cadR shares 34% for CueR and 43% for ZntR. Fold recognition of P. aeruginosa cadR was created by using PHYRE web server. Transcriptional regulator CueR (1q06a) from E. coli was chosen as the template. CadR has 31% identity and the estimated precision was 100%. The cadR gene was cloned in pET30b and transformed into E. coli BL21. The molecular weight protein of cadR was estimated to be 25 kDa by SDS-PAGE. The recombinant E. coli cadR efficiently grow in the Cd supplemented LB medium and agar plate. The order of the resistance of E. coli cadR was Mn > Pb > Cu > Cd > Ni > Zn. These findings can lead to the use of P. aeruginosa BC15 for the remediation of Cd and other heavy metals present in the polluted environment. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. 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

    Pseudomonas savastanoi pv. savastanoi is the causal agent of olive (Olea europaea) knot disease and an unorthodox member of the P. syringae complex, causing aerial tumours instead of the foliar necroses and cankers characteristic of most members of this complex. Olive knot is present wherever olive is grown; although losses are difficult to assess, it is assumed that olive knot is one of the most important diseases of the olive crop. The last century witnessed a large number of scientific articles describing the biology, epidemiology and control of this pathogen. However, most P. savastanoi pv. savastanoi strains are highly recalcitrant to genetic manipulation, which has effectively prevented the pathogen from benefitting from the scientific progress in molecular biology that has elevated the foliar pathogens of the P. syringae complex to supermodels. A number of studies in recent years have made significant advances in the biology, ecology and genetics of P. savastanoi pv. savastanoi, paving the way for the molecular dissection of its interaction with other nonpathogenic bacteria and their woody hosts. The selection of a genetically pliable model strain was soon followed by the development of rapid methods for virulence assessment with micropropagated olive plants and the analysis of cellular interactions with the plant host. The generation of a draft genome of strain NCPPB 3335 and the closed sequence of its three native plasmids has allowed for functional and comparative genomic analyses for the identification of its pathogenicity gene complement. This includes 34 putative type III effector genes and genomic regions, shared with other pathogens of woody hosts, which encode metabolic pathways associated with the degradation of lignin-derived compounds. Now, the time is right to explore the molecular basis of the P. savastanoi pv. savastanoi-olive interaction and to obtain insights into why some pathovars like it necrotic and why some like it knot

  9. High quality draft genome sequence of the type strain of Pseudomonas lutea OK2(T), a phosphate-solubilizing rhizospheric bacterium.

    Science.gov (United States)

    Kwak, Yunyoung; Park, Gun-Seok; Shin, Jae-Ho

    2016-01-01

    Pseudomonas lutea OK2(T) (=LMG 21974(T), CECT 5822(T)) is the type strain of the species and was isolated from the rhizosphere of grass growing in Spain in 2003 based on its phosphate-solubilizing capacity. In order to identify the functional significance of phosphate solubilization in Pseudomonas Plant growth promoting rhizobacteria, we describe here the phenotypic characteristics of strain OK2(T) along with its high-quality draft genome sequence, its annotation, and analysis. The genome is comprised of 5,647,497 bp with 60.15 % G + C content. The sequence includes 4,846 protein-coding genes and 95 RNA genes.

  10. The Effect of Phenazine-1-Carboxylic Acid on Mycelial Growth of Botrytis cinerea Produced by Pseudomonas aeruginosa LV Strain

    Directory of Open Access Journals (Sweden)

    Ane S. Simionato

    2017-06-01

    Full Text Available One of the most important postharvest plant pathogens that affect strawberries, grapes and tomatoes is Botrytis cinerea, known as gray mold. The fungus remains in latent form until spore germination conditions are good, making infection control difficult, causing great losses in the whole production chain. This study aimed to purify and identify phenazine-1-carboxylic acid (PCA produced by the Pseudomonas aeruginosa LV strain and to determine its antifungal activity against B. cinerea. The compounds produced were extracted with dichloromethane and passed through a chromatographic process. The purity level of PCA was determined by reversed-phase high-performance liquid chromatography semi-preparative. The structure of PCA was confirmed by nuclear magnetic resonance and electrospray ionization mass spectrometry. Antifungal activity was determined by the dry paper disk and minimum inhibitory concentration (MIC methods and identified by scanning electron microscopy and confocal microscopy. The results showed that PCA inhibited mycelial growth, where MIC was 25 μg mL-1. Microscopic analysis revealed a reduction in exopolysaccharide (EPS formation, showing distorted and damaged hyphae of B. cinerea. The results suggested that PCA has a high potential in the control of B. cinerea and inhibition of EPS (important virulence factor. This natural compound is a potential alternative to postharvest control of gray mold disease.

  11. Phytoremediation of dyes using Lagerstroemia speciosa mediated silver nanoparticles and its biofilm activity against clinical strains Pseudomonas aeruginosa.

    Science.gov (United States)

    Sai Saraswathi, V; Kamarudheen, Neethu; BhaskaraRao, K V; Santhakumar, K

    2017-03-01

    The aim of this study was to prepare silver nanoparticles by a green method using the aqueous leaves extract of Lagerstroemia speciosa. The prepared silver nanoparticles were characterized, studied for its photocatalytic and biofilm inhibition studies. The maximum absorbance peak was found at 427nm and thus confirming the formation of silver nanoparticles. The average size of silver nanoparticles synthesized was found to be 12nm using XRD and it was spherical in shape. The nanoparticles synthesized was investigated for photocatalytic activity for to two different dye molecules, methyl orange and methylene blue showing 310 and 290min degradation time respectively. The silver nanoparticles biofilm inhibition assay against clinical strains of Pseudomonas aeruginosa showed lowest accumulation at a lower concentration. The biofilm inhibition was also studied by visual interpretation through Scanning Electron Microscopy states that 50μgmL -1 exerts the highest inhibition compared against the control. This evident helps to analysis the silver nanoparticles for various applications in future. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. The draft genome sequence of multidrug-resistant Pseudomonas aeruginosa strain CCBH4851, a nosocomial isolate belonging to clone SP (ST277 that is prevalent in Brazil

    Directory of Open Access Journals (Sweden)

    Melise Silveira

    2014-12-01

    Full Text Available The high occurrence of nosocomial multidrug-resistant (MDR microorganisms is considered a global health problem. Here, we report the draft genome sequence of a MDR Pseudomonas aeruginosa strain isolated in Brazil that belongs to the endemic clone ST277. The genome encodes important resistance determinant genes and consists of 6.7 Mb with a G+C content of 66.86% and 6,347 predicted coding regions including 60 RNAs.

  13. High-resolution melting analysis as a powerful tool to discriminate and genotype Pseudomonas savastanoi pathovars and strains.

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    Andrea Gori

    Full Text Available Pseudomonas savastanoi is a serious pathogen of Olive, Oleander, Ash, and several other Oleaceae. Its epiphytic or endophytic presence in asymptomatic plants is crucial for the spread of Olive and Oleander knot disease, as already ascertained for P. savastanoi pv. savastanoi (Psv on Olive and for pv. nerii (Psn on Oleander, while no information is available for pv. fraxini (Psf on Ash. Nothing is known yet about the distribution on the different host plants and the real host range of these pathovars in nature, although cross-infections were observed following artificial inoculations. A multiplex Real-Time PCR assay was recently developed to simultaneously and quantitatively discriminate in vitro and in planta these P. savastanoi pathovars, for routine culture confirmation and for epidemiological and diagnostical studies. Here an innovative High-Resolution Melting Analysis (HRMA-based assay was set up to unequivocally discriminate Psv, Psn and Psf, according to several single nucleotide polymorphisms found in their Type Three Secretion System clusters. The genetic distances among 56 P. savastanoi strains belonging to these pathovars were also evaluated, confirming and refining data previously obtained by fAFLP. To our knowledge, this is the first time that HRMA is applied to a bacterial plant pathogen, and one of the few multiplex HRMA-based assays developed so far. This protocol provides a rapid, sensitive, specific tool to differentiate and detect Psv, Psn and Psf strains, also in vivo and against other related bacteria, with lower costs than conventional multiplex Real-Time PCR. Its application is particularly suitable for sanitary certification programs for P. savastanoi, aimed at avoiding the spreading of this phytopathogen through asymptomatic plants.

  14. Studies on Molecular Characterizations of the Outer Membrane Proteins, Lipids Profile, and Exopolysaccharides of Antibiotic Resistant Strain Pseudomonas aeruginosa

    Science.gov (United States)

    Yehia, Hany M.; Hassanein, Wesam A.; Ibraheim, Shimaa M.

    2015-01-01

    Susceptibility of the tested Pseudomonas aeruginosa strain to two different antibiotics, tetracycline (TE) and ciprofloxacin (CIP), was carried out using liquid dilution method. Minimum inhibitory concentrations of TE and CIP were 9.0 and 6.0 mg/100 mL, respectively. Some metabolic changes due to both, the mode of action of TE and CIP on P. aeruginosa and its resistance to high concentrations of antibiotics (sub-MIC) were detected. The total cellular protein contents decreased after antibiotic treatment, while outer membrane protein (OMP) contents were approximately constant for both treated and untreated cells. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the OMPs for untreated and TE and CIP treated cells indicated that the molecular changes were achieved as; lost in, induction and stability of some protein bands as a result of antibiotics treatment. Five bands (with mol. wt. 71.75, 54.8, 31.72, 28.63, and 20.33 KDa) were stable in both treated and untreated tested strains, while two bands (with mol. wt. 194.8 and 118.3 KDa) were induced and the lost of only one band (with mol. wt. 142.5 KDa) after antibiotics treatment. On the other hand, total lipids and phospholipids increased in antibiotic treated cells, while neutral lipids decreased. Also, there was observable stability in the number of fatty acids in untreated and treated cells (11 fatty acids). The unsaturation index was decreased to 56% and 17.6% in both TE and CIP treatments, respectively. The produced amount of EPSs in untreated cultures of P. aeruginosa was relatively higher than in treated cultures with sub-MICs of TE and CIP antibiotics. It was also observed that the amounts of exopolysaccharides (EPSs) increased by increasing the incubation period up to five days of incubation in case of untreated and antibiotic treated cultures. PMID:25710016

  15. Gene sequencing, cloning, and expression of the recombinant L- Asparaginase of Pseudomonas aeruginosa SN4 strain in Escherichia coli

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    Arastoo Badoei-dalfard

    2016-03-01

    Full Text Available Introduction: L- asparaginase is in an excessive demand in medical applications and in food treating industries, the request for this therapeutic enzyme is growing several folds every year. Materials and methods: In this study, a L- asparaginase gene from Pseudomonas aeruginosa strain SN4 was sequenced and cloned in E. coli. Primers were designed based on L- asparaginase from P. aeruginosa DSM 50071, which show high similarity to SN4 strain, according to 16S rRNA sequence. The L- asparaginase gene was exposed to restriction digestion with NdeI and XhoI enzymes and then ligated into pET21a plasmid. The ligated sample was transformed into competent E. coli (DE3 pLysS DH5a cells, according to CaCl2 method. The transformed E. coli cells were grown into LB agar plate containing 100 µg/ml ampicillin, IPTG (1 mM. Results: Recombinant L- asparaginase from E. coli BL21 induced after 9 h of incubation and showed high L- asparaginase activity about 93.4 IU/ml. Recombinant L- asparaginase sequencing and alignments showed that the presumed amino acid sequence composed of 350 amino acid residues showed high similarity with P. aeruginosa L- asparaginases about 99%. The results also indicated that SN4 L- asparaginase has the catalytic residues and conserve region similar to other L- asparaginases. Discussion and conclusion: This is the first report on cloning and expression of P. aeruginosa L- asparaginases in Escherichia coli. These results indicated a potent source of L- asparaginase for in vitro and in vivio anticancer consideration. 

  16. Transcriptional activation of multiple operons involved in para-nitrophenol degradation by Pseudomonas sp. Strain WBC-3.

    Science.gov (United States)

    Zhang, Wen-Mao; Zhang, Jun-Jie; Jiang, Xuan; Chao, Hongjun; Zhou, Ning-Yi

    2015-01-01

    Pseudomonas sp. strain WBC-3 utilizes para-nitrophenol (PNP) as a sole carbon and energy source. The genes involved in PNP degradation are organized in the following three operons: pnpA, pnpB, and pnpCDEFG. How the expression of the genes is regulated is unknown. In this study, an LysR-type transcriptional regulator (LTTR) is identified to activate the expression of the genes in response to the specific inducer PNP. While the LTTR coding gene pnpR was found to be not physically linked to any of the three catabolic operons, it was shown to be essential for the growth of strain WBC-3 on PNP. Furthermore, PnpR positively regulated its own expression, which is different from the function of classical LTTRs. A regulatory binding site (RBS) with a 17-bp imperfect palindromic sequence (GTT-N11-AAC) was identified in all pnpA, pnpB, pnpC, and pnpR promoters. Through electrophoretic mobility shift assays and mutagenic analyses, this motif was proven to be necessary for PnpR binding. This consensus motif is centered at positions approximately -55 bp relative to the four transcriptional start sites (TSSs). RBS integrity was required for both high-affinity PnpR binding and transcriptional activation of pnpA, pnpB, and pnpR. However, this integrity was essential only for high-affinity PnpR binding to the promoter of pnpCDEFG and not for its activation. Intriguingly, unlike other LTTRs studied, no changes in lengths of the PnpR binding regions of the pnpA and pnpB promoters were observed after the addition of the inducer PNP in DNase I footprinting. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. High-Resolution Melting Analysis as a Powerful Tool to Discriminate and Genotype Pseudomonas savastanoi Pathovars and Strains

    Science.gov (United States)

    Gori, Andrea; Cerboneschi, Matteo; Tegli, Stefania

    2012-01-01

    Pseudomonas savastanoi is a serious pathogen of Olive, Oleander, Ash, and several other Oleaceae. Its epiphytic or endophytic presence in asymptomatic plants is crucial for the spread of Olive and Oleander knot disease, as already ascertained for P. savastanoi pv. savastanoi (Psv) on Olive and for pv. nerii (Psn) on Oleander, while no information is available for pv. fraxini (Psf) on Ash. Nothing is known yet about the distribution on the different host plants and the real host range of these pathovars in nature, although cross-infections were observed following artificial inoculations. A multiplex Real-Time PCR assay was recently developed to simultaneously and quantitatively discriminate in vitro and in planta these P. savastanoi pathovars, for routine culture confirmation and for epidemiological and diagnostical studies. Here an innovative High-Resolution Melting Analysis (HRMA)-based assay was set up to unequivocally discriminate Psv, Psn and Psf, according to several single nucleotide polymorphisms found in their Type Three Secretion System clusters. The genetic distances among 56 P. savastanoi strains belonging to these pathovars were also evaluated, confirming and refining data previously obtained by fAFLP. To our knowledge, this is the first time that HRMA is applied to a bacterial plant pathogen, and one of the few multiplex HRMA-based assays developed so far. This protocol provides a rapid, sensitive, specific tool to differentiate and detect Psv, Psn and Psf strains, also in vivo and against other related bacteria, with lower costs than conventional multiplex Real-Time PCR. Its application is particularly suitable for sanitary certification programs for P. savastanoi, aimed at avoiding the spreading of this phytopathogen through asymptomatic plants. PMID:22295075

  18. Purification and Characterization of Carbazole 1,9a-Dioxygenase, a Three-Component Dioxygenase System of Pseudomonas resinovorans Strain CA10

    OpenAIRE

    Nam, Jeong-Won; Nojiri, Hideaki; Noguchi, Haruko; Uchimura, Hiromasa; Yoshida, Takako; Habe, Hiroshi; Yamane, Hisakazu; Omori, Toshio

    2002-01-01

    The carbazole 1,9a-dioxygenase (CARDO) system of Pseudomonas resinovorans strain CA10 consists of terminal oxygenase (CarAa), ferredoxin (CarAc), and ferredoxin reductase (CarAd). Each component of CARDO was expressed in Escherichia coli strain BL21(DE3) as a native form (CarAa) or a His-tagged form (CarAc and CarAd) and was purified to apparent homogeneity. CarAa was found to be trimeric and to have one Rieske type [2Fe-2S] cluster and one mononuclear iron center in each monomer. Both His-ta...

  19. Identification of extensive drug resistant Pseudomonas aeruginosa strains: New clone ST1725 and high-risk clone ST233

    Science.gov (United States)

    Aguilar-Rodea, Pamela; Zúñiga, Gerardo; Rodríguez-Espino, Benjamín Antonio; Olivares Cervantes, Alma Lidia; Gamiño Arroyo, Ana Estela; Moreno-Espinosa, Sarbelio; de la Rosa Zamboni, Daniela; López Martínez, Briceida; Castellanos-Cruz, María del Carmen; Parra-Ortega, Israel; Jiménez Rojas, Verónica Leticia; Vigueras Galindo, Juan Carlos; Velázquez-Guadarrama, Norma

    2017-01-01

    Several microorganisms produce nosocomial infections (NIs), among which Pseudomonas aeruginosa stands out as an opportunist pathogen with the capacity to develop multiresistance to first-choice antibiotics. From 2007 to 2013, forty-six NIs produced by P. aeruginosa were detected at a pediatric tertiary care hospital in Mexico with a significant mortality rate (17.39%). All isolates (n = 58/46 patients) were characterized by evaluating their response to several antibiotics as panresistant (PDR), extensively resistant (XDR), multiresistant (MDR) or sensitive (S). In addition, all isolates were typified through multilocus sequencing of seven genes: acsA, aroE, guaA, mutL, nuoD, ppsA and trpE. Furthermore, to establish the genetic relationships among these isolates, we carried out a phylogenetic inference analysis using maximum likelihood to construct a phylogenetic network. To assess evolutionary parameters, recombination was evaluated using the PHI test, and the ratio of nonsynonymous to synonymous substitutions was determined. Two of the strains were PDR (ST1725); 42 were XDR; four were MDR; and ten were S. Twenty-one new sequence types were detected. Thirty-three strains exhibited novel sequence type ST1725. The ratio of nonsynonym to synonym substitutions was 1:1 considering all genes. Phylogenetic analysis showed that the genetic relationship of the PDR, XDR and MDR strains was mainly clonal; however, the PHI test and the phylogenetic network suggest that recombination events occurred to produce a non-clonal population. This study aimed not only to determine the genetic diversity of clinical P. aeruginosa but also to provide a warning regarding the identification and spreading of clone ST1725, its ability to cause outbreaks with high mortality rates, and to remain in the hospital environment for over seven years. These characteristics highlight the need to identify clonal outbreaks, especially where high resistance to most antibiotics is observed, and control

  20. Production of proteasome inhibitor syringolin A by the endophyte Rhizobium sp. strain AP16.

    Science.gov (United States)

    Dudnik, Alexey; Bigler, Laurent; Dudler, Robert

    2014-06-01

    Syringolin A, the product of a mixed nonribosomal peptide synthetase/polyketide synthase encoded by the syl gene cluster, is a virulence factor secreted by certain Pseudomonas syringae strains. Together with the glidobactins produced by a number of beta- and gammaproteobacterial human and animal pathogens, it belongs to the syrbactins, a structurally novel class of proteasome inhibitors. In plants, proteasome inhibition by syringolin A-producing P. syringae strains leads to the suppression of host defense pathways requiring proteasome activity, such as the ones mediated by salicylic acid and jasmonic acid. Here we report the discovery of a syl-like gene cluster with some unusual features in the alphaproteobacterial endophyte Rhizobium sp. strain AP16 that encodes a putative syringolin A-like synthetase whose components share 55% to 65% sequence identity (72% to 79% similarity) at the amino acid level. As revealed by average nucleotide identity (ANI) calculations, this strain likely belongs to the same species as biocontrol strain R. rhizogenes K84 (formely known as Agrobacterium radiobacter K84), which, however, carries a nonfunctional deletion remnant of the syl-like gene cluster. Here we present a functional analysis of the syl-like gene cluster of Rhizobium sp. strain AP16 and demonstrate that this endophyte synthesizes syringolin A and some related minor variants, suggesting that proteasome inhibition by syrbactin production can be important not only for pathogens but also for endophytic bacteria in the interaction with their hosts. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  1. The efficacy of immediate versus delayed antibiotic administration on bacterial growth and biofilm production of selected strains of uropathogenic Escherichia coli and Pseudomonas aeruginosa

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    Leah Gandee

    2015-02-01

    Full Text Available Purpose The treatment of urinary tract infections (UTI with antibiotics is commonly used, but recurrence and antibiotic resistance have been growing and concerning clinicians. We studied whether the rapid onset of a protective biofilm may be responsible for the lack of effectiveness of antibiotics against selected bacteria. Materials and Methods Two established uropathogenic Escherichia coli strains, UTI89 and CFT073, and two Pseudomonas aeruginosa strains, PA01 and Boston-41501, were studied to establish a reliable biofilm formation process. Bacterial growth (BG was determined by optical density at 600 nm (OD 600 using a spectrophotometer, while biofilm formation (BF using crystal violet staining was measured at OD 550. Next, these bacterial strains were treated with clinically relevant antibiotics, ciprofloxacin HCl (200 ng/mL and 2 μg/mL, nitrofurantoin (20 μg/mL and 40 μg/mL and ampicillin (50 μg/mL at time points of 0 (T0 or after 6 hours of culture (T6. All measurements, including controls (bacteria -1% DMSO, were done in triplicates and repeated three times for consistency. Results The tested antibiotics effectively inhibited both BG and BF when administered at T0 for UPEC strains, but not when the antibiotic administration started 6 hours later. For Pseudomonas strains, only Ciprofloxacin was able to significantly inhibit bacterial growth at T0 but only at the higher concentration of 2 μg/mL for T6. Conclusion When established UPEC and Pseudomonas bacteria were allowed to culture for 6 hours before initialization of treatment, the therapeutic effect of selected antibiotics was greatly suppressed when compared to immediate treatment, probably as a result of the protective nature of the biofilm.

  2. Glutathione-Disrupted Biofilms of Clinical Pseudomonas aeruginosa Strains Exhibit an Enhanced Antibiotic Effect and a Novel Biofilm Transcriptome.

    Science.gov (United States)

    Klare, William; Das, Theerthankar; Ibugo, Amaye; Buckle, Edwina; Manefield, Mike; Manos, Jim

    2016-08-01

    Pseudomonas aeruginosa infections result in high morbidity and mortality rates for individuals with cystic fibrosis (CF), with premature death often occurring. These infections are complicated by the formation of biofilms in the sputum. Antibiotic therapy is stymied by antibiotic resistance of the biofilm matrix, making novel antibiofilm strategies highly desirable. Within P. aeruginosa biofilms, the redox factor pyocyanin enhances biofilm integrity by intercalating with extracellular DNA. The antioxidant glutathione (GSH) reacts with pyocyanin, disrupting intercalation. This study investigated GSH disruption by assaying the physiological effects of GSH and DNase I on biofilms of clinical CF isolates grown in CF artificial sputum medium (ASMDM+). Confocal scanning laser microscopy showed that 2 mM GSH, alone or combined with DNase I, significantly disrupted immature (24-h) biofilms of Australian epidemic strain (AES) isogens AES-1R and AES-1M. GSH alone greatly disrupted mature (72-h) AES-1R biofilms, resulting in significant differential expression of 587 genes, as indicated by RNA-sequencing (RNA-seq) analysis. Upregulated systems included cyclic diguanylate and pyoverdine biosynthesis, the type VI secretion system, nitrate metabolism, and translational machinery. Biofilm disruption with GSH revealed a cellular physiology distinct from those of mature and dispersed biofilms. RNA-seq results were validated by biochemical and quantitative PCR assays. Biofilms of a range of CF isolates disrupted with GSH and DNase I were significantly more susceptible to ciprofloxacin, and increased antibiotic effectiveness was achieved by increasing the GSH concentration. This study demonstrated that GSH, alone or with DNase I, represents an effective antibiofilm treatment when combined with appropriate antibiotics, pending in vivo studies. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  3. Does S-metolachlor affect the performance of Pseudomonas sp. strain ADP as bioaugmentation bacterium for atrazine-contaminated soils?

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    Cristina A Viegas

    Full Text Available Atrazine (ATZ and S-metolachlor (S-MET are two herbicides widely used, often as mixtures. The present work examined whether the presence of S-MET affects the ATZ-biodegradation activity of the bioaugmentation bacterium Pseudomonas sp. strain ADP in a crop soil. S-MET concentrations were selected for their relevance in worst-case scenarios of soil contamination by a commercial formulation containing both herbicides. At concentrations representative of application of high doses of the formulation (up to 50 µg g(-1 of soil, corresponding to a dose approximately 50× higher than the recommended field dose (RD, the presence of pure S-MET significantly affected neither bacteria survival (~10(7 initial viable cells g(-1 of soil nor its ATZ-mineralization activity. Consistently, biodegradation experiments, in larger soil microcosms spiked with 20× or 50 × RD of the double formulation and inoculated with the bacterium, revealed ATZ to be rapidly (in up to 5 days and extensively (>96% removed from the soil. During the 5 days, concentration of S-MET decreased moderately to about 60% of the initial, both in inoculated and non-inoculated microcosms. Concomitantly, an accumulation of the two metabolites S-MET ethanesulfonic acid and S-MET oxanilic acid was found. Despite the dissipation of almost all the ATZ from the treated soils, the respective eluates were still highly toxic to an aquatic microalgae species, being as toxic as those from the untreated soil. We suggest that this high toxicity may be due to the S-MET and/or its metabolites remaining in the soil.

  4. Does S-Metolachlor Affect the Performance of Pseudomonas sp. Strain ADP as Bioaugmentation Bacterium for Atrazine-Contaminated Soils?

    Science.gov (United States)

    Viegas, Cristina A.; Costa, Catarina; André, Sandra; Viana, Paula; Ribeiro, Rui; Moreira-Santos, Matilde

    2012-01-01

    Atrazine (ATZ) and S-metolachlor (S-MET) are two herbicides widely used, often as mixtures. The present work examined whether the presence of S-MET affects the ATZ-biodegradation activity of the bioaugmentation bacterium Pseudomonas sp. strain ADP in a crop soil. S-MET concentrations were selected for their relevance in worst-case scenarios of soil contamination by a commercial formulation containing both herbicides. At concentrations representative of application of high doses of the formulation (up to 50 µg g−1 of soil, corresponding to a dose approximately 50× higher than the recommended field dose (RD)), the presence of pure S-MET significantly affected neither bacteria survival (∼107 initial viable cells g−1 of soil) nor its ATZ-mineralization activity. Consistently, biodegradation experiments, in larger soil microcosms spiked with 20× or 50×RD of the double formulation and inoculated with the bacterium, revealed ATZ to be rapidly (in up to 5 days) and extensively (>96%) removed from the soil. During the 5 days, concentration of S-MET decreased moderately to about 60% of the initial, both in inoculated and non-inoculated microcosms. Concomitantly, an accumulation of the two metabolites S-MET ethanesulfonic acid and S-MET oxanilic acid was found. Despite the dissipation of almost all the ATZ from the treated soils, the respective eluates were still highly toxic to an aquatic microalgae species, being as toxic as those from the untreated soil. We suggest that this high toxicity may be due to the S-MET and/or its metabolites remaining in the soil. PMID:22615921

  5. The bean rhizosphere Pseudomonas aeruginosa strain RZ9 strongly reduces Fusarium culmorum growth and infectiveness of plant roots

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    Imen Haddoudi

    2017-07-01

    Full Text Available A faba bean rhizospheric Pseudomonas aeruginosa isolate RZ9 was used for studying its antifungal activity and protecting effects of faba bean and common bean against the root pathogen Fusarium culmorum strain MZB47. The dual culture tests showed that RZ9 inhibits MZB47 in vitro growth by 56%. When mixing RZ9 cell suspension with MZB47 macroconidia at equal proportion, the macroconidia viability was reduced with 70%. Pathogenicity tests conducted in sterile conditions showed that MZB47 caused an intense root rotting in faba bean ‘Aquadulce’ plantlets and a slight level in common bean ‘Coco blanc’. This was associated to significant decreases in plant growth only in ‘Aquadulce’, reducing shoot dry weight (DW by 82% and root DW by 70%. In soil samples, MZB47 caused severe root rotting and induced significant decreases in shoot DW (up to 51% and root DW (up to 60% for both beans. It was associated to a decrease in nodule number by 73% and 52% for faba bean and common bean, respectively. Biocontrol assays revealed that the inoculation of RZ9 to MZB47-treated plantlets enhanced shoot DWs (25% and 110% and root DWs (29% and 67%, in faba bean and common bean, respectively. Moreover, root rotting levels decreased and nodule number increased in treated compared to untreated plantlets. Collected data highlighted the disease severity of F. culmorum and demonstrated the potential of using RZ9 in controlling Fusaria root diseases in beans. Thereby, the current study represents the first report on the biocontrol effectiveness of P. aeruginosa against F. culmorum in beans.

  6. Aerobic degradation of N-methyl-4-nitroaniline (MNA) by Pseudomonas sp. strain FK357 isolated from soil.

    Science.gov (United States)

    Khan, Fazlurrahman; Vyas, Bhawna; Pal, Deepika; Cameotra, Swaranjit Singh

    2013-01-01

    N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway.

  7. A Cyanide-Induced 3-Cyanoalanine Nitrilase in the Cyanide-Assimilating Bacterium Pseudomonas pseudoalcaligenes Strain CECT 5344.

    Science.gov (United States)

    Acera, Felipe; Carmona, María Isabel; Castillo, Francisco; Quesada, Alberto; Blasco, Rafael

    2017-05-01

    Pseudomonas pseudoalcaligenes CECT 5344 is a bacterium able to assimilate cyanide as a sole nitrogen source. Under this growth condition, a 3-cyanoalanine nitrilase enzymatic activity was induced. This activity was encoded by nit4, one of the four nitrilase genes detected in the genome of this bacterium, and its expression in Escherichia coli enabled the recombinant strain to fully assimilate 3-cyanoalanine. P. pseudoalcaligenes CECT 5344 showed a weak growth level with 3-cyanoalanine as the N source, unless KCN was also added. Moreover, a nit4 knockout mutant of P. pseudoalcaligenes CECT 5344 became severely impaired in its ability to grow with 3-cyanoalanine and cyanide as nitrogen sources. The native enzyme expressed in E. coli was purified up to electrophoretic homogeneity and biochemically characterized. Nit4 seems to be specific for 3-cyanoalanine, and the amount of ammonium derived from the enzymatic activity doubled in the presence of exogenously added asparaginase activity, which demonstrated that the Nit4 enzyme had both 3-cyanoalanine nitrilase and hydratase activities. The nit4 gene is located downstream of the cyanide resistance transcriptional unit containing cio1 genes, whose expression levels are under the positive control of cyanide. Real-time PCR experiments revealed that nit4 expression was also positively regulated by cyanide in both minimal and LB media. These results suggest that this gene cluster including cio1 and nit4 could be involved both in cyanide resistance and in its assimilation by P. pseudoalcaligenes CECT 5344.IMPORTANCE Cyanide is a highly toxic molecule present in some industrial wastes due to its application in several manufacturing processes, such as gold mining and the electroplating industry. The biodegradation of cyanide from contaminated wastes could be an attractive alternative to physicochemical treatment. P. pseudoalcaligenes CECT 5344 is a bacterial strain able to assimilate cyanide under alkaline conditions, thus

  8. Chemical Analysis of Cellular and Extracellular Carbohydrates of a Biofilm-Forming Strain Pseudomonas aeruginosa PA14

    Science.gov (United States)

    Coulon, Charlène; Vinogradov, Evgeny; Filloux, Alain; Sadovskaya, Irina

    2010-01-01

    Background Pseudomonas aeruginosa is a Gram-negative bacterium and an opportunistic pathogen, which causes persisting life-threatening infections in cystic fibrosis (CF) patients. Biofilm mode of growth facilitates its survival in a variety of environments. Most P. aeruginosa isolates, including the non-mucoid laboratory strain PA14, are able to form a thick pellicle, which results in a surface-associated biofilm at the air-liquid (A–L) interface in standing liquid cultures. Exopolysaccharides (EPS) are considered as key components in the formation of this biofilm pellicle. In the non-mucoid P. aeruginosa strain PA14, the “scaffolding” polysaccharides of the biofilm matrix, and the molecules responsible for the structural integrity of rigid A–L biofilm have not been identified. Moreover, the role of LPS in this process is unclear, and the chemical structure of the LPS O-antigen of PA14 has not yet been elucidated. Principal Findings In the present work we carried out a systematic analysis of cellular and extracellular (EC) carbohydrates of P. aeruginosa PA14. We also elucidated the chemical structure of the LPS O-antigen by chemical methods and 2-D NMR spectroscopy. Our results showed that it is composed of linear trisaccharide repeating units, identical to those described for P. aeruginosa Lanýi type O:2a,c (Lanýi-Bergman O-serogroup 10a, 10c; IATS serotype 19) and having the following structure: -4)-α-L-GalNAcA-(1–3)-α-D-QuiNAc-(1–3)- α-L-Rha-(1-. Furthermore, an EC O-antigen polysaccharide (EC O-PS) and the glycerol-phosphorylated cyclic β-(1,3)-glucans were identified in the culture supernatant of PA14, grown statically in minimal medium. Finally, the extracellular matrix of the thick biofilm formed at the A-L interface contained, in addition to eDNA, important quantities (at least ∼20% of dry weight) of LPS-like material. Conclusions We characterized the chemical structure of the LPS O-antigen and showed that the O-antigen polysaccharide is

  9. Chemical analysis of cellular and extracellular carbohydrates of a biofilm-forming strain Pseudomonas aeruginosa PA14.

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    Charlène Coulon

    Full Text Available BACKGROUND: Pseudomonas aeruginosa is a gram-negative bacterium and an opportunistic pathogen, which causes persisting life-threatening infections in cystic fibrosis (CF patients. Biofilm mode of growth facilitates its survival in a variety of environments. Most P. aeruginosa isolates, including the non-mucoid laboratory strain PA14, are able to form a thick pellicle, which results in a surface-associated biofilm at the air-liquid (A-L interface in standing liquid cultures. Exopolysaccharides (EPS are considered as key components in the formation of this biofilm pellicle. In the non-mucoid P. aeruginosa strain PA14, the "scaffolding" polysaccharides of the biofilm matrix, and the molecules responsible for the structural integrity of rigid A-L biofilm have not been identified. Moreover, the role of LPS in this process is unclear, and the chemical structure of the LPS O-antigen of PA14 has not yet been elucidated. PRINCIPAL FINDINGS: In the present work we carried out a systematic analysis of cellular and extracellular (EC carbohydrates of P. aeruginosa PA14. We also elucidated the chemical structure of the LPS O-antigen by chemical methods and 2-D NMR spectroscopy. Our results showed that it is composed of linear trisaccharide repeating units, identical to those described for P. aeruginosa Lanýi type O:2a,c (Lanýi-Bergman O-serogroup 10a, 10c; IATS serotype 19 and having the following structure: -4-α-L-GalNAcA-(1-3-α-D-QuiNAc-(1-3- α-L-Rha-(1-. Furthermore, an EC O-antigen polysaccharide (EC O-PS and the glycerol-phosphorylated cyclic β-(1,3-glucans were identified in the culture supernatant of PA14, grown statically in minimal medium. Finally, the extracellular matrix of the thick biofilm formed at the A-L interface contained, in addition to eDNA, important quantities (at least ∼20% of dry weight of LPS-like material. CONCLUSIONS: We characterized the chemical structure of the LPS O-antigen and showed that the O-antigen polysaccharide is

  10. Structural investigation of the exopolysaccharide produced by Pseudomonas flavescens strain B62--degradation by a fungal cellulase and isolation of the oligosaccharide repeating unit.

    Science.gov (United States)

    Cescutti, P; Toffanin, R; Fett, W F; Osman, S F; Pollesello, P; Paoletti, S

    1998-02-01

    Pseudomonas flavescens strain B62 (NCPPB 3063) is a recently described bacterium isolated from walnut blight cankers. This strain has been designated as the type strain of a Pseudomonas rRNA group-I species. Strain B62 produced a mixture of two exopolysaccharides, differing in weight average relative molecular mass and composition. Only the most abundant exopolysaccharide (90% by mass), corresponding to the one with the lower molecular mass, was investigated by use of methylation analysis, partial acid hydrolysis, and NMR spectroscopy. The polysaccharide was depolymerised by the action of the cellulase produced by Penicillum funiculosum and the oligosaccharide obtained, corresponding to the repeating unit, was characterised by NMR spectroscopy and ion-spray mass spectrometry. The repeating unit of the B62 exopolysaccharide is [structure in text] where X is glucose (75%) or mannose (25%), and Lac is lactate. The O-acetyl groups are present only on 75% of the repeating units, and they are linked to the C6 of the hexose residues in non-stoichiometric amounts.

  11. Study of biological characteristics of Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis and from patients with extra-pulmonary infections

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    Eliana Guedes Stehling

    Full Text Available A total of 120 strains of Pseudomonas aeruginosa, isolated from cystic fibrosis (CF patients (n = 80 and from patients having extra-pulmonary infections (n = 40 were studied regarding the presence of some virulence factors (hemolysin, gelatinase and elastase production and presence of the algD and algU genes as detected by polymerase chain reaction-PCR. There was not a significant difference for the production of gelatinase and hemolysin between non-mucoid strains from CF patients and other isolates from extra-pulmonary infections and mucoid strains. The production of elastase was found to be significant among these strains. The algD gene was detected by PCR in all studied strains but the algU gene was detected only in 25% of the mucoid strains. Conclusion withdrawn from the results were: (i hemolysin and gelatinase production although present in many strains of P aeruginosa should not be considered as general virulence factors for the mucoid phenotype but could help in the pathogenic process; (ii elastase production could be a necessary virulence factor for the initial pathogenesis process; (iii mucoid and non-mucoid phenotypes could also be expressed according to the host's tissues or environment, and finally, (iv more than one regulator system for alginate production is probably present in each strain.

  12. Establishing quality control ranges for antimicrobial susceptibility testing of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus: a cornerstone to develop reference strains for Korean clinical microbiology laboratories.

    Science.gov (United States)

    Hong, Sung Kuk; Choi, Seung Jun; Shin, Saeam; Lee, Wonmok; Pinto, Naina; Shin, Nari; Lee, Kwangjun; Hong, Seong Geun; Kim, Young Ah; Lee, Hyukmin; Kim, Heejung; Song, Wonkeun; Lee, Sun Hwa; Yong, Dongeun; Lee, Kyungwon; Chong, Yunsop

    2015-11-01

    Quality control (QC) processes are being performed in the majority of clinical microbiology laboratories to ensure the performance of microbial identification and antimicrobial susceptibility testing by using ATCC strains. To obtain these ATCC strains, some inconveniences are encountered concerning the purchase cost of the strains and the shipping time required. This study was focused on constructing a database of reference strains for QC processes using domestic bacterial strains, concentrating primarily on antimicrobial susceptibility testing. Three strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) that showed legible results in preliminary testing were selected. The minimal inhibitory concentrations (MICs) and zone diameters (ZDs) of eight antimicrobials for each strain were determined according to the CLSI M23. All resulting MIC and ZD ranges included at least 95% of the data. The ZD QC ranges obtained by using the CLSI method were less than 12 mm, and the MIC QC ranges extended no more than five dilutions. This study is a preliminary attempt to construct a bank of Korean QC strains. With further studies, a positive outcome toward cost and time reduction can be anticipated.

  13. Establishing Quality Control Ranges for Antimicrobial Susceptibility Testing of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus: A Cornerstone to Develop Reference Strains for Korean Clinical Microbiology Laboratories

    Science.gov (United States)

    Hong, Sung Kuk; Choi, Seung Jun; Shin, Saeam; Lee, Wonmok; Pinto, Naina; Shin, Nari; Lee, Kwangjun; Hong, Seong Geun; Kim, Young Ah; Lee, Hyukmin; Kim, Heejung; Song, Wonkeun; Lee, Sun Hwa; Lee, Kyungwon; Chong, Yunsop

    2015-01-01

    Quality control (QC) processes are being performed in the majority of clinical microbiology laboratories to ensure the performance of microbial identification and antimicrobial susceptibility testing by using ATCC strains. To obtain these ATCC strains, some inconveniences are encountered concerning the purchase cost of the strains and the shipping time required. This study was focused on constructing a database of reference strains for QC processes using domestic bacterial strains, concentrating primarily on antimicrobial susceptibility testing. Three strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) that showed legible results in preliminary testing were selected. The minimal inhibitory concentrations (MICs) and zone diameters (ZDs) of eight antimicrobials for each strain were determined according to the CLSI M23. All resulting MIC and ZD ranges included at least 95% of the data. The ZD QC ranges obtained by using the CLSI method were less than 12 mm, and the MIC QC ranges extended no more than five dilutions. This study is a preliminary attempt to construct a bank of Korean QC strains. With further studies, a positive outcome toward cost and time reduction can be anticipated. PMID:26354353

  14. Antimicrobial activity of gallic acid against food-related Pseudomonas strains and its use as biocontrol tool to improve the shelf life of fresh black truffles.

    Science.gov (United States)

    Sorrentino, Elena; Succi, Mariantonietta; Tipaldi, Luca; Pannella, Gianfranco; Maiuro, Lucia; Sturchio, Marina; Coppola, Raffaele; Tremonte, Patrizio

    2018-02-02

    Refrigeration alone or in combination with other technologies represents the main tool used in the last decades to preserve the freshness of black truffles. This is principally due to the delicateness and vulnerability of this edible hypogeous fungus, so that other invasive preservation practices cannot be adopted. However, the proliferation of some microbial species during the cold storage still represents an unsolved problem. Pseudomonads are among the main spoiler bacteria responsible for the deterioration of refrigerated black truffles. Their growth ability at low temperatures requires the use of additional hurdles to prolong the shelf-life of truffles without altering their major features. The use of natural compounds may represent an alternative system for the biocontrol of this kind of product. Specifically, gallic acid (GA) is a phenolic acid naturally present in different foods, whose effectiveness was in vitro demonstrated against Pseudomonas spp. In our study, we reported the antimicrobial activity expressed by GA not only in vitro, using as target bacteria Pseudomonas putida DSMZ 291 T , P. fluorescens DSMZ 50090 T , P. fragi DSMZ 3456 T and Pseudomonas spp. P30-4, previously isolated from black truffles, but also in situ on fresh black truffles stored at 4°C for 28days. Our results showed Minimum Inhibitory Concentrations (MIC) of 2.5mg/mL GA for all tested strains, except for P. fluorescens DSMZ 50090 T , having a MIC corresponding to 5mg/mL GA. The Minimum Bactericidal Concentration (MBC) was 10mg/mL for all strains. The analysis of kinetic parameters showed that the survival declined passing from 2.5 to 10mg/mL GA concentrations, with P. fluorescens confirmed to be the most resistant strain. Moreover, images obtained from Scanning Electron Microscopy revealed that Pseudomonas cells were strongly injured by the treatment with GA at 2.5mg/mL concentration, displaying visible pores on the cellular surfaces, absence of flagella and lysis with loss of

  15. Characterisation of the thermostable protease AprX in strains of Pseudomonas fluorescens and impact on the shelf-life of dairy products: preliminary results

    Directory of Open Access Journals (Sweden)

    Nadia Andrea Andreani

    2016-12-01

    Full Text Available Bacterial proteases are involved in food spoilage and shelf-life reduction. Among the bacterial proteases, a predominant role in spoilage of dairy products seems to be played by the thermostable metallo-protease AprX, which is produced by various strains of Pseudomonas fluorescens. Differences in AprX enzyme activity among different strains were highlighted, but the most proteolytic strains were not identified. In this study, the presence of the aprX gene was evaluated in 69 strains isolated from food matrices and 18 reference strains belonging to the P. fluorescens group, which had been previously typed by the multi locus sequence typing method. Subsequently, a subset of reference strains was inoculated in ultra-high temperature milk, and the expression of the aprX gene was evaluated at 22 and 6°C. On the same milk samples, the proteolytic activity was then evaluated through Azocasein and trinitrobenzenesulfonic acid solution assays. Finally, to assess the applicability of the former assay directly on dairy products the proteolityc activity was tested on industrial ricotta samples using the Azocasein assay. These results demonstrate the spread of aprX gene in most strains tested and the applicability of Azocasein assay to monitor the proteolytic activity in dairy products.

  16. Inhibitory and toxic effects of volatiles emitted by strains of Pseudomonas and Serratia on growth and survival of selected microorganisms, Caenorhabditis elegans, and Drosophila melanogaster.

    Science.gov (United States)

    Popova, Alexandra A; Koksharova, Olga A; Lipasova, Valentina A; Zaitseva, Julia V; Katkova-Zhukotskaya, Olga A; Eremina, Svetlana Iu; Mironov, Alexander S; Chernin, Leonid S; Khmel, Inessa A

    2014-01-01

    In previous research, volatile organic compounds (VOCs) emitted by various bacteria into the chemosphere were suggested to play a significant role in the antagonistic interactions between microorganisms occupying the same ecological niche and between bacteria and target eukaryotes. Moreover, a number of volatiles released by bacteria were reported to suppress quorum-sensing cell-to-cell communication in bacteria, and to stimulate plant growth. Here, volatiles produced by Pseudomonas and Serratia strains isolated mainly from the soil or rhizosphere exhibited bacteriostatic action on phytopathogenic Agrobacterium tumefaciens and fungi and demonstrated a killing effect on cyanobacteria, flies (Drosophila melanogaster), and nematodes (Caenorhabditis elegans). VOCs emitted by the rhizospheric Pseudomonas chlororaphis strain 449 and by Serratia proteamaculans strain 94 isolated from spoiled meat were identified using gas chromatography-mass spectrometry analysis, and the effects of the main headspace compounds--ketones (2-nonanone, 2-heptanone, 2-undecanone) and dimethyl disulfide--were inhibitory toward the tested microorganisms, nematodes, and flies. The data confirmed the role of bacterial volatiles as important compounds involved in interactions between organisms under natural ecological conditions.

  17. Inhibitory and Toxic Effects of Volatiles Emitted by Strains of Pseudomonas and Serratia on Growth and Survival of Selected Microorganisms, Caenorhabditis elegans, and Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Alexandra A. Popova

    2014-01-01

    Full Text Available In previous research, volatile organic compounds (VOCs emitted by various bacteria into the chemosphere were suggested to play a significant role in the antagonistic interactions between microorganisms occupying the same ecological niche and between bacteria and target eukaryotes. Moreover, a number of volatiles released by bacteria were reported to suppress quorum-sensing cell-to-cell communication in bacteria, and to stimulate plant growth. Here, volatiles produced by Pseudomonas and Serratia strains isolated mainly from the soil or rhizosphere exhibited bacteriostatic action on phytopathogenic Agrobacterium tumefaciens and fungi and demonstrated a killing effect on cyanobacteria, flies (Drosophila melanogaster, and nematodes (Caenorhabditis elegans. VOCs emitted by the rhizospheric Pseudomonas chlororaphis strain 449 and by Serratia proteamaculans strain 94 isolated from spoiled meat were identified using gas chromatography-mass spectrometry analysis, and the effects of the main headspace compounds—ketones (2-nonanone, 2-heptanone, 2-undecanone and dimethyl disulfide—were inhibitory toward the tested microorganisms, nematodes, and flies. The data confirmed the role of bacterial volatiles as important compounds involved in interactions between organisms under natural ecological conditions.

  18. Pyrrolnitrin and Hydrogen Cyanide Production by Pseudomonas chlororaphis Strain PA23 Exhibits Nematicidal and Repellent Activity against Caenorhabditis elegans.

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    Munmun Nandi

    Full Text Available Pseudomonas chlororaphis strain PA23 is a biocontrol agent able to suppress growth of the fungal pathogen Sclerotinia sclerotiorum. This bacterium produces an arsenal of exometabolites including pyrrolnitrin (PRN, phenazine (PHZ, hydrogen cyanide (HCN, and degradative enzymes. Production of these compounds is controlled at both the transcriptional and posttranscriptional levels by the Gac-Rsm system, RpoS, PsrA, and the Phz quorum-sensing system. Beyond pathogen-suppression, the success of a biocontrol agent is dependent upon its ability to establish itself in the environment where predation by bacterivorous organisms, including nematodes, may threaten persistence. The focus of this study was to investigate whether PA23 is able to resist grazing by Caenorhabditis elegans and to define the role played by exoproducts in the bacterial-nematode interaction. We discovered that both PRN and HCN contribute to fast- and slow-killing of C. elegans. HCN is well-established as having lethal effects on C. elegans; however, PRN has not been reported to be nematicidal. Exposure of L4 stage nematodes to purified PRN reduced nematode viability in a dose-dependent fashion and led to reduced hatching of eggs laid by gravid adults. Because bacterial metabolites can act as chemoattractants or repellents, we analyzed whether PA23 exhibited attractant or repulsive properties towards C. elegans. Both PRN and HCN were found to be potent repellents. Next we investigated whether the presence of C. elegans would elicit changes in PA23 gene activity. Co-culturing the two organisms increased expression of a number of genes associated with biocontrol, including phzA, hcnA, phzR, phzI, rpoS and gacS. Exoproduct analysis showed that PHZ and autoinducer signals were upregulated, consistent with the gene expression profiles. Collectively, these findings indicate that PA23 is able to sense the presence of C. elegans and it is able to both repel and kill the nematodes, which

  19. Pyrrolnitrin and Hydrogen Cyanide Production by Pseudomonas chlororaphis Strain PA23 Exhibits Nematicidal and Repellent Activity against Caenorhabditis elegans

    Science.gov (United States)

    Nandi, Munmun; Selin, Carrie; Brassinga, Ann Karen C.; Belmonte, Mark F.; Fernando, W. G. Dilantha; Loewen, Peter C.; de Kievit, Teresa R.

    2015-01-01

    Pseudomonas chlororaphis strain PA23 is a biocontrol agent able to suppress growth of the fungal pathogen Sclerotinia sclerotiorum. This bacterium produces an arsenal of exometabolites including pyrrolnitrin (PRN), phenazine (PHZ), hydrogen cyanide (HCN), and degradative enzymes. Production of these compounds is controlled at both the transcriptional and posttranscriptional levels by the Gac-Rsm system, RpoS, PsrA, and the Phz quorum-sensing system. Beyond pathogen-suppression, the success of a biocontrol agent is dependent upon its ability to establish itself in the environment where predation by bacterivorous organisms, including nematodes, may threaten persistence. The focus of this study was to investigate whether PA23 is able to resist grazing by Caenorhabditis elegans and to define the role played by exoproducts in the bacterial-nematode interaction. We discovered that both PRN and HCN contribute to fast- and slow-killing of C. elegans. HCN is well-established as having lethal effects on C. elegans; however, PRN has not been reported to be nematicidal. Exposure of L4 stage nematodes to purified PRN reduced nematode viability in a dose-dependent fashion and led to reduced hatching of eggs laid by gravid adults. Because bacterial metabolites can act as chemoattractants or repellents, we analyzed whether PA23 exhibited attractant or repulsive properties towards C. elegans. Both PRN and HCN were found to be potent repellents. Next we investigated whether the presence of C. elegans would elicit changes in PA23 gene activity. Co-culturing the two organisms increased expression of a number of genes associated with biocontrol, including phzA, hcnA, phzR, phzI, rpoS and gacS. Exoproduct analysis showed that PHZ and autoinducer signals were upregulated, consistent with the gene expression profiles. Collectively, these findings indicate that PA23 is able to sense the presence of C. elegans and it is able to both repel and kill the nematodes, which should facilitate

  20. Physiological studies of methane- and methanol-oxidizing bacteria: comparison of a primary alcohol dehydrogenase from Methylococcus capsulatus (Texas strain) and Pseudomonas species M27.

    Science.gov (United States)

    Patel, R N; Bose, H R; Mandy, W J; Hoare, D S

    1972-05-01

    A primary alcohol dehydrogenase has been purified from Methylococcus capsulatus (Texas strain). The purified enzyme catalyzes the oxidation of methanol and formaldehyde to formate; other primary alcohols are oxidized to their corresponding aldehydes. Ammonium ions are required for enzyme activity. The enzyme has a molecular weight of 120,000 daltons and consists of two 62,000 molecular-weight subunits which dissociate at acidic pH. The enzyme is similar to an alcohol dehydrogenase enzyme isolated from Pseudomonas sp. M27.

  1. Antimicrobial activity of honey of africanized bee (Apis mellifera) and stingless bee, tiuba (Melipona fasciculata) against strains of Escherichia coli, Pseudomona aeruginosa and Staphylococcus aureus

    Science.gov (United States)

    Tenório, Eleuza Gomes; Alves, Natália Furtado; Mendes, Bianca Evanita Pimenta

    2017-11-01

    The objective of this study was to investigate the antimicrobial activity of honey of Africanized bees (Apis mellifera) and stingless bees (Melipona fasciculata), produced under the same flowering conditions, in municipalities of Baixada Maranhese, Brazil, against strains of pathogenic bacteria, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. In each municipality, the apiary and meliponario were less than 150 meters away from each other. The Kirby-Bauer method, and the diffusion technique of the agar plate through the extension of the inhibition in millimeters were used. The test results were negative for all samples, which did not demonstrate antimicrobial activity in any of the microorganisms tested.

  2. Safety of spray-dried powder formulated Pseudomonas fluorescens strain CL145A exposure to subadult/adult unionid mussels during simulated open-water treatments

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Waller, Diane L.; Wise, Jeremy K.; Mayer, Denise A.; Aloisi, Douglas B.

    2015-01-01

    The exposure effects of a commercially prepared spray dried powder (SDP) formulation ofPseudomonas fluorescens (strain CL145A) on the survival of seven species of unionid mussels endemic to the Great Lakes and Mississippi River basins was evaluated in this study. The study exposures were completed within replicated 350-liter test tanks contained within a mobile bioassay laboratory sited on the shores of the Black River near La Crosse, Wisconsin. The test tanks were supplied with flowing, filtered river water which was interrupted during the exposure period.

  3. Biosynthesis of indigo dye by newly isolated naphthalene-degrading strain Pseudomonas sp. HOB1 and its application in dyeing cotton fabric.

    Science.gov (United States)

    Pathak, Hilor; Madamwar, Datta

    2010-03-01

    Indigo is one of the oldest dyes manufactured chemically and is mostly used in textile, food, and pharmaceutical industries. However, owing to the environmental hazards posed by the chemical production, the present scenario in the field stipulates a biosynthesis alternative for indigo production. The present study describes an indigenously isolated naphthalene-degrading strain Pseudomonas sp. HOB1 producing a blue pigment when indole was added in the growth medium. This blue pigment was analyzed by high-pressure thin-layer chromatography and other spectroscopic techniques which revealed it to be the indigo dye. Pseudomonas sp. HOB1 showed ability to produce 246 mg indigo liter(-1) of the medium. The K (m) for the enzyme naphthalene dioxygenase which is involved in indigo formation is 0.3 mM, and V (max) was as high as 50 nmol min(-1) mg dry biomass(-1). The bacterial indigo dye was further successfully applied for dyeing cotton fabrics. The high indigo productivity of Pseudomonas sp. HOB1 using naphthalene as growth substrate and its applicability on cotton fabrics, therefore, stems the probability of using this culture for commercial indigo production.

  4. Use of silica-encapsulated Pseudomonas sp. strain NCIB 9816-4 in biodegradation of novel hydrocarbon ring structures found in hydraulic fracturing waters.

    Science.gov (United States)

    Aukema, Kelly G; Kasinkas, Lisa; Aksan, Alptekin; Wackett, Lawrence P

    2014-08-01

    The most problematic hydrocarbons in hydraulic fracturing (fracking) wastewaters consist of fused, isolated, bridged, and spiro ring systems, and ring systems have been poorly studied with respect to biodegradation, prompting the testing here of six major ring structural subclasses using a well-characterized bacterium and a silica encapsulation system previously shown to enhance biodegradation. The direct biological oxygenation of spiro ring compounds was demonstrated here. These and other hydrocarbon ring compounds have previously been shown to be present in flow-back waters and waters produced from hydraulic fracturing operations. Pseudomonas sp. strain NCIB 9816-4, containing naphthalene dioxygenase, was selected for its broad substrate specificity, and it was demonstrated here to oxidize fundamental ring structures that are common in shale-derived waters but not previously investigated with this or related enzymes. Pseudomonas sp. NCIB 9816-4 was tested here in the presence of a silica encasement, a protocol that has previously been shown to protect bacteria against the extremes of salinity present in fracking wastewaters. These studies demonstrate the degradation of highly hydrophobic compounds by a silica-encapsulated model bacterium, demonstrate what it may not degrade, and contribute to knowledge of the full range of hydrocarbon ring compounds that can be oxidized using Pseudomonas sp. NCIB 9816-4. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  5. Use of Silica-Encapsulated Pseudomonas sp. Strain NCIB 9816-4 in Biodegradation of Novel Hydrocarbon Ring Structures Found in Hydraulic Fracturing Waters

    Science.gov (United States)

    Aukema, Kelly G.; Kasinkas, Lisa; Aksan, Alptekin

    2014-01-01

    The most problematic hydrocarbons in hydraulic fracturing (fracking) wastewaters consist of fused, isolated, bridged, and spiro ring systems, and ring systems have been poorly studied with respect to biodegradation, prompting the testing here of six major ring structural subclasses using a well-characterized bacterium and a silica encapsulation system previously shown to enhance biodegradation. The direct biological oxygenation of spiro ring compounds was demonstrated here. These and other hydrocarbon ring compounds have previously been shown to be present in flow-back waters and waters produced from hydraulic fracturing operations. Pseudomonas sp. strain NCIB 9816-4, containing naphthalene dioxygenase, was selected for its broad substrate specificity, and it was demonstrated here to oxidize fundamental ring structures that are common in shale-derived waters but not previously investigated with this or related enzymes. Pseudomonas sp. NCIB 9816-4 was tested here in the presence of a silica encasement, a protocol that has previously been shown to protect bacteria against the extremes of salinity present in fracking wastewaters. These studies demonstrate the degradation of highly hydrophobic compounds by a silica-encapsulated model bacterium, demonstrate what it may not degrade, and contribute to knowledge of the full range of hydrocarbon ring compounds that can be oxidized using Pseudomonas sp. NCIB 9816-4. PMID:24907321

  6. Cepas de Pseudomonas spp. produtoras de metalo-betalactamase isoladas no Hospital Geral de Fortaleza Metallo-betalactamase producing Pseudomonas spp. strains isolated in the Hospital Geral de Fortaleza

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    Júlio César Nogueira Torres

    2006-10-01

    Full Text Available Pseudomonas sp. é um bacilo gram-negativo ubíquo de vida livre e freqüente em ambientes hospitalares. Bactérias produtoras de metalo-betalactamases (MBLs são em grande parte resistentes aos betalactâmicos de largo espectro, incluindo cefalosporinas e carbapenens. Este trabalho objetivou detectar cepas de Pseudomonas spp. resistentes ao imipenem e à ceftazidima, assim como identificar aquelas produtoras de MBLs. Foram estudadas (entre junho de 2002 e junho de 2003 311 cepas isoladas de diversas amostras clínicas no Hospital Geral de Fortaleza (HGF, bem como foram realizados testes de identificação e sensibilidade pelo sistema de automação MicroScan®/WalkAway, sendo as cepas multirresistentes confirmadas através do método de difusão em disco. A triagem para detecção de amostras produtoras de MBLs foi realizada pelo método de dupla difusão, utilizando discos com mercaptoacetato de sódio. Entre essas amostras, 24 (7,71% demonstraram produção de MBLs e padrão de multirresistência entre as cepas estudadas. Os antimicrobianos para os quais as cepas apresentaram maior sensibilidade foram a piperacilina/tazobactam com 255 (82% de sensibilidade, seguido da piperacilina isoladamente, com 229 (73,63%; imipenem com 195 (62,70%; ticarcilina/ácido clavulânico com 193 (62,05%; e ceftazidima com 138 (44,37%. A detecção dessas amostras configura um problema emergente, com importantes implicações na terapêutica antimicrobiana.Pseudomonas sp. is a ubiquitous gram-negative bacilli, of free and frequent life in hospital environment. Metallo-betalactamases (MBLs productive bacteria are largely resistant to betalactamics of wide spectrum, including cephalosporin and carbapenem. The objective of this work was to detect Pseudomonas spp. strains resistant to imipenem and ceftazidime, as well as to identify the MBLs producer ones. It was studied 311 isolated strains from several clinical samples at Fortaleza General Hospital (FGH, from June

  7. Virulence of the Pseudomonas fluorescens clinical strain MFN1032 towards Dictyostelium discoideum and macrophages in relation with type III secretion system

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    Sperandio Daniel

    2012-09-01

    Full Text Available Abstract Background Pseudomonas fluorescens biovar I MFN1032 is a clinical isolate able to grow at 37°C. This strain displays secretion-mediated hemolytic activity involving phospholipase C and cyclolipopeptides, and a cell-associated hemolytic activity distinct from the secreted hemolytic activity. Cell-associated hemolysis is independent of biosurfactant production and remains in a gacA mutant. Disruption of the hrpU-like operon (the basal part of type III secretion system from rhizospheric strains suppresses this activity. We hypothesized that this phenotype could reflect evolution of an ancestral mechanism involved in the survival of this species in its natural niche. In this study, we evaluated the hrpU-like operon’s contribution to other virulence mechanisms using a panel of Pseudomonas strains from various sources. Results We found that MFN1032 inhibited the growth of the amoebae Dictyostelium discoideum and that this inhibition involved the hrpU-like operon and was absent in a gacA mutant. MFN1032 was capable of causing macrophage lysis, if the hrpU-like operon was intact, and this cytotoxicity remained in a gacA mutant. Cell-associated hemolytic activity and macrophage necrosis were found in other P. fluorescens clinical isolates, but not in biocontrol P. fluorescens strains harbouring hrpU-like operon. The growth of Dictyostelium discoideum was inhibited to a different extent by P. fluorescens strains without correlation between this inhibition and hrpU-like operon sequences. Conclusions In P. fluorescens MFN1032, the basal part of type III secretion system plays a role in D. discoideum growth inhibition and macrophage necrosis. The inhibition of D. discoideum growth is dependent on the GacS/GacA system, while cell-associated hemolytic activity and macrophage lysis are not. Virulence against eukaryotic cells based on the hrpU-like operon may be more than just a stochastic evolution of a conserved system dedicated to survival in

  8. Quantitative and qualitative variability of the caseinolytic potential of different strains of Pseudomonas fluorescens: implications for the stability of casein micelles of UHT milks during their storage.

    Science.gov (United States)

    Baglinière, François; Tanguy, Gaëlle; Jardin, Julien; Matéos, Aurélie; Briard, Valérie; Rousseau, Florence; Robert, Benoît; Beaucher, Eric; Humbert, Gérard; Dary, Annie; Gaillard, Jean Luc; Amiel, Caroline; Gaucheron, Frédéric

    2012-12-15

    Pseudomonas fluorescens grows at low temperature and produces thermo-resistant protease(s) that can destabilize UHT (Ultra High Temperature) milk during its storage. The consequences of contamination of microfiltered milk with 9 strains of P. fluorescens on the stability of the corresponding UHT milk during storage had been investigated in this study. The strains were classified in two groups according to their ability to destabilize UHT milk. For the group of highly destabilizing strains, sedimentations of UHT milks, low values to phosphate test and the presence of aggregates were observed. Zeta potential and hydration of casein micelles decreased, whereas non casein nitrogen (NCN) and non protein nitrogen (NPN) contents increased. The analyses of NCN fraction by liquid chromatography coupled to mass spectrometry indicated that the different casein molecules were hydrolyzed in a similar way for the destabilizing strains suggesting that the same enzyme was implicated. For the group of slightly or not destabilizing strains no visual and biochemical alteration were found. This study showed that destabilization of UHT milk by P. fluorescens was highly variable and strain-dependent. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Whole genome sequence analysis of an Alachlor and Endosulfan degrading Pseudomonas strain W15Feb9B isolated from Ochlockonee River, Florida

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    Ashvini Chauhan

    2016-06-01

    Full Text Available We recently isolated a Pseudomonas sp. strain W15Feb9B from Ochlockonee River, Florida and demonstrated potent biodegradative activity against two commonly used pesticides - Alachlor [(2-chloro-2′,6′-diethylphenyl-N (methoxymethylacetanilide] and Endosulfan [(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,3,4-benzo(edi-oxathiepin-3-oxide], respectively. To further identify the repertoire of metabolic functions possessed by strain W15Feb9B, a draft genome sequence was obtained, assembled, annotated and analyzed. The genome sequence of strain 2385 has been deposited in GenBank under accession number JTKF00000000; BioSample number SAMN03151543. The sequences obtained from strain 2385 assembled into 192 contigs with a genome size of 6,031,588, G + C content of 60.34, and 5512 total number of putative genes. RAST annotated a total of 542 subsystems in the genome of strain W15Feb9B along with the presence of 5360 coding sequences. A genome wide survey of strain W15Feb9B indicated that it has the potential to degrade several other pollutants including atrazine, caprolactam, dioxin, PAHs (such as naphthalene and several chloroaromatic compounds.

  10. Whole genome sequence analysis of an Alachlor and Endosulfan degrading Pseudomonas strain W15Feb9B isolated from Ochlockonee River, Florida.

    Science.gov (United States)

    Chauhan, Ashvini; Pathak, Ashish; Ewida, Ayman Y I; Griffiths, Zabrenna; Stothard, Paul

    2016-06-01

    We recently isolated a Pseudomonas sp. strain W15Feb9B from Ochlockonee River, Florida and demonstrated potent biodegradative activity against two commonly used pesticides - Alachlor [(2-chloro-2',6'-diethylphenyl-N (methoxymethyl)acetanilide)] and Endosulfan [(6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,3,4-benzo(e)di-oxathiepin-3-oxide], respectively. To further identify the repertoire of metabolic functions possessed by strain W15Feb9B, a draft genome sequence was obtained, assembled, annotated and analyzed. The genome sequence of strain 2385 has been deposited in GenBank under accession number JTKF00000000; BioSample number SAMN03151543. The sequences obtained from strain 2385 assembled into 192 contigs with a genome size of 6,031,588, G + C content of 60.34, and 5512 total number of putative genes. RAST annotated a total of 542 subsystems in the genome of strain W15Feb9B along with the presence of 5360 coding sequences. A genome wide survey of strain W15Feb9B indicated that it has the potential to degrade several other pollutants including atrazine, caprolactam, dioxin, PAHs (such as naphthalene) and several chloroaromatic compounds.

  11. In-Vivo Expression Profiling of Pseudomonas aeruginosa Infections Reveals Niche-Specific and Strain-Independent Transcriptional Programs

    NARCIS (Netherlands)

    Bielecki, P.; Puchalka, J.; Wos-Oxley, M.L.; Martins Dos Santos, V.A.P.

    2011-01-01

    Pseudomonas aeruginosa is a threatening, opportunistic pathogen causing disease in immunocompromised individuals. The hallmark of P. aeruginosa virulence is its multi-factorial and combinatorial nature. It renders such bacteria infectious for many organisms and it is often resistant to antibiotics.

  12. Biofilm and metallo beta-lactamase production among the strains of Pseudomonas aeruginosa and Acinetobacter spp. at a Tertiary Care Hospital in Kathmandu, Nepal

    Directory of Open Access Journals (Sweden)

    Bandana Baniya

    2017-11-01

    Full Text Available Abstract Introduction Pseudomonas aeruginosa and Acinetobacter spp. are found to be associated with biofilm and metallo-β-lactamase production and are the common causes of serious infections mainly in hospitalized patients. So, the main aims of this study were to determine the rates of biofilm production and metallo beta-lactamase production (MBL among the strains of Pseudomonas aeruginosa and Acinetobacter spp. isolated from hospitalized patients. Methods A total of 85 P. aeruginosa isolates and 50 Acinetobacter spp. isolates isolated from different clinical specimens from patients admitted to Shree Birendra Hospital, Kathmandu, Nepal from July 2013 to May 2014 were included in this study. The bacterial isolates were identified with the help of biochemical tests. Modified Kirby-Bauer disc diffusion technique was used for antimicrobial susceptibility testing. Combined disc diffusion technique was used for the detection of MBL production, while Congo red agar method and tube adherence method were used for detection of biofilm production. Results Around 16.4% of P. aeruginosa isolates and 22% of the strains of Acinetobacter spp. were metallo β-lactamase producers. Out of 85 P. aeruginosa isolates, 23 (27.05% were biofilm producers according to tube adherence test while, only 13 (15.29% were biofilm producers as per Congo red agar method. Similarly, out of 50 Acinetobacter spp. 7 (14% isolates were biofilm producers on the basis of tube adherence test, while only 5 (10% were positive for biofilm production by Congo red agar method. Highest rates of susceptibility of P. aeruginosa as well as Acinetobacter spp. were seen toward colistin. Conclusion In our study, biofilm production and metallo beta-lactamase production were observed among Pseudomonas aeruginosa and Acinetobacter spp. However, no statistically significant association could be established between biofilm production and metallo beta-lactamase production.

  13. Effect of genomic location on horizontal transfer of a recombinant gene cassette between Pseudomonas strains in the rhizosphere and spermosphere of barley seedlings

    DEFF Research Database (Denmark)

    Sengelov, G.; Kristensen, K. J.; Sørensen, Anders Morten Hay

    2001-01-01

    , horizontal transfer of a recombinant gene cassette inserted into the chromosome of a Pseudomonas strutzeri strain, into a mobilizable plasmid (pAGM42), and into a conjugative plasmid (pKJK5) isolated from barley rhizosphere was investigated. Horizontal transfer efficiencies of the gene cassette inserted......The use of genetically engineered bacteria in natural environments constitutes a risk of transfer of recombinant DNA to the indigenous bacteria. However, chromosomal genes are believed to be less likely to transfer than genes on mobilizable and conjugative plasmids. To study this assumption...... efficiencies were up to 4.36 x 10(-3) transconjugants/(donors x recipients)(1/2). Transfer of chromosomal encoded genes could not be detected in the microcosms by conjugation or transformation. However, transformation did occur by using the same bacterial strains under laboratory conditions. The rhizosphere...

  14. 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

  15. A phenazine-1-carboxylic acid producing polyextremophilic Pseudomonas chlororaphis (MCC2693) strain, isolated from mountain ecosystem, possesses biocontrol and plant growth promotion abilities.

    Science.gov (United States)

    Jain, Rahul; Pandey, Anita

    2016-09-01

    The genus Pseudomonas is known to comprise a huge diversity of species with the ability to thrive in different habitats, including those considered as extreme environments. In the present study, a psychrotolerant, wide pH tolerant and halotolerant strain of Pseudomonas chlororaphis GBPI_507 (MCC2693), isolated from the wheat rhizosphere growing in a mountain location in Indian Himalayan Region (IHR), has been investigated for its antimicrobial potential with particular reference to phenazine production and plant growth promoting traits. GBPI_507 showed phenazine production at the temperatures ranged from 14 to 25°C. The benzene extracted compound identified as phenazine-1-carboxylic acid (PCA) through GC-MS exhibited antimicrobial properties against Gram positive bacteria and actinomycetes. The inhibition of phytopathogens in diffusible biocontrol assays was recorded in an order: Alternaria alternata>Phytophthora sp.>Fusarium solani>F. oxysporum. In volatile metabolite assays, all the pathogens, except Phytophthora sp. produced distorted colonies, characterized by restricted sporulation. The isolate also possessed other growth promoting and biocontrol traits including phosphate solubilization and production of siderophores, HCN, ammonia, and lytic enzymes (lipase and protease). Molecular studies confirmed production of PCA by the bacterium GBPI_507 through presence of phzCD and phzE genes in its genome. The polyextremophilic bacterial strain possesses various important characters to consider it as a potential agent for field applications, especially in mountain ecosystem, for sustainable and eco-friendly crop production. Copyright © 2016 Elsevier GmbH. All rights reserved.

  16. Non-target trials with Pseudomonas fluorescens strain CL145A, a lethal control agent of dreissenid mussels (Bivalvia: Dreissenidae

    Directory of Open Access Journals (Sweden)

    Daniel P. Molloy

    2013-01-01

    Full Text Available In an effort to develop an efficacious and environmentally safe method for managing zebra mussels (Dreissena polymorpha and quaggamussels (Dreissena rostriformis bugensis, we initiated a research project investigating the potential use of bacteria and their naturalmetabolic products as biocontrol agents. This project resulted in the discovery of an environmental isolate lethal to dreissenid mussels,Pseudomonas fluorescens strain CL145A (Pf-CL145A. In previous published reports we have demonstrated that: 1 Pf-CL145A’s mode ofaction is intoxication (not infection; 2 natural product within ingested bacterial cells lyse digestive tract epithelial cells leading to dreisseniddeath; and 3 high dreissenid kill rates (>90% are achievable following treatment with Pf-CL145A cells, irrespective of whether thebacterial cells are dead or alive. Investigating the environmental safety of Pf-CL145A was also a key element in our research efforts, andherein, we report the results of non-target trials demonstrating Pf-CL145A’s high specificity to dreissenids. These acute toxicity trials weretypically single-dose, short-term (24-72 h exposures to Pf-CL145A cells under aerated conditions at concentrations highly lethal todreissenids (100 or 200 mg/L. These trials produced no evidence of mortality among the ciliate Colpidium colpoda, the cladoceran Daphniamagna, three fish species (Pimephales promelas, Salmo trutta, and Lepomis macrochirus, and seven bivalve species (Mytilus edulis,Pyganodon grandis, Pyganodon cataracta, Lasmigona compressa, Strophitus undulatus, Lampsilis radiata, and Elliptio complanata. Lowmortality (3-27% was recorded in the amphipod Hyalella azteca, but additional trials suggested that most, if not all, of the mortality couldbe attributed to some other unidentified factor (e.g., possibly particle load or a water quality issue rather than Pf-CL145A’s dreissenidkillingnatural product. In terms of potential environmental safety, the results of

  17. Characterization of a Pseudomonas putida rough variant evolved in a mixed species biofilm with Acinetobacter sp. strain C6

    DEFF Research Database (Denmark)

    Hansen, Susse Kirkelund; Haagensen, Janus Anders Juul; Gjermansen, Morten

    2007-01-01

    Genetic differentiation by natural selection is readily observed among microbial populations, but a more comprehensive understanding of evolutionary forces, genetic causes, and resulting phenotypic advantages is not often sought. Recently, a surface population of Pseudomonas putida bacteria...... to oxygen starvation. A key factor explaining this conditional, nondispersal phenotype is likely to be the acquired ability of the rough variant to coaggregate specifically with Acinetobacter cells. We further show that the P. putida rough variant displayed enhanced production of a cellulose-like polymer...

  18. Chemical Structure of the Lipid A component of Pseudomonas sp. strain PAMC 28618 from Thawing Permafrost in Relation to Pathogenicity

    OpenAIRE

    Han-Gyu Park; Ganesan Sathiyanarayanan; Cheol-Hwan Hwang; Da-Hee Ann; Jung-Ho Kim; Geul Bang; Kyoung-Soon Jang; Hee Wook Ryu; Yoo Kyung Lee; Yung-Hun Yang; Yun-Gon Kim

    2017-01-01

    Climate change causes permafrost thawing, and we are confronted with the unpredictable risk of newly discovered permafrost microbes that have disease-causing capabilities. Here, we first characterized the detailed chemical structure of the lipid A moiety from a Pseudomonas species that was isolated from thawing arctic permafrost using MALDI-based mass spectrometric approaches (i.e., MALDI-TOF MS and MALDI-QIT-TOF MSn). The MALDI multi-stage mass spectrometry (MS) analysis of lipid A extracted...

  19. Enhanced efficacy of putative efflux pump inhibitor/antibiotic combination treatments versus MDR strains of Pseudomonas aeruginosa in a Galleria mellonella in vivo infection model.

    Science.gov (United States)

    Adamson, Dougal H; Krikstopaityte, Vasare; Coote, Peter J

    2015-08-01

    The objectives of this study were to compare the antibiotic susceptibility of Pseudomonas aeruginosa strains with increased efflux pump expression in vitro and in vivo and to use these same strains to evaluate the efficacy of combinations of antibiotics with putative efflux pump inhibitors in vivo. A collection of P. aeruginosa strains that overexpress three efflux pumps (MexAB-OprM, MexCD-OprJ and MexEF-OprN), in addition to a strain with all three Mex pumps deleted, were used. The virulence of these strains and their antibiotic susceptibility was measured in vivo using a Galleria mellonella larval infection model. The inhibitory effect of combinations of putative efflux pump inhibitors (trimethoprim and sertraline) with antibiotics on the strain overexpressing MexAB-OprM was also measured in vitro and compared with their efficacy in vivo in terms of larval survival and bacterial burden. Increased expression of the individual efflux pumps, or deletion of all three, had no significant effect on the virulence of P. aeruginosa in vivo. Expression levels of the efflux pumps clearly influenced antibiotic efficacy in vivo. The efficacy of levofloxacin, piperacillin and meropenem against larvae infected with the efflux pump mutants reflected susceptibility to the same drugs in vitro. Treatment of G. mellonella larvae infected with a strain that overexpressed MexAB-OprM with a combination of putative efflux pump inhibitors and levofloxacin resulted in enhanced therapeutic benefit compared with the constituent monotherapies. This study has demonstrated the utility of using G. mellonella to screen for novel therapeutic options for MDR P. aeruginosa and has shown that antibiotic/efflux pump inhibitor combinations should be further investigated for clinical application. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Characterization of hydrocarbon-degrading and biosurfactant-producing Pseudomonas sp. P-1 strain as a potential tool for bioremediation of petroleum-contaminated soil.

    Science.gov (United States)

    Pacwa-Płociniczak, Magdalena; Płaza, Grażyna Anna; Poliwoda, Anna; Piotrowska-Seget, Zofia

    2014-01-01

    The Pseudomonas sp. P-1 strain, isolated from heavily petroleum hydrocarbon-contaminated soil, was investigated for its capability to degrade hydrocarbons and produce a biosurfactant. The strain degraded crude oil, fractions A5 and P3 of crude oil, and hexadecane (27, 39, 27 and 13% of hydrocarbons added to culture medium were degraded, respectively) but had no ability to degrade phenanthrene. Additionally, the presence of gene-encoding enzymes responsible for the degradation of alkanes and naphthalene in the genome of the P-1 strain was reported. Positive results of blood agar and methylene blue agar tests, as well as the presence of gene rhl, involved in the biosynthesis of rhamnolipid, confirmed the ability of P-1 for synthesis of glycolipid biosurfactant. 1H and 13C nuclear magnetic resonance, Fourier transform infrared spectrum and mass spectrum analyses indicated that the extracted biosurfactant was affiliated with rhamnolipid. The results of this study indicate that the P-1 and/or biosurfactant produced by this strain have the potential to be used in bioremediation of hydrocarbon-contaminated soils.

  1. [blaVIM-2 gene detection in metallo-beta-lactamase-producing Pseudomonas aeruginosa strains isolated in an intensive care unit in Ciudad Bolívar, Venezuela].

    Science.gov (United States)

    Guevara, Armando; de Waard, Jacobus; Araque, María

    2009-08-01

    Ten Pseudomonas aeruginosa strains with resistance to broad-spectrum cephalosporin and carbapenems were studied to determine the presence of genes that mediate the production of metallo-beta-lactamases. These strains were isolated from patients with nosocomial infection at the Intensive Care Unit of the Complejo Hospitalario "Ruiz y Paéz" of Ciudad Bolívar, Bolívar State, Venezuela, from 2003 to 2006. In all isolates a metallo-enzyme activity was detected by using the double disk synergism test. PCR amplification of genes encoding the families IMP, VIM and SPM metallo-beta-lactamases showed the presence of a blaVIM gene in all strains studied. DNA sequencing revealed that all isolates showed the presence of blaVIM-2. These results suggest that it is necessary to keep these strains under epidemiologic surveillance, establish laboratory strategies for opportune detection and the implementation of new policies to ensure the appropriate use of antibiotics in this institution.

  2. Detection and Genetic Characterization of Metallo-β-Lactamase IMP-1 and VIM-2 in Pseudomonas aeruginosa Strains From Different Hospitals in Kermanshah, Iran.

    Science.gov (United States)

    Abiri, Ramin; Mohammadi, Pantea; Shavani, Navid; Rezaei, Mansour

    2015-09-01

    Pseudomonas aeruginosais a frequent nosocomial pathogen that causes severe diseases in many settings. Carbapenems, including meropenem and imipenem, are effective antibiotics against this organism. However, the use of carbapenems has been hampered by the emergence of strains resistant to carbapenemsvia different mechanisms such as the production of metallo-β-lactamases (MBLs), which hydrolyze all carbapenems. Several kinds of MBLs have been reported, among them VIM and IMP types being the most clinically significant carbapenemases. We aimed to determine the distribution of bla VIM-2 and bla IMP-1 transferable genes encoding MBLs in P. aeruginosa isolated from three academic hospitals in Kermanshah. From 22nd June to 22nd September 2012, 225 isolates of P. aeruginosa were collected. These isolates were tested for antibiotic susceptibility with the Kirby-Bauer disk-diffusion method, and the MBLs were assessed using the imipenem-EDTA double-disk synergy test. The isolates were investigated for bla VIM - 2 and bla IMP-1 genes using polymerase chain reaction. Among the 225 isolates, 33.7% (76/225) and 18.1% (41/225) were resistant to imipenem and meropenem, respectively. Of the 76 imipenem-resistant P. aeruginosa strains, 45 (59.2%) were positive for MBLs, 34 (75%) strains carried the bla IMP-1 gene, and 1 (2.2%) strain carried the bla VIM - 2 gene. Our results showed that there was a high frequency of IMP-1 positive P. aeruginosa in the different wards of the hospitals.

  3. Carbapenem-resistant Pseudomonas aeruginosa strains from a Spanish hospital: characterization of metallo-beta-lactamases, porin OprD and integrons.

    Science.gov (United States)

    Rojo-Bezares, Beatriz; Estepa, Vanesa; Cebollada, Rocío; de Toro, María; Somalo, Sergio; Seral, Cristina; Castillo, Francisco Javier; Torres, Carmen; Sáenz, Yolanda

    2014-05-01

    Molecular typing and mechanisms of carbapenem resistance such as alterations in porin OprD and presence of metallo-beta-lactamases (MBLs), as well as integrons have been studied in a collection of carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates from a Spanish hospital. One hundred and twenty-three CRPA isolates were recovered from different samples of 80 patients. Clonal relationship among CRPA was analyzed by SpeI-PFGE. Susceptibility testing to 11 antibiotics and MBL phenotype was determined by microdilution, IP/IPI E-test and double disc method. The oprD gene was studied by PCR and sequencing, and mutations were determined comparing with P. aeruginosa PAO1 sequence. Characterization of MBLs, and class 1 and 2 integrons were studied by PCR and sequencing. SDS-PAGE analysis of outer membrane proteins of selected strains was performed. Seventy-four-per-cent of patients with CRPA were hospitalised in the ICU setting and 50% had long hospitalization stays. Sixty-four different PFGE patterns were detected, and 87 CRPA strains were further analyzed. MBL phenotype was detected in 43 of 87 strains (49.4%), which contained blaVIM-2 gene inside class 1 integrons. VIM-2-producing strains belonged to lineages ST175, ST235, and ST973. A great diversity of nucleotide insertions, deletions, and mutations in oprD gene, and the presence of a new insertion sequence (ISPa45) truncating oprD were identified among CRPA strains. Class 1 integrons were detected in 75% of CRPA strains, blaVIM-2 and the new arrangement aac(3)-Ia+ISPa34+aadA1 (named as In661) being the most frequent gene-cassette arrays detected. Other gene cassettes detected in integrons were: aadB, aadA6, aadA7, aac(6')-Ib', and blaOXA-46. Copyright © 2014 Elsevier GmbH. All rights reserved.

  4. A synergistic interaction between salt-tolerant Pseudomonas and Mesorhizobium strains improves growth and symbiotic performance of liquorice (Glycyrrhiza uralensis Fish.) under salt stress.

    Science.gov (United States)

    Egamberdieva, Dilfuza; Li, Li; Lindström, Kristina; Räsänen, Leena A

    2016-03-01

    Chinese liquorice (Glycyrrhiza uralensis Fish.) is a salt-tolerant medicinal legume that could be utilized for bioremediation of salt-affected soils. We studied whether co-inoculation of the symbiotic Mesorhizobium sp. strain NWXJ19 or NWXJ31 with the plant growth-promoting Pseudomonas extremorientalis TSAU20 could restore growth, nodulation, and shoot/root nitrogen contents of salt-stressed G. uralensis, which was grown in potting soil and irrigated with 0, 50, and 75 mM NaCl solutions under greenhouse conditions. Irrigation with NaCl solutions clearly retarded the growth of uninoculated liquorice, and the higher the NaCl concentration (75 and 100 mM NaCl), the more adverse is the effect. The two Mesorhizobium strains, added either alone or in combination with P. extremorientalis TSAU20, responded differently to the salt levels used. The strain NWXJ19 was a good symbiont for plants irrigated with 50 mM NaCl, whereas the strain NWXJ31 was more efficient for plants irrigated with water or 75 mM NaCl solution. P. extremorientalis TSAU20 combined with single Mesorhizobium strains alleviated the salt stress of liquorice plants and improved yield and nodule numbers significantly in comparison with single-strain-inoculated liquorice. Both salt stress and inoculation raised the nitrogen content of shoots and roots. The nitrogen contents were at their highest, i.e., 30 and 35 % greater compared to non-stressed uninoculated plants, when plants were inoculated with P. extremorientalis TSAU20 and Mesorhizobium sp. NWXJ31 as well as irrigated with 75 mM NaCl solution. From this study, we conclude that dual inoculation with plant growth-promoting rhizobacteria could be a new approach to improve the tolerance of G. uralensis to salt stress, thereby improving its suitability for the remediation of saline lands.

  5. Global transcriptional response of solvent-sensitive and solvent-tolerant Pseudomonas putida strains exposed to toluene

    DEFF Research Database (Denmark)

    Molina-Santiago, Carlos; Udaondo, Zulema; Gómez Lozano, María

    2017-01-01

    for the degradation and synthesis of a wide range of chemicals. For the use of these microbes in bioremediation and biocatalysis, it is critical to understand the mechanisms underlying these phenotypic differences. In this study, RNA-seq analysis compared the short- and long-term responses of the toluene-sensitive KT......2440 strain and the highly-to