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Neil A. R. Gow - One of the best experts on this subject based on the ideXlab platform.

  • paenibacillus polymyxa antagonizes oomycete plant pathogens Phytophthora palmivora and pythium aphanidermatum
    Journal of Applied Microbiology, 2009
    Co-Authors: Salme Timmusk, Pieter Van West, Neil A. R. Gow, Paul R Huffstutler
    Abstract:

    Aim: To find sustainable alternatives to the application of synthetic chemicals for oomycete pathogen suppression. Methods and Results: Here, we present experiments on an Arabidopsis thaliana model system in which we studied the antagonistic properties of rhizobacterium Paenibacillus polymyxa strains towards the oomycete plant pathogens Phytophthora palmivora and Pythium aphanidermatum. We carried out studies on agar plates, in liquid media and in soil. Our results indicate that P. polymyxa strains significantly reduced P. aphanidermatum and P. palmivora colonization in liquid assays. Most plants that had been treated with P. polymyxa survived the P. aphanidermatum inoculations in soil assays. Conclusions: The antagonistic abilities of both systems correlated well with mycoidal substance production and not with the production of antagonistic substances from the biocontrol bacteria. Significance and Impact of the Study: Our experiments highlight the need to take biofilm formation and niche exclusion mechanisms into consideration for biocontrol assays performed under natural conditions.

  • Antagonistic effects of Paenibacillus polymyxa towards the oomycete plant pathogens Phytophthora palmivora and Pythium aphanidermatum
    2003
    Co-Authors: Salme Timmusk, Pieter Van West, Neil A. R. Gow, Gerhart E. H. Wagner
    Abstract:

    Antagonistic effects of Paenibacillus polymyxa towards the oomycete plant pathogens Phytophthora palmivora and Pythium aphanidermatum

  • Proteomic analysis of asexual development of Phytophthora palmivora
    Mycological Research, 2003
    Co-Authors: S. J. Shepherd, Pieter Van West, Neil A. R. Gow
    Abstract:

    Two-dimensional gel electrophoresis was used to analyse stage-specific proteins from Phytophthora palmivora, a pathogen of cocoa and other economically important tropical crops. Approximately 1% of proteins appeared to be specific for each of the mycelial, sporangial, zoospore, cyst and germinated cyst stages of the life-cycle. Three proteins excised from protein gels of P. palmivora were identified as isoforms of actin by database searches to public libraries of Phytophthora infestans. The protein profiles of parallel samples of P. palmivora and P. infestans demonstrated that 30% of proteins precisely co-migrated suggesting that proteomics may be used to examine changes in the specific stages in the life cycles of Phytophthora spp.

  • Electrotaxis of zoospores of Phytophthora palmivora at physiologically relevant field strengths
    Plant Cell and Environment, 1992
    Co-Authors: B. M. Morris, Brian Reid, Neil A. R. Gow
    Abstract:

    Plant roots generate electrical fields in the rhizosphere as a consequence of their ion transport activities. We show here that zoospores of the plant pathogen Phytophthora palmivora exhibit anodal electrotaxis in electrical fields ≥0.5 V m−1 comparable in size to the physiological fields around roots. An experimental protocol for applying weak electrical fields and quantifying electrotaxis is described. In this system, zoospore suspensions are isolated from the electrodes and their products using agarose bridges. Therefore, electrotaxis was not due to movement or trapping of zoospores in chemical, oxygen, pH or inhibitor gradients established by electrolysis. The electrophoretic and electroosmotic mobilities of encysted zoospores were measured. These forces did not influence the distribution of zoospores in electrotactic experiments at physiological field strengths. The electrotactic response saturated at fields above 10 V m−1 was inhibited in media of osmotic strength below 400 Osmol m−3, was maximal at pH 7.5 and increased at high zoospore densities. These data suggest that electrotaxis may be a useful adjunct to chemotaxis in root targeting by zoospores.

Paul R Huffstutler - One of the best experts on this subject based on the ideXlab platform.

  • paenibacillus polymyxa antagonizes oomycete plant pathogens Phytophthora palmivora and pythium aphanidermatum
    Journal of Applied Microbiology, 2009
    Co-Authors: Salme Timmusk, Pieter Van West, Neil A. R. Gow, Paul R Huffstutler
    Abstract:

    Aim: To find sustainable alternatives to the application of synthetic chemicals for oomycete pathogen suppression. Methods and Results: Here, we present experiments on an Arabidopsis thaliana model system in which we studied the antagonistic properties of rhizobacterium Paenibacillus polymyxa strains towards the oomycete plant pathogens Phytophthora palmivora and Pythium aphanidermatum. We carried out studies on agar plates, in liquid media and in soil. Our results indicate that P. polymyxa strains significantly reduced P. aphanidermatum and P. palmivora colonization in liquid assays. Most plants that had been treated with P. polymyxa survived the P. aphanidermatum inoculations in soil assays. Conclusions: The antagonistic abilities of both systems correlated well with mycoidal substance production and not with the production of antagonistic substances from the biocontrol bacteria. Significance and Impact of the Study: Our experiments highlight the need to take biofilm formation and niche exclusion mechanisms into consideration for biocontrol assays performed under natural conditions.

Salme Timmusk - One of the best experts on this subject based on the ideXlab platform.

Lester W. Burgess - One of the best experts on this subject based on the ideXlab platform.

S. S. Kamble - One of the best experts on this subject based on the ideXlab platform.