PLoS Pathog. 2017 Jan 26;13(1):e1006028. doi: 10.1371/journal.ppat.1006028.

Microbial Partnerships of Pathogenic Oomycetes.

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A role for microbiota in plant diseases caused by oomycetes? As for most other pathogens, the regulation of virulence of this major group of eukaryotic plant pathogens are reconsidered by microbial ecologists at the community level. This is based on the statement that pathogen genomes are testimony lands of co-evolution, a co-evolution not only host genome associated but also microbiome related. In this “pearl”1 we highlight part of the state of the art on how infectious processes can be regulated along a disease cycle by interactions between oomycetes or between oomycetes and other microbial species. In addition, with other colleagues, we have recently used an amplicon 16S RNA gene-metagenomics and culture-dependent analyses to investigate bacterial taxa dynamics in response to colonization of tomato roots by the telluric oomycete Phytophthora parasitica2. The results indicated that the colonization of the host surface by the oomycete was associated to a Bacteroidetes/Protebacteria transition. On the basis of these results and on a positive correlation between the abundance of Bacteroidetes in soils and carbon mineralization, we raised the hypothesis according to which the ability of the oomycete for efficient depolymerization of polysaccharides should contribute to the observed enrichment of Bactoridetes. The results also indicate cooperation between P. parasitica and opportunistic Pseudomonas species which is showed by the preferential adhesion of bacteria to the surface of a biofilm formed by the oomycete and the subsequent extension of the bacterial habitat of the rhizosphere to tissues of host plants.

  1. Larousse M, Galiana E: Microbial Partnerships of Pathogenic Oomycetes. PLoS Pathog 2017, 13(1):e1006028.
  2. Larousse M, Rancurel C, Syska C, Palero F, Etienne C, Industri B, Nesme X, Bardin M, Galiana E: Tomato root microbiota and Phytophthora parasitica-associated disease. Microbiome 2017, 5(1):56.