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Diversity of biocontrol-related traits revealed by whole-genome analysis of worldwide-isolated phenazine-producing Pseudomonas spp

Adrien Biessy: Université de Moncton

<div>Plant-beneficial <em>Pseudomonas</em> spp<em>.</em> aggressively colonize the rhizosphere and display plant-growth promotion and/or disease-suppression activities. Some plant-beneficial <em>Pseudomonas</em> spp<em>. </em>strains within the <em>P</em>. <em>fluorescens</em> species complex produce several phenazine derivatives, such as phenazine-1-carboxylic acid (PCA), phenazine-1-carboxamide acid (PCN) and 2-hydroxyphenazine (2-OH-PHZ), which are inhibitory to numerous soilborne plant fungal and bacterial pathogens. In this project, we assembled a collection encompassing 63 representative strains of the worldwide diversity of plant-beneficial phenazine-producing <em>Pseudomonas</em> spp. Genome sequencing and comparative genomics revealed an important diversity, illustrated by a large pangenome accounting for 25 413 protein-coding genes. It also displayed insight into the evolutionary history of the phenazine biosynthetic operon. Given its diverse genomic context, it is likely that this operon was relocated several times during <em>Pseudomonas</em> evolution or independently acquired by horizontal gene transfer. We also identified numerous biocontrol-related traits, including antibiotics, siderophores and cyclic lipopeptides biosynthesis, some of which were previously unknown in these microorganisms. Strains were further characterized for their role in the biocontrol of three major potato pathogens, <em>Phytophthora infestans</em>, <em>Verticillium dahliae</em> and <em>Streptomyces scabies</em>.</div>