Viscosin synthesis influencePseudomonas fluorescensSBW25 colonization and microbial assembly at the wheat rhizoplane in response to plant genotype

Abstract The importance of microbial functions for plant health and performance is unquestioned. Beneficial rhizosphere bacteria such as Pseudomonas spp. promote plant growth and protect against pathogens by producing a range of bioactive compounds, including cyclic lipopeptides (CLPs) known for their antimicrobial activities. However, the natural roles of CLPs during interactions between bacteria and plants remain underexplored especially in natural systems. Here, Pseudomonas fluorescens SBW25 producing the CLP viscosin was used to unravel the impact of viscosin on bacterial colonization potential and microbiome assembly at the plant root. Two varieties of winter wheat were inoculated with SBW25 or its viscosin-deficient mutant. Viscosin was shown to improve colonization potential and have a significant effect on assembly of both bacterial and protist communities at the root-soil interphase. This effect was shown to be plant cultivar dependent and pinpoints the importance of microbe-microbe interactions in colonization of plant roots. This study provides new insights into the natural role of viscosin and specifically the importance of viscosin for the bacterial colonization of plant roots and in shaping the microbial communities associated with different wheat varieties.