Pan-genome analysis identifies intersecting roles for <i>Pseudomonas</i> specialized metabolites in potato pathogen inhibition.

Abstract

Agricultural soil harbors a diverse microbiome that can form beneficial relationships with plants, including the inhibition of plant pathogens. <i>Pseudomonas</i> spp. are one of the most abundant bacterial genera in the soil and rhizosphere and play important roles in promoting plant health. However, the genetic determinants of this beneficial activity are only partially understood. Here, we genetically and phenotypically characterize the <i>Pseudomonas fluorescens</i> population in a commercial potato field, where we identify strong correlations between specialized metabolite biosynthesis and antagonism of the potato pathogens <i>Streptomyces scabies</i> and <i>Phytophthora infestans</i>. Genetic and chemical analyses identified hydrogen cyanide and cyclic lipopeptides as key specialized metabolites associated with <i>S. scabies</i> inhibition, which was supported by in planta biocontrol experiments. We show that a single potato field contains a hugely diverse and dynamic population of <i>Pseudomonas</i> bacteria, whose capacity to produce specialized metabolites is shaped both by plant colonization and defined environmental inputs.