Resistance towards and biotransformation ofPseudomonas-produced secondary metabolites during community invasion

Abstract

AbstractThe role of antagonistic secondary metabolites produced byPseudomonas protegensin suppression of soil-borne phytopathogens has been clearly documented. However, their contribution to the ability ofP. protegensto establish in soil and rhizosphere microbiomes remains ambiguous. Here, we use a four-species synthetic community to determine how antibiotic production contributes toP. protegenscommunity invasion and identify community traits that alter the abundance of keyP. protegensantimicrobial metabolites (DAPG, pyoluteorin and orfamide A). Surprisingly, mutants deficient in antimicrobial production caused similar perturbations in community composition compared to invasion by wildtypeP. protegens. Intriguingly, while pyoluteorin and orfamide A are secreted at levels toxic to individual bacterial strains, community-level resistance circumvents toxicity. Here, we identify the underlying mechanism by which the cyclic lipopeptide, orfamide A, is inactivated and degraded byRhodococcus globerulusD757 andStenotrophomonas indicatrixD763. Altogether, the demonstration that the synthetic community constrainsP. protegensinvasion by detoxifying its antibiotics may provide a mechanistic explanation to inconsistencies in biocontrol effectivenessin situ.