GNPS - Effect of jasmonic acid (JA) on the metabolome of actinobacteria

Actinobacteria are prevalent in the rhizosphere and phyllosphere of diverse plant species where they help to enhance tolerance of plants against biotic and abiotic stresses. Here, we show that the plant hormones jasmonic acid (JA) and methyljasmonate (MeJA) alter growth, development and specialized metabolism of Streptomyces. Exposure of Streptomyces coelicolor to JA or MeJA led to enhanced production of the polyketide antibiotic actinorhodin. JA also exhibited toxicity towards Streptomycetaceae, whereby streptomycetes were more tolerant to JA than members of the genus Streptacidiphilus. This defensive response was associated with amino acid conjugation of JA with glutamine (Gln)-JA as the most prevalent conjugant, while conjugates with Val, Tyr, Phe and Leu/Ile were identified after longer exposure to JA. Synthetic JA conjugates failed to activate antibiotic production and showed significantly reduced toxicity. Thus, our findings shed light on a previously unknown defense mechanism deployed by Streptomyces, with amino acid conjugation protecting against the toxic effects of plant hormones. This study adds to the growing body of evidence that plant hormones can have a significant impact on members of the plant microbiome by affecting their growth, development, and secondary metabolism.