Bacillus velezensis 83 protects Arabidopsis thaliana against Botrytis cinerea by triggering JA ‐, and SA ‐dependent induced systemic resistance

Abstract BACKGROUND Modern agriculture is based on the application of synthetic agrochemicals to control multiple abiotic and biotic stresses. Nevertheless, owing to their negative effect on ecosystems and human health, their application is increasingly restricted. The use of plant growth‐promoting bacteria (PGPB) as well as biological control agents (BCAs) represents a sustainable alternative to chemical pesticides and fertilizers. Bacillus velezensis 83 ( Bv83 ) has been described as a BCA against several fungal phytopathogens. RESULTS In this work, we further study the molecular mechanisms behind the biological control capabilities of Bv83 using the pathosystem Arabidopsis thaliana–Botrytis cinerea . We used an in vitro system that can determine whether Bv83 can protect the plant triggering induced systemic resistance to B. cinerea . This protection was mediated by the accumulation of acetoin and the activation of phytohormone‐induced mechanisms, in particular, jasmonic acid‐ and salicylic acid (SA)‐mediated defense responses. Remarkably, we determined that in SA‐impaired mutants, acetoin biosynthesis was severely reduced. CONCLUSION Our work provides valuable information that advances our understanding of the biostimulant effect induced by the BCA Bv83 . © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.