Bipolaris maydis foliar infection modifies maize root metabolites to recruit Pseudomonas for host resistance

Abstract Southern corn leaf blight (SCLB), caused by Bipolaris maydis , poses a significant threat to maize production. Traditional disease control methods, such as resistant varieties and fungicides, are compromised by resistance development in pathogens. Here, we discovered that foliar infection by B. maydis alters maize rhizosphere bacterial communities, particularly enriching Pseudomonas species. Inoculation of Pseudomonas CMS27 into the maize rhizosphere significantly bolstered resistance against B. maydis . Root exudates from maize plants treated with B. maydis and methyl jasmonate (MeJA) obviously attracted CMS27. GC–MS analysis revealed that B. maydis infection increased the secretion of specific metabolites (lauric acid, quinic acid, butyl oleate, oleamide, and palmitoleic acid) in root exudates, which promoted CMS27 chemotaxis, growth, and biofilm formation. Critically, the combined application of CMS27 with oleamide or palmitoleic acid, as well as foliar MeJA spraying, significantly enhanced maize resistance to SCLB. Collectively, our study uncovers a metabolite-mediated mechanism whereby foliar pathogen challenge or JA signaling recruits beneficial rhizobacteria for systemic resistance. These findings provide a mechanistic foundation for developing sustainable SCLB management strategies based on harnessing rhizosphere interactions, specifically through the application of CMS27-metabolite consortia or JA analog-induced immune priming.