Multifunctional antagonistic mechanisms of the soybean nodule endophyte Pseudomonas sp. JDE115 against Agroathelia rolfsii

Abstract Soil-borne pathogens such as southern blight, caused by Agroathelia rolfsii, threaten soybean production and are difficult to control with chemicals. To reduce reliance on fungicides, we evaluated the soybean nodule endophyte Pseudomonas sp. JDE115 as a sustainable biocontrol agent. In vitro and greenhouse assays showed strong suppression of fungal hyphae and sclerotia, with treated plants remaining symptom-free. Scanning electron microscopy revealed collapsed sclerotia, while functional assays confirmed siderophore, protease, and hydrogen cyanide production. Gas chromatography–mass spectrometry identified volatile organic compounds, including 1-undecene and dimethyl disulfide, as key antifungal metabolites. These findings highlight JDE115 as a multifunctional antagonist with potential integration into integrated pest management programs, supporting reduced chemical inputs, soil health, and resilient agroecosystems.