Building a Microecological Barrier: How Resistant Soybean Cultivars Integrate Metabolite Secretion and Microbial Consortia to Combat Root Rot

The composition of the root microbiota plays a crucial role in plant responses to soil-borne pathogens. Nevertheless, the defence mechanisms underlying multi-resistant soybean cultivars ability to combat major root rot pathogens remain poorly understood. This study aimed to elucidate how a resistant soybean, Heinong 531 (HN531), mitigates root rot through root metabolite secretion, microbial interactions, and biochemical strategies. We analysed the rhizosphere microbial community, secretion of antifungal compounds, and soil enzyme activities in HN531. A "protective microbial consortium" was identified and its role in pathogen suppression was investigated. Our results indicate that this community is associated with an enrichment of beneficial microorganisms, enhanced plant defence capacity, and increased soil enzyme activity, correlating with a disease control efficacy of up to 70% against root rot. These interactions involve the secretion of antimicrobial compounds and partially reshape the rhizosphere microbial structure, forming a protective microecological barrier. Our findings provide novel molecular targets for disease-resistant soybean breeding and highlight potential microbial resources for sustainable agriculture.