Bacillus velezensis M03 enhances peanut stress resistance and optimizes soil microecology, thereby increasing its resistance to Ralstonia solanacearum

Introduction Against the background of excessive application of chemical pesticides, which has caused the imbalance of soil microecosystems and the aggravation of pathogen resistance, the control of soil-borne diseases such as peanut bacterial wilt has become a major challenge in agricultural production. The traditional management mode relying on chemical pesticides is not only unsustainable, but also increasingly reveals its limitations. Methods This study explores the effects of Bacillus velezensis M03 on enhancing peanut stress resistance and optimizing soil microecology, systematically evaluating its ability to improve peanut resistance to Ralstonia solanacearum . Results It showed that B. velezensis M03 significantly inhibited the occurrence and spread of R. solanacearum , reducing the incidence of bacterial wilt from 50.00% to 16.67% three days after inoculation, with a disease index inhibition rate of 74.99%. B. velezensis M03 significantly increased the activities of SOD, POD, and CAT enzymes in peanut leaves, reduced MDA content, enhanced reactive oxygen species scavenging capacity, and mitigated membrane lipid peroxidation damage. B. velezensis M03 promoted soil nutrient transformation, significantly increasing the contents of nitrate nitrogen, available phosphorus, available potassium, and available sulfur, enhancing the activities of key soil enzymes such as phosphatase and urease, and optimizing nutrient availability. Microbial community analysis showed that B. velezensis M03 effectively inhibited the proliferation of R. solanacearum , promoted the enrichment of beneficial bacteria such as Streptomyces and Trichoderma, restored the bacterial network structure and modularity, and enhanced the functional stability of the microbial community. Discussion B. velezensis M03 significantly enhanced the systemic resistance of peanuts to bacterial wilt by synergistically regulating plant physiological resistance, soil nutrient cycling, and microbial community structure, providing a theoretical basis and technical support for the microbial control of soil-borne diseases.