A Multifunctional Bacillus ‐Nanozyme Biohybrid for Control of Tobacco Crown Rot Through Cuproptosis‐Like Antifungal Activity and Rhizosphere Regulation

Tobacco crown rot caused by Fusarium oxysporum is difficult to control because the pathogen persists in soil and disrupts both plant physiology and rhizosphere function. Herein, we developed a multifunctional bacteria‐nanozyme biohybrid by immobilizing copper‐piceatannol‐functionalized mesoporous silica nanoparticles on Bacillus subtilis (BS@MCP). The composite retained bacterial viability while exhibiting peroxidase‐like catalytic activity and cuproptosis‐like antifungal effects. BS@MCP showed broad‐spectrum antimicrobial activity against F. oxysporum , Candida albicans , methicillin‐resistant Staphylococcus aureus and carbapenem‐resistant Escherichia coli , with H 2 O 2 further enhancing microbial inhibition. Mechanistic analyses indicated that BS@MCP disrupted fungal membrane integrity, promoted ROS accumulation and lipid peroxidation, increased intracellular copper content, impaired respiratory‐chain activity, depleted ATP and induced pyruvate accumulation. Antioxidant and copper‐chelation rescue experiments further supported the cooperative involvement of oxidative damage and copper‐dependent cell death. In non‐sterile soil, BS@MCP/H 2 O 2 reduced the disease index from 91.0% in infected plants to 24.7%, while increasing plant height by 63.5%, root length by 120.7%, fresh biomass by 99.7%, and dry biomass by 225.6%. The treatment enhanced antioxidant and defense‐related responses, as well as rhizosphere soil organic matter and total nitrogen. Together, BS@MCP integrates nanozyme‐mediated pathogen suppression with microbial biocontrol, host defense activation and rhizosphere improvement, providing a multifunctional strategy for managing soil‐borne crop disease.