Microencapsulated biocontrol agent B. amyloliquefaciens W26 for managing B. cinerea and tomato postharvest preservation

Tomato production and postharvest preservation are severely challenged by gray mold disease caused by Botrytis cinerea . The effectiveness of biocontrol agents against this pathogen is often constrained by their poor environmental stability and low foliar adhesion to plant surfaces. To address these limitations, this study developed a functionally enhanced microcapsule system by chemically grafting sodium alginate with polyacrylic acids (SA-PAAs) for protecting biocontrol bacterium B. amyloliquefaciens W26. The optimized W26@SA-PAAs microcapsules exhibited a high encapsulation efficiency of 86.1 %, superior storage stability (maintaining 78.8 % viability after 160 days at room temperature), and enhanced resilience to heat and UV radiation. Furthermore, this formulation displayed intelligent pH-responsive release behavior, with a maximum release of 86.0 % at pH 7.0 within 10 h, and significantly improved foliar adhesion, retaining 85.2 % of retention. Application of W26@SA-PAAs dramatically reduced the disease rate and disease index in tomato seedlings by 93.38 % and 96.44 %, respectively. This protective effect was associated with elevated activities of defense-related enzymes (SOD and POD), The use of W26@SA-PAAs also resulted in a 50 % reduction in postharvest fruit decay. These results indicate that the W26@SA-PAAs microcapsules effectively enhanced the stability and functional performance of B. amyloliquefaciens W26, offering a highly efficient and environmentally sustainable strategy for plant managing plant diseases and extending postharvest shelf life.