Biocontrol potential of Streptomyces alboflavus LNU-CPARS28 against tomato gray mold caused by Botrytis cinerea

Tomato gray mold, caused by the necrotrophic fungal pathogen Botrytis cinerea, represents one of the most destructive diseases affecting tomato cultivation worldwide. While chemical fungicides remain the predominant control method, their intensive and prolonged application has resulted in significant environmental contamination and the emergence of resistant pathogen strains. In recent years, the utilization of antagonistic actinobacteria has emerged as a promising sustainable alternative for plant pathogen management. In this study, we demonstrated that Streptomyces alboflavus LNU-CPARS28 with strong antifungal activity against B. cinerea (85.56 ± 0.83 %) by inhibiting the mycelium growth and spores germination, disrupted the cell membrane, and caused mycelium deformation and the leakage of cellular contents. Its cell-free culture filtrate significantly reduced the infection of B. cinerea to tomato gray mold (with a control efficacy of 90.00 ± 0.58 %). Additionally, the strain demonstrated resistance-inducing properties in tomato seedlings. It also positively modulated the structure and function of the tomato rhizosphere microbial community by recruiting microbes associated with disease resistance while significantly upregulating metabolic pathways related to energy metabolism in tomato plants. These findings suggested that S. alboflavus LNU-CPARS28 shows strong potential as a biocontrol agent for the managing tomato gray mold.