An endophytic strain Bacillus velezensis JZ51 controlled pink mold rot of postharvest apple fruit via antagonistic action and disease resistance induction

Postharvest pink mold rot caused by Trichothecium roseum affects the storage and quality of apple fruit. However, the effective methods to prevent this disease were limited. The candidate biocontrol agent Bacillus velezensis strain JZ51 was isolated from apple fruit, and strain JZ51 exhibited a strong antagonistic ability against T. roseum in vitro. B. velezensis JZ51 significantly reduced the occurrence of apple pink mold rot, and JZ51 had a long-term colonization ability on apple fruit. Scanning electron microscopy showed that JZ51 suppressed conidial germination and hyphal growth of T. roseum during infection on apple fruit. Moreover, JZ51 induced disease resistance of apple fruit via increasing the activities of antioxidant and defense-related enzymes. In addition, strain JZ51 application did not affect the parameters of fruit quality. Taken together, this study developed a promising biocontrol agent to prevent pink mold rot.