Abstract: Objective: This study investigated the inhibitory effect of Bacillus amyloliquefaciens PTL16 on the fungal pathogen Colletotrichum gloeosporioides in yellow passion fruit, as well as its impacts on the appearance, antioxidant capacity and disease resistance of the fruit. Methods: Fresh passion fruit was sprayed with B. amyloliquefaciens PTL16 suspension and stored at (25 ± 1) ℃ and 85% relative humidity (RH) for up to 16 days. Appearance, reactive oxygen species (ROS) metabolism and resistance metabolism-related indicators were evaluated during the storage period. The results showed that treatment with B. amyloliquefaciens PTL16 significantly inhibited the fungal pathogen in passion fruit, reduced the spore germination rate and significantly slowed down the decay of the fruit, effectively decreased the production and accumulation of superoxide anion radical and malondialdehyde (MDA), and significantly enhanced the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), as well as the content of reduced glutathione (GSH). Additionally, it effectively increased the activities of resistance-related metabolic enzymes, including phenylalanine ammonia-lyase (PAL), peroxidase (POD), chitinase (CHI), β-1,3-glucanase (GLU), cinnamate-4-hydroxylase (C4H), and 4-coumarate:CoA ligase (4-CL). These effects collectively contributed to maintaining the storage quality of passion fruit. Conclusion: B. amyloliquefaciens PTL16 is capable of maintaining the postharvest quality of passion fruit and shows potential as a biological control agent for the preservation of the fruit.

Key words: Bacillus amyloliquefaciens PTL16; Passiflora edulis f. flavicarpa?Degener; reactive oxygen metabolism; resistance metabolism