Effects of Bacillus velezensis BG-2 on storage quality and defense enzyme activity of muskmelon

Abstract:

[Background] The white mould disease caused by Fusarium oxysporum seriously affects the quality of muskmelon and causes economic losses.[Objective] To study the effect of Bacillus velezensis BG-2 on F. oxysporum and the storage quality of postharvest muskmelon.[Methods] The effects of storage temperatures (25℃ and 4℃) on fruit decay rate, weight loss rate, flesh firmness, titratable acid content, soluble solid content, and vitamin C content of muskmelon were studied with B. velezensis BG-2. At the same time, the activities of catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) were determined. Furthermore, the effects of B. velezensis BG-2 on F. oxysporum and the storage quality of postharvest muskmelon were explored. [Results] B. velezensis BG-2 suspension inhibited the growth of F. oxysporum. At the concentration of 1×10⁷ CFU/mL, B. velezensis BG-2 presented the inhibition zone diameter of (20.45±0.39) mm and the inhibition titer of 144.48 mm/mL. Meanwhile, B. velezensis BG-2 slowed down the declines in flesh hardness, vitamin C content, soluble solid content, and titratable acid content, and inhibited fruit weight loss and decay, which can maintain fruit quality and inhibit the weakening of defense enzyme activities.[Conclusion] B. velezensis BG-2 can significantly inhibit the growth of F. oxysporum, delay the post ripening of muskmelon, and maintain the fruit quality and defense enzyme activity of postharvest muskmelon, demonstrating good control effect on muskmelon rot.