贝莱斯芽孢杆菌BG-2对厚皮甜瓜贮藏品质及防御酶活性的影响

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

摘要:

【背景】厚皮甜瓜白霉病主要由尖孢镰刀菌引起，严重影响厚皮甜瓜品质，从而造成经济损失。【目的】研究贝莱斯芽孢杆菌BG-2对尖孢镰刀菌的抑制作用，以及对采后厚皮甜瓜贮藏品质的影响。【方法】以贝莱斯芽孢杆菌为供试菌株，研究其对2种不同贮藏温度（25℃和4℃）下厚皮甜瓜果实腐烂率、失重率、果肉硬度、可滴定酸、可溶性固形物含量和维生素C含量的影响，同时测定过氧化氢酶（catalase，CAT）、过氧化物酶（peroxidase，POD）和超氧化物歧化酶（superoxide dismutase，SOD）防御酶活性，进而探究Bacillus velezensis BG-2对尖孢镰刀菌的抑制作用及对厚皮甜瓜贮藏品质的影响。【结果】贝莱斯芽孢杆菌BG-2菌悬液能有效抑制尖孢镰刀菌的生长，菌悬液浓度为1×10⁷ CFU/mL时抑菌圈直径为（20.45±0.39） mm，抑菌效价为144.48 mm/mL；同时，B. velezensis BG-2能有效减缓果肉硬度、维生素C含量、可溶性固形物含量和可滴定酸的下降，抑制果实失重和腐烂，能较好地保持果实的品质，抑制防御酶活性的下降。【结论】B. velezensis BG-2能显著抑制尖孢镰刀菌的生长，延缓厚皮甜瓜的后熟，维持采后甜瓜果实较高的品质和防御酶活性，对甜瓜腐烂有较好的防治效果。

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.