橄榄假丝酵母控制苹果果实青霉病的效果及机制

通过橄榄假丝酵母与扩展青霉同孔和异孔接种实验、平板对峙实验以及酵母挥发性物质抑菌实验,结合苹果组织伤口处酵母生长情况及伤口周围组织抗病相关酶活力的变化,阐明橄榄假丝酵母对苹果采后青霉的控制效果及其可能存在的抑菌机理。结果表明:橄榄假丝酵母处理果实的发病率和病斑直径显著低于对照组(无菌水处理)果实(P0.05);橄榄假丝酵母不能产生抑菌的次生代谢产物,其挥发性物质对青霉菌的生长无显著抑制作用(P0.05);橄榄假丝酵母具有较强的繁殖生长和定殖能力,能在苹果果皮定殖、扩增,从而抑制果实接种发病率和病斑直径的增加;同时,橄榄假丝酵母还能显著诱导果实过氧化物酶、多酚氧化酶和苯丙氨酸解氨酶活力增加(P0.05)。综上所述,橄榄假丝酵母抑制苹果扩展青霉发病的机制包括诱导果实抗病性以及与病原菌的营养和空间竞争。

Effect and Possible Modes of Action of Candida oleophila on Controlling Penicillium expansum in Apples

In order to explore the effect and possible modes of action of Candida oleophila on controlling Penicillium expansum in apples, plate confrontation tests of the yeast against the pathogen were carried out and the bacteriostatic effect of volatile compounds produced by the yeast on the pathogen was investigated; furthermore, the strains were inoculated separately or together into wounds of apple fruits to observe yeast growth and the activities of enzymes related to postharvest disease resistance. The results showed that C. oleophila treated fruits had lower disease incidence and lesion diameters than the control (P < 0.05). C. oleophila could not produce antifungal secondary metabolites, and its volatile substance had no significant inhibitory effect on the growth of P. expansum (P > 0.05). C. oleophila could colonize and amplify quickly in apple peel, and inhibit the increase of disease incidence and lesion diameter in fruits. C. oleophila also could effectively enhance the activities of peroxidase (POD), polyphenol oxidase (PPO) and phenylalanine ammonialyase (PAL) (P < 0.05). Based on the above analysis, the inhibitory mechanisms of C. oleophila against P. expansum in apples are through inducing disease resistance and competing for space and nutrition.