鹿蹄草素对桃褐腐病菌的抑制作用及其抑菌机理

Inhibitory Effect and Antimicrobial Mechanism of Pyrolin on Monilinia fructicola in Peach

【目的】探讨鹿蹄草素对桃褐腐病菌的抑制活性及作用机理。【方法】采用生长速率法和果实接菌的方法测定鹿蹄草素对桃褐腐病菌菌丝体生长的抑制作用;采用倍比稀释法测定鹿蹄草素最小抑菌浓度(MIC)和最小杀菌浓度(MFC);观测接上鹿蹄草素和桃褐腐病菌对桃果实多酚氧化酶(PPO)、过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)活性的诱导情况;并用扫描电镜和透射电镜观察鹿蹄草素对桃褐腐病菌超微结构的影响。【结果】鹿蹄草素对桃褐腐病菌有较强的抑制活性,且浓度越高,抑制作用越强,其MIC为0.032mg·ml-1,MFC为0.156mg·ml-1;桃果实接上鹿蹄草素+病原菌后,PPO、POD和PAL活性开始升高,并在整个试验过程中一直保持较高的水平;扫描电镜下可见,菌丝扭曲变形,菌丝体之间相互粘连,细胞壁破裂,表面出现絮状凝集物。透射电镜下可见,细胞壁明显变薄,细胞内部组成紊乱,细胞结构遭到严重的破坏。【结论】鹿蹄草素对桃褐腐病菌具有较强的抗菌作用;可使菌丝体超微结构发生改变。

[Objective] To explore the antifungal activity and potential mechanism ofpyrolin against Moniliniafructicola. [Method] Agar plate tests was conducted to test the inhibitory effect in-vitro and in vivo ofpyrolin. And doubling dilution method was used to determine the minimal inhibitory concentration （MIC） and minimal fugicide concentration （MFC）. Polyphenol oxidase （PPO）, peroxidase （POD） and phenylalanine ammonium-lyase （PAL） activities induced by inoculation with pyrolin and M. fructicola were studied in peach. The ultrastructure of M. fructicola treated by pyrolin was observed through scanning electron microscope （SEM） and transmission electron microscope （TEM）. [ Result ] Pyrolin displayed strong antifungal activity to M. fructicola and the activity was significantly increased when the applied concentration was higher, the MIC value of 0.032 mg·mL^-1 and MFC value of 0.156 mg·mL^-1. The activities of PPO, POD and PAL in peach increased significantly when inoculated with pyrolin and M. fructicola, and maintained at a high level throughout the experiment. The observations with SEM revealed that the hyphae distorted, the adhesions mycelium occurred, the cell wall was rupture, cell surface occurred substance of flocculent agglutination. The observations with TEM showed that the hypha became thinning obviously, the inner structure confused, the hyphal cell was damaged severely. [ Conclusion ] Pyrolin has a strong antifungal activity and exerts a potent impact on the ultrastructure of M. fructicola.