多粘类芽孢杆菌CP7对荔枝霜疫霉菌的抗菌活性及其作用机制

多粘类芽孢杆菌Paenibacillus polymyxa CP7菌株分泌的抗菌物质对荔枝霜疫霉菌等真菌具有很强的抑杀作用。用光学显微镜、扫描电镜和透射电镜观察发现,荔枝霜疫霉菌菌丝体经CP7菌株的抗菌物质处理后,菌丝发生不规则扭曲、萎蔫、干瘪,菌丝端部膨大等形态变化;经处理的菌体细胞组织结构受损,细胞膜结构模糊不清,看不到完整的外膜结构,细胞器消溶。处理后的荔枝霜疫霉菌孢子囊出现凹陷、干瘪、畸形;孢子囊外壁严重受损,原来厚实的外壁只剩一薄层,孢子囊内原有的微细结构消失,结构模糊不清,细胞器溶解,孢囊内物质大量外泄。抗菌物质还引起菌体细胞内磷的外泄,并对细胞呼吸速率和NADH氧化酶活力有抑制作用。

Antibacterial Activity and Mechanism of Paenibacillus polymyxa CP7 Against Peronophythora litchi

Paenibacillus polymyxa CP7 antibacterial substance has a significant inhibitory action on fungus, such as Peronophythora litchi. The morphology of mycelium and sporangium of Peronophythora litchi were observed under the optic microscope, the scanning electronic microscope and transmission electronic microscope. The mycelium of Peronophythora litchi treated by CP7 antibacterial substance show morphological aberrance such as irregular distorted, wizened and swelled of mycelium. It also show the expanded end of the mycelium. The cell tissue structure of mycelium is damaged that showing the incompleted cell wall and the cell membrane, the blurred cell membrane structure, incompleted external membrane structure, and the dissolved partial cell organs. The sporangium of Peronophythora litchi treated by CP7 antibacterial substance become hollow, withered and abnormal. The wall of sporangium is injuried seriously that original massiness external cell wall only remain a thin layer, original fine structure of the　sporangium is disappeared. It causes the blurred cell structure, dissolved cell organs and leakage of substances of the sporangium. In addition, the antibacterial substance also causes bacterial cells releasing of phosphorus, and inhibit cell respiration rate and NADH oxidase activity.