绿僵菌侵染小菜蛾体表过程的显微观察

Microscopic observations of infection process of Metarhizium anisopliae on the cuticle of the diamondback moth, Plutella xylostella

采用扫描电镜研究了小菜蛾 Plutella xylostella体表结构对绿僵菌入侵行为的影响及绿僵菌的侵染过程。结果表明: 绿僵菌孢子在小菜蛾体表萌发后可形成附着胞, 寄主体表结构影响形成附着胞的快慢、多少及穿透体壁时芽管长度, 在平缓结构区和刺状结构区比嵴状结构区更易形成附着胞, 且芽管较短。在所有结构区, LF68菌株穿透芽管均短于LD65菌株的芽管。接种后7 h, 分生孢子在小菜蛾体表开始萌发, LF68与LD65菌株分别于接种后10 h和13 h出现侵染构造穿透体壁。

The infection mode of the diamondback moth, Plutella xylostella by two isolates of the entomopathogenic fungus Metarhizium anisopliae was studied using scanning electron microscopy. The results indicated surface topography of host affected infection behavior, especially appressoria production. There were more appressoria formed and shorter germ tubes grew before penetrating in gentle and spinous surface topography than in acanthoid surface topography. The germ tubes of LF68 isolate were shorter than that of LD65 isolate before the appressoria formed or penetration occurred in all kinds of surface topography. Conidia germinated within 7 h postinoculation for the two isolates, but penetrations were observed within 10 h and 13 h for LF68 and LD65 isolates, respectively.