红火蚁病原真菌AUGM47早期发育超微结构研究

在前期筛选已获得对红火蚁Solenopsis invicta Buren高效致病真菌罗伯茨绿僵菌Metarhizium robertsii AUGM47的基础上，为进一步明确病原真菌对寄主昆虫的侵染机制。本试验在室内条件下，以红火蚁工蚁为侵染对象，利用荧光显微镜和透射电镜观察了罗伯茨绿僵菌AUGM47侵染单元分生孢子在体表附着萌发、穿透和体内增殖的早期发育过程。结果表明，菌株AUGM47分生孢子在红火蚁体表可萌发并形成附着胞侵入，接种后12 h观察到萌发，在36 h内普遍出现穿透结构穿透体壁。接种后48 h为菌体在血腔内的增殖阶段。菌丝体在穿透表皮和体腔内增殖过程中伴随着机械压力和酶的活动。接种后96 h，观察到自噬现象，菌体通过自噬降解并回收细胞器，为从体内穿出的晚期发育过程提供物质基础。本研究对罗伯茨绿僵菌AUGM47分生孢子在红火蚁体外至体内的发育进程研究证实了菌株的高致病性，为红火蚁生防真菌菌种改良和后续开发利用奠定理论基础。

Ultrastructural study of early infection of entomopathogenic fungi Metarhizium robertsii against Solenopsis invicta

In this study, based on the previous screening of the high pathogenic Metarhizium robertsii strain AUGM47 of Solenopsis invicta, to better understand the infection mechanism of this entomopathogenic fungi against pest host, the development at an early-stage associate with germination, attachment, penetration and conidial reproduction of M. robertsii strain AUGM47 in worker ant of S. invicta were observed using fluorescent microscopy and transmission electron microscope methods. Comparative observation with light microscopy and electron microscopy showed: Appressoria formation was the terminal act of germination. Strains AUGM47 began to germinate within 12 h, and penetrations were commonly observed within 36 h. Within 48 h post-inoculation, the hyphal bodies colonized the body cavity. The penetration and propagation of the hyphal bodies was accompanied by a combination of mechanical pressure and enzymatic action during the infection process. After 96 h post-inoculation, autophagy occurs, organelles were degraded and recycled through an autophagic process, to provide energy needs of late stage of infection in vitro. The structural characteristics of conidial development were explored while the highly pathogenic of M. robertsii strain AUGM47 was confirmed, this study will further provide the theoretical basis and reference for strain improvement and field application.