Study On The Pathological Process And Molecular Biology Of Antheraea Pernyi Infected With Beauveria Bassiana

White muscardine is a kind of fungal disease of A.pernyi that caused by the infectionof B.bassiana.If it is popular that will cause huge economic losses in the sericulture.But people have not effective means to prevent white muscardine now,and know a littie about molecular mechanism of infection A.pernyi by B.bassiana.In this study,the morphological changes in the epidermis and fat body of A.pernyi pupae infected by B.bassiana was observed by electron microscopy,respectively.Meanwhile,the expression levels of Ap-PGRP-A,βGRP,Ap-hemolin-like,Immulectin A,Aplipophorin-Ⅲ,Ap CP8,Sepin like protein4,Lysozyme,Ap Def,Ap-s HSP21.4,Glutathione S-transferase theta and Apdorsal A,12immune-related genes in the epidermis,hemolymph and fat body of A.pernyi after being infected with B.bassiana were detected using Real-Time quantitative PCR(q RT-PCR).Moreover,the change of enzyme activity including SOD,POD and CAT were detected.SEM observation indicated that the main infections of B.bassiana in A.pernyi pupae occurred at valves,bristles root and the intersegmental membrane between the head and chest.Besides,conidia penetrated into the body directly from the thick and hard wall of the body.TEM observation indicated that in the fat body,organelles except mitochondria were first infected,and then the fat droplets were eroded.The color of the infected fat droplets became shallow,the surface appeared many holes,deformation,and the fat droplets divided into small fat droplets,indicating that they were completely eroded.When pupae were rigid,fat cells were completely destroyed,leaving only the blastospores and hyphae.Results of q RT-PCR indicated that Ap-PGRP-A,βGRP,Ap-hemolin-like,Ap CP8,Sepin like protein4,Lysozyme and Ap Def,7 immune-related genes in the three tissues of A.pernyi pupae were significantly up-regulated,after being challenged by B.bassiana.We suggest that they play an important role in A.pernyi against B.bassiana infection.The expression levels of Aplipophorin-Ⅲ,Immulectin A,Ap-s HSP21.4 and Glutathione S-transase theta,4 genes were significantly up-regulated in some tissues,they might be involved in innate immunity response of A.pernyi.The results of enzyme activity detection indicated that the activity of SOD was increased firstly and then decreased,the activity of CAT trended down-up-down and the activity of POD was up-down-up,in the hemolymph and fat body of A.pernyi.In addition,in the hemolymph of A.pernyi,SOD and POD played an important role in the preliminary stage of the infection of B.bassiana,and POD took a significant role in the late.However,in the fatbody of A.pernyi,SOD and POD played an important role in the preliminary stage;then POD and CAT played a major role,and SOD played a supplementary role in the later phase.