Cloning and expression analysis of a detoxification enzyme BmmGSTo3 gene in wild silkworm, Bombyx mandarina (Lepidoptera: Bombycidae)

Bombyx mandarina is one of prevalent pests in mulberry gardens during summer and autumn, posing significant challenges to sericulture across China. Glutathione S-transferase (GST), a vital detoxification enzyme in insects, plays a crucial role in protecting organisms from DNA damage and oxidative stress. In this study, the GSTo3 gene, coding glutathione S-transferase of B. mandarina, was cloned and its physicochemical properties and structures were predicted using bioinformatics tools. The relative expression levels in various tissues and induced transcriptional levels were detected by using qRT-PCR. Results revealed a 99.17% sequence similarity of GSTo3 gene between B. mandarina and Bombyx mori. It is mainly distributed in the head, fat body and epidermis tissues of B. mandarina larvae. After BmNPV infection, elevated GSTo3 expression levels were observed in the midgut. The transcriptional levels of GSTo3 gene were significantly up-regulated after exposure to phoxim, deltamethrin and chlorfenapyr exposure respectively in the fat body and midgut of B. mandarina. These findings underscore the significance of GSTo3 gene in exogenous materials metabolism and provide a new perspective on the resistance mechanism in B. mandarina.