Identification of 14 glutathione S-transferase genes from Lasioderma serricorne and characterization of LsGSTe1 involved in lambda-cyhalothrin detoxification.

In insects, glutathione S-transferases (GSTs) play a pivotal role in the detoxification of a wide range of pesticides. The cigarette beetle, Lasioderma serricorne, is an economically important pest insect of stored products. Recently, pyrethroid insecticides have been used to control this pest. However, little is known concerning the responses and functions of GSTs in L. serricorne under pyrethroid exposure. In this study, transcriptome sequencing was performed on L. serricorne, and a total of 14 GSTs were identified by retrieving the unigene dataset. Of these, 13 predicted GSTs fell into six cytosolic classes, namely, delta, epsilon, omega, sigma, theta, and zeta, and one was assigned to an "unclassified" group. The GST genes were differentially expressed in various larval tissues and at different developmental stages. Exposure to the pyrethroid insecticide lambda-cyhalothrin (LCT) caused oxidative stress in L. serricorne larvae and led to significantly elevated expression levels of six genes, among which LsGSTe1 was the most upregulated. Recombinant LsGSTE1 protein displayed LCT-metabolizing activity. Furthermore, LsGSTE1 protects cells against oxidative stress. Moreover, knockdown of LsGSTe1 by RNA interference dramatically increased the susceptibility of L. serricorne larvae to LCT treatment. The results from this study provide sequence resources and expression data for GST genes in L. serricorne. Our findings indicate that LsGSTE1 plays a dual role in LCT detoxification by metabolizing the pesticide and by preventing LCT-induced oxidative stress. Thus, the LsGSTe1 gene could be used as a potential target for sustainable management of the cigarette beetle.