Characterization of Two UDP-Glycosyltransferase Genes in Grapholita molesta and Their Detoxification Roles Against...

Grapholita molesta is a major pest of economically important fruit crops worldwide. UDP-glycosyltransferases (UGTs), as phaseⅡdetoxification enzymes, play a crucial role in insect detoxification metabolism. However, the molecular characteristics and insecticide detoxification functions of G. molesta UGTs remain unknown. In this study, UGT40BA1 and UGT46A28-two UGT genes-were cloned, characterized, and subjected to phylogenetic analysis. Results showed UGT40BA1 is closely related to Spodoptera exigua's homolog and UGT46A28 to Bombyx mori's. While UGT40BA1 was highly expressed in the second-instar and UGT46A28 in the first and third, both genes showed high expression in the adult midgut. Exposure to imidacloprid and lambda-cyhalothrin significantly altered the expression of both UGT genes, whereas avermectin treatment did not induce significant transcriptional changes. Furthermore, inhibition of UGT activity by sulfinpyrazone significantly enhanced the susceptibility of G. molesta to the three insecticides. These results suggest that UGT40BA1 and UGT46A28 may participate in the detoxification of these insecticides in G. molesta.