PcUGT203E1 and PcUGT203B2 are involved in abamectin susceptibility in Panonychus citri

UDP-glycosyltransferases (UGTs) are important phase II enzymes involved in the detoxification of exogenous substances. Previous studies found that PcUGT203E1 and PcUGT203B2 are upregulated in abamectin-resistant Panonychus citri strain. However, the relationship between the upregulation of PcUGT203E1 and PcUGT203B2, and abamectin resistance is still unclear. In this study, PcUGT203E1 and PcUGT203B2 were found to be significantly upregulated after exposure to abamectin. Molecular docking analyses revealed that both PcUGT203E1 and PcUGT203B2 can interact with abamectin through hydrogen bonding. Silencing of PcUGT203E1 and PcUGT203B2 by RNAi increased the susceptibility of P. citri to abamectin. Transgenic expression in Drosophila melanogaster of PcUGT203E1 and PcUGT203B2 significantly decreased susceptibility of D. melanogaster to abamectin. Recombinant expression and in vitro inhibiting assays demonstrated that abamectin had inhibitory effects on the catalytic activity of PcUGT203E1 and PcUGT203B2, and the PcUGT203E1 and PcUGT203B2 exhibited abamectin-depleting capacity. These results indicated that PcUGT203E1 and PcUGT203B2 contribute to abamectin susceptibility in P. citri, which broaden understanding of the molecular mechanism of abamectin resistance.