UDP-glycosyltransferase confers anthranilic diamide resistance in Bemisia tabaci

UDP-glycosyltransferases (UGTs) are key Phase II detoxification enzymes in insects, playing a crucial role in resistance to a variety of insecticides, including diamides. Cyantraniliprole (CYA) is a systemic diamide insecticide with high toxicity against Bemisia tabaci, a major global agricultural pest transmitting over 200 plant viruses. While B. tabaci has developed medium-level resistance to CYA, the role of UGTs in this resistance remains poorly understood.

This study aimed to investigate the role of UGTs in B. tabaci resistance to CYA and further elucidate the underlying mechanisms.

Synergism bioassays and enzymatic activity analyses were conducted to assess the contribution of UGTs to CYA resistance. RNA sequencing and RT-qPCR were employed to identify differentially expressed BtUGT genes associated with resistance. The functions of UGTs and the UDP-glucose (UDPG) biosynthesis pathway in CYA resistance were confirmed through RNA interference and transgenic Drosophila melanogaster lines. The metabolites of CYA in the resistant strain were identified using LC-MS/MS. A cross-resistance study to chlorantraniliprole was performed to further confirm the role of UGTs in the diamide resistance of B. tabaci.

Higher expression of UGTs represents a key metabolic resistance mechanism of B. tabaci to CYA. Specifically, overexpression of BtUGT352B2 and BtUGT352F1, along with the UDP-glucose biosynthesis pathway, contributed significantly to resistance. Four glycoside metabolites of CYA were putatively identified in resistant whiteflies. Significant cross-resistance to chlorantraniliprole confirmed that the UGT-mediated metabolism plays a crucial role in anthranilic diamide resistance in B. tabaci.

This research advances our understanding of UGT-mediated insecticide resistance mechanisms and provides valuable insights for the development of more sustainable pest management strategies to combat pesticide resistance.