Gossypol detoxification by UDP-glycosyltransferase in Helicoverpa zea

Herbivorous insects have evolved detoxification mechanisms to cope with plant chemical defenses. Helicoverpa zea is a major pest in the United States that feeds on a wide range of plants, including cotton, despite the presence of the toxic defense compound gossypol. However, the specific detoxification enzymes responsible for this tolerance are not fully understood. In this study, we investigated the role of UDP-glycosyltransferases (UGTs) in mediating gossypol detoxification and facilitating host plant adaptation in H. zea. Gene expression analysis revealed that several UGT genes (HzUGT33B9, HzUGT40D1, HzUGT41B1, and HzUGT41D1) were significantly upregulated in larvae exposed to gossypol. Knocking down each of HzUGT33B9, HzUGT40D1, and HzUGT41B1 led to increased larval susceptibility to gossypol and reduced weight gain, confirming their role in detoxification. HzUGT41B1, among others, showed the highest glucosylation activity toward gossypol and several other plant toxins when it was expressed in Sf9 cells. Currently, we are investigating the in vivo functional analysis of HzUGT41B1 in host plant adaptation by generating CRISPR/Cas9 knockout mutants of HzUGT41B1 in H. zea. These findings highlight a molecular mechanism by which H. zea adapts to cotton plants and provide new insights into the evolutionary and functional significance of UGTs in herbivore-plant interactions.