Functional analysis of the UDP‑glycosyltransferase gene family involved in gossypol detoxification in the cotton pest Helicoverpa zea

Gossypol, a yellow-colored sesquiterpene dimer, is a major secondary metabolite produced by cotton plants to defend against insect herbivores and pathogens. Insect UDP-glycosyltransferases (UGTs) act upon diverse phytotoxins and insecticides as phase II detoxification enzymes. Identifying the detoxification roles of UGT genes is essential for discovering the molecular mechanisms underlying insect adaptation to plant secondary metabolites. However, the genetic factors that enable cotton-feeding insects to tolerate gossypol remain unclear. In this study, we tested the effect of gossypol on the corn earworm (Helicoverpa zea) and the soybean looper (Chrysodeixis includens), two important pests of cotton plants in the southern U.S. Larval feeding studies revealed that 0.1% gossypol diet significantly inhibited larval growth in C. includens, whereas there was no detectable effect on H. zea at the same dose, suggesting greater tolerance to gossypol in H. zea.Transcriptome and qRT-PCR analyses in H. zea larvae identified four UGT genes, HzUGT33e, HzUGT40a, HzUGT41a, and HzUGT41c, that were significantly upregulated after dietary exposure to gossypol. Further functional analyses of these candidate UGTs involved in gossypol detoxification will be presented, along with their gene structure, genomic orientation, and phylogenetic analysis, functional characterization, and evolutionary analysis. This study deepens our understanding of the evolutionary mechanisms driving host adaptation and provides practical insights into the utilization of cottonseed meals in the feed industry.