<p>UGT sequences in this study.</p>

How insects integrate distinct detoxification systems to overcome diverse phytochemicals, and how such mechanisms contribute to host-range divergence, remains poorly understood. Here, we uncover a cooperative cytochrome P450–UDP-glycosyltransferase (UGT) cascade that mediates furanocoumarin tolerance in <i>Helicoverpa armigera</i>.

Comparative genomic analyses across <i>Helicoverpa</i> and related noctuid species revealed that the UGT33 family is the most extensively expanded and dynamically diversified UGT lineage in <i>Helicoverpa</i>. Targeted CRISPR–Cas9 knockouts of UGT33 gene clusters in polyphagous <i>H. armigera</i> demonstrated their essential roles in detoxifying the furanocoumarins xanthotoxin and imperatorin. Combined metabolic and functional assays further established a sequential detoxification pathway, in which the cytochrome P450 CYP6AE19 catalyses either the O-dealkylation of xanthotoxin to yield xanthotoxol or the aromatic-carbon hydroxylation of xanthotoxin to form 5-hydroxyxanthotoxin, which are subsequently glycosylated by UGT33 enzymes to form their less-toxic glucosides.