Find in Library

Juvenile hormone diol kinase (JHDK) is a critical enzyme involved in juvenile hormone degradation in insects. In this study, <i>HvJHDK</i> in the <i>Heortia vitessoides</i> Moore (Lepidoptera: Crambidae) transcriptional library was cloned. Stage-specific expression patterns of <i>HvJHDK</i>, <i>HvJHEH</i>, and <i>HvJHE</i> as well as juvenile hormone titers were determined. The three tested enzymes participated in juvenile hormone degradation. Moreover, juvenile hormone titers peaked after larval&#8722;larval molts, consistent with a role for juvenile hormone in inhibition of metamorphosis. <i>HvJHDK</i> was subsequently suppressed using RNA interference (RNAi) to reveal its functions. Different concentrations of ds<i>JHDK</i> elicited the optimal interference efficiency at different life stages of <i>H. vitessoides</i>. Suppression of <i>HvJHDK</i> decreased HvJHDK content and increased the juvenile hormone titer, thereby resulting in reduced triglyceride content, sharply declined survival rate, clearly lethal phenotypes, and extended larval growth. Moreover, suppression of <i>HvJHDK</i> upregulated <i>HvJHEH</i> and <i>HvJHE</i> expression levels, suggesting that there is feedback regulation in the juvenile hormone metabolic pathway. Taken together, our findings provide molecular references for the selection of novel insecticidal targets.