Abstract

Simple SummaryThe South American tomato leaf miner,Tuta absoluta, is a highly destructive invasive pest of solanaceous crops worldwide. Intensive reliance on chemical insecticides has led to widespread resistance and heightened environmental concerns, underscoring the need for species-specific and physiologically informed alternatives. Chitinases, which mediate chitin turnover during molting and metamorphosis, represent promising molecular targets for RNA interference (RNAi)-based control strategies. Therefore, this study aims to systematically characterize the chitinase family genes inT. absolutaand investigate their roles in larva–pupa–adult transitions through molecular characterization, spatiotemporal expression, and RNAi analyses. These findings reveal that four key chitinases (TaCht5,TaCht7,TaCht10, andTaIDGF) are indispensable for the molting physiology and metamorphic progression ofT. absoluta, thereby providing potential molecular targets for leaf miner pest management.Chitinases are crucial in the molting process of insects and represent potential targets for the development of RNA interference (RNAi)-based insecticidal strategies. In this study, we identified and characterized 11 chitinase genes (TaChts) inT. absoluta, each harboring at least one GH18 catalytic domain. Phylogenetic analysis placed these proteins into 11 established groups (I-X and h), revealing conserved lineage-specific patterns. Spatiotemporal expression profiling showed that mostTaChtspeak during key developmental transitions.TaCht1,TaCht2,TaCht3,TaCht5,TaCht6,TaCht7,TaCht10,TaCht-h, andTaIDGFwere predominantly expressed in the integument, whereasTaCht8andTaCht11showed gut-enriched expression, indicating functional specialization. Stage-tailored RNAi assays demonstrated that silencingTaCht5,TaCht7,TaCht10, andTaIDGFcaused pronounced mortality in both larvae and pupae. In larvae, delivery of dsRNA using carbon quantum dots (CQDs) disrupted molting: knockdown ofTaCht7,TaCht10, andTaIDGF