Trypsin-Mediated Control of Metabolic Flux Sustains Detoxification and Reproduction under Chronic Thermal Stress

Abstract Global warming and intensive insecticide use impose concurrent demands on pests, yet mechanisms coordinating resource allocation between stress responses and life-history traits remain poorly understood. We identify midgut trypsins as key regulators of this coordination in the diamondback moth, Plutella xylostella. Using CRISPR/Cas9, we show that two trypsin genes, PxTryCFT1-like and PxTry-like, are dispensable for acute thermal tolerance but essential under chronic stress. Mutant lines exhibit severe reproductive failure under prolonged high temperatures and display broad-spectrum hypersensitivity (2- to 22-fold) to multiple insecticides. Mechanistically, trypsin loss disrupts amino acid supply, suppressing major detoxification systems including cytochrome P450s, glutathione S-transferases, and carboxylesterases. By elucidating the noncanonical role of midgut trypsins in modulating trade-offs between growth and stress defense, we demonstrate how nutrient acquisition fuels stress-response networks.