A rationally designed peptide targeting trypsin-like enzymes impairs feeding and redox homeostasis in Anticarsia gemmatalis (Lepidoptera: Erebidae)

Anticarsia gemmatalis Hübner, 1818 (Lepidoptera: Erebidae) is one of the major threats to soybean productivity, and its management still depends largely on chemical insecticides, which may promote environmental contamination and the selection of resistant insect populations. Therefore, the development of environmentally friendly control molecules is essential. This study evaluated the synthetic pentapeptide GORE3, derived from the regulatory region of trypsin, as a potential inhibitor of trypsin-like digestive enzymes in A. gemmatalis through structural, biochemical, and biological approaches. Caterpillars were fed diets containing GORE3, benzamidine, soybean Kunitz trypsin inhibitor (SKTI), or water as the control.

Molecular docking predicted more favorable AutoDock Vina scores for GORE3 (mean score = -8.82 kcal mol^-1) than for benzamidine (-5.68 kcal mol^-1), providing a structural hypothesis for GORE3-trypsin interactions. Enzyme kinetic assays revealed that benzamidine acted as a competitive inhibitor (inhibition constant (Kᵢ) = 0.042 mm), whereas GORE3 exhibited a mixed-type inhibition mechanism (Kᵢ = 0.26 mm), suggesting distinct interaction modes with the enzyme. Bioassays showed a significant reduction in maize leaf area consumption in all treatments, with GORE3 being the most effective, reducing foliar consumption by approximately 73% relative to the control. Feeding preference assays also indicated lower acceptance of treated substrates. Physiologically, both GORE3 and benzamidine modulated antioxidant enzymes and increased reactive oxygen species and oxidative damage markers, including lipid peroxidation and protein carbonyl formation.

The inhibition of trypsin-like digestive enzymes by synthetic peptides induced integrated effects involving enzymatic modulation, oxidative stress, and reduced feeding performance in A. gemmatalis. These responses ultimately decreased the potential for foliar damage, supporting the use of protease-inhibiting peptides such as GORE3 as promising biotechnological tools for sustainable pest management. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.