Abstract:

Objective Aphis craccivora is a globally prominent agricultural pest that severely threatens the yield of peanuts and other crops. Afidopyropen, as a novel and highly efficient insecticide, demonstrates potent control efficacy against sap-sucking pests. Clarifying the metabolic resistance mechanisms of A. craccivora to afidopyropen is of critical importance for the development of scientifically robust field management strategies. Method The sensitivity of A. craccivora to afidopyropen was evaluated through leaf-dip bioassay. The role of glutathione S-transferases (GSTs) in detoxification metabolism was assessed through enzyme activity assays and synergist toxicity bioassays. Tissue expression pattern, developmental expression pattern, and insecticide-induced expression profiles of GSTs were analyzed via quantitative real-time PCR (RT-qPCR). RNA interference (RNAi) was employed to identify key GSTs associated with tolerance to afidopyropen. Result Afidopyropen treatment significantly increased GST activity in A. craccivora. Pretreatment with the synergist diethyl maleate (DEM) enhanced the susceptibility of A. craccivora to afidopyropen, indicating the involvement of GSTs in detoxification metabolism in A. craccivora. Tissue and temporal expression pattern analyses revealed that most GSTs were highly expressed in the midgut and fat body, with expressions rising markedly during developmental progression. Afidopyropen induced the upregulation of GSTT2 and GSTS2. RNAi-mediated silencing of GSTT2 significantly increased the sensitivity to the afidopyropen in A. craccivora. Conclusion GSTT2 plays an important role in response to afidopyropen stress by reducing its sensitivity to the insecticide. This finding lays the foundation for further investigation into the detoxification mechanisms of A. craccivora against afidopyropen.

Key words: Aphis craccivora, GSTs, afidopyropen, detoxification metabolism