Identification and expression analysis of G protein-coupled receptors in the cotton aphid, Aphis gossypii Glover

Abstract

G protein-coupled receptors play important roles in mediating signal transformation and physiological processes. As a new type of insecticide target, GPCRs have attracted much attention in recent years. However, GPCRs have not yet been identified in Aphis gossypii. In the present study, a total of 87 GPCRs were identified from A. gossypii, including 65 Family A, 12 Family B, 7 Family C, and 3 Family F receptors. Most of the GPCRs in A. gossypii showed considerable sequence identity, and all of them have conserved transformmembrane domains. Newly identified GPCR genes were differentially expressed in different developmental stages and tissues. Moreover, we found that 34 GPCR genes were highly overexpressed in a sulfoxaflor-resistant strain, 4 and 10 of them were highly induced by LC₁₅ and LC₅₀ of sulfoxaflor, respectively. Furthermore, silencing of two highly overexpressed GPCRs by RNAi indicated that suppression the expression of AgoGPCR48 and AgoGPCR53 significantly increased the susceptibility of A. gossypii to sulfoxaflor, suggesting that these GPCR genes may be associated with sulfoxaflor resistance in A. gossypii. Our results imply that the overexpression of GPCR genes contribute to the sulfoxaflor resistance development in A. gossypii and provide useful targets for developing novel insecticides to manage this pest.

Keywords: Aphis gossypii; G protein-coupled receptors (GPCRs); Gene expression; Resistance.