Abstract: 【Aim】 Nicotinic acetylcholine receptors (nAchRs), as the most crucial neurotransmitter receptors in the central nervous system of insects, are the important targets of spinetoram. This study aims to clone the nAchR genes of Spodoptera frugiperda and investigate their response to spinetoram stress. 【Methods】 Genes of nAchR α6 and α7 subunits of S. frugiperda were cloned via RTPCR and RACE based on the previous transcriptome database of S. frugiperda. After the 3rd instar larvae of S. frugiperda were exposed to spinetoram (0.400 mg/L) for 48 h, the changes of expression levels of nAchR α6 and α7 subunit genes were assayed by RT-qPCR. 【Results】 The full-length ORF of nAchR α6 subunit gene (GenBank accession no.: MT951400) is 1 506 bp in length, encoding 502 amino acids with transmembrane region and signal peptide. The full-length ORF of nAchR α7 subunit gene (GenBank accession no.: MW557608) is 1 524 bp in length, encoding 508 amino acids with transmembrane region and signal peptide. nAchR α6 and α7 subunits of S. fruiperda have the typical characteristic of nAchR α family according to amino acid sequence multiple alignment analysis. After the 3rd instar larvae of S. frugiperda were exposed to 0.400 mg/L spinetoram for 48 h, the expression level of their nAchR α6 subunit gene increased significantly, while that of nAchR α7 subunit gene did not change significantly. 【Conclusion】 Spinetoram may have an impact on the nAchR α6 subunit of S. fruiperda. This study lays a preliminary foundation for future in-depth research on the underlying target resistance mechanisms of S. frugiperda in response to spinetoram.

Key words:  Spodoptera frugiperda, nicotinic acetylcholine receptors, spinetoram, gene cloning, expression analysis