Discovery of Novel Potential Insecticide-Resistance Mutations in Spodoptera frugiperda

The fall armyworm (FAW), Spodoptera frugiperda, is a worldwide agricultural pest that invaded China in 2018, and has developed resistance to multiple insecticides. The evolution of insecticide resistance is facilitated by mutations of target genes responsible for conferring resistance. In this study, amplicon sequencing analyzed 21 sites in six resistance genes. In addition to known mutations, unknown variants were also found, including novel variants: F290C (ace-1 gene, 0.1% frequency), I1040T/V (CHSA gene, 0.1% frequency), A309T (GluCl gene, 0.1% frequency), and I4790T/V (RyR gene, 0.1% frequency). Additionally, molecular docking was employed to investigate the impact of the aforementioned new mutations on insecticide binding to proteins. The analyses indicated that the binding abilities were reduced, similar to the resistance mutations that were reported, implying these novel mutations may confer transitional resistance. This study may provide a foundation for understanding the functions of these novel mutations in the evolutionary processes that drive the emergence of insecticide resistance in this invasive species.