Discovery of Novel Potential Insecticide-Resistance Mutations in ISpodoptera frugiperda/I

The fall armyworm (FAW) is a pest that can cause severe damage to crops, particularly maize and cotton, resulting in agricultural losses. It has developed resistance to various types of insecticides due to certain gene mutations in its body. Our study aims to investigate how these genes affect the pest’s sensitivity to insecticides. We utilized amplicon sequencing to analyze 21 sites within six related genes and identified both known and unknown mutations. Subsequently, molecular docking simulations were employed to assess the impact of these mutations on the binding ability between insecticides and proteins. Our findings indicate that these mutations reduce the binding ability, potentially contributing to increased insecticide resistance. Thus, our study could unveil the variation and evolution of resistance genes in FAW. 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.