GSTD1 Mediates the Tolerance to Abamectin and Beta-Cypermethrin in the Fall Armyworm Spodoptera frugiperda

Glutathione S-transferase (GST) is a class of detoxifying enzymes in the second stage of insect metabolism and plays a key role in insecticide resistance. In this study, based on the transcriptome sequences of S. frugiperda, the full-length cDNA of SfGSTD1 was cloned and characterized. The temporal and spatial expression pattern showed that SfGSTD1 was highly expressed in Malpighian tubules, which are key excretion organs. Knocking down SfGSTD1 reduced S. frugiperd tolerance to abamectin and beta-cypermethrin. The overexpression of SfGSTD1 enhanced the viability of Sf9 cell under abamectin and beta-cypermethrin treatment. Furthermore, SfGSTD1 was overexpressed in Drosophila melanogaster using the GAL4/UAS binary expression system, and this overexpression strain was also less susceptible to abamectin and beta-cypermethrin. The enzyme activity of recombinant SfGSTD1 could also be significantly inhibited by abamectin and beta-cypermethrin. Taken together, our findings indicate that SfGSTD1 might be involved in the tolerance of abamectin and beta-cypermethrin in S. frugiperda. And these results provide theoretical foundations for understanding the resistance mechanism of S. frugiperda to abamectin and beta-cypermethrin.