MicroRNA-23a changes chlorantraniliprole susceptibility by targeting CYP9F1 in Spodoptera frugiperda

The fall armyworm (FAA) Spodoptera frugiperda (Smith) has caused considerable losses in grain production and is primarily controlled by chemical insecticides. However, frequent use of insecticides leads to the development of resistance. Cytochrome P450 in insects plays a crucial role in the detoxification of insecticides. CYP9F1 expression has been found to be induced significantly by chlorantraniliprole. However, the regulatory mechanism of CYP9F1 expression has yet to be elucidated. In this study, a target of isolated miR-23a was located in the 3 ' UTR of CYP9F1 in the FAA. Luciferase reporter assays showed that miR-23a could bind to the 3 ' UTR of CYP9F1 and suppress its expression via a site in the FAA. Injected miR-23a agomir significantly reduced CYP9F1 abundance, also improving chlorantraniliprole suscep-tibility, while injected miR-23a antagomir significantly improved CYP9F1 abundance and thus reduced chlorantraniliprole susceptibility in FAA larvae. These results provide a basis for research on the posttranscriptional regulatory mechanism(s) of CYP9F1 and will help further study the function of miRNAs in regulating susceptibility to chlorantraniliprole in the FAA.