CYP321F3介导抗氯虫苯甲酰胺二化螟种群对四唑虫酰胺的交互抗性OA

[Aim]Chilo suppressalis is a major pest on rice.Previous studies have shown that C.suppressalis in Yuhang,Zhejiang,Southeast China has developed significant resistance to chlorantraniliprole,and also developed cross-resistance to tetraniliprole,which has not been applied before.Additionally,significant overexpression of CYP321F3 was observed in the Yuhang chlorantraniliprole-resistant field population of C.suppressalis.This study aims to explore the role of CYP321F3 in mediating the cross-resistance of the chlorantraniliprole-resistant populations of C.suppressalis to tetraniliprole.[Methods]The resistance level of the Yuhang chlorantraniliprole-resistant field population of C.suppressalis to tetraniliprole was detected by the rice seedling dipping method,and the expression levels of CYP321F3 in the Yuhang chlorantraniliprole-resistant field population and the susceptible strain were detected by qRT-PCR.Overexpression of C.suppressalis CYP321F3 in Drosophila melanogaster was achieved via microinjection and the GAL4/UAS system,and the changes in the susceptibility of the 2-3-day-old female adults of transgenic D.melanogaster to chlorantraniliprole and tetraniliprole were detected using bioassays.C.suppressalis CYP321F3 was heterologously expressed in Sf9 cells using the insect baculovirus expression system to obtain the recombinant CYP321F3,and the binding abilities of the recombinant CYP321F3 to three insecticides were detected.[Results]The Yuhang chlorantraniliprole-resistant field population of C.suppressalis showed 16.59-fold resistance to tetraniliprole,and had significantly up-regulated expression level of CYP321F3 compared with the susceptible strain.Compared to the da＞9755 strain(control),D.melanogaster da＞CYP321F3 strain overexpressing C.suppressalis CYP321F3 showed significantly reduced mortality rates when exposed to both chlorantraniliprole and tetraniliprole.The recombinant CYP321F3 not only exhibited robust O-demethylation activity towards p-nitroanisole(PNA)and O-deethylation activity towards 7-ethoxycoumarin(EC),but also had significantly lower median inhibitory concentration(ICs0)values for inhibition by chlorantraniliprole and tetraniliprole(1.18 and 1.29 μmol/L,respectively)than that by etofenprox(positive control)(14.09μmol/L).These results confirmed strong binding abilities of the recombinant CYP321F3 to both chlorantraniliprole and tetraniliprole.[Conclusion]This study preliminarily confirmed that CYP321F3 is one of the mechanisms mediating the cross-resistance of chlorantraniliprole-resistant C.suppressalis to tetraniliprole,providing a theoretical basis for the resistance monitoring and management of C.suppressalis.