posted on 2021-05-21, 16:35authored byDongzhi Li, Chengshuai He, Lanfen Xie, Fanbin Kong, Yanbing Wu, Mingwang Shi, Runqiang Liu, Li Xu
Glutathione S-transferase genes in the epsilon
group were reported to function in insecticide resistance. SlGSTE12 was validated to be overexpressed in pyrethroid-
and organophosphate-resistant populations of Spodoptera
litura compared to a susceptible population. A functional
study of heterologously expressed SlGSTE12 showed that Km and Vmax for 1-chloro-2,4-dinitrobenzene
(CDNB) conjugating activity were 0.70 ± 0.18 mmol L–1 and 90.6 ± 9.4 nmol mg–1 min–1, respectively. β-Cypermethrin and cyhalothrin showed much
weaker inhibition of SlGSTE12 activity to CDNB conjugation than fenvalerate,
chlorpyrifos, and phoxim. Ultrahigh-performance liquid
chromatography analysis showed that SlGSTE12 had significant
metabolism activity to fenvalerate and phoxim both in vitro and in Escherichia coli, especially
to chlorpyrifos, and slight metabolism activity toward cyhalothrin
only in vitro. Silencing of SlGSTE12 by RNAi increased the mortality to fenvalerate, cyhalothrin, and
chlorpyrifos significantly. SlGSTE12 also had a significant antioxidant
ability against cumene hydroperoxide. Our study suggested that SlGSTE12
could metabolize phoxim, fenvalerate, cyhalothrin, and especially
chlorpyrifos. SlGSTE12 might also participate in pyrethroid and organophosphate
resistance by antioxidant activity.