The phenylpyrazole insecticide fipronil blocks resistance to dieldrin(RDL)γ-aminobutyric acid(GABA)receptors in insects,thereby impairing inhibitory neurotransmission.Some insect species,such as the diamondback moth(...The phenylpyrazole insecticide fipronil blocks resistance to dieldrin(RDL)γ-aminobutyric acid(GABA)receptors in insects,thereby impairing inhibitory neurotransmission.Some insect species,such as the diamondback moth(Plutella xylostella),possess more than one Rdl gene.The involvement of multiple Rdls in fipronil toxicity and resistance remains largely unknown.In this study,we investigated the roles of two Rdl genes,PxRdl1 and PxRdl2,in P.xylostella fipronil action.In Xenopus oocytes,RvRDL2 receptors were 40 times less sensitive to fipronil than P.vRDL1.P.vRDL2 receptors were also less sensitive to GABA compared with PxRDL1.Knockout of the fipronil-sensitive PxRdll reduced the fipronil potency 10-fold,whereas knockout of the fipronil-resistant PxRdl2 enhanced the fipronil potency 4.4-fold.Furthermore,in two fipronil-resistant diamondback moth field populations,PxRdl2 expression was elevated 3.7-and 4.1-fold compared with a susceptible strain,whereas PxRdl1 expression was comparable among the resistant and susceptible strains.Collectively,our results indicate antagonistic effects of PxRDLl and PxRDL2 on fipronil action in vivo and suggest that enhanced expression of fipronil-resistant PxRdl1 is potentially a new mechanism of fipronil resistance in insects.展开更多
基金supported by the National Key R&D Program of China(2018YFD0200300)the Project of Science and Technology in Guangdong Province(2018A030313188)+1 种基金the Natural Science Foundation of Guangdong Province(2017A030310490)the Research and Innovation Team of Key Technologies in Modern Agricultural Industry in Guangdong Province(2019KJ130).
文摘The phenylpyrazole insecticide fipronil blocks resistance to dieldrin(RDL)γ-aminobutyric acid(GABA)receptors in insects,thereby impairing inhibitory neurotransmission.Some insect species,such as the diamondback moth(Plutella xylostella),possess more than one Rdl gene.The involvement of multiple Rdls in fipronil toxicity and resistance remains largely unknown.In this study,we investigated the roles of two Rdl genes,PxRdl1 and PxRdl2,in P.xylostella fipronil action.In Xenopus oocytes,RvRDL2 receptors were 40 times less sensitive to fipronil than P.vRDL1.P.vRDL2 receptors were also less sensitive to GABA compared with PxRDL1.Knockout of the fipronil-sensitive PxRdll reduced the fipronil potency 10-fold,whereas knockout of the fipronil-resistant PxRdl2 enhanced the fipronil potency 4.4-fold.Furthermore,in two fipronil-resistant diamondback moth field populations,PxRdl2 expression was elevated 3.7-and 4.1-fold compared with a susceptible strain,whereas PxRdl1 expression was comparable among the resistant and susceptible strains.Collectively,our results indicate antagonistic effects of PxRDLl and PxRDL2 on fipronil action in vivo and suggest that enhanced expression of fipronil-resistant PxRdl1 is potentially a new mechanism of fipronil resistance in insects.
