title: Metabolic resistance in Nilaparvata lugens to etofenprox, a non-ester pyrethroid insecticide.
abstract: Etofenprox, a non-ester pyrethroid insecticide, will be registered to control rice pests such as the brown planthopper (BPH, Nilaparvata lugens Stål) in mainland China. Insecticide resistance is always a problem to the effective control of N. lugens by chemical insecticides. An etofenprox resistance selection of N. lugens was performed in order to understand the related mechanisms. Through successive selection by etofenprox for 16 generations in the laboratory, an etofenprox-resistant strain (G16) with the resistance ratio (RR) of 422.3-fold was obtained. The resistance was partly synergised (2.68-fold) with the metabolic inhibitor PBO, suggesting a role for P450 monooxygenases. In this study, 11 P450 genes were significantly up-regulated in G16, among which eight genes was above 2.0-fold higher than that in US16, a population with the same origin of G16 but without contacting any insecticide in the laboratory. The expression level of four genes (CYP6AY1, CYP6FU1 and CYP408A1 from Clade 3, and CYP425A1 from Clade 4) were above 4.0-fold when compared to US16. RNA interference (RNAi) was performed to evaluate the importance of the selected P450s in etofenprox resistance. When CYP6FU1, CYP425A1 or CYP6AY1 was interfered, the susceptibility was significantly recovered in both G16 and US16, while the knockdown of CYP408A1 or CYP353D1 did not cause significant changes in etofenprox susceptibility. We supposed that CYP6FU1 was the most important P450 member for etofenprox resistance because of the highest expression level and the most noticeable effects on resistance ratios following RNAi.
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
authors.forename: Huahua
authors.initials: H
authors.lastname: Sun
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China; Rice Technology Research and Development Center, China National Rice Research Institute, Hangzhou 310006, China.
authors.forename: Baojun
authors.initials: B
authors.lastname: Yang
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
authors.forename: Yixi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China. Electronic address: liuzewen@njau.edu.cn.
authors.forename: Zewen
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000818:Animals; D065607:Cytochrome P-450 Enzyme Inhibitors / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006430:Hemiptera / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides / Q000633:toxicity*; D010755:Organophosphates / Q000494:pharmacology; D010882:Piperonyl Butoxide / Q000494:pharmacology; D011722:Pyrethrins / Q000633:toxicity*; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D065607:Cytochrome P-450 Enzyme Inhibitors; D019476:Insect Proteins; D007306:Insecticides; D010755:Organophosphates; D011722:Pyrethrins; D012333:RNA, Messenger; C076840:ethofenprox; D003577:Cytochrome P-450 Enzyme System; D010882:Piperonyl Butoxide; C005445:triphenyl phosphate
keywords: Etofenprox; Nilaparvata lugens; P450 gene; Resistance mechanism