title: No cross-resistance between imidacloprid and pymetrozine in the brown planthopper: status and mechanisms.
abstract: Cross-resistance between insecticides, especially from different groups, can be extremely unpredictable, and it has been a serious concern in pest control. Pymetrozine has been widely used to control Nilaparvata lugens with the suspension of imidacloprid for the resistance, and N. lugens has showed obvious pymetrozine resistance in recent years. To investigate the possible cross-resistance between imidacloprid and pymetrozine is very important to avoid the adverse effects on resistance development and pest control. Bioassays of two field populations in five consecutive years showed that imidacloprid resistance decreased greatly, while pymetrozine resistance increased significantly. The synergist piperonyl butoxide (PBO) could synergize both imidacloprid and pymetrozine in all field populations, which indicated the importance of P450s in the resistance to two insecticides. Imidacloprid resistance was reported to be associated with two P450s, CYP6AY1 and CYP6ER1, which could metabolize imidacloprid efficiently. However, the recombinant proteins of these two P450s did not show any enzymatic activity to metabolize pymetrozine. The pymetrozine susceptibility did not change when CYP6AY1 and CYP6ER1 mRNA levels were reduced by RNA interference (RNAi), although which could obviously decrease imidacloprid resistance. In vivo and in vitro studies provided evidences to demonstrate that there was no cross-resistance between imidacloprid and pymetrozine in N. lugens, which was different from the findings in Bemisia tabaci.
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: Yuanxue
authors.initials: Y
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: Lixin
authors.initials: L
authors.lastname: Huang
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: Yunchao
authors.initials: Y
authors.lastname: Wang
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.
authors.forename: Siqi
authors.initials: S
authors.lastname: Fang
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; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006430:Hemiptera / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D007093:Imidazoles / Q000378:metabolism; D007305:Insecticide Resistance / Q000235:genetics; D007306:Insecticides / Q000378:metabolism; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000378:metabolism; D012329:RNA, Bacterial; D060888:Real-Time Polymerase Chain Reaction; D014227:Triazines / Q000378:metabolism
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C042027:RNA I; D012329:RNA, Bacterial; D014227:Triazines; C082359:imidacloprid; D003577:Cytochrome P-450 Enzyme System; C480311:pymetrozine
keywords: Cross-resistance; Imidacloprid; Nilaparvata lugens; P450; Pymetrozine