title: Identification of key amino acid differences between Cyrtorhinus lividipennis and Nilaparvata lugens nAChR α8 subunits contributing to neonicotinoid sensitivity.
abstract: High sensitivity to neonicotinoid insecticides have been reported in the miridbug Cyrtorhinus lividipennis, an important predatory enemy of rice planthoppers, such as Nilaparvata lugens (brown planthopper). In the present study, the sensitivity of neonicotinoid insecticides between C. lividipennis and N. lugens were detected and compared. The results showed that neonicotinoid insecticides were much more toxic to the miridbug than to the brown planthopper. A nicotinic acetylcholine receptor subunit was cloned from the miridbug and denoted as α8 subunit (Clα8) according to sequence similarities and important functional motifs. Key amino acid differences were found in specific loops from α8 subunits between C. lividipennis (Clα8) and N. lugens (Nlα8). In order to understand the roles of key amino acid differences in insecticide sensitivities, the different amino acid residues in specific loops of Nlα8 were introduced into the corresponding sites in Clα8 to construct several subunit mutants. Clα8 or subunit mutants were co-expressed with rat β2 to obtain the functional receptors in Xenopus oocytes. The single mutation N191F in loop B reduced imidacloprid sensitivity, with EC50 value in Clα8(N191F)/β2 of 15.21μM and 5.74μM in Clα8/β2. Interestingly, although the single mutation E240T in loop C did not cause the significant change in imidacloprid sensitivity, it could enhance the effects of N191F and cause more decrease in imidacloprid sensitivity. The results indicated that E240T might contribute to neonicotinoid sensitivity in an indirect way.
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Beina
authors.initials: B
authors.lastname: Guo
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, 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, Nanjing 210095, China.
authors.forename: Xiangkun
authors.initials: X
authors.lastname: Meng
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; Institute of Plant Protection, Jiansu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Bao
authors.affiliation: Institute of Plant Protection, Jiansu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Jichao
authors.initials: J
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, Nanjing 210095, China. Electronic address: liuzewen@njau.edu.cn.
authors.forename: Zewen
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D006146:Guanidines; D006430:Hemiptera / Q000378:metabolism; D020062:Heteroptera / Q000378:metabolism; D007093:Imidazoles; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D007306:Insecticides; D008969:Molecular Sequence Data; D009154:Mutation; D000073943:Neonicotinoids; D009574:Nitro Compounds; D009865:Oocytes / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D011725:Pyridines; D051381:Rats; D011950:Receptors, Cholinergic / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D013843:Thiazines; D013844:Thiazoles; D014981:Xenopus
chemical_list: D006146:Guanidines; D007093:Imidazoles; D019476:Insect Proteins; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D021122:Protein Subunits; D011725:Pyridines; D011950:Receptors, Cholinergic; D013843:Thiazines; D013844:Thiazoles; C480342:clothianidin; C082359:imidacloprid; C417209:thiacloprid
keywords: Cyrtorhinus lividipennis; Neonicotinoid selectivity; Nicotinic acetylcholine receptor; α8 subunit