title: Proteomic analysis of Cry2Aa-binding proteins and their receptor function in Spodoptera exigua.
abstract: The bacterium Bacillus thuringiensis produces Crystal (Cry) proteins that are toxic to a diverse range of insects. Transgenic crops that produce Bt Cry proteins are grown worldwide because of their improved resistance to insect pests. Although Bt "pyramid" cotton that produces both Cry1A and Cry2A is predicted to be more resistant to several lepidopteran pests, including Spodoptera exigua, than plants that produce Cry1Ac alone, the mechanisms responsible for the toxicity of Cry2Aa in S. exigua are not well understood. We identified several proteins that bind Cry2Aa (polycalin, V-ATPase subunits A and B, actin, 4-hydroxybutyrate CoA-transferase [4-HB-CoAT]), and a receptor for activated protein kinase C (Rack), in S. exigua. Recombinant, expressed versions of these proteins were able to bind the Cry2Aa toxin in vitro assays. RNA interference gene knockdown of the Se-V-ATPase subunit B significantly decreased the susceptibility of S. exigua larvae to Cry2Aa, whereas knockdown of the other putative binding proteins did not. Moreover, an in vitro homologous competition assay demonstrated that the Se-V-ATPase subunit B binds specifically to the Cry2Aa toxin, suggesting that this protein acts as a functional receptor of Cry2Aa in S. exigua. This the first Cry2Aa toxin receptor identified in S. exigua brush-border membrane vesicles.
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Qiu
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Boyao
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Lang
authors.initials: L
authors.lastname: Liu
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Ma
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Wang
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Chaoliang
authors.initials: C
authors.lastname: Lei
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
authors.forename: Lizhen
authors.initials: L
authors.lastname: Chen
mesh_terms: D000818:Animals; D000906:Antibodies / Q000008:administration & dosage; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D004731:Endotoxins / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D006460:Hemolysin Proteins / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D008871:Microvilli / Q000378:metabolism; D011485:Protein Binding; D040901:Proteomics; D000075370:Receptors for Activated C Kinase / Q000378:metabolism*; D018411:Spodoptera / Q000235:genetics / Q000378:metabolism*
chemical_list: D000906:Antibodies; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D000075370:Receptors for Activated C Kinase; C030956:insecticidal crystal protein, Bacillus Thuringiensis