title: Expression of cry3A gene and its toxicity against Asian Gray Weevil Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae).
abstract: Coleopterans are the most damaging pests of many agricultural and forestry crops; there is an urgent need to develop effective biopesticides against these insects. Enhancers of Bt toxicity typify an opportunity to improve currently available commercial products into more effective control agents against diverse pests. A 1.9 kb DNA fragment, PCR amplified from native isolates of Bt using cry3A gene specific primers was cloned in expression vector pQE-80L and then used for transformation of Escherichia coli M15 cells. The sequence of the cloned crystal protein gene showed almost complete homology with a Coleopteran active Cry3A toxin gene with 117 mutations scattered in different domain regions encoding a protein of 645 amino acid residues in length, with a predicted molecular mass of 77.4 kDa. Phylogenetic analysis could be compulsive for new/novel Bacillus thuringiensis strains, allowing them to be grouped with related Cry proteins. The toxicity of Bt protein was determined against Myllocerus undecimpustulatus undatus Marshall (Coleoptera: Curculionidae) LC50 152 ng cm(-2). Genes coding for Coleopteran active Cry3A proteins have been isolated and their efficient expression will provide the tools necessary to increase the efficacy of Cry-based biopesticide against economically important beetles.
authors: Bio-Pesticide Laboratory (BPL), Division of Biotechnology, Indian Institute of Horticultural Research (IIHR), Hessaraghatta Lake Post, Bangalore, Karnataka, India. clintonbio@gmail.com
authors: H M
authors: HM
authors: Mahadeva Swamy
authors: R
authors: R
authors: Asokan
authors: Geetha G
authors: GG
authors: Thimmegowda
authors: Riaz
authors: R
authors: Mahmood
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000633:toxicity*; D003001:Cloning, Molecular; D001517:Coleoptera / Q000235:genetics; D004731:Endotoxins / Q000235:genetics* / Q000633:toxicity*; D004926:Escherichia coli / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics* / Q000633:toxicity*; D007306:Insecticides / Q000494:pharmacology* / Q000633:toxicity; D007928:Lethal Dose 50; D008969:Molecular Sequence Data; D009154:Mutation; D010572:Pest Control, Biological / Q000379:methods*; D010802:Phylogeny; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000633:toxicity; D017386:Sequence Homology, Amino Acid; D048889:Weevils
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; D011994:Recombinant Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Curculionidae; E. coli M15 cells; Recombinant protein; Toxicity; cry3A gene