title: Construction of an environmental safe Bacillus thuringiensis engineered strain against Coleoptera.
abstract: Cloning of new toxic genes from Bacillus thuringiensis (Bt) and construction of Bt engineered strains are two key strategies for bio-control of coleopteran pests in agriculture and forestry. In this study, we cloned a new cry3Aa-type gene, cry3Aa8, from wild Bt strain YC-03 against coleopteran, and constructed a Bt engineered strain, ACE-38, containing insecticidal protein-encoding gene cry3Aa8. The engineered strain, with almost four times of Cry3Aa yield compared with strain YC-03, was an antibiotic marker-free strain. Though no selective pressure was presented in the medium, cry3Aa8 in the engineered strain ACE-38 remained stable. The yield of Cry3Aa by strain ACE-38 reached 2.09 mg/ml in the optimized fermentation medium. The activity of strain ACE-38 against Plagiodera versicolora was tested, and the LC50 of ACE-38 cultures in the optimized fermentation medium was 1.13 μl/ml. Strain ACE-38 is a non-antibiotic Bt engineered strain with high Chrysomelidae toxicity and exhibits good fermentation property. The modified indigenous site-specific recombination system constructed in this study might be useful for the construction of Bt engineered strains containing genes that cannot be expressed in the indigenous site-specific recombination system using plasmid pBMB1205R.
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China.
authors.forename: Yihui
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China. mygao@wh.iov.cn.
authors.forename: Meiying
authors.initials: M
authors.lastname: Gao
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity*; D001681:Biological Assay; D003001:Cloning, Molecular; D001517:Coleoptera / Q000382:microbiology* / Q000502:physiology*; D004731:Endotoxins / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity*; D042822:Genomic Instability; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism* / Q000633:toxicity*; D030781:Organisms, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010572:Pest Control, Biological / Q000379:methods; D016019:Survival Analysis
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Bacillus thuringiensis; Bt engineered strain; Coleopteran; Environmental safety