title: Use of a Cry1Ac-resistant line of Helicoverpa armigera (Lepidoptera: Noctuidae) to detect novel insecticidal toxin genes in Bacillus thuringiensis.
abstract: This paper describes a screening strategy incorporating resistant insect lines for discovery of new Bacillus thuringiensis toxins against a background of known genes that would normally mask the activity of additional genes and the application of that strategy. A line of Helicoverpa armigera with resistance to Cry1Ac (line ISOC) was used to screen Cry1Ac-expressing strains of B. thuringiensis for additional toxins with activity against H. armigera. Using this approach, a number of Cry1Ac-producing strains with significant toxicity toward Cry1Ac-resistant H. armigera were identified. When the insecticidal protein complement of one of these strains, C81, was examined in detail, a novel cry2 gene (cry2Af1) was detected.
authors.affiliation: CSIRO Entomology, GPO Box 1700, Canberra, ACT 2601, Australia.
authors.forename: Cheryl E
authors.initials: CE
authors.lastname: Beard
authors.forename: Leon
authors.initials: L
authors.lastname: Court
authors.forename: Roslyn G
authors.initials: RG
authors.lastname: Mourant
authors.forename: Bill
authors.initials: B
authors.lastname: James
authors.forename: Jeroen
authors.initials: J
authors.lastname: Van Rie
authors.forename: Luke
authors.initials: L
authors.lastname: Masson
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Akhurst
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001681:Biological Assay; D004731:Endotoxins / Q000235:genetics / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism*; D007305:Insecticide Resistance / Q000502:physiology*; D007915:Lepidoptera / Q000187:drug effects / Q000382:microbiology / Q000502:physiology*; D009154:Mutation
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis