title: Novel genetic basis of field-evolved resistance to Bt toxins in Plutella xylostella.
abstract: Insecticidal toxins from Bacillus thuringiensis (Bt) are widely used to control pest insects, but evolution of resistance threatens their continued efficacy. The most common type of Bt resistance ('Mode 1') is characterized by recessive inheritance, > 500-fold resistance to at least one Cry1A toxin, negligible cross-resistance to Cry1C, and reduced binding of Bt toxins to midgut membrane target sites. Mutations affecting a Cry1A-binding midgut cadherin protein are linked to laboratory-selected Mode 1 resistance in Heliothis virescens and Pectinophora gossypiella. Here we show that field-evolved Mode 1 resistance in the diamondback moth, Plutella xylostella, has a different genetic basis, indicating that screening for resistance in the field should not be restricted to a previously proposed DNA-based search for cadherin mutations.
authors.affiliation: CESAR, Department of Genetics, University of Melbourne, Victoria, Australia.
authors.forename: S W
authors.initials: SW
authors.lastname: Baxter
authors.forename: J-Z
authors.initials: JZ
authors.lastname: Zhao
authors.forename: L J
authors.initials: LJ
authors.lastname: Gahan
authors.forename: A M
authors.initials: AM
authors.lastname: Shelton
authors.forename: B E
authors.initials: BE
authors.lastname: Tabashnik
authors.forename: D G
authors.initials: DG
authors.lastname: Heckel
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015820:Cadherins / Q000235:genetics; D004731:Endotoxins; D008040:Genetic Linkage; D006460:Hemolysin Proteins; D019476:Insect Proteins / Q000235:genetics; D007305:Insecticide Resistance / Q000235:genetics*; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics*; D009154:Mutation; D010802:Phylogeny
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015820:Cadherins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis