title: Three cadherin alleles associated with resistance to Bacillus thuringiensis in pink bollworm.
abstract: Evolution of resistance by pests is the main threat to long-term insect control by transgenic crops that produce Bacillus thuringiensis (Bt) toxins. Because inheritance of resistance to the Bt toxins in transgenic crops is typically recessive, DNA-based screening for resistance alleles in heterozygotes is potentially much more efficient than detection of resistant homozygotes with bioassays. Such screening, however, requires knowledge of the resistance alleles in field populations of pests that are associated with survival on Bt crops. Here we report that field populations of pink bollworm (Pectinophora gossypiella), a major cotton pest, harbored three mutant alleles of a cadherin-encoding gene linked with resistance to Bt toxin Cry1Ac and survival on transgenic Bt cotton. Each of the three resistance alleles has a deletion expected to eliminate at least eight amino acids upstream of the putative toxin-binding region of the cadherin protein. Larvae with two resistance alleles in any combination were resistant, whereas those with one or none were susceptible to Cry1Ac. Together with previous evidence, the results reported here identify the cadherin gene as a leading target for DNA-based screening of resistance to Bt crops in lepidopteran pests.
authors.affiliation: Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Shai
authors.initials: S
authors.lastname: Morin
authors.forename: Robert W
authors.initials: RW
authors.lastname: Biggs
authors.forename: Mark S
authors.initials: MS
authors.lastname: Sisterson
authors.forename: Laura
authors.initials: L
authors.lastname: Shriver
authors.forename: Christa
authors.initials: C
authors.lastname: Ellers-Kirk
authors.forename: Dawn
authors.initials: D
authors.lastname: Higginson
authors.forename: Daniel
authors.initials: D
authors.lastname: Holley
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Gahan
authors.forename: David G
authors.initials: DG
authors.lastname: Heckel
authors.forename: Yves
authors.initials: Y
authors.lastname: Carrière
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Dennehy
authors.forename: Judith K
authors.initials: JK
authors.lastname: Brown
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Tabashnik
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis / Q000472:pathogenicity*; D001681:Biological Assay; D015820:Cadherins / Q000737:chemistry / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage; D020022:Genetic Predisposition to Disease; D007915:Lepidoptera / Q000235:genetics / Q000382:microbiology*; D008297:Male; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D015820:Cadherins