DNA-based detection of Bt resistance alleles in pink bollworm.
Evolution of resistance by pests is the main threat to long-term insect control by transgenic crops that produce Bacillus thuringiensis (Bt) toxins. We previously identified three mutant alleles (r1, r2, r3) of a cadherin gene in pink bollworm (Pectinophora gossypiella) linked with recessive resistance to Bt toxin Cry1Ac and survival on transgenic Bt cotton. Here we describe a polymerase chain reaction (PCR)-based method that detects the mutation in genomic DNA of each of the three resistant alleles. Using primers that distinguish between resistant and susceptible (s) alleles, this method enables identification of 10 genotypes (r1r1, r1r2, r1r3, r2r2, r2r3, r3r3, r1s, r2s, r3s, and ss) at the cadherin locus. For each of the three resistant alleles, the method detected the resistance allele in a single heterozygote (r1s, r2s, or r3s) pooled with DNA from the equivalent of 19 susceptible (ss) individuals. The results suggest that the DNA-based detection method described here could greatly increase the efficiency of monitoring for resistance to Cry1Ac compared to bioassays that detect rare individuals with homozygous resistance.
Morin
Shai
S
Department of Entomology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel. morin@agri.huji.ac.il
Henderson
Scottie
S
Fabrick
Jeffrey A
JA
Carrière
Yves
Y
Dennehy
Timothy J
TJ
Brown
Judith K
JK
Tabashnik
Bruce E
BE
D000483:Alleles; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000494:pharmacology*; D001483:Base Sequence; D015820:Cadherins / Q000235:genetics; D004247:DNA / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004731:Endotoxins / Q000494:pharmacology*; D005091:Exons; D017344:Genes, Insect; D003368:Gossypium / Q000235:genetics / Q000469:parasitology; D006460:Hemolysin Proteins; D006579:Heterozygote; D006720:Homozygote; D019476:Insect Proteins / Q000235:genetics; D007305:Insecticide Resistance / Q000235:genetics; D007438:Introns; D007915:Lepidoptera / Q000187:drug effects* / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D015820:Cadherins; D017931:DNA Primers; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D004247:DNA