title: DNA-based screening for an intracellular cadherin mutation conferring non-recessive Cry1Ac resistance in field populations of Helicoverpa armigera.
abstract: A number of cadherin mutants conferring resistance to Bt toxin Cry1Ac have been reported in three major lepidopteran pests, including Helicoverpa armigera. Unlike most of the cadherin mutants conferring recessive resistance, an allele (r15) with a 55aa deletion in the intracellular domain of cadherin (HaCad) was previously identified to cause non-recessive resistance to Cry1Ac in H. armigera. In the present study, a DNA-based PCR method was developed to screen the r15 allele from field populations of H. armigera collected from the main cotton planting areas of China in 2011 and 2012. Three heterozygous r15 alleles were detected from 562 moths collected from northern China (with intensive Bt cotton planting), and r15 allele frequency was estimated to be 0.0027. However, no r15 allele was detected from 314 moths collected from Xinjiang (with limited Bt cotton use). Although all the r15 alleles have the same deletion in the cDNA sequence, at least four different indels causing loss of exon 32 have been detected in the genomic DNA sequences flanking exon 32 of HaCad. Multiple origins of the r15 alleles illustrate parallel genotypic adaption of H. armigera to the selection pressure of Bt cotton.
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Haonan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Mingyi
authors.initials: M
authors.lastname: Tang
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Yihua
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: wyd@njau.edu.cn.
authors.forename: Yidong
authors.initials: Y
authors.lastname: Wu
mesh_terms: D000483:Alleles; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D015820:Cadherins / Q000235:genetics*; D004247:DNA / Q000235:genetics; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics; D007306:Insecticides; D009036:Moths / Q000235:genetics*; D009154:Mutation; D010572:Pest Control, Biological
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D015820:Cadherins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D004247:DNA
keywords: Bacillus thuringiensis; Cadherin; Cotton bollworm; Molecular detection