Shared genetic basis of resistance to Bt toxin Cry1Ac in independent strains of pink bollworm

Bruce E Tabashnik, Yong Biao Liu, Devika C. Unnithan, Yves Carriere, Timothy J. Dennehy, Shai Morin

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Classical and molecular genetic analyses show that two independently derived resistant strains of pink bollworm, Pectinophora gossypiella (Saunders), share a genetic locus at which three mutant alleles confer resistance to Bacillus thuringiensis (Bt) toxin Cry1Ac. One laboratory-selected resistant strain (AZP-R) was derived from individuals collected in 1997 from 10 Arizona cotton fields, whereas the other (APHIS-98R) was derived from a long-term susceptible laboratory strain. Both strains were previously reported to show traits of "mode 1" resistance, the most common type of lepidopteran resistance to Cry1A toxins. Inheritance of resistance to a diagnostic concentration of Cry1Ac (10 μg per gram of diet) was recessive in both strains. In interstrain complementation tests for allelism, F1 progeny from crosses between the two strains were resistant to the diagnostic concentration of Cry1Ac. These results indicate that a major resistance locus is shared by the two strains. Analysis of DNA from the pink bollworm cadherin gene (BtR) using allele-specific polymerase chain reaction (PCR) tests showed that the previously identified resistance alleles (r1, r2, and r3) occurred in both strains, but their frequencies differed between strains. In conjunction with previous findings, the results reported here suggest that PCR-based detection of the three known cadherin resistance alleles might be useful for monitoring resistance to Cry1Ac-producing Bt cotton in field populations of pink bollworm.

Original languageEnglish (US)
Pages (from-to)721-726
Number of pages6
JournalJournal of Economic Entomology
Volume97
Issue number3
StatePublished - Jun 2004

Fingerprint

Pectinophora gossypiella
Bacillus thuringiensis
toxin
allele
toxins
polymerase chain reaction
cotton
alleles
cadherins
diet
DNA
Animal and Plant Health Inspection Service
allelism
gene
loci
monitoring
molecular genetics
inheritance (genetics)
Lepidoptera
testing

Keywords

  • Bacillus thuringiensis
  • Genetically modified crops
  • Genetics
  • Pectinophora gossypiella
  • Resistance

ASJC Scopus subject areas

  • Insect Science

Cite this

Shared genetic basis of resistance to Bt toxin Cry1Ac in independent strains of pink bollworm. / Tabashnik, Bruce E; Liu, Yong Biao; Unnithan, Devika C.; Carriere, Yves; Dennehy, Timothy J.; Morin, Shai.

In: Journal of Economic Entomology, Vol. 97, No. 3, 06.2004, p. 721-726.

Research output: Contribution to journalArticle

Tabashnik, Bruce E ; Liu, Yong Biao ; Unnithan, Devika C. ; Carriere, Yves ; Dennehy, Timothy J. ; Morin, Shai. / Shared genetic basis of resistance to Bt toxin Cry1Ac in independent strains of pink bollworm. In: Journal of Economic Entomology. 2004 ; Vol. 97, No. 3. pp. 721-726.
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