Submitted to: Journal of Insect Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/20/2007
Publication Date: 3/17/2008
Citation: Coates, B.S., Sumerford, D.V., Lewis, L.C. 2008. Segregation of European corn borer, Ostrinia nubilalis, aminopeptidase 1, cadherin, and bre5-like alleles, from a colony resistant to Bacillus thuringiensis Cry1Ab toxins, are not associated ...fed a diet containing Cry1Ab. Journal of Insect Science. 8:21. Interpretive Summary: Genetically-engineered (transgenic) crop plants kill insects that feed upon them. Scientists and crop producers see benefits in these plants because they offer control of insect pests without harmful environmental effects of conventional chemical insecticide use. Reduced chemical usage translates into less surface and ground water contamination, and improved farm worker safety. European corn borer, an important pest of corn in the United States, is controlled by transgenic Bacillus thuringiensis (Bt) corn. Damage and control costs for this insect exceed $1 billion from an annual crop valued at more than $22 billion. Nearly complete control of European corn borer on Bt transgenic corn, however, has many scientists concerned that this pest may become resistant to these plants. In this study three genes that cause resistance to Bt toxins in other insect pests, aminopeptidase N, bre5 (Bt resistance gene 5), and cadherin were tested for involvement in resistance to the Bt toxin Cry1Ab in the European corn borer. The outcomes of this research provide stakeholders a molecular tool for characterization of possible resistance genes. The genetics of insect resistance will be useful for all stakeholders interested in finding novel ways to control European corn borers and sustain Bt technology.
Technical Abstract: Peptide receptors may be required for activated Bacillus thuringiensis (Bt) Cry toxins to bind midgut epithelium prior to pore formation. Single nucleotide polymorphism (SNP) markers from two Ostrinia nubilalis midgut peptide receptors, cadherin (OnCad) and aminopeptidase N 1 (OnAPN1), and OnBre5 (Onb3GalT5) were used to examine segregation in F2 families derived from paired matings of Cry1Ab-resistant females and Cry1Ab-susceptible males. Genotypic frequencies for these markers did not deviate from Mendelian expectations. Analysis of F2 larvae indicate the segregation of alleles for OnAPN1, OnBre5 (Onb3GalT5), and OnCad marker loci were independent of the segregation of log10 weights of larvae feeding on Cry1Ab diet.