Submitted to: Insect Biochemistry and Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 18, 2006
Publication Date: April 2, 2007
Citation: Coates, B.S., Sumerford, D.V., Hellmich II, R.L., Lewis, L.C. 2007. A Beta-1,3-galactosyltransferase and brainiac/bre5 homolog expressed in the midgut did not contribute to a Cry1Ab toxin resistance trait in Ostrinia nubilalis. Insect Biochemistry and Molecular Biology. 37(4):346-355. Interpretive Summary: Genetically-engineered (transgenic) crop plants have been produced to kill insects that feed upon them. Scientists and crop producers see benefits in these plants because they offer an effective way to kill pests without harmful environmental effects of conventional chemical insecticides. Reduced chemical usage translates into less surface and ground water contamination. 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 could become resistant to these plants. In this study, a gene causing resistance to Bt toxins in nematodes, bre5 (Bt resistance gene 5), was isolated and tested for involvement in resistance to Bt toxin in the European corn borer. This research provides a molecular tool for characterization of the possible resistance gene. 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: Postranslational glycosylation of midgut epithelial peptide and lipid receptors may be required prior to activated Bacillus thuringiensis (Bt) Cry toxin binding. A 931 nt mRNA encoding a putative 297 residue Beta-1,3-galactosyltransferase (Beta3GalT5) was isolated from larval O. nubilalis midgut tissue, and showed homology to Drosophila brainiac (brn) and Caenorhabditis elegans bre5 peptides. Single nucleotide polymorphisms (SNPs) were detected between coding and promoter regions of O. nubilalis Beta3GalT5 (OnBeta3GalT5) alleles, of which 3 of 31 CDS SNPs were non-synonymous. SNPs within HaeIII and MspI recognition sites were confirmed by PCR-RFLP, and are Mendelian inherited. Analysis of F2 pedigrees suggested an M2 OnBeta3GalT5 allele fixed within a Cry1Ab resistant colony was not correlated with Cry1Ab resistance.