|SIEGFRIED, BLAIR - University Of Nebraska|
Submitted to: Insect Biochemistry and Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2015
Publication Date: 6/17/2015
Citation: Coates, B.S., Siegfried, B.D. 2015. Linkage of an ABCC transporter to a single QTL that controls Ostrinia nubilalis larval resistance to the Bacillus thuringiensis Cry1Fa toxin. Insect Biochemistry and Molecular Biology. 63: 86-96.
Interpretive Summary: Genetically-engineered (transgenic) crop plants that express Bacillus thuringiensis (Bt) toxins kill insects that feed upon them. Scientists and crop producers benefit from growing Bt plants because they offer control of insect damage without the harmful environmental effects and farm worker safety issues associated with conventional chemical insecticides. The European corn borer (ECB), an important pest of corn in the United States, is controlled by transgenic Bt corn. Despite a lack of resistance in the field, ECB remains valuable for use in scientific investigations into how resistance might develop. In this study, genes we applied genome sequencing technologies to generate thousands of genetic markers for ECB, which we used to show that a regions of the ECB genome encoding an ATP binding cassette gene is tightly inherited among with Cry1F. The outcomes of this research provides stakeholders a molecular tool for characterization of a genome region that possibly controls the inheritance of resistance in related moth species. The genetics of insect resistance will be useful for all stakeholders interested in sustaining Bt technology.
Technical Abstract: Field evolved resistance of insect populations to Bacillus thuringiensis (Bt) crystalline (Cry) toxins expressed by crop plants has resulted in reduced control of insect feeding damage to field crops, and threatens the sustainability of Bt transgenic technologies. A single quantitative trait locus (QTL) that determines resistance of Ostrinia nubilalis larvae capable of surviving on reproductive stage transgenic corn that express the Bt Cry1Fa toxin was previously mapped to linkage group 12 (LG12) in pedigree FQ4. Fine mapping with high-throughput single nucleotide polymorphism (SNP) anchor markers, a candidate ABC transport transporter (abcc2) marker, and de novo mutations predicted SNPs from a genotyping-by-sequencing (GBS) data redefined a 268.8 cM LG12. The single QTL on LG12 spanned an approximate 46.1 cM region, in which marker 02302.286 and abcc2 were = 2.81 cM, and the GBS marker 697 was an estimated 1.89 cM distant from the causal genetic factor. This positional mapping data showed that an O. nubilalis genome region encoding an abcc2 transporter is in proximity to a single QTL involved in the inheritance of Cry1F resistance, and will assist in the future identification the mutation(s) involved with this phenotype.