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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Research Project #436177

Research Project: Risk of Resistance to Cry34/35Ab1 by Western Corn Rootworm

Location: Corn Insects and Crop Genetics Research

Project Number: 5030-22000-018-18-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Oct 1, 2018
End Date: Aug 31, 2021

Objective:
To link single nucleotide polymorphism (SNP) markers in genes or genome regions with the inheritance of Bt Cry34/35Ab1 toxin resistance traits in the Western corn rootworm.

Approach:
A series of pedigrees will be established by the single-pair mating of individuals from a field-collected strain of Western corn rootworm that show increased survival on corn plants that express the Bt Cry34/35Ab1 toxin with susceptible individuals. The resulting F1 individuals will be inter--mated, and the F2 larvae will be phenotyped for their level of Cry34/35Ab1 resistance using seedling bioassays. DNA will be extracted from Western corn rootworm larvae from each pedigree, and then genotyped using single nucleotide polymorphism (SNP) markers generated by genotype-by-sequencing (GBS) approaches. The co-segregation between SNP markers and inheritance of high levels of Cry3Bb1 resistance traits will be determined using statistical methods, and the regions of the Western corn rootworm genome involved in the Bt toxin resistance will be identified. Using an available draft whole genome assembly full-genome re-sequencing data will be generated, mapped to the draft reference genome, and genome regions (scaffolds and contigs) identified that show an increase proportion of nucleotide changes between Cry34/35Ab1 survivors compared to susceptible cohorts across all pedigrees. These results will improve the knowledge regarding the evolution of Bt toxin resistance in field populations, and may lead to recommendations that delay the onset of resistance.