Location: Corn Insects and Crop Genetics ResearchTitle: Role of a gamma-aminobutryic acid (GABA) receptor mutation in the evolution and spread of Diabrotica virgifera virgifera resistance to cyclodiene insecticides Author
Submitted to: Insect Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2013
Publication Date: 7/11/2013
Citation: Wang, H., Coates, B.S., Chen, H., Sappington, T.W., Guillemaud, T., Siegfried, B.D. 2013. Role of a gamma-aminobutryic acid (GABA) receptor mutation in the evolution and spread of Diabrotica virgifera virgifera resistance to cyclodiene insecticides. Insect Molecular Biology. 22(5):473-484. Interpretive Summary: Western corn rootworm (WCR) is a highly damaging insect pest of corn crops in the United States and Europe. Damage and control costs for this insect exceed $1 billion from an annual crop valued at more than $22 billion in the U.S. alone. Understanding the evolution of resistance to chemical insecticides is important at the genetic and genomic levels. A gene, called the GABA receptor, was identified in the WCR genome. A single mutation within the WCR GABA receptor gene was further shown to provide resistance resistance to the cyclodiene class of chemical insecticides. This information will be important for understanding and developing strategies to counteract the accumulation of resistance to chemical insecticides in WCR populations.
Technical Abstract: An alanine to serine amino acid substitution within the Rdl subunit of the gamma-aminobutyric acid (GABA) receptor confers resistance to cyclodiene insecticides in many species. The corn rootworm, Diabrotica virgifera virgifera, is a damaging pest of cultivated corn that was partially controlled by applications of cyclodiene insecticides from the late 1940’s until resistance evolved approximately 10 years later. During this time, a range expansion from the western plains into the eastern United States also occurred. The non-synonymous single nucleotide polymorphism (SNP) G/T at the GABA receptor cDNA position 969 (G/T969) of D. v. virgifera resulted in the alanine to serine change, and the co-dominant SNP allele T969 was genetically linked to survival of beetles in aldrin bioassays. Variation in susceptibility to the cyclodiene insecticide, aldrin (= 17-fold difference in proportions of resistant beetles) and a phenotypic gradient of decreasing susceptibility within the eastern range of the species was inversely correlated with observed frequencies of the resistant T969 allele. The preferential migration or survival (fitness) of aldrin resistant D. v. virgifera within the species' range expansion may be consistent with current phenotypic and genotypic distributions within the United States.