Quantitative trait locus mapping and functional genomics of an organophosphate resistance trait in the western corn rootworm, Diabrotica virgifera virgifera

Authors: Coates, Brad; ALVEZ, A - University Of Nebraska; WANG, HAICHUAN - University Of Nebraska; ZHOU, ZUGUO - University Of Nebraska; NOWASTSKI, TIM - University Of Nebraska; CHEN, HONG - University Of Nebraska; RANGASAMY, MURUGESAN - University Of Nebraska; ROBERTSON, HUGH - University Of Illinois; WHITFIELD, CHARLES - University Of Illinois; WALDEN, KIMBERLY - University Of Illinois; KACHMAN, STEVEN - University Of Nebraska; French, Bryan; MEINKE, LANCE - University Of Nebraska; HAWTHORNE, DAVID - University Of Maryland; Abel, Craig; Sappington, Thomas; SIEGFRIED, BLAIR - University Of Nebraska; MILLER, NICHOLAS - University Of Nebraska

Submitted to: Insect Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2015
Publication Date: 1/4/2016
Citation: Coates, B.S., Alvez, A., Wang, H., Zhou, Z., Nowastski, T., Chen, H., Rangasamy, M., Robertson, H.M., Whitfield, C.W., Walden, K.K., Kachman, S.D., French, B.W., Meinke, L.J., Hawthorne, D., Abel, C.A., Sappington, T.W., Siegfried, B.D., Miller, N.J. 2016. Quantitative trait locus mapping and functional genomics of an organophosphate resistance trait in the western corn rootworm, Diabrotica virgifera virgifera. Insect Molecular Biology. 25(1):1-15. doi: 10.1111/imb.12194.

Interpretive Summary: Western corn rootworm (WCR) is a serious insect pest of corn through most of the United States, where crop damage and control costs associated with this insect are greater than $1 billion per year. Efforts to control damage to corn crops has become increasing difficult due to selection for WCR populations that are resistant to multiple different chemical insecticides, which includes populations in western areas of the corn belt that cannot be controlled by organophosphate (OP) insecticides. In order to understand the genetic basis of OP resistance in WCR, ARS scientists and university collaborators identified a single genome region that is associated with inheritance of OP resistance. This research additionally showed that four genes that encode enzymes known to degrade chemical bonds of insecticide molecules are expressed at higher levels in OP resistant compared to susceptible WCR beetles. This might suggest OP resistant WCR have an increased capacity to detoxify the pesticide when they are exposed to field sprays. These data will likely assist university and private-sector scientists in understanding the genetic basis of OP pesticide resistance in WCR.

Technical Abstract: The western corn rootworm (WCR), Diabrotica virgifera virgifera, is an insect pest of corn, and population suppression with chemical insecticides is an important management tool. Traits conferring organophosphate insecticide resistance have increased in frequency among WCR populations, resulting in the reduced efficacy in many corn growing regions of the United States. We used comparative functional genomic and quantitative trait locus (QTL) mapping approaches to investigate the genetic basis of WCR resistance to the organophosphate, methyl-parathion. RNA from adult methyl-parathion resistant and susceptible adults was hybridized to 8,331 microarray probes. Results predicted that 11 transcripts were significantly up-regulated in resistant phenotypes, with the most significant being a cytochrome P450 monooxygenase and two esterase-like transcripts. Differential expression was validated only for esterase3, with 8- to 30-fold greater expression in methyl-parathion resistant adults. Progeny with a segregating methyl-parathion resistance trait were obtained from a reciprocal backcross design. QTL analyses of high-throughput single nucleotide polymorphism (SNP) genotype data predicted involvement of a single genome interval. These data implicate the involvement of a specific carboyxesterase in field-evolved WCR resistance to organophosphates.