Location: Genomics and Gene Discovery
Title: Genetic association and disassociation of OPR and LOX genes with resistance to Hessian fly in hexaploid wheat Authors
Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 17, 2013
Publication Date: N/A
Interpretive Summary: Hessian fly [Hf, Mayetiola destructor (Say)] is one of the most destructive pests of wheat in the United States and worldwide. This frequently occurring pest causes annual losses to wheat production in the USA of $112-252/ha. Deployment of natural and genetic resistance in locally adapted wheat cultivars is the most effective, economical, and environmentally safe method to control this damaging insect. More than 33 Hessian fly resistance genes have been identified. Among them, only 8 resistance genes are identified in bread wheat. In this study, a wheat mapping population derived from a cross between a resistance line (2174) and a susceptible line (Jagger). Two genetic regions (QTLs) that confer the resistance were identified in the mapping population using molecular markers closely associated to the resistance traits. These molecular markers are useful for developing Hessian fly resistance wheat cultivars through marker-assisted breeding program.
Technical Abstract: The Hessian fly is one of the most destructive pests of wheat. The genes encoding 12-oxo-phytodienoic acid reductase (OPR) and lipoxygenase (LOX) play critical roles in the insect resistance pathway in higher plants, but little is known about genes controlling the insect in wheat. In this study, 154 F6:8 recombinant inbred lines (RILs) generated from a cross between hexaploid wheat cultivars, ‘Jagger’ and ‘2174’, were used to map genes associated with resistance to the Hessian fly. Two QTLs were identified. The first one was a major QTL on chromosome 1A (QHf.osu-1A), which explained 70% of the total phenotypic variation. The resistant allele at this locus in 2174 could be orthologous to one or more of the previously mapped resistance genes (H9, H10, H11, H16, and H17) in tetraploid wheat. The second QTL was a minor QTL on chromosome 2A (QHf.osu-2A), which accounted for 18% of the total phenotypic variation. The resistant allele at this locus in 2174 is collinear to an Yr17-containing-fragment translocated from chromosome 2N in Jagger. Genetic mapping results showed that two OPR genes, TaOPR1-A and TaOPR2-A, were tightly associated with QHf.osu-1A and QHf.osu-2A, respectively. Another OPR gene and three LOX genes were mapped but not associated with Hessian fly resistance in the segregating population. These findings provide clues for the genetic association and disassociation of Hessian fly resistance with OPR and LOX genes.