Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2006
Publication Date: 3/21/2006
Citation: Guo, P.G., Bai, G., Li, R., Shaner, G., Baum, M. 2006. Resistance gene analogs associated with fhb resistance in wheat. Euphytica 151:251-261. Interpretive Summary: Fusarium head blight (FHB) is one of the most destructive diseases of wheat worldwide. A resistance gene analog (RGA) is a piece of DNA that has similar sequence as known resistance genes. It can be used as molecular marker for tracking disease resistance genes or a gene candidate for cloning of resistance genes. To identify potential RGAs associated with FHB resistance in wheat, a mapping population of recombinant inbred lines (RILs) segregating for FHB resistance was derived from the cross Ning7840 and Clark. Five RGAs were significantly associated with FHB resistance. A breeder-friendly marker was successfully converted from RGA18-356. This marker in combination with markers linked to the major gene on chromosome 3BS could be used in marker-assisted selection (MAS) to enhance FHB resistance.
Technical Abstract: Fusarium head blight (FHB) is one of the most destructive diseases of wheat. Identification of resistance gene analogs (RGAs) may provide candidate genes for cloning of FHB resistance genes and molecular markers for marker-assisted improvement of wheat FHB resistance. To identify potential RGAs associated with FHB resistance in wheat, 18 primer pairs of RGAs were screened between two parents (Ning7840 and Clark) and seven informative RGA primer combinations were analyzed in their recombinant inbred lines (RILs). Results indicated that five RGAs showed significant association with FHB resistance. Three of them (RGA14-310, RGA16-462, RGA18-356) were putatively assigned to chromosome 1AL and explained 7% to 13% of the phenotypic variation for FHB resistance in F7 population and 3% to 10 % in F10 population, suggesting that these RGAs may enhance the FHB resistance in wheat. Sequence analysis indicates that RGA16-462, RGA14-339 and RGA18-754 have high homology with wheat high molecular weight (HMW) glutenin A gene, maize polyprotein and wheat leaf rust resistance gene Lr21, respectively. Analysis of nucleotide sequence motifs demonstrated that all the RGA markers contain a heat shock factor that initiates the production of heat shock proteins. A sequence tagged site (STS) marker was successfully converted from RGA18-356, and validated in fourteen other cultivars. Significant interaction between the minor quantitative trait locus (QTL) on 1AL and the major QTL on 3BS was detected. This STS marker in combination with markers linked to the major QTL on 3BS could be used in marker-assisted selection (MAS) to enhance FHB resistance.