Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/20/2007
Publication Date: 12/1/2007
Citation: Zhu, X., Chen, X., Faris, J.D., Hu, J., Stack, R.S., Adhikari, T., Elias, E.M., Kianian, S.F., Cai, X. 2007. Toward a better understanding of a major FHB resistance QTL in tetraploid wheat. Meeting Abstract. National Wheat Genomics Conference abstracts p. 12
Technical Abstract: Fusarium head blight (FHB), mainly caused by the fungus Fusarium graminearum, is a destructive disease of wheat and poses a serious threat to wheat production and health of wheat consumers worldwide. Partial resistance to FHB has been identified in common wheat (Triticum aestivum L.). A source of effective resistance to FHB, however, has not been found in durum wheat (T. turgidum L. ssp. durum). A major FHB resistance QTL, Qfhs.ndsu-3AS, was identified and mapped to chromosome 3A of T. turgidum L. ssp. dicoccoides, a wild relative of durum wheat, in a previous study. This QTL explains 42% of the phenotypic variation for FHB resistance and is not homoeologous to Qfhs.ndsu-3BS, a major FHB resistance QTL identified in the Chinese common wheat cultivar Sumai 3. We have saturated the genomic region harboring the QTL using EST-derived TRAP (target region amplified polymorphism), STS (sequence tagged site), and SSR (simple sequence repeat) markers and been developing a high resolution map of this FHB resistance QTL. We used the genomic sequences from 10 PACs on the short arm of rice chromosome 1, which are collinear with the chromosomal regions harboring Qfhs.ndsu-3AS, to search the wheat EST pool and identified 404 unmapped wheat ESTs for marker development. To date, a total of 58 new molecular marker loci have been detected on chromosome 3A. Five new EST-derived STS markers mapped to a chromosomal interval of 10.7 cM harboring the QTL in a population of 83 recombinant inbred chromosome lines (RICLs). One of the STS markers was derived from the EST of a gene which expression was induced by the FHB pathogen Fusarium graminearum in the common wheat cultivar Frontana. This STS marker mapped 0.6 cM proximal to Xgwm2, an SSR marker closely linked to the QTL peak. ‘Frontana’ also contains a major FHB resistance QTL on chromosome 3A. In addition, we have been genotyping a large F2 population (>2,000 individuals) derived from the cross between LDN and a RICL that has a small T. dicoccoides chromosomal fragment (10.7 cM) harboring Qfhs.ndsu-3AS for fine mapping of the QTL. This research facilitates the use of Qfhs.ndsu-3AS in wheat breeding and germplasm development through marker-assisted selection and map-based cloning of the QTL.