Toward a better understanding of the genomic region harboring Fusarium head blight resistance QTL Qfhs.ndsu-3AS in durum wheat

Authors: ZHU, XIANWEN - North Dakota State University; ZHONG, SHAOBIN - North Dakota State University; Chao, Shiaoman; Gu, Yong; Kianian, Shahryar; ELIAS, ELIAS - North Dakota State University; CAI, XIWEN - North Dakota State University

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2015
Publication Date: 1/1/2016
Publication URL: http://handle.nal.usda.gov/10113/61845
Citation: Zhu, X., Zhong, S., Chao, S., Gu, Y.Q., Kianian, S.F., Elias, E., Cai, X. 2016. Toward a better understanding of the genomic region harboring Fusarium head blight resistance QTL Qfhs.ndsu-3AS in durum wheat. Theoretical and Applied Genetics. 129:31-43.

Interpretive Summary: Fusarium head blight (FHB) is a destructive fungal disease of wheat. Infection and development of FHB are accelerated by warm and humid conditions. Outbreak of FHB can cause severe losses of grain yield and quality in both bread wheat and durum wheat. Developing cultivars with adequate disease resistance has been the most economical means to prevent wheat from damages caused by disease outbreak. Multiple genes for FHB resistance have been identified and successfully deployed in bread wheat cultivars. In durum wheat, FHB remains a major threat to its production due to the lack of effective resistance sources. Transferring FHB resistance genes from bread wheat into durum has not been very successful because of the complex inheritance of hexaploid-derived FHB resistance in the durum background. Wild emmer, a close relative of cultivated durum wheat, is known to be a rich source of genetic variations for disease resistance. Previously a chromosome region containing FHB resistance genes of wild emmer origin has been identified and mapped to chromosome 3A. In this study, further efforts were made to characterize the gene region and identify derived lines carrying the shortened wild emmer chromosome fragment at the gene region for FHB resistance evaluation. These derived lines should provide useful resources for breeding FHB resistance in durum wheat.

Technical Abstract: The wild emmer wheat (Triticum dicoccoides)-derived Fusarium head blight (FHB) resistance quantitative trait locus (QTL) Qfhs.ndsu-3AS previously mapped to the short arm of chromosome 3A (3AS) in a population of recombinant inbred chromosome lines (RICLs). This study aimed to attain a better understanding of the genomic region harboring Qfhs.ndsu-3AS and to improve the utility of the QTL in wheat breeding. Micro-collinearity of the QTL region with rice chromosome 1 and Brachypodium chromosome 2 was identified and used for marker development in saturation mapping. A total of 42 new EST-derived sequence tagged site (STS) and simple sequence repeat (SSR) markers were developed and mapped to the QTL and nearby regions on 3AS. Comparative analysis of the QTL and nearby regions on 3AS with their collinear counterparts of rice and Brachypodium revealed a complex collinearity between the genomic regions. Fine mapping of the QTL region in a large F2 population (n=372) resolved five co-segregating markers (Xwgc1186/Xwgc716/Xwgc1143/Xwgc501/Xwgc1204) into three distinct loci proximal to Xgwm2, a marker previously reported to be closely linked to the QTL. Four other markers (Xwgc1226, Xwgc510, Xwgc1296, and Xwgc1301) mapped farther proximal to the above markers in the QTL region with a higher resolution. Five homozygous recombinants with shortened T. dicoccoides chromosomal segments in the QTL region were recovered by molecular marker analysis and evaluated for FHB resistance. Qfhs.ndsu-3AS was positioned to a 5.2 cM interval flanked by the marker Xwgc501 and Xwgc510. The recombinants with shortened T. dicoccoides chromosomal segments harboring Qfhs.ndsu-3AS and new markers defining the QTL will facilitate utilization of this resistance source in wheat breeding.