Submitted to: International Fusarium Workshop
Publication Type: Proceedings
Publication Acceptance Date: 10/15/2004
Publication Date: 12/11/2004
Citation: Chen, X., Hu, J., Kianian, S., Cai, X. 2004. Saturation mapping of the FHB resistance QTL Qfhs-ndsu-3A in tetraploid wheat. Symposium on Fusarium Head Blight Proceedings. 2nd International Symposium on Fusarium Head Blight, December 11-15, 2004, Orlando, FL. v. 1. p. 240. Interpretive Summary: Fusarium head blight (FHB) is a serious disease of wheat worldwide. The host resistance to FHB is controlled by multiple genes. A previous study has mapped a major quantitative trait locus (QTL), Qfhs.ndsu-3AS, spanning a 29.3 cM interval on chromosome 3A. The new TRAP marker technique was employed with other existing marker techniques to generate more markers in this region for fine mapping of this QTL. The mapping population consists of 83 recombinant inbred chromosome lines (RICLs) derived from LDN×LDN-DIC 3A. Thirty markers have been mapped in the 29.3 cM interval and the major FHB resistance QTL, Qfhs.ndsu-3AS, has been confined within a 10.1 cM by these markers. The markers within this region will be useful in marker-assisted selection in FHB resistance breeding programs.
Technical Abstract: Fusarium head blight (FHB), a destructive disease of wheat, has posed a significant threat to wheat production, processing, and consumption. Sources of effective resistance to FHB have not been found in durum wheat (Triticum turgidum var. durum L., 2n=4x=28, AABB). A major FHB resistance quantitative trait locus (QTL) Qfhs.ndsu-3AS was identified from a wild tetraploid wheat accession (T. dococcoides L., 2n=4x=28, AABB) and mapped within a 29.3 cM interval on chromosome 3A. A mapping population of 83 recombinant inbred chromosome lines (RICLs) derived from a cross between the T. turgidum var. durum cv. Langdon (LDN)-T. dicoccoides substitution line 3A and LDN has been used for saturation mapping of this QTL region in the present study. To date, we have assigned 30 new molecular markers to the QTL region, which extended the map distance from 155.2 cM to 248.4 cM. These markers, including SSR, STS, TRAP (target region amplification polymorphism), SSCP (single-strand conformation polymorphism), and CAPS (cleaved amplified polymorphic sequence), were generated from the ESTs mapped within the deletion bin 3AS-4 where the microsatellite marker closely linked with the peak of the QTL, Xgwm2, was assigned. We have identified new markers flanking the QTL and placed the QTL within a 9.4 cM chromosomal interval that is over three times smaller than the previous interval (29.3 cM). Thermal asymmetric interlaced PCR (TAILPCR) has been employed to extend DNA sequences surrounding the loci of interest. Single or low-copy TAIL-PCR products have been used to screen BAC libraries of LDN and T. tauschii (2n=2x=14, DD) and generate more markers to saturate this QTL region. A large F2 population (over 1,000 individuals) was developed from a cross between LDN and a RICL with a smaller T. dicoccoides chromosomal fragment containing Qfhs.ndsu-3AS. This population has been used to generate more recombinants for fine mapping of the QTL region. F3 offspring of the heterozygous recombinant F2 individuals were produced to generate homozygous recombinants for FHB evaluation. Comparative mapping suggested that the FHB resistance QTL Qfhs.ndsu- 3AS and Qfhs.ndsu-3BS localized on the short arm of chromosome 3A and 3B respectively, are not homoeoloci.