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United States Department of Agriculture

Agricultural Research Service

Title: Saturation Mapping of a Major Fusarium Head Blight Resistance Qtl Region in Tetraploid Wheat

Authors
item Chen, X - NORTH DAKOTA STATE UNIV.
item Hu, Jinguo
item Kianian, S - NORTH DAKOTA STATE UNIV.
item Cai, X - NORTH DAKOTA STATE UNIV.

Submitted to: National Fusarium Head Blight Forum Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 15, 2003
Publication Date: December 13, 2003
Citation: Chen, X., Hu, J., Kianian, S., Cai, X. 2003. Saturation mapping of a major Fusarium head blight resistance QTL region in tetraploid wheat. 2003 National Fusarium Head Blight Forum Proceedings. National Fusarium Head Blight Forum, December 13-15, 2003, Bloomington, MN. p. 11. Available: http://www.scabusa.org/pdfs/forum_03_proc_bio.pdf

Interpretive Summary: Previous screening for Fusarium head blight (FHB) resistance identified a Triticum dicoccoides accession carrying FHB resistance gene(s). Using T. durum cv. 'Langdon'-T.dicoccoides chromosome 3A recombinant inbred chromosome lines (RICLs), a major quantitative trait locus (QTL) Qfhs.ndsu-3AS, that explains 55% of the genetic variation for FHB resistance, and a microsatellite locus, Xgwm2, tightly linked to the highest point of the QTL peak have been identified (Otto et al. 2002). This QTL spanned a 29.3cM interval on chromosome 3A. The objective of this study is to saturate the QTL Qfhs.ndsu-3AS region and identify recombinants for a smaller donor chromosomal segment carrying this QTL. Screening of the T. monococuum bacterial artificial chromosome (BAC) library with the DNA-based probe NDSU.fhb.3A derived from the microsatellite marker Xgwm2 has identified 15 BAC clones. We are isolating low or single copy sequences from these BACs to generate more markers for saturating the QTL region. A novel marker technique Target Region Amplification Polymorphism (TRAP) has been used to generate markers in this study (Hu et al. 2003). We designed 50 fixed primers based on the EST sequences mapped on the short arm of chromosome 3A (3AS) and the conserved domain sequences of the leucine rich repeat (LRR) of disease resistance genes. Nine polymorphic markers were generated with these fixed primers in combination with random primers. All these 9 markers were mapped on chromosome 3A. In addition, we have designed 9 pairs of microsatellite primers based on the 3' and 5' sequences of the ESTs mapped on 3AS and have been trying to generate more markers within the QTL region. Two microsatellite markers, Xgwm493 and Xgwm389, mapped in a major FHB resistance QTL Qfhs.ndsu-3BS region, showed no polymorphism between the two parents of the RICLs. Fourteen out of 28 STS primer pairs developed from the ESTs mapped on chromosome 3B by Dr. J. A. Anderson (Liu et al. 2003) showed polymorphism between the two parents of the RICLs. Six STS markers generated through this approach have been mapped on chromosome 3A. Based on microcolinearity between wheat homoeologous group 3 chromosomes and rice chromosome 1, we have been identifying the rice genomic sequences in the collinear region and using them to identify wheat ESTs that have not yet been mapped in the wheat genomes. These ESTs will be used to develop STS markers for saturating the QTL region. Concurrently, a large F2 population has been developed by crossing Langdon with a RICL carrying a smallest T.dicoccoides chromosomal fragment spanning the Qfhs.ndsu-3AS. This population is being employed to identify more recombinants within the QTL region for fine mapping.

Technical Abstract: Previous screening for Fusarium head blight (FHB) resistance identified a Triticum dicoccoides accession carrying FHB resistance gene(s). Using T. durum cv. 'Langdon'-T.dicoccoides chromosome 3A recombinant inbred chromosome lines (RICLs), a major quantitative trait locus (QTL) Qfhs.ndsu-3AS, that explains 55% of the genetic variation for FHB resistance, and a microsatellite locus, Xgwm2, tightly linked to the highest point of the QTL peak have been identified (Otto et al. 2002). This QTL spanned a 29.3cM interval on chromosome 3A. The objective of this study is to saturate the QTL Qfhs.ndsu-3AS region and identify recombinants for a smaller donor chromosomal segment carrying this QTL. Screening of the T. monococuum bacterial artificial chromosome (BAC) library with the DNA-based probe NDSU.fhb.3A derived from the microsatellite marker Xgwm2 has identified 15 BAC clones. We are isolating low or single copy sequences from these BACs to generate more markers for saturating the QTL region. A novel marker technique Target Region Amplification Polymorphism (TRAP) has been used to generate markers in this study (Hu et al. 2003). We designed 50 fixed primers based on the EST sequences mapped on the short arm of chromosome 3A (3AS) and the conserved domain sequences of the leucine rich repeat (LRR) of disease resistance genes. Nine polymorphic markers were generated with these fixed primers in combination with random primers. All these 9 markers were mapped on chromosome 3A. In addition, we have designed 9 pairs of microsatellite primers based on the 3' and 5' sequences of the ESTs mapped on 3AS and have been trying to generate more markers within the QTL region. Two microsatellite markers, Xgwm493 and Xgwm389, mapped in a major FHB resistance QTL Qfhs.ndsu-3BS region, showed no polymorphism between the two parents of the RICLs. Fourteen out of 28 STS primer pairs developed from the ESTs mapped on chromosome 3B by Dr. J. A. Anderson (Liu et al. 2003) showed polymorphism between the two parents of the RICLs. Six STS markers generated through this approach have been mapped on chromosome 3A. Based on microcolinearity between wheat homoeologous group 3 chromosomes and rice chromosome 1, we have been identifying the rice genomic sequences in the collinear region and using them to identify wheat ESTs that have not yet been mapped in the wheat genomes. These ESTs will be used to develop STS markers for saturating the QTL region. Concurrently, a large F2 population has been developed by crossing Langdon with a RICL carrying a smallest T.dicoccoides chromosomal fragment spanning the Qfhs.ndsu-3AS. This population is being employed to identify more recombinants within the QTL region for fine mapping.

Last Modified: 4/16/2014
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