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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Research » Research » Publications at this Location » Publication #345090

Research Project: Genetic Improvement of Durum and Spring Wheat for Quality and Resistance to Diseases and Pests

Location: Cereal Crops Research

Title: Identification, mapping, and marker development of stem rust resistance genes in durum wheat 'Lebsock'

Author
item Saini, Jyoti - North Dakota State University
item Faris, Justin
item Zhang, Qijun - North Dakota State University
item Rouse, Matthew - Matt
item Jin, Yue
item Long, Yunming - North Dakota State University
item Klindworth, Daryl
item Elias, Elias - North Dakota State University
item Mcclean, Phillip - North Dakota State University
item Edwards, Michael
item Xu, Steven

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2018
Publication Date: 5/28/2018
Citation: Saini, J., Faris, J.D., Zhang, Q., Rouse, M.N., Jin, Y., Long, Y., Klindworth, D.L., Elias, E.M., McClean, P.E., Edwards, M.C., Xu, S.S. 2018. Identification, mapping, and marker development of stem rust resistance genes in durum wheat 'Lebsock'. Molecular Breeding. 38:77. https://doi.org/10.1007/s11032-018-0833-y.
DOI: https://doi.org/10.1007/s11032-018-0833-y

Interpretive Summary: Wheat production in many wheat-growing regions is vulnerable to stem rust disease, caused by the fungal pathogen Puccinia graminis f. sp. tritici (Pgt). Several previous studies showed that most of the durum wheat cultivars growing in the upper Great Plains of the U.S. have good resistance to the major Pgt races, including the Ug99 race group. To identify the stem rust resistance (Sr) genes in the durum variety ‘Lebsock’, a tetraploid mapping population derived from a cross between Lebsock and Persian wheat (Triticum turgidum ssp. carthlicum) was evaluated using Pgt races TTKSK, TRTTF, and TTTTF. The stem rust and genotypic data were then used to identify chromosomal regions associated with resistance. We identified one chromosomal region each on chromosome arms 4AL, 6AS, 6AL, and 2BL. We postulated that the chromosomal regions associated with the resistance on 4AL, 6AS, 6AL, and 2BL correspond to the genes Sr7a, Sr8155B1, Sr13, and likely Sr9e, respectively. Among these genes, Sr8155B1 was recently identified and shown to be unique for its susceptibility to the original Ug99 race TTKSK, but it has resistance to Ug99 variant race TTKST. The results indicated that most of the U.S. durum germplasm adapted to the upper Great Plains likely harbors the four major Sr genes characterized in this study. In addition, new genetic markers were developed for genes Sr7a and Sr8155-B1. Knowledge of the Sr genes present in durum germplasm and the new molecular markers are useful for stacking and deployment of multiple Sr genes in future durum and wheat cultivars.

Technical Abstract: Wheat production in many wheat-growing regions is vulnerable to stem rust, caused by Puccinia graminis f. sp. tritici (Pgt). Several previous studies showed that most of the durum cultivars adapted to the upper Great Plains in the U.S. have good resistance to the major Pgt pathotypes, including the Ug99 race group. To identify the stem rust resistance (Sr) genes in the durum variety ‘Lebsock’, a tetraploid doubled haploid (DH) population derived from a cross between Lebsock and Triticum turgidum ssp. carthlicum PI 94749 was screened with three Pgt races, TTKSK, TRTTF, and TTTTF. The stem rust data and the genotypic data previously developed were used to identify quantitative trait loci (QTL) associated with the resistance. We identified one QTL each on chromosome arms 4AL, 6AS, 6AL, and 2BL. Based on marker and race-specification analysis, we postulated that the QTL on 4AL, 6AS, 6AL, and 2BL correspond to Sr7a, Sr8155B1, Sr13, and likely Sr9e, respectively. The results indicated that most of the U.S. durum germplasm adapted to the upper Great Plains likely harbors the four major Sr genes characterized in this study. Among these genes, Sr8155B1 was recently identified and shown to be unique in its susceptibility to TTKSK but resistance to variant race TTKST. Two and three thermal asymmetric reverse PCR (STARP) markers were developed for Sr7a and Sr8155-B1, respectively. The knowledge of the Sr genes in durum germplasm and the new STARP markers are useful for pyramiding and deployment of multiple Sr genes in future durum and wheat cultivars.