Introgression of a novel Ug99-effective stem rust resistance gene into wheat and development of Dasypyrum villosum chromosome specific markers via genotyping-by-sequencing (GBS)

Authors: Ando, Kaori; KRISHNAN, VANDHANA - Washington State University; Rouse, Matthew; DANILOVA, TATIANA - Kansas State University; FRIEBE, BERND - Kansas State University; See, Deven; PUMPHREY, MICHAEL - Washington State University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2019
Publication Date: 5/17/2019
Citation: Ando, K., Krishnan, V., Rouse, M.N., Danilova, T., Friebe, B., See, D.R., Pumphrey, M. 2019. Introgression of a novel Ug99-effective stem rust resistance gene into wheat and development of Dasypyrum villosum chromosome specific markers via genotyping-by-sequencing (GBS). Plant Disease. https://doi.org/10.1094/PDIS-05-18-0831-RE.
DOI: https://doi.org/10.1094/PDIS-05-18-0831-RE

Interpretive Summary: The disease wheat stem rust threatens United States wheat production because a new strain of the wheat stem rust pathogen called Ug99 is virulent to the majority of wheat varieties worldwide and few genetic resources are available that confer resistance. We identified an accession of the wheat relative species Dasypyrum villosum that is resistant to Ug99. We crossed this D. villosum accession to durum (pasta) wheat and then crossed the derived amphiploid to common wheat in order to obtain common wheat lines with single D. villosum chromosomes. We found that D. villosum chromosome 2V possesses a new wheat stem rust resistance gene. We then developed molecular markers linked to the D. villosum chromosome with the new wheat stem rust resistance gene. After further directed chromosome engineering, this new Ug99-effective resistance gene can be incorporated into wheat breeding programs with the aid of the linked molecular markers in order to develop wheat varieties with resistance to Ug99. Wheat varieties with resistance to Ug99 would avert wheat yield losses in the United States if Ug99 were to spread from Africa and Asia to the United States.

Technical Abstract: Dasypyrum villosum is a wild relative of common wheat (Triticum aestivum L.) with highly-effective resistance to Puccinia graminis f. sp. tritici (Pgt), the causal agent of stem rust, including the highly virulent race TTKSK (Ug99). In order to transfer resistance, Triticum durum-D. villosum amphiploids were initially developed and used as a bridge to create wheat-D. villosum introgression lines. Conserved ortholog set (COS) markers were used to identify D. villosum chromosome introgression lines, which were then subjected to seedling Pgt resistance screening with race TTKSK. A COS marker-verified line carrying chromosome 2V with TTKSK resistance was further characterized by combined genomic in situ and fluorescent in situ analyses to confirm a monosomic substitution line MS2V(2D) (20”+1’ 2V(2D). This is the first report of stem rust resistance on 2V, which was temporarily designated as SrTA10276-2V. To facilitate the use of this gene in wheat improvement, a complete set of previously developed wheat-D. villosum disomic addition lines was subjected to genotyping-by-sequencing analysis to develop D. villosum chromosome-specific markers. An average of 350 markers per chromosome were identified. These markers can be used to develop diagnostic markers for D. villosum-derived genes of interest in wheat improvement.