|NIU, Z - Former ARS Employee|
|ZHANG, Q - North Dakota State University|
|Rouse, Matthew - Matt|
|CAI, X - North Dakota State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2017
Publication Date: 4/23/2017
Citation: Xu, S.S., Klindworth, D.L., Niu, Z., Zhang, Q., Chao, S., Friesen, T.L., Jin, Y., Rouse, M.N., Cai, X. 2017. Introgression of a new stem rust resistance gene from Aegilops markgrafii into wheat [abstract]. 13th International Wheat Genetics Symposium, April 23-28, 2017, Tulln, Austria. p. 38-39.
Technical Abstract: In a prior study, we reported that an Alcedo/Aegilops markgrafii disomic addition line, AIII(D) (2n=44), was resistant to three races of the Ug99 lineage and five North American races of stem rust pathogen in wheat and the resistance originated from the alien chromosome. In this study, our objective was to translocate a minimal alien segment carrying the stem rust resistance gene to a homoeologous wheat chromosome. The Ae. markgrafii chromosome in AIII(D) was identified as a group-6 chromosome based on SSR marker analysis. Therefore, AIII(D) was crossed to Chinese Spring (CS) monosomic 6A (M6A) and resistant F2 progeny with 42 chromosomes were screened for presence of an induced Robertsonian translocation chromosome (1’het ) using genomic in situ hybridization (GISH). A plant carrying a Robertsonian translocation was identified and it was backcrossed to CS ph1b. The stem rust resistant BC1F1 plants that were homozygous for ph1b were backcrossed as male to CS. A population of 1049 BC2F1 plants were tested for resistance to race TMLKC and 471 and 566 plants were found to be resistant (IT 0;1) and 566 susceptible (IT 34), respectively. The 471 resistant BC2F1 plants were genotyped with seven SSR markers linked to the Ae. markgrafii chromosome using capillary electrophoresis. Dissociation of the alien segment carrying the stem rust resistance gene was detected in 19 plants. These included 15 plants with dissociation of 6 markers, 1 plant with dissociation of 5 markers, 1 plant with dissociation of 3 markers, and 2 plants yet to be determined. Marker order (proximal to distal) was Xcfd6, Xgdm147, Xwmc773, Xwmc621, Xdupw217, Xgwm332, and Xwmc232. Marker and GISH analysis of the dissociation lines indicated that the stem rust resistance gene was located very near the telomere and tightly linked to Xwmc232 on the chromosome 6AL.