|GILL, B - North Dakota State University|
|NIU, Z - Former ARS Employee|
|Rouse, Matthew - Matt|
|CAI, X - North Dakota State University|
Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/24/2015
Publication Date: 1/8/2016
Citation: Gill, B.K., Niu, Z., Klindworth, D.L., Chao, S., Friesen, T.L., Jin, Y., Rouse, M.N., Cai, X., Xu, S.S. 2016. Introgression of a new Ug99-resistant gene from Thinopyrum junceum into wheat [abstract]. Plant and Animal Genome Conference, January 9-13, 2016, San Diego, CA.
Technical Abstract: A wheat 'Chinese Spring' (CS) - Thinopyrum junceum disomic addition line, HD3505 (2n = 44), was previously identified to be resistant to three races in the Ug99 race group and several North American races of the stem rust pathogen (Puccinia graminis. f. sp. tritici). The objective of this study was to transfer the resistance gene from the Th. junceum chromosome in HD3505 into wheat through chromosome engineering. The Th. junceum chromosome in HD3505 was identified as a group-4 chromosome based on marker analysis. Therefore, HD3505 was crossed to CS monosomic 4D and resistant F2 progeny with 42 chromosomes were analyzed for the presence of an induced Robertsonian translocation chromosome using genomic in situ hybridization (GISH). A resistant plant carrying a Robertsonian translocation chromosome with the short arm of wheat chromosome 4D and the long arm of the Th. junceum group-4 chromosome was identified and backcrossed to CS ph1b. The resistant BC1F1 plants that were homozygous for ph1b were backcrossed to CS. From 1,207 BC2F1 plants tested for resistance to race TMLKC, we identified 172 resistant plants. Based on molecular marker and GISH analysis, 14 BC2F1 plants were identified to carry a translocation chromosome with reduced Th. junceum chromatin. Marker and GISH analyses of the translocation lines indicated that the stem rust resistance gene was located in the distal region of chromosome arm 4DL.