|Abate, Zewdie -|
|Zhang, Wenjun -|
|Rouse, Matt -|
|Elias, Elias -|
|Dubcovsky, Jorge -|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 13, 2010
Publication Date: February 1, 2011
Citation: Simons, K.J., Abate, Z., Chao, S., Zhang, W., Rouse, M., Jin, Y., Elias, E., Dubcovsky, J. 2011. Genetic mapping of stem rust resistance gene Sr13 in tetraploid wheat (Triticum turgidum subsp. durum L.). Theoretical and Applied Genetics. 122:649-658. Interpretive Summary: Wheat stem rust caused by Puccinia graminis f. sp. tritici, can cause significant crop loss. The development of resistant cultivars has been the most cost effective means of protecting wheat from rust epidemics. Wheat breeders have deployed resistance genes both individually and by combining multiple resistant genes in cultivars with the hope to extend the resistance durability. A new race of stem rust, TTKSK (Ug99), was discovered in Uganda in 1999. This race renders most of the resistance genes currently deployed ineffective, and is rapidly spreading to other regions of the world. It is therefore important to identify, locate resistance genes on wheat chromosomes, and deploy resistance genes that are still effective against TTKSK. One of these resistance genes, Sr13, was previously assigned to the long arm of chromosome 6A, but its precise map location is not known. We present here the genetic map locations of Sr13 in relation to molecular DNA markers using three mapping populations developed in durum wheat genetic background segregating for the resistance gene. The first population was from the cross between Kofa and UC1113, and the resistance gene was contributed by Kofa. The second and third populations include crosses between Mindum and Medora or Sceptre. In these last two populations the resistance was contributed by Medora and Sceptre. The genetic mapping results based on these three populations showed that the Sr13 gene was located at the similar location, suggesting that these durum lines carry the same resistance gene. These maps will be the foundation for developing diagnostic markers, for high-density mapping, and for the eventual position cloning of Sr13gene.
Technical Abstract: Wheat stem rust caused by Puccinia graminis f. sp. tritici, can cause significant yield losses. To combat the disease breeders have deployed resistance genes both individually and in combinations to extend the resistance durability. A new race, TTKSK (Ug99), identified in Uganda in 1999, is virulent on most of the resistance genes currently deployed, and is rapidly spreading to other regions of the world. It is therefore important to identify, map, and deploy resistance genes that are still effective against TTKSK. One of these resistance genes, Sr13, was previously assigned to the long arm of chromosome 6A but its precise map location was not known. In this study, the genome location of Sr13 was determined in three tetraploid wheat (T. turgidum subsp. durum) mapping populations. The first population included 93 recombinant inbred lines from the cross between UC1113 and Kofa, and the resistance gene contributed by Kofa was mapped on chromosome 6AL between markers gwm617 and BE471213. The other two populations were from crosses between Mindum and Medora (97 F2 lines) or Sceptre (80 F2 lines). In these two populations the resistance was contributed by Medora and Sceptre, and was mapped to a similar location as in the UC1113 x Kofa population. These results suggest that these durum lines carry the same resistance gene. Based on its chromosome location and infection types against different races, this gene is postulated to be Sr13. These maps will be the foundation for developing high-density maps, identifying diagnostic markers, and positional cloning of Sr13.