Agriculture and Agri-Food Canada, Cereal Research Centre, 195 Dafoe Rd., Winnipeg, MB, R3T 2M9, Canada.
Theor Appl Genet. 2011 Jan;122(1):143-9. doi: 10.1007/s00122-010-1430-6. Epub 2010 Aug 20.
Stem rust (caused by Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & E. Henn.) has re-emerged as a threat to wheat production with the evolution of new pathogen races, namely TTKSK (Ug99) and its variants, in Africa. Deployment of resistant wheat cultivars has provided long-term control of stem rust. Identification of new resistance genes will contribute to future cultivars with broad resistance to stem rust. The related Canadian cultivars Peace and AC Cadillac show resistance to Ug99 at the seedling stage and in the field. The purpose of this study was to elucidate the inheritance and genetically map resistance to Ug99 in these two cultivars. Two populations were produced, an F(2:3) population from LMPG/AC Cadillac and a doubled haploid (DH) population from RL6071/Peace. Both populations showed segregation at the seedling stage for a single stem rust resistance (Sr) gene, temporarily named SrCad. SrCad was mapped to chromosome 6DS in both populations with microsatellite markers and a marker (FSD_RSA) that is tightly linked to the common bunt resistance gene Bt10. FSD_RSA was the closest marker to SrCad (≈ 1.6 cM). Evaluation of the RL6071/Peace DH population and a second DH population, AC Karma/87E03-S2B1, in Kenya showed that the combination of SrCad and leaf rust resistance gene Lr34 provided a high level of resistance to Ug99-type races in the field, whereas in the absence of Lr34 SrCad conferred moderate resistance. A survey confirmed that SrCad is the basis for all of the seedling resistance to Ug99 in Canadian wheat cultivars. While further study is needed to determine the relationship between SrCad and other Sr genes on chromosome 6DS, SrCad represents a valuable genetic resource for producing stem rust resistant wheat cultivars.
茎锈病（由 Puccinia graminis Pers.：Pers. f. sp. tritici Eriks. & E. Henn.引起）随着新病原体菌株 TTKSK（Ug99）及其变体在非洲的出现，再次成为小麦生产的威胁。抗锈病小麦品种的应用为茎锈病的长期控制提供了保障。新抗性基因的鉴定将有助于未来培育出具有广谱抗茎锈病的品种。相关的加拿大品种 Peace 和 AC Cadillac 在幼苗期和田间表现出对 Ug99 的抗性。本研究旨在阐明这两个品种对 Ug99 的遗传和基因图谱抗性。产生了两个群体，一个来自 LMPG/AC Cadillac 的 F(2:3)群体和一个来自 RL6071/Peace 的加倍单倍体 (DH)群体。两个群体在幼苗期都表现出单一茎锈病抗性（Sr）基因的分离，暂时命名为 SrCad。SrCad 在两个群体中均通过微卫星标记和与常见黑穗病抗性基因 Bt10 紧密连锁的标记（FSD_RSA）映射到 6DS 染色体上。FSD_RSA 是与 SrCad 最接近的标记（≈1.6 cM）。对 RL6071/Peace DH 群体和肯尼亚的第二个 DH 群体 AC Karma/87E03-S2B1 的评估表明，SrCad 与叶锈病抗性基因 Lr34 的组合在田间提供了对 Ug99 型菌株的高水平抗性，而在没有 Lr34 的情况下，SrCad 提供了中度抗性。一项调查证实，SrCad 是加拿大小麦品种对 Ug99 所有幼苗抗性的基础。虽然需要进一步研究来确定 SrCad 与 6DS 染色体上其他 Sr 基因之间的关系，但 SrCad 代表了生产抗茎锈病小麦品种的宝贵遗传资源。
