The University of Sydney Plant Breeding Institute-Cobbitty, PB4011, Narellan, NSW, 2567, Australia.
Theor Appl Genet. 2011 Jan;122(1):1-7. doi: 10.1007/s00122-010-1417-3. Epub 2010 Aug 1.
Stem rust resistance gene Sr22 transferred to common wheat from Triticum boeoticum and T. monococcum remains effective against commercially prevalent pathotypes of Puccinia graminis f. sp. tritici, including Ug99 and its derivatives. Sr22 was previously located on the long arm of chromosome 7A. Several backcross derivatives (hexaploid) possessing variable sized Sr22-carrying segments were used in this study to identify a closely linked DNA marker. Expressed sequenced tags belonging to the deletion bin 7AL-0.74-0.86, corresponding to the genomic location of Sr22 were screened for polymorphism. In addition, RFLP markers that mapped to this region were targeted. Initial screening was performed on the resistant and susceptible DNA bulks obtained from backcross derivatives carrying Sr22 in three genetic backgrounds with short T. boeoticum segments. A cloned wheat genomic fragment, csIH81, that detected RFLPs between the resistant and susceptible bulks, was converted into a sequence tagged site (STS) marker, named cssu22. Validation was performed on Sr22 carrying backcross-derivatives in fourteen genetic backgrounds and other genotypes used for marker development. Marker cssu22 distinguished all backcross-derivatives from their respective recurrent parents and co-segregated with Sr22 in a Schomburgk (+Sr22)/Yarralinka (-Sr22)-derived recombinant inbred line (RIL) population. Sr22 was also validated in a second population, Sr22TB/Lakin-derived F(4) selected families, containing shortened introgressed segments that showed recombination with previously reported flanking microsatellite markers.
从野生二粒小麦和节节麦中导入普通小麦的茎锈病抗性基因 Sr22 仍然对普遍存在的小麦条锈菌生理小种（Puccinia graminis f. sp. tritici）有效，包括 Ug99 及其衍生品种。Sr22 先前位于 7A 染色体的长臂上。本研究使用了几个携带不同大小 Sr22 片段的回交衍生系（六倍体）来鉴定紧密连锁的 DNA 标记。属于缺失 bin 7AL-0.74-0.86 的表达序列标签被筛选用于多态性。此外，还针对该区域的 RFLP 标记进行了靶向筛选。在三个遗传背景下，用携带 Sr22 的回交衍生系获得的抗性和感病 DNA 块进行了初步筛选，这三个遗传背景中短的野生二粒小麦片段。从携带 Sr22 的回交衍生系中筛选到的一个克隆小麦基因组片段 csIH81 检测到了抗性和感病块之间的 RFLP，将其转化为一个序列标签位点（STS）标记，命名为 cssu22。在 14 个遗传背景和其他用于标记开发的基因型上对携带 Sr22 的回交衍生系进行了验证。标记 cssu22 可将所有回交衍生系与其各自的轮回亲本区分开来，并在 Schomburgk（+Sr22）/Yarralinka（-Sr22）衍生的重组自交系（RIL）群体中与 Sr22 共分离。在另一个群体，Sr22TB/Lakin 衍生的 F4 选择家系中也验证了 Sr22，这些家系包含缩短的导入片段，与之前报道的侧翼微卫星标记发生了重组。
