Detection of virulence to resistance gene Sr24 within race TTKS of Puccinia graminis f. sp tritici
Detection of virulence to resistance gene Sr24 within race TTKS of Puccinia graminis f. sp tritici
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DOI：
10.1094/pdis-92-6-0923
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发表时间：
2008-06-01
期刊：
影响因子：
4.5
通讯作者：
Fetch, T., Jr.
中科院分区：
文献类型：
--
作者：
Jin, Y.;Szabo, L. J.;Fetch, T., Jr.
茎锈病抗性基因Sr24对禾柄锈菌f的大多数小种均有效。 sp。 tritici，包括 TTKS 品种（同义词 Ug99），广泛用于全球商业小麦品种。 2006年，在肯尼亚恩乔罗的田间茎锈病筛选苗圃中，在携带Sr24的小麦品系和品种上观察到了易感感染反应。我们从 2006 年 Njoro 苗圃收集的茎锈病样本中分离出 28 个单脓疱菌株。对 16 个北美茎锈病差异系的毒力进行了评估；携带 Sr24、Sr31、Sr38 和 SrMcN 的小麦品系；以及 Sr24 和 Sr31 组合的小麦品种。所有分离株均被鉴定为 TTKS 种族，对 Sr31 和 Sr38 具有额外的毒力。这些分离株分为两组：A 组（7 个分离株和 2 个对照分离株），产生低感染型；B 组（21 个分离株），分别产生 Sr24 高感染型。 B 组分离株代表 TTKS 种族的新变种，对 Sr24 具有毒力。使用 18 个简单序列重复 (SSR) 标记来检查 TTKS 种族和代表不同谱系组的五个北美种族（MCCF、QCCQ、RCRS、RTHS 和 TPMK）中这两组分离株之间的遗传关系。 TTKS 种族的所有分离株都具有相同的 SSR 基因型，并且与北美种族明显不同。毒力和 SSR 数据表明，具有 Sr24 毒力的 TTKS 种族新变种可能是通过 TTKS 遗传谱系内的突变而产生的。我们建议修订北美茎锈病命名系统，添加四个基因（Sr24、Sr31、Sr38 和 SrMcN）作为第五组。此修订版认识到 Sr31 的毒力，并将 TTKS 种族内的分离株区分为两个独立的种族：TTKSK 和 TTKST，分别对 Sr24 具有无毒力和毒力。对 Sr24 和 Sr31 具有联合毒力的 TTKST 小种的出现大大增加了全世界小麦对茎锈病的脆弱性。
The stem rust resistance gene Sr24 is effective against most races of Puccinia graminis f. sp. tritici, including race TTKS (syn. Ug99), and is used widely in commercial wheat cultivars worldwide. In 2006, susceptible infection responses were observed on wheat lines and cultivars carrying Sr24 in a field stem rust screening nursery at Njoro, Kenya. We derived 28 single-pustule isolates from stem rust samples collected from the 2006 Njoro nursery. The isolates were evaluated for virulence on 16 North American stem rust differential lines; on wheat lines carrying Sr24, Sr31, Sr38, and SrMcN; and on a wheat cultivar with a combination of Sr24 and Sr31. All isolates were identified as race TTKS with additional virulence on Sr31 and Sr38. These isolates were divided into two groups: group A (seven isolates and the two control isolates), producing a low infection type, and group B (21 isolates), producing a high infection type on Sr24, respectively. Isolates of group B represented a new variant of race TTKS with virulence to Sr24. Eighteen simple sequence repeat (SSR) markers were used to examine the genetic relationship between these two groups of isolates in race TTKS and five North American races (MCCF, QCCQ, RCRS, RTHS, and TPMK) that are representative of distinct lineage groups. All isolates of race TTKS shared an identical SSR genotype and were clearly different from North American races. The virulence and SSR data indicated that the new variant of race TTKS with Sr24 virulence likely has arisen via mutation within the TTKS genetic lineage. We propose to revise the North American stem rust nomenclature system by the addition of four genes (Sr24, Sr31, Sr38, and SrMcN) as the fifth set. This revision recognizes the virulence on Sr31 and differentiates isolates within race TTKS into two separate races: TTKSK and TTKST, with avirulence and virulence on Sr24, respectively. The occurrence of race TTKST with combined virulence on Sr24 and Sr31 has substantially increased the vulnerability of wheat to stem rust worldwide.