Department of Plant Sciences, University of California, Davis, CA, 95616, USA.
Peking University Institute of Advanced Agricultural Sciences, Weifang, Shandong, 261000, China.
New Phytol. 2020 Jan;225(2):948-959. doi: 10.1111/nph.16169. Epub 2019 Oct 19.
Wheat stem rust, caused by Puccinia graminis Pers. f. sp. tritici (Pgt), is a devastating fungal disease threatening global wheat production. The present paper reports the identification of stem rust resistance gene Sr60, a race-specific gene from diploid wheat Triticum monococcum L. that encodes a protein with two putative kinase domains. This gene, designated as WHEAT TANDEM KINASE 2 (WTK2), confers intermediate levels of resistance to Pgt. WTK2 was identified by map-based cloning and validated by transformation of a c.10-kb genomic sequence including WTK2 into susceptible common wheat variety Fielder (Triticum aestivum L.). Transformation of Fielder with WTK2 was sufficient to confer Pgt resistance. Sr60 transcripts were transiently upregulated 1 d post-inoculation with Pgt, but not in mock-inoculated plants. The upregulation of Sr60 was associated with stable upregulation of several pathogenesis-related genes. The Sr60-resistant haplotype found in T. monococcum was not found in polyploid wheat, suggesting an opportunity to introduce a novel resistance gene. Sr60 was successfully introgressed into hexaploid wheat, and we developed a diagnostic molecular marker to accelerate its deployment and pyramiding with other resistance genes. The cloned Sr60 also can be a useful component of transgenic cassettes including other resistance genes with complementary resistance profiles.
小麦秆锈病由禾柄锈菌（Puccinia graminis Pers. f. sp. tritici，Pgt）引起，是一种严重威胁全球小麦生产的真菌病害。本文报道了从二倍体小麦普通小麦（Triticum monococcum L.）中鉴定出的秆锈病抗性基因 Sr60，该基因编码一个具有两个假定激酶结构域的蛋白，是一个专化性基因。将该基因命名为 WHEAT TANDEM KINASE 2（WTK2），它赋予 Pgt 中等水平的抗性。WTK2 是通过基于图谱的克隆鉴定的，并通过将包含 WTK2 的约 10kb 基因组序列转化到感病普通小麦品种 Fielder（Triticum aestivum L.）中得到验证。WTK2 转化 Fielder 足以赋予 Pgt 抗性。在接种 Pgt 后 1 天，Sr60 转录本瞬时上调，但在模拟接种的植物中没有上调。Sr60 的上调与几个与发病机制相关基因的稳定上调有关。在 T. monococcum 中发现的 Sr60 抗性单倍型在多倍体小麦中没有发现，这为引入新的抗性基因提供了机会。Sr60 已成功导入六倍体小麦，我们开发了一种诊断分子标记，以加速其与其他抗性基因的部署和聚合。克隆的 Sr60 也可以成为包括具有互补抗性谱的其他抗性基因的转基因盒的有用组成部分。
