Agriculture & Food, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia.
Plant Breeding Institute, The University of Sydney, Cobbitty, NSW, Australia.
Plant Biotechnol J. 2021 Jun;19(6):1206-1215. doi: 10.1111/pbi.13542. Epub 2021 Mar 6.
Leaf rust, caused by Puccinia hordei, is a devastating fungal disease affecting barley (Hordeum vulgare subsp. vulgare) production globally. Despite the effectiveness of genetic resistance, the deployment of single genes often compromises durability due to the emergence of virulent P. hordei races, prompting the search for new sources of resistance. Here we report on the cloning of Rph15, a resistance gene derived from barley's wild progenitor H. vulgare subsp. spontaneum. We demonstrate using introgression mapping, mutation and complementation that the Rph15 gene from the near-isogenic line (NIL) Bowman + Rph15 (referred to as BW719) encodes a coiled-coil nucleotide-binding leucine-rich repeat (NLR) protein with an integrated Zinc finger BED (ZF-BED) domain. A predicted KASP marker was developed and validated across a collection of Australian cultivars and a series of introgression lines in the Bowman background known to carry the Rph15 resistance. Rph16 from HS-680, another wild barley derived leaf rust resistance gene, was previously mapped to the same genomic region on chromosome 2H and was assumed to be allelic with Rph15 based on genetic studies. Both sequence analysis, race specificity and the identification of a knockout mutant in the HS-680 background suggest that Rph15- and Rph16-mediated resistances are in fact the same and not allelic as previously thought. The cloning of Rph15 now permits efficient gene deployment and the production of resistance gene cassettes for sustained leaf rust control.
叶锈病由禾柄锈菌引起，是一种严重影响全球大麦（Hordeum vulgare subsp. vulgare）生产的真菌病害。尽管遗传抗性有效，但由于毒性更强的禾柄锈菌菌株的出现，单一基因的部署常常会降低其耐久性，因此需要寻找新的抗性来源。在这里，我们报告了 Rph15 的克隆，它是一种来自大麦野生近缘种 H. vulgare subsp. spontaneum 的抗性基因。我们通过导入系作图、突变和互补实验证明，来自近等基因系（NIL）Bowman + Rph15（称为 BW719）的 Rph15 基因编码一个卷曲螺旋核苷酸结合亮氨酸丰富重复（NLR）蛋白，具有整合的锌指 BED（ZF-BED）结构域。开发并验证了一个预测的 KASP 标记，该标记在澳大利亚品种系列和一系列Bowman 背景的导入系中均有效，这些导入系已知携带 Rph15 抗性。另一个来自野生大麦的叶锈病抗性基因 HS-680 的 Rph16 先前被映射到 2H 染色体上的相同基因组区域，并且基于遗传研究被假定为与 Rph15 等位。序列分析、菌株特异性以及在 HS-680 背景下敲除突变体的鉴定表明，Rph15 和 Rph16 介导的抗性实际上是相同的，而不是以前认为的等位基因。Rph15 的克隆现在允许高效地部署基因，并产生抗性基因盒，以实现持久的叶锈病控制。
