Wheat, Peanut, and Other Field Crops Research Unit, USDA-ARS, Stillwater, OK, 74075, USA.
USDA-ARS Cereal Disease Laboratory, St. Paul, MN, 55106, USA.
Theor Appl Genet. 2022 Aug;135(8):2725-2734. doi: 10.1007/s00122-022-04145-5. Epub 2022 Jun 18.
The novel, leaf rust seedling resistance gene, Lr81, was identified in a Croatian breeding line and mapped to a genomic region of less than 100 Kb on chromosome 2AS. Leaf rust, caused by Puccinia triticina, is the most common and widespread rust disease in wheat. Races of Puccinia triticina evolve rapidly in the southern Great Plains of the USA, and leaf rust resistance genes often lose effectiveness shortly after deployment in wheat production. PI 470121, a wheat breeding line developed by the University of Zagreb in Croatia, showed high resistance to Puccinia triticina races collected from Oklahoma, suggesting that PI 470121 could be a leaf rust resistance source for the southern Great Plains of the USA. Genetic analysis based on an F population and F families derived from the cross PI 470121 × Stardust indicated that PI 470121 carries a dominant seedling resistance gene, designated as Lr81. Linkage mapping delimited Lr81 to a genomic region of 96,148 bp flanked by newly developed KASP markers Xstars-KASP320 and Xstars-KASP323 on the short arm of chromosome 2A, spanning 67,030,206-67,132,354 bp in the Chinese Spring reference assembly (IWGSC RefSeq v1.0). Deletion bin mapping assigned Lr81 to the terminal bin 2AS-0.78-1.00. Allelism tests indicated that Lr81 is a distinctive leaf rust resistance locus with the physical order Lr65-Lr17-Lr81. Marker-assisted selection based on a set of markers closely linked to leaf rust resistance genes in PI 470121 and Stardust enabled identification of a recombinant inbred line RIL92 carrying Lr81 only. Lr81 is a valuable leaf rust resistance source that can be rapidly introgressed into locally adapted cultivars using KASP markers Xstars-KASP320 and Xstars-KASP323.
新型叶锈病幼苗抗性基因 Lr81 是在克罗地亚的一个育种系中发现的，该基因被定位在 2AS 染色体上不到 100 Kb 的基因组区域内。叶锈病是由小麦叶锈病菌引起的，是小麦上最常见和广泛的锈病。在美国南部大平原，小麦叶锈病菌的小种迅速进化，叶锈病抗性基因在小麦生产中应用后不久往往会失效。PI 470121 是由克罗地亚萨格勒布大学开发的一个小麦育种系，对从俄克拉荷马州采集的小麦叶锈病菌小种表现出高度抗性，这表明 PI 470121 可能是美国南部大平原的一个叶锈病抗性来源。基于 F 群体和源自 PI 470121 × Stardust 杂交的 F 家系的遗传分析表明，PI 470121 携带一个显性幼苗抗性基因，命名为 Lr81。连锁图谱将 Lr81 定位在 2A 染色体短臂上由新开发的 KASP 标记 Xstars-KASP320 和 Xstars-KASP323 侧翼的 96148 bp 基因组区域内，在中华春参考组装（IWGSC RefSeq v1.0）中跨越 67030206-67132354 bp。缺失 bin 图谱将 Lr81 分配到末端 bin 2AS-0.78-1.00。等位基因测试表明，Lr81 是一个独特的叶锈病抗性基因座，其物理顺序为 Lr65-Lr17-Lr81。基于与 PI 470121 和 Stardust 中叶锈病抗性基因紧密连锁的一组标记，对 Lr81 进行了标记辅助选择，鉴定出仅携带 Lr81 的重组自交系 RIL92。Lr81 是一个有价值的叶锈病抗性基因，可以使用 KASP 标记 Xstars-KASP320 和 Xstars-KASP323 快速导入到适应性强的品种中。
