Fukuoka Agricultural Research Center, 587 Yoshiki, Chikushino, Fukuoka, 818-8549, Japan.
Theor Appl Genet. 2012 Feb;124(3):577-83. doi: 10.1007/s00122-011-1730-5. Epub 2011 Oct 29.
PK23-2, a line of six-rowed barley (Hordeum vulgare L.) originating from Pakistan, has resistance to Japanese strains I and III of the barley yellow mosaic virus (BaYMV). To identify the source of resistance in this line, reciprocal crosses were made between the susceptible cultivar Daisen-gold and PK23-2. Genetic analyses in the F(1) generation, F(2) generation, and a doubled haploid population (DH45) derived from the F(1) revealed that PK23-2 harbors one dominant and one recessive resistance genes. A linkage map was constructed using 61 lines of DH45 and 127 DNA markers; this map covered 1268.8 cM in 10 linkage groups. One QTL having a LOD score of 4.07 and explaining 26.8% of the phenotypic variance explained (PVE) for resistance to BaYMV was detected at DNA marker ABG070 on chromosome 3H. Another QTL having a LOD score of 3.53 and PVE of 27.2% was located at marker Bmag0490 on chromosome 4H. The resistance gene on chromosome 3H, here named Rym17, showed dominant inheritance, whereas the gene on chromosome 4H, here named rym18, showed recessive inheritance in F(1) populations derived from crosses between several resistant lines of DH45 and Daisen-gold. The BaYMV recessive resistance genes rym1, rym3, and rym5, found in Japanese barley germplasm, were not allelic to rym18. These results revealed that PK23-2 harbors two previously unidentified resistance genes, Rym17 on 3H and rym18 on 4H; Rym17 is the first dominant BaYMV resistance gene to be identified in primary gene pool. These new genes, particularly dominant Rym17, represent a potentially valuable genetic resource against BaYMV disease.
PK23-2 是源自巴基斯坦的六棱皮大麦（Hordeum vulgare L.）品系，具有抗日本株 I 和 III 型大麦黄花叶病毒（BaYMV）的特性。为了确定该品系的抗性来源，将感病品种大善金与 PK23-2 进行正反交。在 F1 代、F2 代和由 F1 代衍生的加倍单倍体群体（DH45）中进行的遗传分析表明，PK23-2 含有一个显性和一个隐性抗性基因。利用 61 条 DH45 系和 127 个 DNA 标记构建了连锁图谱；该图谱覆盖了 10 个连锁群中的 1268.8cM。在第 3H 染色体上的 ABG070 标记处检测到一个 LOD 得分 4.07、解释 BaYMV 抗性表型变异 26.8%（PVE）的 QTL。在第 4H 染色体上的 Bmag0490 标记处检测到另一个 LOD 得分 3.53、PVE 为 27.2%的 QTL。第 3H 染色体上的抗性基因，命名为 Rym17，表现为显性遗传，而第 4H 染色体上的基因，命名为 rym18，在由 DH45 几个抗性系与大善金杂交衍生的 F1 群体中表现为隐性遗传。在日本大麦种质资源中发现的 BaYMV 隐性抗性基因 rym1、rym3 和 rym5 与 rym18 并非等位基因。这些结果表明，PK23-2 含有两个先前未被识别的抗性基因，第 3H 染色体上的 Rym17 和第 4H 染色体上的 rym18；Rym17 是第一个在初级基因库中鉴定的显性 BaYMV 抗性基因。这些新基因，特别是显性 Rym17，代表了一种对抗 BaYMV 病害的潜在有价值的遗传资源。
