Department of plant sciences, North Dakota State University, Fargo, ND 58102, USA.
Theor Appl Genet. 2012 Jun;125(1):121-31. doi: 10.1007/s00122-012-1820-z. Epub 2012 Feb 21.
The major genes controlling sunflower downy mildew resistance have been designated as Pl genes. Ten of the more than 20 Pl genes reported have been mapped. In this study, we report the molecular mapping of gene Pl(16) in a sunflower downy mildew differential line, HA-R4. It was mapped on the lower end of linkage group (LG) 1 of the sunflower reference map, with 12 markers covering a distance of 78.9 cM. One dominant simple sequence repeat (SSR) marker, ORS1008, co-segregated with Pl(16), and another co-dominant expressed sequence tag (EST)-SSR marker, HT636, was located 0.3 cM proximal to the Pl(16) gene. The HT636 marker was also closely linked to the Pl(13) gene in another sunflower differential line, HA-R5. Thus the Pl(16) and Pl(13) genes were mapped to a similar position on LG 1 that is different from the previously reported Pl(14) gene. When the co-segregating and tightly linked markers for the Pl(16) gene were applied to other germplasms or hybrids, a unique band pattern for the ORS1008 marker was detected in HA-R4 and HA-R5 and their F(1) hybrids. This is the first report to provide two tightly linked markers for both the Pl(16) and Pl(13) genes, which will facilitate marker-assisted selection in sunflower resistance breeding, and provide a basis for the cloning of these genes.
控制向日葵霜霉病抗性的主要基因已被指定为 Pl 基因。已报道的 20 多个 Pl 基因中有 10 个已被定位。在这项研究中，我们报告了基因 Pl(16)在向日葵霜霉病差异系 HA-R4 中的分子作图。它被定位在向日葵参考图谱的连锁群 (LG) 1 的下端，有 12 个标记覆盖 78.9cM 的距离。一个显性简单重复序列 (SSR) 标记 ORS1008 与 Pl(16)共分离，另一个共显性表达序列标签 (EST)-SSR 标记 HT636 位于 Pl(16)基因的近端 0.3cM 处。HT636 标记与另一个向日葵差异系 HA-R5 中的 Pl(13)基因也紧密连锁。因此，Pl(16)和 Pl(13)基因被定位在 LG 1 上的相似位置，与先前报道的 Pl(14)基因不同。当 Pl(16)基因的共分离和紧密连锁标记应用于其他种质或杂种时，在 HA-R4 和 HA-R5 及其 F(1)杂种中检测到 ORS1008 标记的独特带型。这是首次报道为 Pl(16)和 Pl(13)基因提供两个紧密连锁的标记，这将有助于向日葵抗性育种中的标记辅助选择，并为这些基因的克隆提供基础。
