Laboratory of Plant Breeding, Wageningen University and Research Centre, Wageningen, The Netherlands.
Theor Appl Genet. 2011 Dec;123(8):1331-40. doi: 10.1007/s00122-011-1670-0. Epub 2011 Aug 30.
The use of resistant varieties is an important tool in the management of late blight, which threatens potato production worldwide. Clone MaR8 from the Mastenbroek differential set has strong resistance to Phytophthora infestans, the causal agent of late blight. The F1 progeny of a cross between the susceptible cultivar Concurrent and MaR8 were assessed for late blight resistance in field trials inoculated with an incompatible P. infestans isolate. A 1:1 segregation of resistance and susceptibility was observed, indicating that the resistance gene referred to as R8, is present in simplex in the tetraploid MaR8 clone. NBS profiling and successive marker sequence comparison to the potato and tomato genome draft sequences, suggested that the R8 gene is located on the long arm of chromosome IX and not on the short arm of chromosome XI as was suggested previously. Analysis of SSR, CAPS and SCAR markers confirmed that R8 was on the distal end of the long arm of chromosome IX. R gene cluster directed profiling markers CDP(Sw5)4 and CDP(Sw5)5 flanked the R8 gene at the distal end (1 cM). CDP(Tm2)1-1, CDP(Tm2)1-2 and CDP(Tm2)2 flanked the R8 gene on the proximal side (2 cM). An additional co-segregating marker (CDP(Hero)3) was found, which will be useful for marker assisted breeding and map based cloning of R8.
利用抗性品种是防治晚疫病的重要手段，晚疫病对全球马铃薯生产构成威胁。Mastenbroek 鉴别系中的克隆 MaR8 对晚疫病菌具有很强的抗性，晚疫病菌是晚疫病的病原体。将易感品种 Concurrent 与 MaR8 杂交的 F1 代在田间试验中接种不亲和的 P. infestans 分离物，评估其对晚疫病的抗性。抗性和易感的分离比为 1:1，表明 MaR8 四倍体中单倍体存在被称为 R8 的抗性基因。NBS 图谱分析和与马铃薯和番茄基因组草图序列的连续标记序列比较表明，R8 基因位于染色体 IX 的长臂上，而不是以前认为的染色体 XI 的短臂上。SSR、CAPS 和 SCAR 标记分析证实 R8 位于染色体 IX 的长臂末端。R 基因簇定向图谱标记 CDP(Sw5)4 和 CDP(Sw5)5 在 R8 基因的远端（1 cM）侧翼。CDP(Tm2)1-1、CDP(Tm2)1-2 和 CDP(Tm2)2 在 R8 基因的近端（2 cM）侧翼。发现了一个额外的共分离标记（CDP(Hero)3），这将有助于 R8 的标记辅助选择和基于图谱的克隆。
