马铃薯晚疫病抗性基因R11的遗传定位

由致病疫霉菌(Phytophthora infestans)引起的晩疫病是世界范围内最具毁灭性的马铃薯(Solanum tuberosum)病害。以含有晚疫病抗性基因R11的材料MaR11和不含已知抗性基因的品种Katahdin为亲本进行有性杂交，对获得的F₁分离群体的83个基因型进行了晚疫病菌株接种鉴定和遗传分析。结果表明，R11为主效单基因，在MaR11中以单式形式(R_11r11r11r11)存在。应用比较作图和分离群体分组分析(BSA)，开发了6个与R11连锁的分子标记，并将R11定位于11号染色体长臂末端。R11距C2_At5g59960标记最近，约为2.4 cM。通过遗传图谱比较表明，R11较晚疫病抗性基因R3a和R10更靠近染色体端粒区。本研究所获得的遗传图谱为进一步构建R11高密度遗传图谱提供了基础。

Genetic Mapping of R11 Gene Conferring Resistance to Late Blight in Potato(Solanum tuberosum)

Late blight caused by Phytophthora infestans is the most destructive disease for potato (Solanum tuberosum). A F₁ segregating population consisting of 83 genotypes, derived from R11 differential MaR11 and the susceptible potato cultivar Katahdin, was assessed for late blight resistance in detached leaves assay and genetically analyzed. The results showed that the distribution for R11 was clearly bimodal with the two peaks coinciding with the blight scores of the MaR11 (the resistant parent) and Katahdin (the susceptible parent), and the observed segregation with 39 resistant and 44 susceptible plants fitted a 1:1 ratio. It indicated that _R11 was inherited as a major dominant R gene and presented in the simplex condition in MaR11. There was a major late blight resistance locus (MLB) in potato on the long arm of chromosome 11, where R11 showed allelic versions of the R3 and R10 loci. Using the combination of comparative mapping and bulked segregant analysis, we developed six markers linked to R11 which was located on the end of the long arm of chromosome 11 with a distance of about 2.4 cM to marker C2_At5g59960. R11 was telomeric to the R3a and R10 gene. The genetic map constructed in this paper provides a basis for further construction of high-resolution genetic map of the R11 gene.