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选用从大麦、小麦和水稻中分离的RFLP标记 ,构建了大麦半矮秆基因brh1精细图谱。以快中子处理六棱大麦品种Steptoe的种子 ,从M2 代中选择出brh1突变体FN5 3。brh1是一个极易鉴别的形态学标记 ,通过对FN5 3×Morex的F2 代群体进行鉴定表明 ,brh1基因为隐性 ,前人通过BSA法将其初步定位在大麦第 1染色体 (7H)短臂上 ,靠近端粒区。这一区间还有一个控制秆锈病抗性的显性基因Rpg1。所以 ,brh1的精细定位不仅对研究其本身具有重要意义 ,同时 ,也为Rpg1的图位克隆和功能研究提供了更大的重组配子群体。定位实验全部以F2 中具有brh1特征的个体为对象完成 ,鉴定工作在苗期进行。在该精细图上 ,brh1区间长15 .2cM ,各标记间的平均距离为 0 .8cM。其中 ,大麦的cDNA克隆MWG2 0 74B与brh1共分离。 2 0 74A在靠近着丝点一侧 ,与brh1相距 0 .8cM。BCD12 9和R3139在定位群体内呈现与MWG2 0 74A共分离。CDO5 4 5位于端粒一侧 ,距离brh1为 0 .8cM。根据禾谷类作物基因组的共线性原理 ,CDO5 4 5成功定位在水稻的同源染色体即第 6染色体短臂brh1区间内。然而 ,由于在定位亲本间缺乏多态性 ,BCD12 9和MWG2 0 74的 2条主带A和B均未能定位在水稻的共线性区段内。推测MWG2 0 74的其他各带可能被定位在水稻的目标区间内 ,从而有?
The RFLP markers isolated from barley, wheat and rice were used to construct the brh1 map of barley semidwarf gene. Seeds of the hexaploid barley variety Steptoe were treated with fast neutrons and the brh1 mutant FN5 3 was selected from the M2 generation. brh1 is an easily identifiable morphological marker. The identification of the F2 population of FN5 3 × Morex showed that the brh1 gene is recessive. The former was initially mapped on the short arm of chromosome 1 (7H) On the telomere zone. There is also a dominant gene Rpg1 that controls stem rust resistance in this interval. Therefore, the fine mapping of brh1 is not only important for the study itself, but also provides a larger recombinant gametophyte population for map-based cloning and function studies of Rpg1. Positioning experiments all with F2 characteristics of brh1 individuals as the object to complete the identification of seedlings. On this fine map, the brh1 interval is 15.2 cM in length, with an average distance between the markers of 0.8 cM. Among them, the barley cDNA clone MWG2074B was co-segregated with brh1. 2 0 74A On the side close to the centromere, 0,8 cM away from brh1. BCD129 and R3139 showed co-segregation with MWG2074A in the mapped population. CDO5 4 5 is located on the telomere side and is 0.8 cM from brh1. According to the colinearity principle of cereal crops genome, CDO5 4 5 was successfully located in the brh1 region of chromosome 6, the homologous chromosome of rice. However, due to the lack of polymorphism in the mapped parents, the two major bands A and B of BCD129 and MWG2074 were unable to locate in the colinearity section of rice. It is speculated that the other bands of MWG2074 may be located within the target range of rice,