玉米大斑病抗性基因ht2的原位杂交物理定位

THE PHYSICAL LOCATION OF MAIZE HELMINTHOSPORIUM TURCICUM RESISTANCF GENE ht2 By IN SITU HYBRDIZATION

通过对与玉米大斑病（Ｈｅｌｍｉｎｔｈｏｓｐｏｒｉｕｍｔｕｒｃｉｃｕｍ）抗性基因ｈｔ２紧密连锁的２个玉米ＲＦＬＰ分子标记ｂｎｌ１２．３０和ｕｍｃ９３的染色体原位杂交定位，推断了大斑病抗性基因ｈｔ２的物理位置．ｂｎｌ１２．３０和ｕｍｃ９３在遗传图中位于第八连锁群上，它们的探针分别同时与第三和八染色体进行了杂交，平均信号检出率为１２．１３％；它们在第八号染色体长臂上杂交信号与着丝粒的百分距离分别是３３．３０±１．４１和３４．４７±２．７５，在第三号染色体长臂上杂交信号与着丝粒的百分距离分别是５１．４１±２．７５和５６．５４±２．９４．基因ｈｔ２在遗传图上位于第八连锁群的ｂｎｌ１２．３０和ｕｍｃ９３之间，因此，ｈｔ２在染色体上的物理位置应为第八号染色体长臂，百分距离为３３．３０和３４．４７之间．在第三号染色体长臂上两个供试ＲＦＬＰ标记的分布区之间也可能有ｈｔ２的同源顺序．

s Two RFLP markers linked to Helminthosporium turcium resistance genes ht2,bnll2.30 and umc93 were physically located onto chromosomes in maize by in situ hybridization.According to the results,the physical position of benes ht2 were deduced. The RFLP markers,bnl 12.30 and umc93 were located onto linkage group 8 in the genetic map.The two probes of the RFLP markers were physically mapped onto the long arms of both chromosome 3 and 8. The average detection ratio was 12.13%.The percent distance from the centromeres to the detected sites were 33.30±1.41 and 34.47±2.75 on 8 L (the long arm of chromosome 8) and 51.41±2.75 and 56.54±2.94 on 3 L respectively.It showed that ht2 gene was between bnl 12.30 and umc93 belonging to linkage group 8 in the linkage map.So it could be conclude that the physical location of ht2 was between 33.30 and 34.47 on 8 L.Probably there was homologous sequence of ht2 gene between 51.41±2.75 and 56.54±2.94 on 3 L.