Bph3在栽培稻和药用野生稻中的BAC-FISH比较物理定位

用栽培稻(Oryza sativa L.)遗传图第四连锁群中与抗褐稻虱基因Bph3紧密连锁的RFLP标记RZ69及筛选出来的BAC克隆38J9作探针,对药用野生稻(O.officinalis Well ex Watt)和栽培稻荧光原位杂交,供试标记RZ69及38J9均被定位于药用野生稻和栽培稻第4染色体的短臂上,药用野生稻杂交信号的百分距分别为22.12±3.44和20.00±5.40,而栽培稻均为0.在栽培稻中,信号检出率相应地为6.29%和56.10%,在药用野生稻中则为6.14%和50.00%.BAC克隆和RFLP标记探针杂交信号的百分距十分接近,说明在栽培稻和野生稻中RFLP标记RZ69都在同一BAC克隆的大插入片段中.由此推知,药用野生稻与抗性基因Bph3的同源顺序就在第4染色体信号出现的相应位置.在未封阻的情况下,药用野生稻的BAC杂交在多条染色体上具有信号,这表明它和栽培稻的Cot-1 DNA重复顺序也在一定程度上具有同源性.药用野生稻第4染色体是根据栽培稻与药用野生稻的比较遗传图选用与Gm-6连锁的RG214通过FISH确定的.讨论了栽培稻BAC克隆对药用野生稻比较原位杂交物理作图的可行性问题.

Comparative Physical Mapping of Bph3 with BAC-FISH in Oryza officinalis and O.sativa

A FISH procedure was adopted to physical mapping rice RFLP marker RZ69 and the BAC clone 38J9 screened by RZ69 which is linked to gene Bph3 in Oryza sativa L. and O. officinalis Well ex Watt. The FISH results showed that both 38J9 and RZ69 were located in the middle of 4S in O. officinalis and the centromere area of 4S in O. sativa. In O. officinalis the percentage distances from the centromere to the hybridization sites were 20.00±5.40 and 22.12±3.44, the detection rates were 50.00% and 6.14%, but in O.sativa they were 0 and 0,56.10% and 6.29% correspondingly. The results obtained from the BAC and RFLP clone were almost the same in the cultivated rice and O. officinalis. It was suggested that the marker RZ69 of the cultivated rice and its homologous sequence in O.officinalis were in the same BAC clone, the homologous sequence of Bph3 in O. officinalis should be located at the sites hybridized by both RZ69 and 38J9. Many signals on different chromosomes of O. officinal is were observed under no blocking with Cot-1 DNA, showing that the repetitive sequences were also homologous between O. sativa and O. officinalis. The identification of chromosome 4 of O. officinalis is based on comparative map with RG214 and BAC clone screened by RG214. The feasibility of comparative physical mapping performed between O. sativa and O. officinal is with rice BAC clones was discussed. 