利用BAC-ISH对抗性基因Bph3物理定位及水稻第四染色体着丝粒识别的研究

Physical Location of Resistance Gene, Bph3 and Identification of Chromosome 4 in Oryza sativa with BAC-ISH

用水稻BAC克隆21K19作探针进行了ISH。这个克隆是由第4染色体着丝粒连锁的RFLP标记RZ69筛选得到。在Cot-Ⅰ DNA封阻条件下,DAB均获得第4染色体着丝粒区和间期染色质上的一对信号。这一方法不仅可用于特定染色体识别,而且可区分其长臂和短臂。因此,还获得了第四染色体的臂比值以作为它的形态识别依据。由于RFLP标记RZ69与抗性基因Bph3紧密连锁,从而确定抗性基因Bph3位于水稻第4染色体着丝粒处。相对于常规的RFLP-FISH,BAC-ISH可以提高5倍以上的检出率。

Rice chromosome 4 was identified by ISH of centromere—linked BAC clone 21K19. This clone was screened by a single copy RFLP marker RZ69. It only showed a pair of signal spots on centromere regions of each member of one chromosome pair, i. e. ,chromosome 4 as well as interphase chromatin under the blocking of rice Cot-1 DNA with DAB detection system. This is applicable not only for the recognizing of chromosome 4 but also for the distinguishing of its long and short arms. Therefore, we also obtained the arm ratio data of chromosome 4 for its morphological identifica- tion. From the molecular genetic map, we know that the RZ69 linked to resistance gene. Bph3. so in this study, resist- ance gene. Bph3 was physical located in centromere region of chromosome 4 in Oryza. sativa. Compared with the routine FISH of single copy RFLP marker can increase the detection rate more than five times.