【摘要】 Xa14是一个高抗菲律宾白叶枯病生理小种5的显性基因,位于水稻第4染色体长臂末端。本研究利用中国国家基因中心的水稻第4染色体测序结果,用SSR标记对Xa14进行遗传定位,为进一步用图位克隆法克隆该基因奠定基础。利用775株IRBB14/IR24F2中的145株高感群体,将基因Xa14限定在SSR标记HZR970-8和HZR988-1之间,与两个分子标记的距离各为0.34cM,并找到了在该群体中与基因共分离的HZR645-4、HZR669-2、HZR669-5和HZR669-7四个SSR标记。利用763株IRBB14/珍珠矮F2中158株高感群体,将基因Xa14限定在分子标记HZR648-5与RM280之间的区段,找到与基因紧密连锁的SSR标记HZR648-5,与基因的距离为1.90cM。将两个F2群体的定位结果进行整合,表明Xa14位于分子标记HZR970-8和HZR988-1之间的3个BAC克隆上,并与这两个标记紧密连锁。更多还原

【Abstract】 Bacterial blight of rice, which is a vascular bundle disease caused by Xanthomonas oryzae pv. oryzae (Xoo), is one of the most serious diseases of rice worldwide, and leads to the yield of rice reduced greatly. The dominant gene Xa14 is highly re-sistant to Philippine race 5 of bacterial blight. The gene was located at the distal end on the long arm of chromosome 4 by Taura et al. Near-isogenic line in the background of IR24, namely IRBB14 carrying the gene Xa14 has been developed at International Rice Research Institute (IRRI). In order to construct the high-resolution likage maps for the Xa14 region on chromosome 4 for finally clone by positional cloning, two F2 populations were used to estimate linkage based on marker genotype and reaction to disease inoculation with Xanthomonas oryzae pv. oryzae. Using 145 highly susceptible individuals from a total of 775 plants of F2 population of the cross between IRBB14 and IR24, the gene Xa14 was located in a 0.68 cM region on the nearby end of chromosome 4, which was flanked by the molecular markers HZR970-8 and HZR988-1, with the distance of 0.34 cM between the flanked markers and Xa14, respectively, and completely cosegregated with the SSR markers HZR645-4, HZR669-2, HZR669-5, and HZR669-7 in this population. Using 158 highly susceptible individuals from a total of 763 plants of F2 population of the cross between IRBB14 and ZZA, the gene Xa14 locus was mapped to the interval between HZR648-5 and RM280, and was 1.90 cM away from HZR648-5 which was the closest marker flanking the Xa14 locus. Combining recombination frequencies for the two populations together, the gene Xa14 was mapped to 3 BAC clones spanned approximately 300 kb in length between SSR markers HZR970-8 and HZR988-1.更多还原