【摘要】 水稻白叶枯病抗性基因Ｘａ４已被定位于第１１染色体长臂末端的分子标记Ｇ１８１和Ｌ１０４４之间，并与抗性基因同源序列片段ＲＳ１３共分离．利用这３个标记筛选ＩＲＢＢ５６的ＢＡＣ文库，共得到１２８个阳性ＢＡＣ克隆，其中ＲＳ１３获得１８个阳性克隆，这ＩＳ个克隆中有４个和６个克隆分别同时为Ｇ１８１和Ｌ１０４４的阳性克隆．选其中的１２个克隆进行分析，构建了一个从Ｇ１８１到Ｌ１０４４区间的ＢＡＣ跨叠克隆群，全长４２０ｋｂ，并且５６Ｍ２２、１０６Ｐ１３和１０４Ｂ１５ ３个ＢＡＣ克隆可覆盖整个跨叠克隆群。这一研究结果为进一步分离Ｘａ４基因打下了基础。更多还原

【Abstract】 The gene Xa4 confers dominantly resistance to rice bacterial blight which has been finely mapped between RFLP markers G181 and L1044, and co-segregated with the resistance gene homologues sequence marker RS13. The three markers were used to screen a rice Basterial Artificial Chromosome (BAC library constructed from IRBB56, a Xa4--harboning indica variety, resulting in the detection of totally 128 positive clones. Of the 18 positive clones picked out by RS13, 4 and 6 clones were simultaneously detected by G181 and L1044, respectively. Based on their HindIII restriction patterns, 12 clones were selected out to construct a contig that spanned about 420 kb covering the Xa4 locus, which is a solid base for the isolation of Xa4 gene.更多还原