细菌性条斑病非寄主抗性基因Rxo1在水稻中同源序列的表达和遗传定位分析

利用在玉米中克隆到的一个抗水稻细菌性条斑病的非寄主抗性基因Rxo1中含有NBS LRR结构的开放读码框（ORF）在水稻基因组中搜索到16个抗性基因同源序列，进一步研究发现，位于第11染色体上的同源序列基因RPR1与细菌性条斑病的抗性有一定关系。首先，以RPR1为模板设计的两对引物都只在供试的细菌性条斑病抗病品种中扩增出目标带；再者RT PCR的结果表明RPR1的表达能被细菌性条斑病菌接种所诱导，说明来自不同物种的结构相似的抗性基因可以表达相同或相似的功能。但从对RPR1定位的结果看，RPR1与之前定位的抗细菌性条斑病主效QTL之间尚有9 cM的图距，两者之间的连锁并不紧密，说明RPR1的表达并不能解释抗病品种Dular对细菌性条斑病的抗性，RPR1并不是水稻表达细菌性条斑病抗性的关键因子。

Expression and Localization Analysis of Analogue for the Non-Host Bacterial Leaf Streak Resistance Gene Rxo1 in Rice

The main open reading frame (ORF) DNA sequence containing nucleotide binding site and leucine-rich repeats (NBS-LRR) domain of Rxo1, which was cloned from maize and found to be a non-host gene conferring resistance to rice bacterial leaf streak (BLS),was used to Blast the Genbank, and 16 resistance gene analogues (RGAs) were obtained from rice genome. One of the RGAs, RPR1, which located on chromosome 11, was found to be related to BLS resistance because, firstly, primer pairs designed based on the RPR1 sequence amplified target band only in the resistant genotypes, and secondly, the expression of RPR1 could be induced by BLS pathogen inoculation, indicating that the gene analogues came from different species may have common functions. On the other hand, the long map distance (9 cM) between RPR1 and qBLSR-11-1, a major resistance QTL identified formerly,implied that RPR1 might not be a key factor for BLS resistance in rice.