Abstract: The progress of molecular biology researches on rice bacterial blight disease resistance gene, Xa21, were reviewed. Xa21 localizing on the chromosome 11, linked to one marker (RG103 ) and two PCR products(RAPD248 and RAPD818). With RG103 as a hybridization probe, a 9. 6 kb Kpn I DNA fragment was isolatedfrom bacterial artificial chromos ome (BAC) and cosmid libraries, this fragment contained a s ingle, large open reading frame of 3075 base pares which was interupted by a intron of 843 base pares. Xa21 encoded a receptor kinase-like protein of 1025 amino acid sequences which contained a leusine-rich repeat(LRR) domain and a serine-threonine kinase (STK) was similar to Cf-9. N and PTO. The resistance molecular mechanism of Xa21 has been unknown.

Key words: molecular biology, resistance gene, Xanthomonas oryzae pv. oryzae, bacterial blight

摘要： 介绍了水稻抗白叶枯病害基因 Xa21的分子生物学研究进展。Xa21定位于水稻第11号染色体上, 与分子标记RG103，以及PCR产物RAPD248、RAPD818等紧密连锁, 利用标记RG103作探针已从细菌人工染色体(BAC)和粘粒文库中克隆出包含 Xa21基因位点的9.6 kb Kpn Ⅰ片段, 该片段包含一个3075 bp的开放阅读框, 中间有一个843 bp的内含子。Xa21基因产物为一1025个氨基酸的受体蛋白, 具有LRR和STK区,结构与Cf-9、N、PTO等蛋白相似,其抗病分子机制尚不太清楚。

关键词: 分子生物学, 水稻白叶枯病, 抗性基因