Wu Xiaoming, Li Xianghua, Xu Caiguo, Wang Shiping
National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China.
Theor Appl Genet. 2008 Dec;118(1):185-91. doi: 10.1007/s00122-008-0888-y. Epub 2008 Sep 16.
Bacterial blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), is the most devastating plant bacterial disease worldwide. Different bacterial blight resistance (R) genes confer race-specific resistance to different strains of Xoo. We fine mapped a fully recessive gene, xa24, for bacterial blight resistance to a 71-kb DNA fragment in the long arm of rice chromosome 2 using polymerase chain reaction-based molecular markers. The xa24 gene confers disease resistance at the seedling and adult stages. It mediates resistance to at least the Philippine Xoo races 4, 6 and 10 and Chinese Xoo strains Zhe173, JL691 and KS-1-21. Sequence analysis of the DNA fragment harboring the dominant (susceptible) allele of xa24 suggests that this gene should encode a novel protein that is not homologous to any known R proteins. These results will greatly facilitate the isolation and characterization of xa24. The markers will be convenient tools for marker-assisted selection of xa24 in breeding programs.
由水稻白叶枯病菌（Xanthomonas oryzae pv. oryzae，简称Xoo）引起的白叶枯病是全球最具毁灭性的植物细菌性病害。不同的白叶枯病抗性（R）基因对不同的Xoo菌株具有小种特异性抗性。我们利用基于聚合酶链反应的分子标记，将一个对白叶枯病具有完全隐性抗性的基因xa24精细定位到水稻第2号染色体长臂上一个71 kb的DNA片段上。xa24基因在幼苗期和成年期均赋予抗病性。它介导对至少菲律宾Xoo小种4、6和10以及中国Xoo菌株浙173、JL691和KS-1-21的抗性。对携带xa24显性（感病）等位基因的DNA片段进行序列分析表明，该基因应编码一种与任何已知R蛋白都不同源的新蛋白。这些结果将极大地促进xa24的分离和鉴定。这些标记将成为在育种计划中对xa24进行分子标记辅助选择的便捷工具。
