Liu Wei-Dong, Wang Shi-Ping
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
Yi Chuan Xue Bao. 2002 Oct;29(10):875-9.
The encoding products of the disease resistance (R) gene of barley, Mlo, and the maize R gene, Hm1, do not contain the recognizable structural domains of most of the known plant R gene products. The two genes do not comply with the gene-for-gene theory in the response to pathogen infection either. Two sequences, OsMlo-1 and DFR-1 which were homologous to the barley Mlo and maize Hm1, respectively, were isolated from rice. The OsMlo-1 was mapped between two molecular markers, RZ667 and RG424, and located at a distance of 20.6 centi-Morgan (cM) from RZ667 and 6.0 cM from RG424 on rice chromosome 6. The DFR-1 was flanked by molecular markers R2635 and RG462 with an estimated genetic distance of 11.3 cM from R2635 and 23.9 cM from RG462 on rice chromosome 1. Using other published rice molecular linkage maps as references, it was found that the chromosomal locations of OsMlo-1 and DFR-1 were correspondence with two previously identified rice blast resistant QTLs (quantitative trait loci), respectively. The results suggest that the genes homologous to barley Mlo and maize Hm1 in rice may be involved in defense responses induced by pathogen infection.
大麦抗病（R）基因Mlo和玉米R基因Hm1的编码产物不包含大多数已知植物R基因产物的可识别结构域。这两个基因在对病原体感染的反应中也不符合基因对基因理论。分别从水稻中分离出与大麦Mlo和玉米Hm1同源的两个序列OsMlo-1和DFR-1。OsMlo-1被定位在两个分子标记RZ667和RG424之间，在水稻第6号染色体上距RZ667 20.6厘摩（cM），距RG424 6.0 cM。DFR-1两侧是分子标记R2635和RG462，在水稻第1号染色体上距R2635估计遗传距离为11.3 cM，距RG462为23.9 cM。以其他已发表的水稻分子连锁图谱为参考，发现OsMlo-1和DFR-1的染色体位置分别与两个先前鉴定的水稻稻瘟病抗性QTL（数量性状位点）相对应。结果表明，水稻中与大麦Mlo和玉米Hm1同源的基因可能参与病原体感染诱导的防御反应。
