经基因工程改良的抗白叶枯病水稻粳型恢复系“C418-Xa21”及其杂交稻

A Genetically Modified Japonica Restorer Line,C418-Xa21,and Its Hybrid Rice with Bacterial Blight Resistance

通过农杆菌介导的转化系统 ,将业已克隆的水稻抗白叶枯病基因Xa2 1导入重要的粳型杂交稻恢复系“C418”。PCR和抗性分析表明单拷贝整合的Xa2 1在T1 代的分离比为 3∶1。在T2 代通过PCR和抗性分析选择了Xa2 1纯合的转基因株系“C418 Xa2 1”。将选择的转基因纯合系“C418 Xa2 1”与常用的雄性不育系“屉锦A”杂交 ,产生了带有转基因Xa2 1的杂交稻“屉优 418 Xa2 1”(简称转基因杂交稻 )。分子分析表明转基因Xa2 1在杂交稻“屉优418 Xa2 1”中能稳定遗传 ;抗性分析表明转基因恢复系“C418 Xa2 1”和转基因杂交稻“屉优 418 Xa2 1”对白叶枯病具有高度的广谱抗性 ,并保持了受体对照的优良农艺性状。另外我们还发现转基因杂交稻“屉优 418 Xa2 1”对白叶枯病的抗性水平高于转基因恢复系“C418 Xa2 1” ,这可能是遗传背景的差异所致。抗白叶枯病转基因粳型恢复系和杂交稻的育成将有益于杂交稻在我国北方稻区的推广。

The cloned bacterial blight (BB) resistance gene Xa21 was transferred into C418,a major restorer line of japonica hybrid rice in China,using an Agrobacterium-mediated system.The integrated single copy of transgene displayed a 3∶1 segregation ratio in T 1 generation in PCR and resistance analyses.The transgenic homozygous C418-Xa21 lines were selected in T 2 generation through PCR and resistance analyses.The selected transgenic restorer lines were then crossed with a commonly used sterile line,TijinA,to produce Xa21 transgenic hybrid rice.Molecular analysis revealed that the produced hybrid rice,named as Tiyou418-Xa21,inherited the transgene.Both C418-Xa21 and Tiyou418-Xa21 plants displayed high resistance with a broad spectrum to Xoo races and maintained their normal elite agronomic characters.We also observed that the resistance level of Tiyou418-Xa21 was obviously higher than that of C418-Xa21 which may be attributed to their differences in genetic background.The propagation of this BB resistant hybrid variety with the transgene Xa21 with extend hybrid rice production in north China.