水稻苯达松敏感突变研究进展

Progress on the Study of the Bentazon Sensitive Mutants in Rice

采用γ-射线辐射诱变技术,日本和中国学者分别从粳稻和籼稻中获得了苯达松敏感致死突变体农林8号m和M8077S。水稻苯达松敏感突变也表现对磺酰脲类除草剂敏感,但对供试的其他除草剂没有差异反应。遗传分析表明,这两个突变体表现为等位的隐性单基因突变,对这两种除草剂的敏感是同一个基因突变的效应。对M8077S的突变位点进行了精细定位、基因克隆和互补试验,证明农林8号m和M8077S都是源于第3染色体上的一个细胞色素P450基因(CYP81A6)的单碱基缺失导致的移码突变:农林8号m中的CYP81A6自转录起始密码子ATG起第507位缺失了一个C,而M8077S中的CYP81A6第2058位缺失了一个G。水稻苯达松敏感突变用于两系法杂交水稻的除杂保纯,已经成功选育出3个具有苯达松敏感突变标记的光温敏雄性不育系(M8064S、苯88S、苯63S)以及相配套的3个杂交组合(丰两优2号、苯两优9号和苯两优639),分别通过了湖北和江西省品种审定;用于杂交水稻混植法制种,已经成功选育出具有苯达松敏感标记的恢复系(MC526)以及相配套的杂交组合(混制1号),制定了机械化混播制种的生产规程和技术要点。还展望了CYP81A6基因在抗除草剂育种、转基因水稻安全控制以及水稻化学杀雄方面的应用前景。

Two rice bentazon-lethal mutants,Norin 8m and M8077S,were obtained from japonica and indica rice independently by γ-ray radiation in Japan and China. Both mutants were sensitive to the sulfonylurea herbicides,but insensitive to the other hebicides. Genetic analysis showed that both mutants were controlled by a single recessive gene,and the sensitivities to bentazon and sulfonylurea were controlled by the same gene. Gene mapping,gene cloning and complementation experiment showed that both Norin 8m and M8077S were resulted from a single-base deletion of CYP81A6,a cytochrome P450 gene. A single-base deletion of C at the 507th nucleotide coding sequence starting from ATG of CYP81A6 in Norin 8m were identified,compared with a single-base deletion of G at the 2058th nucleotide in coding sequence starting from ATG of CYP81A6 in M8077S. The bentazon-lethal mutants have been used for hybrid seed reproduction to ensure hybrid seed purity for the two-line hybrid seed production. Three photo-thermo-sensitive genic male sterility （P/TGMS） lines （M8064S,B88S,and B63S） marked with bentazon-lethality and 3 relevant hybrids （Fengliangyou 2,Benliangyou 639,and Benliangyou 9） have been successfully developed and registered in Hubei and Jiangxi Provinces,China. These bentazon-lethal mutants have been also used for mixed-planting hybrid seed production. A bentazon-senstive restorer line MC526 and its matched hybrid combination Hunzhi 1 have been developed successfully. The procedures of mixed planting and the key techniques for mechanized production of hybrid seeds have been set up. The paper also reviewed the future applications of CYP81A6 gene in herbicide resistant rice breeding,the safety control of genetically modified rice and the application prospects of chemical emasculation.