籼稻93-11辐射诱变突变体库的创建及其筛选

Construction and Screening of an Irradiation-induced Mutant Library of indica Rice 93-11

人工诱变突变体库是植物种质资源创新和基因组功能分析的有力工具。本研究以具有优异农艺性状且已完成基因组测序的籼稻常规品种93-11（O.sativa ssp.indica cv.93-11）为材料,创建了一个包含3617个家系的辐射诱变突变体库。通过在M2和M3代各生育期的筛选,从该突变体库中获得308个表型稳定的突变体。这些突变体的表型可以分成15类,包括株高、分蘖数、株型、穗型、小穗结构、育性、叶色、叶型、抽穗期、苯达松抗性等,突变频率为0.03%~2.74%。使用反向遗传学策略,鉴定出了2个雄性不育突变体和2个苯达松敏感突变体中的基因突变位点。其中,2个雄性不育突变体的突变表型是由于CYP704B2分别在第3和第4外显子发生碱基替换和片段缺失造成的,而2个苯达松敏感突变体的突变表型是由于CYP81A6中第1和第2外显子分别缺失了一个7bp和一个23bp的片段造成的。4个突变体家系中野生型和突变体植株的分离比均符合3∶1,属单基因隐性突变。这一籼稻突变体库将有助于籼稻基因组的功能分析,并且为水稻遗传改良提供了有价值的材料。

Mutant libraries are powerful tools for plant germplasm creation and functional analysis of genome. Using 93- 11 （O. sativa ssp. indica ev. 93-11）, an elite variety with complete genome sequences available, we established an irradiation-induced mutant library containing 3617 lines. Three hundred and eight mutant lines were obtained from M2 and M3 generations and classfied into 15 types of mutation, including plant height, tiller number, plant architecture, inflorescence architecture, spikelet architecture, fertility, leaf color, leaf shape, heading date, and bentazon resistance. The mutation frequencies ranged from 0.03 % to 2.74 %. Using reverse genetics approach, we found that CYP704B2 is the causal gene for two male sterile mutants and CYP81A6 is responsible for two bentazon-lethal mutations. For the two male sterile mutants, nucleotide substitution and deletion were detected in the third and fourth exons of CYP704B2, respectively. For the two bentazowlethal mutants, a 7-bp and a 23 bp deletion were detected in the first and second exons of CYP81A6, respectively. Genetic studies revealed that wild-type plants and mutant plants segregated at 3 ： 1 ratio, suggesting that these mutant traits were controlled by single recessive genes. Our study showed that this mutant library is a useful resource for rice genome functional analysis and rice genetic improvement.