一个显性矮秆水稻突变体的获得及其遗传分析

Genetic Analysis of a Dominant Dwarf Mutant in Rice (Oryza sativa L.)

【目的】分析该研究组已发现的一个显性矮秆水稻突变体的遗传组成及背景。【方法】利用农杆菌介导法转化粳稻品种武香粳9号,产生T-DNA插入群体。在筛选和鉴定水稻T-DNA插入突变体的过程中,发现一个矮秆突变体。利用PCR扩增、Southern杂交等分子生物学方法对该突变体后代进行鉴定及遗传分析。【结果】突变体自交后代群体中出现矮秆和正常株高两种类型,分离比为3﹕1,符合一对显性单基因的遗传,并且矮秆性状的表现与T-DNA插入共分离。利用籼稻品种龙特甫与其纯合矮秆植株进行杂交,杂交F2代的矮秆株与正常株的比例同样呈3:1分离,符合一对显性单基因的遗传规律。利用SSR等分子标记,将该基因定位在水稻的第4染色体上。【结论】该矮秆性状由一对显性基因控制,由T-DNA插入引起,位于水稻第4染色体上,可作为进一步分离该基因的遗传材料。

【Objective】Selection and genetic characterization of a dominant dwarf mutant in rice were made.【Method】A dwarf mutant was identified from a T-DNA insertion population derived from a japonica rice variety,Wuxiangjing 9.Molecular characterization and genetic analysis was conducted of the mutant and its related genetic populations.【Result】Genetic analysis of the mutant showed that two kinds of phenotype,such as dwarf and normal height plants in the segregating population derived from the T-DNA insertion heterozygote plant.They were fit for the ratio of 3（dwarf type）：1（normal type）,indicating the dwarf gene is dominant mutation.The dwarf gene was further mapped on rice chromosome 4 using a segregation population derived from the mutant crossed with an indica rice variety,Longtepu.Test for HPT resistance showed the dwarf plants were all resistant while the normal height plants were susceptive,and the ratio of resistance and susceptible plants was 3：1,indicating that the dwarf mutation was co-segregating with HPT resistance.These results were consistent with only one copy exogenous gene which was detected in the transgenic rice genome revealed by Southern analysis.【Conclusion】The rice dwarf mutant phenotype is controlled by a dominant gene mutation,which is caused by T-DNA insertion.