一个水稻温敏黄化突变体的表型分析和基因定位

摘要

对水稻叶色进行表型分析与基因定位,可为图位克隆该类基因和研究水稻光合系统功能奠定基础.利用甲基磺酸乙酯(ethyl methanesulfonate,EMS)诱变的方法,从籼稻品种"南京11"(简称NJ11)中获得温敏黄化突变体dy1;与野生型相比,dy1在自然环境下,从苗期至成熟期始终表现叶片黄化,透射电镜显示dy1类囊体结构异常;同时株高、分蘖数、结实率等农艺性状也表现出极显著的差异;实验室光照培养箱条件下,dy1苗期在20℃下表现白化,在25℃表现黄化,在30℃下为浅绿的表型;遗传分析表明水稻温敏黄化突变体dy1的表型是由1对隐性基因控制;将突变体与粳稻广亲和品"02428"杂交,构建F2群体,从中选出隐性极端个体,通过基因定位,将控制黄化的基因限定在第1染色体长臂上标记Y-4和Y-35之间的115 kb的区间内,含有16个开放阅读框(ORF),测序发现,dy1中编码尿嘧啶核苷酸激酶的基因LOC_Os01g73450的第4个内含子与第5个外显子交界处存在单碱基替换,拟作为候选基因;且叶绿体合成相关基因表达量显著降低,猜测该基因可能参与了叶绿素合成途径.%Phenotypic analysis and gene mapping of rice leaf color could lay a foundation for map-based cloning of related genes and the function research of rice photosynthetic system. Leaf yellow mutant dy1 was obtained from rice cultivar "Nanjing 11"(abbreviated as NJ11) mutated by ethyl methanesulfonate (EMS). The mutant dy1 showed leaf yellowing at seedling stage and maturity stage in natural environment, with an abnormal structure of thylakoids under TEM, and significant differences in plant height, tiller number, seed setting rate and so on. The mutant dy1 showed albinism in 20℃, etiolation in 25℃ and virescence in 30℃. The rice leaf yellow mutant dy1 was controlled by a single recessive gene. F2 population was constructed by crossing the mutant with "02428", and the mutant phenotypes of extreme individuals were selected to map gene dy1. The gene was located in the 115 kb region of the long arm of chromosome 1, and contained 16 ORFs. Sequencing analysis showed that LOC_Os01g73450 controlling a uracil nucleotide kinase, with a single base substitution in the junction of the fourth intron and the fifth exon in dy1, might be a candidate gene. And the expression of genes related to chloroplast synthesis was significantly decreased, indicating dy1 may involve in the chloroplast synthesis