一个水稻黄绿叶突变体ygl15的鉴定和基因定位

由籼稻品系杂交后代中发现1个黄绿叶突变体,命名为ygl15。为揭示突变体ygl15叶色变异机制,对其进行了表型鉴定和基因定位分析。结果表明,突变体ygl15从苗期开始表现为黄绿叶,叶片中的叶绿素和类胡萝卜素含量较野生型显著下降,并最终导致其农艺性状受到影响,表现为株高、有效穗数、单株总粒数和单株实粒数显著下降,穗长、每穗粒数和结实率的变化不显著,千粒重略有提高;基因表达分析表明,突变体ygl15叶片中,叶绿素合成和光合系统相关的基因表达上调,但血红素合成相关的基因表达下调或不变。遗传分析表明,ygl15的突变表型受1对细胞核隐性基因控制。以突变体ygl15和中花11杂交的F_2群体为定位群体,经过初步定位和精细定位,将ygl15基因定位在水稻第3号染色体上的分子标记M08124～M08175之间,物理距离约79 kb。本研究结果为进一步克隆ygl15突变基因和研究基因功能奠定了一定的理论基础。

Identification and Gene Mapping of a Yellow-green Leaf Mutant ygl15 in Rice

A yellow-green leaf mutant, named ygl15, was identified from the hybrid progeny of indica rice lines. Phenotype identification and gene mapping were performed in this study to clarify the leaf color variation mechanism of the ygl15 mutant. The results showed that yellow-green leaves appeared in the ygl15 mutant at the seedling stage, meantime the chlorophyll and carotenoid contents in leaves decreased significantly compared with the wild type. The agronomic characters of the ygl15 mutants were affected. The plant height, the effective panicle number, the total grain number per plant, and the filled grain number per plant decreased. While the panicle length, the grain number per panicle, and the seed setting rate kept stable, and the thousand-grain weight increased slightly. Gene expression analysis suggested that, the expressions were up-regulated for genes related to chlorophyll synthesis and photosynthetic system but down-regulated or stable for genes related to heme synthesis in the leaves of ygl15 mutant. Genetic analysis showed that the mutant phenotype of ygl15 was controlled by a single nuclear recessive gene. Using the F₂ population of the ygl15 mutant crossed with Zhonghua 11, the ygl15 gene was located within a 79 kb region between markers M08124 and M08175 on the third chromosome of rice through the preliminary mapping and fine mapping. This study laid a solid foundation for further cloning ygl15 mutant gene and studying gene function.