水稻叶色突变体ygr的遗传分析与基因定位

Genetic Analysis and Gene Mapping of Rice Leaf Color Mutant ygr

叶色突变体是研究水稻叶绿体发育、光合色素合成与降解的理想材料。前期研究在水稻保持系大面积繁殖时发现一株转绿型淡黄叶突变体ygr,为了阐明其叶色调控机理,本试验比较了ygr与野生型的主要农艺性状和光合色素含量,并对该突变体进行了遗传分析和基因定位。结果表明,与野生型相比,ygr的始穗期推迟2 d,株高、单株有效穗数、穗长、穗粒数、结实率和千粒重等主要农艺性状均无显著差异,而苗期和抽穗期的叶绿素a、叶绿素b、总叶绿素和类胡萝卜素等光合色素含量均显著降低。遗传分析表明,ygr叶色突变性状受单隐性核基因控制,暂时将其命名为YGR。以ygr与日本晴杂交的F_2群体作为定位群体,将YGR基因定位在水稻第1号染色体分子标记WY8到WY20之间,其遗传距离分别为0.2 cM和0.5 cM。本研究结果为该基因的克隆和功能分析以及解析其突变机制奠定了基础。

Leaf color mutant was an ideal material for studying chloroplast development, photosynthetic pigment synthesis and degradation in rice. In the early study, a green revertible leaf color mutants ygr was obtained from extened propagation of rice maintainers. In order to clarify the leaf color regulation mechanism, the main agronomic traits and photosynthetic pigment content of ygr were compared with wild type, and genetic analysis and gene mapping of this mutant were conducted in this study. The results showed that initial heading stage of ygr was delayed by 2 days compared to the wild type, and the plant height, the no. of effective panicles per plant, the panicle length, the no. of grains per panicle, seed setting rate and 1 000 grain weight were similar with the wild type. Genetic analysis showed that the leaf color mutant traits of ygr were controlled by a single recessive nuclear gene, and was temporarily named YGR. With the F2 population developed from the cross between ygr and the green leaf variety Nipponbare, the YGR gene was mappled between WY8 and WY20, and the genetic distances were 0. 2 cM and 0.5 cM, respectively. This study laid the foundation for luther cloning and functional analysis of this gene and to analyse the mutation mechanism.