在粳稻品种Dongjin大田种植过程中,发现一个黄绿叶自然突变体,命名为djyg。该突变体在苗期表现明显的黄绿叶表型,抽穗以后,叶色逐渐恢复正常。叶绿素含量测定结果表明,在苗期、分蘖盛期及抽穗期叶绿素b的含量分别下降53%、62%、36%。电镜结果表明,分蘖期突变体中基粒、类囊体垛堆凌乱、排列疏松,类囊体基质较为稀薄。qRT-PCR结果证实,PORA、Cab1R、PsbA的表达量在突变体中均较野生型明显下调。遗传分析结果表明,黄绿叶突变体djyg由一对隐性主效核基因控制,图位克隆确定该候选基因为编码叶绿素合成酶基因YGL1的一个新等位基因。该突变体未影响植株的主要农艺性状,可作为一个理想的表型标记应用于杂交稻育种工作中。

A spontaneous yellow-green mutant was obtained from the japonica rice cultivar Dongjin in the field, designated as djyg. The mutant showed obvious yellow-green leaf phenotype at the seedling stage but the chlorotic leaves returned to green after the heading stage. Consistent with the phenotype, the chlorophyll b content of the mutant was reduced by 53%, 62% and 36% at the seedling, tillering and heading stages, respectively, compared with that of the wild type (WT). At the tillering stage, we observed that the granas and thylakoid stacks displayed a mess and loose structure, as well as less density in the mutant djyg compared with the WT under a transmission electron microscopy. The transcriptional levels of PORA, Cab1R, PsbA were also decreased in the mutant djyg. Genetic analysis and map-based cloning demonstrated that the phenotype of the mutant was controlled by a major recessive nuclear gene, which is an allele of chlorophyll synthase YGL1. The mutant djyg can be used as a phenotypic marker in rice breeding program since the main agronomic traits of the mutant djyg are normal compared with those of the WT.