水稻叶缘白化突变体mal的遗传分析与基因定位

植物叶色变化对叶绿体发育和叶绿素生物合成等光合系统结构和调控机制的研究有着重要的理论意义。水稻叶缘白化突变体mal(marginal albino leaf),来源于恢复系缙恢10号(Oryza sativa L.ssp.indica)的EMS诱变群体,经过多代自交,其突变性状遗传稳定。与野生型相比,mal突变体整个生育期叶片边缘白化且叶片变窄,抽穗期倒三叶叶片、倒二叶叶边缘以及倒三叶叶边缘的叶绿素含量极显著降低。透射电镜观察发现,mal突变体叶片绿色部位细胞与叶绿体发育完全,白化部分叶肉细胞大部分中空,无明显完整的细胞器,叶绿体内部完全降解。遗传分析表明该突变体受隐性核基因控制,MAL被定位在第8染色体上SSR标记M22和InDel标记ID27之间,物理距离为171 kb。本研究将为MAL基因的图位克隆及功能研究奠定基础。

Genetic Analysis and Gene Mapping of a Marginal Albino Leaf Mutant mal in Rice

The research on the color change of plant leaf is very important to clarify the structure and mechanism of photosynthetic system, such as chloroplast development and chlorophyll biosynthesis. A novel rice mutant mal (marginal albino leaf) with marginal albino leaf, was derived from the EMS-treated restorer line Jinhui 10. The mutant trait inherited steadily after several generations’ self-crossing. The mal leaf displayed albino margin and narrow blade in the whole life. Compared with the wild type, mal decreased contents of photosynthetic pigments very significantly in the whole third leaf blade, margin parts of the second and third leaves at heading stage. The observation by that transmission electronic microscopy showed cells and chloroplasts in the green part of mal leaf developed normally, while in the albino part, the mesophyll cells were nearly hollow without obvious intact organelles and the chloroplast were fully degraded. Genetic analysis showed that the mutant trait was controlled by single recessive nuclear gene. MAL was finally mapped between SSR marker M22 and InDel marker ID27 with an interval of 171 kb on chromosome 8. These results provide a foundation for cloning and function analysis of MAL.