低温冷害是影响水稻光合功能和产量的重要环境胁迫因素之一，大量研究表明，低温导致水稻光合作用功能下降，但其分子机理一直不清楚。为了研究水稻低温敏感的分子机理，我们从水稻突变体库中筛选到一个低温黄化的突变体，图位克隆了突变基因CIC1，并证实CIC1蛋白定位于叶绿体。前期研究显示，CIC1基因突变引起低温下水稻叶片黄化，光合活性下降，叶绿体基因编码蛋白积累减少。本项目在已有工作的基础上，通过分析水稻cic1突变体低温下的表型和功能，研究CIC1蛋白在低温下水稻叶绿体基因表达和光合系统功能损伤中的作用，找寻和CIC1蛋白功能相关的其它调控因子，阐明CIC1蛋白参与低温下叶绿体基因表达和光合作用调控的分子机制。

Low temperature is one of the major environmental factors limiting photosynthetic activities and yield of rice. Numerous reports indicate that chilling reduces photosynthetic function of rice seedlings, but its molecular mechanism is not clear. To study the mechanism of chilling sensitivity of rice plants, we obtained a chilling-induced chlorotic mutant from the rice mutant library. We isolated the gene by map-based cloning. The CIC1 protein was found to be localized in the chloroplast. Phenotypic and biochemical analyses revealed that cic1 mutant developed chlorotic leaves, showed reduced photosynthetic activities and accumulation of chloroplast-encoded proteins under chilling stress. In order to investigate the molecular mechanism of CIC1 protein in the chloroplast gene expression and photosynthesis of rice seedlings under chilling stress, phenotype of cic1 mutant, functional characterization of CIC1 gene expression and the associated proteins of CIC1 will be studied.