SCD基因调控叶绿体分裂和发育的分子机理

在高等植物的幼嫩叶片中，细胞分裂旺盛，叶绿体也分裂活跃，且不成熟。随着叶片的成熟，叶绿体分裂趋缓，最后停止。过度的分裂，不仅不利于叶绿体的功能，也不利于植物的生长发育。过去几十年里，在叶绿体分裂领域人们研究的主要问题是叶绿体分裂及其正向调控机制。然而叶绿体分裂也需要负向调控来控制，但这方面的研究却几乎没有。为了研究这一问题，我们对几个叶绿体分裂突变体进行了抑制子筛选，已得到了几个表型完全或部分恢复的突变体—suppressor of chloroplast division（scd）。这些突变体的叶绿体分裂加速，发育延迟，说明其基因的功能在于抑制叶绿体分裂和促进叶绿体发育。本项目将综合利用遗传学、细胞生物学和生物化学等各种手段，通过分析抑制子对有关叶绿体蛋白质、叶绿体膜脂和有关基因表达调控的影响，深入研究其抑制叶绿体分裂的分子机制，揭示植物细胞中叶绿体分裂的负向调控机理。

In the young leaves of higher plants, cells divide frequently, accompanied by the active division of immature chloroplasts. As leaves getting mature, chloroplast division slows down and eventually stops. Over division of chloroplasts is detrimental to the function of chloroplasts and the growth and development of plants. In the past decades, the main topic in the field of chloroplast division is the mechanism of chloroplast division and its positive regulation. However, chloroplast division also needs to be controlled by negative regulation, but almost no research was done in this direction. To study this question, we screened suppressors of some chloroplast division mutants, and obtained some mutants—suppressor of chloroplast division (scd), which can fully or partially recover the chloroplast division phenotypes. In these mutants, chloroplast division is accelerated, chloroplast development is delayed, suggesting the function of the corresponding genes are suppressing the division and promoting the development of chloroplasts. This project will use various molecular genetics, cell biology and biochemistry approaches, study the molecular mechanism of suppressors in the repressing of chloroplast division in depth by analyzing their effects on the related chloroplast proteins, chloroplast membrane lipids and the expression of related genes, and provide some insights into the negative regulation mechanism of chloroplast division in plant cells.