Gene Discovery for chloroplast proteins involved in stress response and photosynthesis in Arabidopsis using the homozygous knockout lines.

我们在拟南芥中收集了大约1300个编码叶绿体蛋白的基因的纯合Ds或T-DNA标记系，没有明显的表型。通过对这些纯合子植物在含有不同试剂的琼脂板上生长的生化测量，我们确定了6个突变体，它们在恶劣的胁迫条件下具有不同的生存能力。大多数植物对百草枯表现出异常反应，产生超氧自由基，破坏光合作用过程中的细胞膜和细胞质。此外，通过筛选叶绿素荧光图像，我们还鉴定了13个光合荧光参数改变的光合突变体。从两种筛选结果来看，我们对纯合突变体的系统收集是筛选具有异常胁迫反应的叶绿体突变体的有力工具，并且可以被证明是一种优势。

We have collected about 1, 300 homozygous Ds or T-DNA tagged-lines without a visible phenotype for genes encoding chloroplast proteins in Arabidopsis. By means of biochemical measurements of these homozygous plants grown on agar plates containing various reagents, we have identified 6 mutants with different capabilities to survive under severe stress conditions. Most of them showed abnormal responses to paraquat that generate superoxide radicals which damage cell membrane and cytoplasm during photosynthesis. Moreover, by screening of chlorophyll-fluorescence images, we also identified 13 photosynthetic mutants with altered photosynthetic-fluorescence parameters. Judging from both screening results, our systematic collection of homozygous mutants is a powerful tool for the screening of chloroplast mutants with abnormal stress responses and could be proved to be an advantage.