Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ 08901, USA.
Science. 2012 Feb 17;335(6070):843-7. doi: 10.1126/science.1213561.
The primary endosymbiotic origin of the plastid in eukaryotes more than 1 billion years ago led to the evolution of algae and plants. We analyzed draft genome and transcriptome data from the basally diverging alga Cyanophora paradoxa and provide evidence for a single origin of the primary plastid in the eukaryote supergroup Plantae. C. paradoxa retains ancestral features of starch biosynthesis, fermentation, and plastid protein translocation common to plants and algae but lacks typical eukaryotic light-harvesting complex proteins. Traces of an ancient link to parasites such as Chlamydiae were found in the genomes of C. paradoxa and other Plantae. Apparently, Chlamydia-like bacteria donated genes that allow export of photosynthate from the plastid and its polymerization into storage polysaccharide in the cytosol.
大约 10 亿年前，真核生物的初级内共生起源导致了藻类和植物的进化。我们分析了基础分化的藻类蓝藻 Cyanophora paradoxa 的基因组和转录组草图数据，并为真核生物超组植物中初级质体的单一起源提供了证据。C. paradoxa 保留了淀粉生物合成、发酵和质体蛋白易位的祖先特征，这些特征在植物和藻类中很常见，但缺乏典型的真核光捕获复合物蛋白。在 C. paradoxa 和其他植物的基因组中发现了与衣原体等寄生虫的古老联系的痕迹。显然，类衣原体细菌捐赠了一些基因，这些基因允许质体中的光合作用产物输出，并将其聚合到细胞质中的储存多糖中。
