Reyes-Prieto Adrian, Weber Andreas P M, Bhattacharya Debashish
Department of Biological Sciences and Roy J. Carver Center for Comparative Genomics, University of Iowa, Iowa City, IA 52242-1324, USA.
Annu Rev Genet. 2007;41:147-68. doi: 10.1146/annurev.genet.41.110306.130134.
The establishment of the photosynthetic organelle (plastid) in eukaryotes and the diversification of algae and plants were landmark evolutionary events because these taxa form the base of the food chain for many ecosystems on our planet. The plastid originated via a putative single, ancient primary endosymbiosis in which a heterotrophic protist engulfed and retained a cyanobacterium in its cytoplasm. Once successfully established, this plastid spread into other protist lineages through eukaryote-eukaryote (secondary and tertiary) endosymbioses. This process of serial cell capture and enslavement explains the diversity of photosynthetic eukaryotes. Recent genomic and phylogenomic approaches have significantly clarified plastid genome evolution, the movement of endosymbiont genes to the "host" nuclear genome (endosymbiotic gene transfer), and plastid spread throughout the eukaryotic tree of life. Here we review these aspects of plastid evolution with a focus on understanding early events in plastid endosymbiosis.
真核生物中光合细胞器（质体）的建立以及藻类和植物的多样化是具有里程碑意义的进化事件，因为这些类群构成了地球上许多生态系统食物链的基础。质体起源于一种假定的单一古老的初级内共生事件，即一个异养原生生物在其细胞质中吞噬并保留了一个蓝细菌。一旦成功建立，这种质体通过真核生物 - 真核生物（次级和三级）内共生事件传播到其他原生生物谱系中。这种连续的细胞捕获和奴役过程解释了光合真核生物的多样性。最近的基因组学和系统发育基因组学方法显著阐明了质体基因组的进化、内共生体基因向“宿主”核基因组的转移（内共生基因转移）以及质体在整个真核生物生命树中的传播。在此，我们回顾质体进化的这些方面，重点是理解质体内共生的早期事件。
