Laboratory of Evolutionary Protistology, Department of Invertebrate Biology, Evolution and Conservation, Institute of Environmental Biology, University of Wrocław, ul. Przybyszewskiego 65, 51-148, Wrocław, Poland.
Biol Rev Camb Philos Soc. 2018 Feb;93(1):201-222. doi: 10.1111/brv.12340. Epub 2017 May 23.
The evolution of plastids has a complex and still unresolved history. These organelles originated from a cyanobacterium via primary endosymbiosis, resulting in three eukaryotic lineages: glaucophytes, red algae, and green plants. The red and green algal plastids then spread via eukaryote-eukaryote endosymbioses, known as secondary and tertiary symbioses, to numerous heterotrophic protist lineages. The number of these horizontal plastid transfers, especially in the case of red alga-derived plastids, remains controversial. Some authors argue that the number of plastid origins should be minimal due to perceived difficulties in the transformation of a eukaryotic algal endosymbiont into a multimembrane plastid, but increasingly the available data contradict this argument. I suggest that obstacles in solving this dilemma result from the acceptance of a single evolutionary scenario for the endosymbiont-to-plastid transformation formulated by Cavalier-Smith & Lee (1985). Herein I discuss data that challenge this evolutionary scenario. Moreover, I propose a new model for the origin of multimembrane plastids belonging to the red lineage and apply it to the dinoflagellate peridinin plastid. The new model has several general and practical implications, such as the requirement for a new definition of cell organelles and in the construction of chimeric organisms.
质体的进化历史复杂且尚未解决。这些细胞器起源于蓝细菌的初级内共生，导致了三个真核生物谱系：蓝藻、红藻和绿色植物。然后，红藻和绿藻质体通过真核生物-真核生物内共生，即二次和三次共生，传播到许多异养原生生物谱系中。这些水平质体转移的数量，尤其是红藻衍生质体的数量，仍然存在争议。一些作者认为，由于将真核藻类内共生体转化为具有多个膜的质体的难度，质体起源的数量应该最小，但越来越多的可用数据反驳了这一观点。我认为，解决这一困境的障碍源于接受 Cavalier-Smith 和 Lee（1985）提出的内共生体向质体转化的单一进化方案。在此，我讨论了挑战这一进化方案的数据。此外，我提出了一个新的模型，用于解释红藻谱系中多膜质体的起源，并将其应用于甲藻的虫黄藻质体。新模型具有几个一般和实际的意义，例如需要对细胞细胞器进行新的定义，以及在嵌合体的构建中。
