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 …