What is it? An apicoplast (apicomplexan plastid) is a vestigial plastid found in parasites belonging to the phylum Apicomplexa. Plastids are better known as the green, subcellular compartment of plants and algae in which photosynthesis occurs. Apicoplasts are non-photosynthetic, pigment-free versions of plastids. Phylum Apicomplexa comprises some 6,000 species of parasites, the most notorious of which is the genus Plasmodium that causes malaria in humans, other primates, rodents, bats, birds and reptiles. Less deadly, but more common, is Toxoplasma gondii, an apicomplexan that infects most mammals ( Figure 1). Apicomplexa also cause coccidiosis of fouls, red water fever of cattle, and babesiosis (tick fever) of cattle and dogs. The common human diarrhoeal apicomplexan Cryptosporidium is the only parasite in the group known to lack the apicoplast, though it might also be absent from gregarines, a large but poorly studied group of Apicomplexa that infects mostly invertebrates and protists.
McFadden, G. I. (2014, March 31). Apicoplast. Current Biology. Cell Press. https://doi.org/10.1016/j.cub.2014.01.024