title: A photosynthetic alveolate closely related to apicomplexan parasites.
abstract: Many parasitic Apicomplexa, such as Plasmodium falciparum, contain an unpigmented chloroplast remnant termed the apicoplast, which is a target for malaria treatment. However, no close relative of apicomplexans with a functional photosynthetic plastid has yet been described. Here we describe a newly cultured organism that has ultrastructural features typical for alveolates, is phylogenetically related to apicomplexans, and contains a photosynthetic plastid. The plastid is surrounded by four membranes, is pigmented by chlorophyll a, and uses the codon UGA to encode tryptophan in the psbA gene. This genetic feature has been found only in coccidian apicoplasts and various mitochondria. The UGA-Trp codon and phylogenies of plastid and nuclear ribosomal RNA genes indicate that the organism is the closest known photosynthetic relative to apicomplexan parasites and that its plastid shares an origin with the apicoplasts. The discovery of this organism provides a powerful model with which to study the evolution of parasitism in Apicomplexa.
authors.affiliation: School of Molecular and Microbial Biosciences, University of Sydney, Darlington, New South Wales 2006, Australia.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Moore
authors.forename: Miroslav
authors.initials: M
authors.lastname: Oborník
authors.forename: Jan
authors.initials: J
authors.lastname: Janouskovec
authors.forename: Tomás
authors.initials: T
authors.lastname: Chrudimský
authors.forename: Marie
authors.initials: M
authors.lastname: Vancová
authors.forename: David H
authors.initials: DH
authors.lastname: Green
authors.forename: Simon W
authors.initials: SW
authors.lastname: Wright
authors.forename: Noel W
authors.initials: NW
authors.lastname: Davies
authors.forename: Christopher J S
authors.initials: CJ
authors.lastname: Bolch
authors.forename: Kirsten
authors.initials: K
authors.lastname: Heimann
authors.forename: Jan
authors.initials: J
authors.lastname: Slapeta
authors.forename: Ove
authors.initials: O
authors.lastname: Hoegh-Guldberg
authors.forename: John M
authors.initials: JM
authors.lastname: Logsdon
authors.forename: Dee A
authors.initials: DA
authors.lastname: Carter
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D003062:Codon / Q000235:genetics; D005057:Eukaryotic Cells / Q000145:classification* / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D010271:Parasites / Q000145:classification* / Q000166:cytology* / Q000235:genetics / Q000648:ultrastructure; D010788:Photosynthesis; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000145:classification; D018087:Plastids / Q000235:genetics / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000235:genetics
chemical_list: D003062:Codon; D012335:RNA, Ribosomal; D002734:Chlorophyll; D000077194:Chlorophyll A