A photosynthetic alveolate closely related to apicomplexan parasites.
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.
Moore
Robert B
RB
School of Molecular and Microbial Biosciences, University of Sydney, Darlington, New South Wales 2006, Australia.
Oborník
Miroslav
M
Janouskovec
Jan
J
Chrudimský
Tomás
T
Vancová
Marie
M
Green
David H
DH
Wright
Simon W
SW
Davies
Noel W
NW
Bolch
Christopher J S
CJ
Heimann
Kirsten
K
Slapeta
Jan
J
Hoegh-Guldberg
Ove
O
Logsdon
John M
JM
Carter
Dee A
DA
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
D003062:Codon; D012335:RNA, Ribosomal; D002734:Chlorophyll; D000077194:Chlorophyll A