Origins of plastids and glyceraldehyde-3-phosphate dehydrogenase genes in the green-colored dinoflagellate Lepidodinium chlorophorum.
The dinoflagellate Lepidodinium chlorophorum possesses "green" plastids containing chlorophylls a and b (Chl a+b), unlike most dinoflagellate plastids with Chl a+c plus a carotenoid peridinin (peridinin-containing plastids). In the present study we determined 8 plastid-encoded genes from Lepidodinium to investigate the origin of the Chl a+b-containing dinoflagellate plastids. The plastid-encoded gene phylogeny clearly showed that Lepidodinium plastids were derived from a member of Chlorophyta, consistent with pigment composition. We also isolated three different glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes from Lepidodinium-one encoding the putative cytosolic "GapC" enzyme and the remaining two showing affinities to the "plastid-targeted GapC" genes. In a GAPDH phylogeny, one of the plastid-targeted GapC-like sequences robustly grouped with those of dinoflagellates bearing peridinin-containing plastids, while the other was nested in a clade of the homologues of haptophytes and dinoflagellate genera Karenia and Karlodinium bearing "haptophyte-derived" plastids. Since neither host nor plastid phylogeny suggested an evolutionary connection between Lepidodinium and Karenia/Karlodinium, a lateral transfer of a plastid-targeted GapC gene most likely took place from a haptophyte or a dinoflagellate with haptophyte-derived plastids to Lepidodinium. The plastid-targeted GapC data can be considered as an evidence for the single origin of plastids in haptophytes, cryptophytes, stramenopiles, and alveolates. However, in the light of Lepidodinium GAPDH data, we need to closely examine whether the monophyly of the plastids in the above lineages inferred from plastid-targeted GapC genes truly reflects that of the host lineages.
Takishita
Kiyotaka
K
Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan.
Kawachi
Masanobu
M
Noël
Mary-Hélène
MH
Matsumoto
Takuya
T
Kakizoe
Natsuki
N
Watanabe
Makoto M
MM
Inouye
Isao
I
Ishida
Ken-Ichiro
K
Hashimoto
Tetsuo
T
Inagaki
Yuji
Y
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004141:Dinoflagellida / Q000201:enzymology*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D018087:Plastids; D016133:Polymerase Chain Reaction
D017931:DNA Primers; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases