Phylogeny of the psbC gene, coding a photosystem II component CP43, suggests separate origins for the peridinin- and fucoxanthin derivative–containing plastids of dinoflagellates

Abstract

K. Takishita, K.-I. Ishida, M. Ishikura and T. Maruyama. 2005. Phylogeny of the psbC gene, coding a photosystem II component CP43, suggests separate origins for the peridinin- and fucoxanthin derivative–containing plastids of dinoflagellates. Phycologia 44: 26–34.Recently, the evolutionary relationship between peridinin- and fucoxanthin derivative (19′-hexanoyloxy-fucoxanthin and 19′-butanoyloxy-fucoxanthin)–containing plastids in dinoflagellates has become a controversial issue. It was widely accepted that the peridinin- and the fucoxanthin derivative–type plastids originated from independent photosynthetic organisms: the former type from a red alga through secondary endosymbiosis, and the latter from a haptophyte through tertiary endosymbiosis. However, a recent phylogenetic analysis using two plastid-encoded genes, psaA (encoding the P700 chlorophyll a apoprotein of photosystem I) and psbA (encoding the D1 protein of photosystem II) has suggested that the two types of dinoflagellate plastids share a single common haptophyte ancestor. In the present study, nucleotide sequences of another representative plastid gene, psbC (coding the CP43 of photosystem II), from both peridinin- and fucoxanthin derivative–containing dinoflagellates were determined using the reverse transcription polymerase chain reaction, cloning and sequencing for phylogenetic analysis. The phylogenetic tree showed that the peridinin- and fucoxanthin derivative–type species of dinoflagellates were not monophyletic, although both of them were placed within the monophyletic clade of other chlorophyll-a/c–containing organisms (a cryptophyte, a heterokont and haptophytes) and red algae. Furthermore, the fucoxanthin derivative–type species had phylogenetic affinity with haptophytes, whereas the peridinin-type did not. These results support the conventional view of separate origins for the peridinin- and fucoxanthin derivative–type plastids of dinoflagellates.