Sequencing and analysis of the complete organellar genomes of Parmales, a closely related group to Bacillariophyta (diatoms).
We sequenced the complete plastid and mitochondrial genomes of the unicellular marine phytoplankton Triparma laevis, belonging to the order Parmales (Heterokonta). The cells of Parmales are surrounded by silicified cell walls, similar to Bacillariophyta (diatoms). T. laevis was recognized as a sister group of Bacillariophyta using a molecular phylogenetic analysis based on SSU rDNA and rbcL sequences. Bacillariophyta are the most successful group of phytoplankton in the modern ocean, but the origin and early evolution of them have not been clearly established. Detailed molecular analyses of T. laevis may increase our understanding of the evolutionary relationships among Parmales and Bacillariophyta. The gene contents of the plastid and mitochondrial genomes are similar between T. laevis and Bacillariophyta. The gene order of the plastid genome is also similar to Bacillariophyta, whereas the gene order of the mitochondrial genome is not conserved in Bacillariophyta, but the structure is more compact than Bacillariophyta. Phylogenetic analyses, using plastid-encoded concatenated amino acid datasets and mitochondria-encoded concatenated amino acid datasets suggest that T. laevis is a sister group of Bacillariophyta. These results suggest that the characteristics of the organellar genomes of T. laevis are similar and conserve ancestral characteristics more than Bacillariophyta.
Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan. naoT507@bio.c.u-tokyo.ac.jp.
Naoyuki
N
Tajima
National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa, 236-8648, Japan.
Kenji
K
Saitoh
Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, 980-8577, Japan.
Shusei
S
Sato
Graduate School of Medicine and Faculty of Medicine Kyoto University, Section of Microbiology, Yoshida-Konoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
Fumito
F
Maruyama
Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Tsukide 3-1-100, Higashi, Kumamoto, 862-8502, Japan.
Mutsuo
M
Ichinomiya
Faculty of Marine Bioscience, Fukui Prefectural University, 1-1 Gakuen-cho, Obama, Fukui, 917-0003, Japan.
Shinya
S
Yoshikawa
Department of Biological Information, Tokyo Institute of Technology, 4259-B65, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan.
Ken
K
Kurokawa
Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B65, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan.
Hiroyuki
H
Ohta
Kazusa DNA Research Institute, Kazusa-Kamatari 2-6-7, Kisarazu, Chiba, 292-0818, Japan.
Satoshi
S
Tabata
Tohoku National Fisheries Research Institute, Japan Fisheries Research and Education Agency, Shinhamacho 3-27-5, Shiogama, Miyagi, 985-0001, Japan.
Akira
A
Kuwata
Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan.
Naoki
N
Sato
D019295:Computational Biology / Q000379:methods; D017377:Diatoms / Q000145:classification* / Q000235:genetics*; D019143:Evolution, Molecular; D054629:Genome, Mitochondrial; D023281:Genomics; D058977:Molecular Sequence Annotation; D016366:Open Reading Frames; D010802:Phylogeny; D018087:Plastids / Q000235:genetics*; D017422:Sequence Analysis, DNA
Genome sequencing; Heterokonta; Mitochondrial genome; Parmales; Plastid genome; Triparma laevis