title: Evolution of Green Plants Accompanied Changes in Light-Harvesting Systems.
abstract: Photosynthetic organisms have various pigments enabling them to adapt to various light environments. Green plants are divided into two groups: streptophytes and chlorophytes. Streptophytes include some freshwater green algae and land plants, while chlorophytes comprise the other freshwater green algae and seawater green algae. The environmental conditions driving the divergence of green plants into these two groups and the changes in photosynthetic properties accompanying their evolution remain unknown. Here, we separated the core antennae of PSI and the peripheral antennae [light-harvesting complexes (LHCs)] in green plants by green-native gel electrophoresis and determined their pigment compositions. Freshwater green algae and land plants have high Chl a/b ratios, with most Chl b existing in LHCs. In contrast, seawater green algae have low Chl a/b ratios. In addition, Chl b exists not only in LHCs but also in PSI core antennae in these organisms, a situation beneficial for survival in deep seawater, where blue-green light is the dominant light source. Finally, low-energy Chl (red Chl) of PSI was detected in freshwater green algae and land plants, but not in seawater green algae. We thus conclude that the different level of Chl b accumulation in core antennae and differences in PSI red Chl between freshwater and seawater green algae are evolutionary adaptations of these algae to their habitats, especially to high- or low-light environments.
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819 Japan.
authors.forename: Motoshi
authors.initials: M
authors.lastname: Kunugi
authors.affiliation: Graduate School of Life and Environmental Sciences, Kyoto Prefecture University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, 606-8522 Japan.
authors.forename: Soichirou
authors.initials: S
authors.lastname: Satoh
authors.affiliation: Center for Gene Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602 Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Ihara
authors.affiliation: AIMEN Co., Ltd, 81-1 Takaoka-cho, Matsuyama, Ehime, 791-8036 Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Shibata
authors.affiliation: Faculty of Life Science and Biotechnology, Fukuyama University, 1 Sanzo, Gakuen-cho, Fukuyama, Hiroshima, 729-0292 Japan.
authors.forename: Yukimasa
authors.initials: Y
authors.lastname: Yamagishi
authors.affiliation: Faculty of Science, Hokkaido University, N10 W8 Kita-ku, Sapporo, 060-0810 Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kogame
authors.affiliation: Graduate School of Life and Environmental Sciences, Kyoto Prefecture University, 1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto, 606-8522 Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Obokata
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819 Japan CREST, JST, N19 W8 Kita-ku, Sapporo, 060-0819 Japan takabayashi@pop.lowtem.hokudai.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takabayashi
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819 Japan CREST, JST, N19 W8 Kita-ku, Sapporo, 060-0819 Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Tanaka
mesh_terms: D000595:Amino Acid Sequence; D005075:Biological Evolution; D002734:Chlorophyll / Q000378:metabolism; D000460:Chlorophyta / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004734:Energy Metabolism / Q000528:radiation effects; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D045331:Photosystem I Protein Complex / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D000072417:Protein Domains; D012623:Seawater; D013050:Spectrometry, Fluorescence; D013057:Spectrum Analysis; D057948:Viridiplantae / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll
keywords: Evolution; Green algae; Land plants; Light adaptation; Photosystem