title: Essential role of the PSI-LHCII supercomplex in photosystem acclimation to light and/or heat conditions by state transitions.
abstract: Light and temperature affect state transitions through changes in the plastoquinone (PQ) redox state in photosynthetic organisms. We demonstrated that light and/or heat treatment induced preferential photosystem (PS) I excitation by binding light-harvesting complex II (LHCII) proteins. The photosystem of wheat was in state 1 after dark overnight treatment, wherein PQ was oxidized and most of LHCII was not bound to PSI. At the onset of the light treatment [25 °C in the light (100 µmol photons m-2s-1)], two major LHCIIs, Lhcb1 and Lhcb2 were phosphorylated, and the PSI-LHCII supercomplex formed within 5 min, which coincided with an increase in the PQ oxidation rate. Heat treatment at 40 °C of light-adapted wheat led to further LHCII protein phosphorylation of, resultant cyclic electron flow promotion, which was accompanied by ultrafast excitation of PSI and structural changes of thylakoid membranes, thereby protecting PSII from heat damage. These results suggest that LHCIIs are required for the functionality of wheat plant PSI, as it keeps PQ oxidized by regulating photochemical electron flow, thereby helping acclimation to environmental changes.
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan.|Technology Innovation Center, Sumika Chemical Analysis Service, Ltd., 3-1-135, Kasugade-naka, Konohana-ku, Osaka, 554-0022, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Marutani
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan. yamauchi@kobe-u.ac.jp.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yamauchi
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Higashiyama
authors.affiliation: Faculty of Agriculture, Kobe University, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Miyoshi
authors.affiliation: Molecular Photoscience Research Center, Kobe University, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Akimoto
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan.|Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka, 567-0047, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Inoue
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Ken-Ichi
authors.initials: KI
authors.lastname: Ikeda
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Mizutani
authors.affiliation: Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe, 657-8501, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Sugimoto
mesh_terms: D000222:Adaptation, Physiological; D006358:Hot Temperature; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry*; D010766:Phosphorylation; D045331:Photosystem I Protein Complex / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D020524:Thylakoids / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex
keywords: Heat stress; Photosynthetic electron flow; Photosystem; Protein phosphorylation; State transition; Thylakoid membrane; Wheat