title: Simultaneous regulation of antenna size and photosystem I/II stoichiometry in Arabidopsis thaliana.
abstract: The photosystem I/II ratio increased when antenna size was enlarged by transient induction of CAO in chlorophyll b -less mutants, thus indicating simultaneous regulation of antenna size and photosystem I/II stoichiometry. Regulation of antenna size and photosystem I/II stoichiometry is an indispensable strategy for plants to acclimate to changes to light environments. When plants grown in high-light conditions are transferred to low-light conditions, the peripheral antennae of photosystems are enlarged. A change in the photosystem I/II ratio is also observed under the same light conditions. However, our knowledge of the correlation between antenna size modulation and variation in photosystem I/II stoichiometry remains limited. In this study, chlorophyll a oxygenase was transiently induced in Arabidopsis thaliana chlorophyll b-less mutants, ch1-1, to alter the antenna size without changing environmental conditions. In addition to the accumulation of chlorophyll b, the levels of the peripheral antenna complexes of both photosystems gradually increased, and these were assembled to the core antenna of both photosystems. However, the antenna size of photosystem II was greater than that of photosystem I. Immunoblot analysis of core antenna proteins showed that the number of photosystem I increased, but not that of photosystem II, resulting in an increase in the photosystem I/II ratio. These results clearly indicate that antenna size adjustment was coupled with changes in photosystem I/II stoichiometry. Based on these results, the physiological importance of simultaneous regulation of antenna size and photosystem I/II stoichiometry is discussed in relation to acclimation to light conditions.
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-ku, Sapporo, 060-0819, Japan.
authors.forename: Ting
authors.initials: T
authors.lastname: Jia
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-ku, Sapporo, 060-0819, Japan. ito98@lowtem.hokudai.ac.jp.|CREST, Japan Science and Technology Agency, N19 W8, Kita-ku, Sapporo, 060-0819, Japan. ito98@lowtem.hokudai.ac.jp.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ito
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-ku, Sapporo, 060-0819, Japan.|CREST, Japan Science and Technology Agency, N19 W8, Kita-ku, Sapporo, 060-0819, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Tanaka
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant; D015151:Immunoblotting; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D008954:Models, Biological; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism; D010788:Photosynthesis; D045331:Photosystem I Protein Complex / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D014170:Transformation, Genetic
chemical_list: D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D012333:RNA, Messenger; D002734:Chlorophyll; C037184:chlorophyll b; D010105:Oxygenases; C115272:chlorophyll a oxygenase; D000077194:Chlorophyll A
keywords: Chlorophyll a oxygenase; Chlorophyll b; Peripheral antenna complexes; Photosystem reassembly; Photosystem stoichiometry