Respiration accumulates Calvin cycle intermediates for the rapid start of photosynthesis in Synechocystis sp. PCC 6803 |
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| Authors: | Ginga Shimakawa Tomohisa Hasunuma Akihiko Kondo Mami Matsuda Amane Makino |
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| Affiliation: | 1. Faculty of Agriculture, Department of Biological and Environmental Science, Graduate School of Agricultural Science, Kobe University, Kobe, Japan;2. Organization of Advanced Science and Technology, Kobe University, Kobe, Japan;3. Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Tokyo, Japan;4. Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan;5. Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan;6. Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan;7. Department of Agriculture, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan |
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| Abstract: | We tested the hypothesis that inducing photosynthesis in cyanobacteria requires respiration. A mutant deficient in glycogen phosphorylase (?GlgP) was prepared in Synechocystis sp. PCC 6803 to suppress respiration. The accumulated glycogen in ΔGlgP was 250–450% of that accumulated in wild type (WT). The rate of dark respiration in ΔGlgP was 25% of that in WT. In the dark, P700+ reduction was suppressed in ΔGlgP, and the rate corresponded to that in (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone)-treated WT, supporting a lower respiration rate in ?GlgP. Photosynthetic O2-evolution rate reached a steady-state value much slower in ?GlgP than in WT. This retardation was solved by addition of d-glucose. Furthermore, we found that the contents of Calvin cycle intermediates in ?GlgP were lower than those in WT under dark conditions. These observations indicated that respiration provided the carbon source for regeneration of ribulose 1,5-bisphosphate in order to drive the rapid start of photosynthesis. |
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| Keywords: | cyanobacteria respiration photosynthesis glycogen phosphorylase |
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