Diversity in photosynthetic electron transport under [CO2]-limitation: the cyanobacterium Synechococcus sp. PCC 7002 and green alga Chlamydomonas reinhardtii drive an O2-dependent alternative electron flow and non-photochemical quenching of chlorophyll fluorescence during CO2-limited photosynthesis
Autor: | Ayumi Wada, Keiichiro Shaku, Seiji Akimoto, Yuichiro Takahashi, Yoshifumi Ueno, Chikahiro Miyake, Ginga Shimakawa |
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Rok vydání: | 2016 |
Předmět: |
0106 biological sciences
0301 basic medicine Cyanobacteria Quenching (fluorescence) biology Non-photochemical quenching Chlamydomonas reinhardtii Cell Biology Plant Science General Medicine biology.organism_classification Photosynthesis Photochemistry 01 natural sciences Biochemistry Electron transport chain 03 medical and health sciences 030104 developmental biology Green algae Chlorophyll fluorescence 010606 plant biology & botany |
Zdroj: | Photosynthesis Research. 130:293-305 |
ISSN: | 1573-5079 0166-8595 |
DOI: | 10.1007/s11120-016-0253-y |
Popis: | Some cyanobacteria, but not all, experience an induction of alternative electron flow (AEF) during CO2-limited photosynthesis. For example, Synechocystis sp. PCC 6803 (S. 6803) exhibits AEF, but Synechococcus elongatus sp. PCC 7942 does not. This difference is due to the presence of flavodiiron 2 and 4 proteins (FLV2/4) in S. 6803, which catalyze electron donation to O2. In this study, we observed a low-[CO2] induced AEF in the marine cyanobacterium Synechococcus sp. PCC 7002 that lacks FLV2/4. The AEF shows high affinity for O2, compared with AEF mediated by FLV2/4 in S. 6803, and can proceed under extreme low [O2] (about a few µM O2). Further, the transition from CO2-saturated to CO2-limited photosynthesis leads a preferential excitation of PSI to PSII and increased non-photochemical quenching of chlorophyll fluorescence. We found that the model green alga Chlamydomonas reinhardtii also has an O2-dependent AEF showing the same affinity for O2 as that in S. 7002. These data represent the diverse molecular mechanisms to drive AEF in cyanobacteria and green algae. In this paper, we further discuss the diversity, the evolution, and the physiological function of strategy to CO2-limitation in cyanobacterial and green algal photosynthesis. |
Databáze: | OpenAIRE |
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