Abstract
Whereas photosynthetic function under steady-state light conditions has been well characterized, little is known about its changes that occur in response to light fluctuations. Chlororespiration, a simplified respiratory chain, is widespread across all photosynthetic lineages, but its role remains elusive. Here, we show that chlororespiration plays a crucial role in intermittentlight conditions in the green alga Chlamydomonas reinhardtii. Chlororespiration, which is localized in thylakoid membranes together with the photosynthetic electron transfer chain, involves plastoquinone reduction and plastoquinol oxidation by a Plastid Terminal Oxidase (PTOX). We show that PTOX activity is critical for growth under intermittent light, with severe growth defects being observed in a mutant lacking PTOX2, the major plastoquinol oxidase. We demonstrate that the hampered growth results from a major change in the kinetics of redox relaxation of the photosynthetic electron transfer chain during the dark periods. This change, in turn, has a dramatic effect on the physiology of photosynthesis during the light periods, notably stimulating cyclic electron flow at the expense of the linear electron flow.
Original language | English |
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Pages (from-to) | 630-639 |
Number of pages | 10 |
Journal | Plant Physiology |
Volume | 179 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2019 |
Funding
1This work was supported by the French Ministry of Education to W.J.N. and was further funded by the Centre National de la Recherche Scientifique, by Sorbonne University, and by the Agence Natio-nale de la Recherche Labex DYNAMO (ANR-11-LABX-0011-01).
Funders | Funder number |
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Agence Natio-nale de la Recherche Labex DYNAMO | |
French Ministry of Education | |
Centre National de la Recherche Scientifique | ANR-11-LABX-0011-01 |
Sorbonne Université |