caa a22 4500 445889942 CHVBK 20180317145612.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1007/s11120-011-9686-5 doi (NATIONALLICENCE)springer-10.1007/s11120-011-9686-5 Interplay between non-photochemical plastoquinone reduction and re-oxidation in pre-illuminated Chlamydomonas reinhardtii [Elektronische Daten] a chlorophyll fluorescence study [Pierre-Alain Houyoux, Bart Ghysels, Renaud Lecler, Fabrice Franck] In photosynthetic eukaryotes, the redox state of the plastoquinone (PQ) pool is an important sensor for mechanisms that regulate the photosynthetic electron transport. In higher plants, a multimeric nicotinamide adenine dinucleotide (phosphate) (NAD(P))H dehydrogenase (NDH) complex and a plastid terminal oxidase (PTOX) are involved in PQ redox homeostasis in the dark. We recently demonstrated that in the microalgae Chlamydomonas reinhardtii, which lacks the multimeric NDH complex of higher plants, non-photochemical PQ reduction is mediated by a monomeric type-II NDH (Nda2). In this study, we further explore the nature and the importance of non-photochemical PQ reduction and oxidation in relation to redox homeostasis in this alga by recording the ‘dark' chlorophyll fluorescence transients of pre-illuminated algal samples. From the observation that this fluorescence transient is modified by addition of propyl gallate, a known inhibitor of PTOX, and in a Nda2-deficient strain we conclude that it reflects post-illumination changes in the redox state of PQ resulting from simultaneous PTOX and Nda2 activity. We show that the post-illumination fluorescence transient can be used to monitor changes in the relative rates of the non-photochemical PQ reduction and reoxidation in response to different physiological situations. We study this fluorescence transient in algae acclimated to high light and in a mutant deficient in mitochondrial respiration. Some of our observations indicate that the chlororespiratory pathway participates in redox homeostasis in C. reinhardtii. Springer Science+Business Media B.V., 2011 Plastid terminal oxidase nationallicence Plastoquinone nationallicence Propyl gallate nationallicence Chlamydomonas reinhardtii nationallicence Chlororespiration nationallicence Plastid NAD(P)H dehydrogenase nationallicence NAD(P)H : Nicotinamide adenine dinucleotide (phosphate) nationallicence PSI : Photosystem I nationallicence PSII : Photosystem II nationallicence PQ : Plastoquinone nationallicence PTOX : Plastid terminal oxidase nationallicence Nda2 : Type 2 plastid NAD(P)H dehydrogenase nationallicence PG : Propyl gallate nationallicence Houyoux Pierre-Alain Laboratory of Bioenergetics, Institute of Plant Biology B22, University of Liège, Sart Tilman, 4000, Liège, Belgium aut Ghysels Bart Laboratory of Bioenergetics, Institute of Plant Biology B22, University of Liège, Sart Tilman, 4000, Liège, Belgium aut Lecler Renaud Laboratory of Genetics of Microorganisms, Institute of Plant Biology B22, University of Liège, Sart Tilman, 4000, Liège, Belgium aut Franck Fabrice Laboratory of Bioenergetics, Institute of Plant Biology B22, University of Liège, Sart Tilman, 4000, Liège, Belgium aut Photosynthesis Research Springer Netherlands 110/1(2011-10-01), 13-24 0166-8595 110:1<13 2011 110 11120 https://doi.org/10.1007/s11120-011-9686-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9686-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Houyoux Pierre-Alain Laboratory of Bioenergetics, Institute of Plant Biology B22, University of Liège, Sart Tilman, 4000, Liège, Belgium aut NATIONALLICENCE 700 1- Ghysels Bart Laboratory of Bioenergetics, Institute of Plant Biology B22, University of Liège, Sart Tilman, 4000, Liège, Belgium aut NATIONALLICENCE 700 1- Lecler Renaud Laboratory of Genetics of Microorganisms, Institute of Plant Biology B22, University of Liège, Sart Tilman, 4000, Liège, Belgium aut NATIONALLICENCE 700 1- Franck Fabrice Laboratory of Bioenergetics, Institute of Plant Biology B22, University of Liège, Sart Tilman, 4000, Liège, Belgium aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 110/1(2011-10-01), 13-24 0166-8595 110:1<13 2011 110 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer