Reference : Interplay between non-photochemical plastoquinone reduction and re-oxidation in pre-i...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/101114
Interplay between non-photochemical plastoquinone reduction and re-oxidation in pre-illuminated Chlamydomonas reinhardtii: a chlorophyll fluorescence study
English
Houyoux, Pierre-Alain [> >]
Ghysels, Bart mailto [Université de Liège - ULg > > Labo de Bioénergétique >]
Lecler, Renaud mailto [Université de Liège - ULg > > Labo de Bioénergétique >]
Franck, Fabrice mailto [Université de Liège - ULg > > Labo de Bioénergétique >]
24-Sep-2011
Photosynthesis Research
110
13-24
Yes (verified by ORBi)
International
0166-8595
1573-5079
[en] Plastid terminal oxidase ; Plastoquinone ; Chlamydomonas reinhardtii ; Chlororespiration ; Plastid NAD(P)H dehydrogenase
[en] 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 dehydroge- nase (NDH) complex and a plastid terminal oxidase (PTOX) are involved in PQ redox homeostasis in the dark. We recently demonstrated that in the microalgae Chla- mydomonas 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 tran- sient 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 fluo- rescence transient can be used to monitor changes in the relative rates of the non-photochemical PQ reduction and reoxidation in response to different physiological situa- tions. We study this fluorescence transient in algae acclimated to high light and in a mutant deficient in mitochondrial respiration. Some of our observations indi- cate that the chlororespiratory pathway participates in redox homeostasis in C. reinhardtii.
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/101114
10.1007/s11120-011-9686-5

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