Induction of Photosynthetic Carbon Fixation in Anoxia Relies on Hydrogenase Activity and Proton-Gradient Regulation-Like1-Mediated Cyclic Electron Flow in <i>Chlamydomonas reinhardtii</i>

Godaux, Damien; Bailleul, Benjamin; Berne, Nicolas; Cardol, Pierre

doi:10.1104/pp.15.00105

Cited by 61 publications

(61 citation statements)

References 68 publications

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“…In addition, TOR‐inhibited cells exhibited adverse effects on electron transport rate (ETR PSII ) parameter as well where ETR PSII showed significant drop by 4, 8, and 12 hr of TOR kinase inhibition (Figure c). We note that in the same experiment, control untreated cells exhibited ETR PSII values that were similar to the previously reported values (Godaux, Bailleul, Berne, & Cardol, ). Thus, our studies indicate that TOR inhibition causes significant loss in chloroplast function, which is also reflected by alterations in chloroplast morphology.…”

Section: Resultssupporting

confidence: 91%

Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii

Upadhyaya

Rao

2019

Plant Direct

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While the role of TOR kinase in the chloroplast biogenesis and transcriptional regulation of photosynthesis is well documented in Arabidopsis, the functional relevance of this metabolic sensor kinase in chloroplast–mitochondria cross talk is unknown. Using Chlamydomonas reinhardtii as the model system, we demonstrate the role of TOR kinase in the regulation of chloroplast and mitochondrial functions: We show that TOR kinase inhibition impairs the maintenance of high ETR associated with PSII and low NPQ and inhibits efficient state transitions between PSII and PSI. While compromised photosynthetic functions are observed in TOR kinase inhibited cells, same conditions lead to augmentation in mitochondrial basal respiration rate by twofold and concomitantly a rise in ATP production. Interestingly, such upregulated mitochondrial functions in TOR‐inhibited cells are mediated by fragmented mitochondria via upregulating COXIIb and downregulating Hxk1 and AOX1 protein levels. We propose that TOR kinase may act as a sensor that counter‐regulates chloroplast versus mitochondrial functions in a normal C. reinhardtii cell.

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Section: Resultssupporting

confidence: 91%

Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii

Upadhyaya

Rao

2019

Plant Direct

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“…This is in agreement with the proposal that PQH 2 replaces PhQ in the A 1 site of PSI in anoxia and prevents photosynthetic electron transfer in the mend mutant (McConnell et al ., ). As a result, long‐term reactivation (>5 min) of PSII electron transfer in anoxia, which relies on both PSI‐dependent hydrogenase activity and PGRL1‐dependent PSI cyclic electron flow in wild‐type Chlamydomonas cells (Godaux et al ., ), is fully compromised in the men mutant (Figure b). Loss of PhQ thus severely impairs electron transfer in anoxia in our men mutants, as has already been shown in the mend mutant (Lefebvre‐Legendre et al ., ; McConnell et al ., ).…”

Section: Discussionmentioning

confidence: 92%

“…The ratio between active PSI and PSII centers was estimated as previously described (Godaux et al ., ) on cells adapted to the dark for 30 min. Briefly, the amplitude of the fast phase (<1 ms) of the ECS signal (at 520–546 nm) after illumination with a single‐turnover laser flash was monitored with a JTS‐10 spectrophotometer (Bio‐Logic).…”

Section: Methodsmentioning

confidence: 99%

Isolation and characterization of mutants corresponding to the MENA, MENB, MENC and MENE enzymatic steps of 5′‐monohydroxyphylloquinone biosynthesis in Chlamydomonas reinhardtii

et al. 2016

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SummaryPhylloquinone (PhQ), or vitamin K1, is an essential electron carrier (A1) in photosystem I (PSI). In the green alga Chlamydomonas reinhardtii, which is a model organism for the study of photosynthesis, a detailed characterization of the pathway is missing with only one mutant deficient for MEND having been analyzed. We took advantage of the fact that a double reduction of plastoquinone occurs in anoxia in the A1 site in the mend mutant, interrupting photosynthetic electron transfer, to isolate four new phylloquinone‐deficient mutants impaired in MENA,MENB,MENC (PHYLLO) and MENE. Compared with the wild type and complemented strains for MENB and MENE, the four men mutants grow slowly in low light and are sensitive to high light. When grown in low light they show a reduced photosynthetic electron transfer due to a specific decrease of PSI. Upon exposure to high light for a few hours, PSI becomes almost completely inactive, which leads in turn to lack of phototrophic growth. Loss of PhQ also fully prevents reactivation of photosynthesis after dark anoxia acclimation. In silico analyses allowed us to propose a PhQ biosynthesis pathway in Chlamydomonas that involves 11 enzymatic steps from chorismate located in the chloroplast and in the peroxisome.

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“…Maturation of the [FeFe]‐hydrogenase requires HydE, HydF and HydG maturation factors. The [FeFe]‐hydrogenase maturation factors (maturase) were first identified in the green alga Chlamydomonas , while the HydE and HydF are fused to form one protein HydEF in Chlamydomonas , and hydrogen evolution was barely detected in the hydEF‐1 mutant, as well as hydG‐1 and hydG‐2 mutants . The HydEF and HydG are all hydrogenase maturation factors, while the distinctions between HydEF and HydG have not been revealed in Chlamydomonas .…”

Section: Hydrogen Synthesizing Enzymes In Microalgaementioning

confidence: 99%

“…The [FeFe]-hydrogenase maturation factors (maturase) were first identified in the green alga Chlamydomonas, while the HydE and HydF are fused to form one protein HydEF in Chlamydomonas, and hydrogen evolution was barely detected in the hydEF-1 mutant, [46] as well as hydG-1 [90] and hydG-2 mutants. [91] The HydEF and HydG are all hydrogenase maturation factors, while the distinctions between HydEF and HydG have not been revealed in Chlamydomonas. In vivo, when [FeFe]-hydrogenase was expressed in E. coli without maturase, an inactive protein lacking H-cluster was generated, [92] and the subsequent evidences indicated that active H-cluster is responsible for the 10-100 folds higher activity of [FeFe]hydrogenase than that of [NiFe]-hydrogenase.…”

Section: The Maturation Of [Fefe]-hydrogenasementioning

confidence: 99%

Microalgal Hydrogen Production

et al. 2020

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Microalgae, as facultative aerobic organisms, convert solar energy to produce biohydrogen under anaerobic condition. Biohydrogen is a kind of ideal clean and renewable energy source with great commercial potential. Many endeavors have been focused on improving the biohydrogen yields by various means. Here, the research history of hydrogen production by microalgae (including cyanobacteria and green algae), the characteristics of nitrogenase and hydrogenase, the mechanisms of hydrogen production, the technological progress, and the application of enzymatic, genetic, and metabolic engineering methods to improve hydrogen production by microalgae are reviewed. In addition, the regulation of anaerobic metabolisms of Chlamydomonas reinhardtii after the disruption of key enzymes functioning in the fermentative pathways is discussed. Finally, the main challenges and obstacles facing the more efficient production and commercialization of hydrogen production from microalgae in the future are proposed.

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Induction of Photosynthetic Carbon Fixation in Anoxia Relies on Hydrogenase Activity and Proton-Gradient Regulation-Like1-Mediated Cyclic Electron Flow in Chlamydomonas reinhardtii

Cited by 61 publications

References 68 publications

Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii

Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii

Isolation and characterization of mutants corresponding to the MENA, MENB, MENC and MENE enzymatic steps of 5′‐monohydroxyphylloquinone biosynthesis in Chlamydomonas reinhardtii

Microalgal Hydrogen Production

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