Alternative electron pathways of photosynthesis power green algal CO2 capture

Journal Article · 13 May 2024 · The Plant Cell

DOI: https://doi.org/10.1093/plcell/koae143 · OSTI ID:2455055

Peltier, Gilles ; Stoffel, Carolyne ; Findinier, Justin ; Madireddi, Sai Kiran ; Dao, Ousmane ; Epting, Virginie ; Morin, Amélie ; Grossman, Arthur ; Li-Beisson, Yonghua ; Burlacot, Adrien

Abstract Microalgae contribute to about half of global net photosynthesis, which converts sunlight into the chemical energy (ATP and NADPH) used to transform CO2 into biomass. Alternative electron pathways of photosynthesis have been proposed to generate additional ATP that is required to sustain CO2 fixation. However, the relative importance of each alternative pathway remains elusive. Here, we dissect and quantify the contribution of cyclic, pseudo-cyclic, and chloroplast-to-mitochondrion electron flows for their ability to sustain net photosynthesis in the microalga Chlamydomonas reinhardtii. We show that (i) each alternative pathway can provide sufficient additional energy to sustain high CO2 fixation rates, (ii) the alternative pathways exhibit cross-compensation, and (iii) the activity of at least one of the three alternative pathways is necessary to sustain photosynthesis. We further show that all pathways have very different efficiencies at energizing CO2 fixation, with the chloroplast–mitochondrion interaction being the most efficient. Overall, our data lay bioenergetic foundations for biotechnological strategies to improve CO2 capture and fixation.

• Research Organization: Carnegie Inst. of Washington, Washington, DC (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC)
• Grant/Contract Number: SC0019417
• OSTI ID: 2455055
• Journal Information: The Plant Cell, Journal Name: The Plant Cell Journal Issue: 10 Vol. 36; ISSN 1040-4651
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United States
• Language: English