Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism - Archive ouverte HAL Access content directly
Journal Articles Proceedings of the National Academy of Sciences of the United States of America Year : 2015

Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism

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Xiaobo Li
Jaruswan Warakanont
  • Function : Author
Alexandra Dubini
  • Function : Author
Mark Page
  • Function : Author
Sarah D’adamo
  • Function : Author
Marko Boehm
  • Function : Author
Christoph Benning
  • Function : Author
Sabeeha Merchant
  • Function : Author
Matthew Posewitz
  • Function : Author
Arthur Grossman

Abstract

Photosynthetic microorganisms typically have multiple isoforms of the electron transfer protein ferredoxin, although we know little about their exact functions. Surprisingly, a Chlamydomonas reinhardtii mutant null for the ferredoxin-5 gene (FDX5) completely ceased growth in the dark, with both photosynthetic and respiratory functions severely compromised; growth in the light was unaffected. Thylakoid membranes in dark-maintained fdx5 mutant cells became severely disorganized concomitant with a marked decrease in the ratio of monogalactosyldiacylglycerol to digalactosyldiacylglycerol, major lipids in photosynthetic membranes, and the accumulation of triacylglycerol. Furthermore, FDX5 was shown to physically interact with the fatty acid desaturases CrΔ4FAD and CrFAD6, likely donating electrons for the desaturation of fatty acids that stabilize monogalactosyldiacylglycerol. Our results suggest that in photosynthetic organisms, specific redox reactions sustain dark metabolism, with little impact on daytime growth, likely reflecting the tailoring of electron carriers to unique intracellular metabolic circuits under these two very distinct redox conditions.

Dates and versions

cea-01820387 , version 1 (21-06-2018)

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Cite

Wenqiang Yang, Tyler Wittkopp, Xiaobo Li, Jaruswan Warakanont, Alexandra Dubini, et al.. Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism. Proceedings of the National Academy of Sciences of the United States of America, 2015, 112 (48), pp.14978 - 14983. ⟨10.1073/pnas.1515240112⟩. ⟨cea-01820387⟩
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