Functional Accumulation of Antenna Proteins in Chlorophyll b-Less Mutants of Chlamydomonas reinhardtii

Sandrine Bujaldon, Natsumi Kodama, Fabrice Rappaport, Rajagopal Subramanyam, Catherine de Vitry, Yuichiro Takahashi, Francis André Wollman

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14 Citations (Scopus)

Abstract

The green alga Chlamydomonas reinhardtii contains several light-harvesting chlorophyll a/b complexes (LHC): four major LHCIIs, two minor LHCIIs, and nine LHCIs. We characterized three chlorophyll b-less mutants to assess the effect of chlorophyll b deficiency on the function, assembly, and stability of these chlorophyll a/b binding proteins. We identified point mutations in two mutants that inactivate the CAO gene responsible for chlorophyll a to chlorophyll b conversion. All LHCIIs accumulated to wild-type levels in a CAO mutant but their light-harvesting function for photosystem II was impaired. In contrast, most LHCIs accumulated to wild-type levels in the mutant and their light-harvesting capability for photosystem I remained unaltered. Unexpectedly, LHCI accumulation and the photosystem I functional antenna size increased in the mutant compared with in the wild type when grown in dim light. When the CAO mutation was placed in a yellow-in-the-dark background (yid-BF3), in which chlorophyll a synthesis remains limited in dim light, accumulation of the major LHCIIs and of most LHCIs was markedly reduced, indicating that sustained synthesis of chlorophyll a is required to preserve the proteolytic resistance of antenna proteins. Indeed, after crossing yid-BF3 with a mutant defective for the thylakoid FtsH protease activity, yid-BF3-ftsh1 restored wild-type levels of LHCI, which defines LHCI as a new substrate for the FtsH protease.

Original languageEnglish
Pages (from-to)115-130
Number of pages16
JournalMolecular Plant
Volume10
Issue number1
DOIs
Publication statusPublished - Jan 9 2017

Keywords

  • CAO gene
  • Chlamydomonas reinhardtii
  • antenna protein
  • chlorophyll b-less mutant

ASJC Scopus subject areas

  • Molecular Biology
  • Plant Science

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    Bujaldon, S., Kodama, N., Rappaport, F., Subramanyam, R., de Vitry, C., Takahashi, Y., & Wollman, F. A. (2017). Functional Accumulation of Antenna Proteins in Chlorophyll b-Less Mutants of Chlamydomonas reinhardtii. Molecular Plant, 10(1), 115-130. https://doi.org/10.1016/j.molp.2016.10.001