Photoprotection strategies of the alga Nannochloropsis gaditana

Volha U. Chukhutsina, Rikard Fristedt, Tomas Morosinotto, Roberta Croce*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Nannochloropsis spp. are algae with high potential for biotechnological applications due to their capacity to accumulate lipids. However, little is known about their photosynthetic apparatus and acclimation/photoprotective strategies. In this work, we studied the mechanisms of non-photochemical quenching (NPQ), the fast response to high light stress, in Nannochloropsis gaditana by “locking” the cells in six different states during quenching activation and relaxation. Combining biochemical analysis with time-resolved fluorescence spectroscopy, we correlated each NPQ state with the presence of two well-known NPQ components: de-epoxidized xanthophylls and stress-related antenna proteins (LHCXs). We demonstrated that after exposure to strong light, the rapid quenching that takes place in the antennas of both photosystems was associated with the presence of LHCXs. At later stages, quenching occurs mainly in the antennas of PSII and correlates with the amount of de-epoxidised xanthophylls. We also observed changes in the distribution of excitation energy between photosystems, which suggests redistribution of excitation between photosystems as part of the photo-protective strategy. A multistep model for NPQ induction and relaxation in N. gaditana is discussed.

Original languageEnglish
Pages (from-to)544-552
Number of pages9
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1858
Issue number7
DOIs
Publication statusPublished - 1 Jul 2017

Keywords

  • Heterokonta
  • Nannochloropsis
  • Non-photochemical quenching
  • Photosynthesis
  • Xanthophyll cycle

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