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A dual strategy to cope with high light in Chlamydomonas reinhardtii.
- Source :
-
The Plant cell [Plant Cell] 2013 Feb; Vol. 25 (2), pp. 545-57. Date of Electronic Publication: 2013 Feb 19. - Publication Year :
- 2013
-
Abstract
- Absorption of light in excess of the capacity for photosynthetic electron transport is damaging to photosynthetic organisms. Several mechanisms exist to avoid photodamage, which are collectively referred to as nonphotochemical quenching. This term comprises at least two major processes. State transitions (qT) represent changes in the relative antenna sizes of photosystems II and I. High energy quenching (qE) is the increased thermal dissipation of light energy triggered by lumen acidification. To investigate the respective roles of qE and qT in photoprotection, a mutant (npq4 stt7-9) was generated in Chlamydomonas reinhardtii by crossing the state transition-deficient mutant (stt7-9) with a strain having a largely reduced qE capacity (npq4). The comparative phenotypic analysis of the wild type, single mutants, and double mutants reveals that both state transitions and qE are induced by high light. Moreover, the double mutant exhibits an increased photosensitivity with respect to the single mutants and the wild type. Therefore, we suggest that besides qE, state transitions also play a photoprotective role during high light acclimation of the cells, most likely by decreasing hydrogen peroxide production. These results are discussed in terms of the relative photoprotective benefit related to thermal dissipation of excess light and/or to the physical displacement of antennas from photosystem II.
- Subjects :
- Chlamydomonas reinhardtii drug effects
Fluorescence
Light
Light-Harvesting Protein Complexes genetics
Molecular Sequence Data
Mutation
Nigericin pharmacology
Photosynthesis
Photosystem I Protein Complex metabolism
Photosystem II Protein Complex metabolism
Plant Proteins genetics
Plant Proteins metabolism
Protein Serine-Threonine Kinases genetics
Protein Serine-Threonine Kinases metabolism
Chlamydomonas reinhardtii physiology
Light-Harvesting Protein Complexes metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1532-298X
- Volume :
- 25
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- The Plant cell
- Publication Type :
- Academic Journal
- Accession number :
- 23424243
- Full Text :
- https://doi.org/10.1105/tpc.112.108274