The causes of altered chlorophyll fluorescence quenching induction in the Arabidopsis mutant lacking all minor antenna complexes
| Autor: | Alexandra J. Townsend, Francesco Saccon, Petra Ungerer, Vasco Giovagnetti, Alexander V. Ruban, Samuel H. Wilson |
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| Rok vydání: | 2018 |
| Předmět: |
Chlorophyll
0301 basic medicine Photosystem II Arabidopsis Light-Harvesting Protein Complexes Biophysics Thylakoids Biochemistry Fluorescence Light-harvesting complex 03 medical and health sciences chemistry.chemical_compound Zeaxanthins Photosynthesis Chlorophyll fluorescence Quenching (fluorescence) Non-photochemical quenching Cell Biology Plants Genetically Modified Plant Leaves 030104 developmental biology chemistry Thylakoid Photosynthetic membrane |
| Zdroj: | Biochimica et Biophysica Acta (BBA)-Bioenergetics |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/j.bbabio.2018.03.005 |
| Popis: | Non-photochemical quenching (NPQ) of chlorophyll fluorescence is the process by which excess light energy is harmlessly dissipated within the photosynthetic membrane. The fastest component of NPQ, known as energy-dependent quenching (qE), occurs within minutes, but the site and mechanism of qE remain of great debate. Here, the chlorophyll fluorescence of Arabidopsis thaliana wild type (WT) plants was compared to mutants lacking all minor antenna complexes (NoM). Upon illumination, NoM exhibits altered chlorophyll fluorescence quenching induction (i.e. from the dark-adapted state) characterised by three different stages: (i) a fast quenching component, (ii) transient fluorescence recovery and (iii) a second quenching component. The initial fast quenching component originates in light harvesting complex II (LHCII) trimers and is dependent upon PsbS and the formation of a proton gradient across the thylakoid membrane (ΔpH). Transient fluorescence recovery is likely to occur in both WT and NoM plants, but it cannot be overcome in NoM due to impaired ΔpH formation and a reduced zeaxanthin synthesis rate. Moreover, an enhanced fluorescence emission peak at ~679 nm in NoM plants indicates detachment of LHCII trimers from the bulk antenna system, which could also contribute to the transient fluorescence recovery. Finally, the second quenching component is triggered by both ΔpH and PsbS and enhanced by zeaxanthin synthesis. This study indicates that minor antenna complexes are not essential for qE, but reveals their importance in electron stransport, ΔpH formation and zeaxanthin synthesis. |
| Databáze: | OpenAIRE |
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