In Diatoms, the Transthylakoid Proton Gradient Regulates the Photoprotective Non-photochemical Fluorescence Quenching Beyond its Control on the Xanthophyll Cycle

Johann Lavaud (1, 2) , Peter G. Kroth (3)

1 LIENSs - LIttoral ENvironnement et Sociétés
2 CNRS - Centre National de la Recherche Scientifique
3 Fachbereich Biologie [Konstanz]

In diatoms, the non-photochemical fluorescence quenching (NPQ) regulates photosynthesis during light fluctuations. NPQ is associated with an enzymatic xanthophyll cycle (XC) which is controlled by the light-driven transthylakoid proton gradient (ΔpH). In this report, special illumination conditions and chemicals were used to perturb the kinetics of the ΔpH build-up, of the XC and of NPQ. We found that the ΔpH-related acidification of the lumen is also needed for NPQ to develop by switching the xanthophylls to an ‘activated’ state, probably via the protonation of light-harvesting antenna proteins. It confirms the NPQ model previously proposed for diatoms.

Domaines: Biologie végétale; Sciences de l'environnement

Johann Lavaud, Peter G. Kroth. In Diatoms, the Transthylakoid Proton Gradient Regulates the Photoprotective Non-photochemical Fluorescence Quenching Beyond its Control on the Xanthophyll Cycle. Plant and Cell Physiology, 2006, 47, pp.1010-1016. ⟨10.1093/pcp/pcj058⟩. ⟨hal-01094659⟩