In diatoms, the transthylakoid proton gradient regulates the photoprotective non-photochemical fluorescence quenching beyond its control on the xanthophyll cycle.
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 (delta pH). In this report, special illumination conditions and chemicals were used to perturb the kinetics of the delta pH build-up, of the XC and of NPQ. We found that the delta pH-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.
Lavaud
Johann
J
Group of Plant Ecophysiology, Biology Department, University of Konstanz, Germany. Johann.Lavaud@uni-konstanz.de
Kroth
Peter G
PG
D017377:Diatoms / Q000502:physiology*; D005453:Fluorescence; D008027:Light; D010788:Photosynthesis / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000502:physiology; D011522:Protons; D020524:Thylakoids / Q000502:physiology*; D024341:Xanthophylls / Q000502:physiology*
D045332:Photosystem II Protein Complex; D011522:Protons; D024341:Xanthophylls