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bioRxiv · 10.1101/2024.10.17.618902

Resolving an unconventional non-photochemical quenching signature at the light-to-dark transition

Lam, L.·Patel-Tupper, D.·Lam, H. E.·Steen, C. J.·Ma, A.·Ma, S. A.·Leipertz, A.·Lee, T.-Y.·Fleming, G.·Niyogi, K. K.
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Abstract

Non-photochemical quenching (NPQ) protects photosynthetic organisms via diverse molecular players contributing at varying timescales. However, in the absence of one of the largest contributors to NPQ, energy-dependent quenching (qE), we observe an unusual but universal phenomenon: a transient increase in quenching in the dark following high light exposure. To mechanistically interrogate this light-to-dark (LtD) NPQ phenotype, we performed chlorophyll fluorescence lifetime snapshot measurements across a diverse array of Arabidopsis mutant backgrounds and chemical treatments. We found that the electrochemical gradient across the thylakoid membrane is essential for this phenomenon. Through analysis of higher-order Arabidopsis mutants, we also found that LtD NPQ is independent of the known forms of photoprotective NPQ, as well as the major and minor light-harvesting complexes (LHCII). Our results point to LtD NPQ as a photoinhibition (qI)-related, reaction center quenching with implications for photoprotection in fluctuating light.

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Lam, L., Patel-Tupper, D., Lam, H. E., Steen, C. J., Ma, A., Ma, S. A., Leipertz, A., Lee, T.-Y., Fleming, G., Niyogi, K. K.. 2024-10-21. Resolving an unconventional non-photochemical quenching signature at the light-to-dark transition. https://doi.org/10.1101/2024.10.17.618902

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