Ion antiport accelerates photosynthetic acclimation in fluctuating light environments.

TitleIon antiport accelerates photosynthetic acclimation in fluctuating light environments.
Publication TypeJournal Article
Year of Publication2014
AuthorsArmbruster, U, L Carrillo, R, Venema, K, Pavlovic, L, Schmidtmann, E, Kornfeld, A, Jahns, P, Berry, JA, Kramer, DM, Jonikas, MC
JournalNat Commun
Volume5
Pagination5439
Date Published2014 Nov 13
ISSN2041-1723
KeywordsAdaptation, Physiological, Arabidopsis, Arabidopsis Proteins, Body Temperature Regulation, Down-Regulation, Environment, Light, Photosynthesis, Photosystem II Protein Complex, Potassium-Hydrogen Antiporters
Abstract

<p>Many photosynthetic organisms globally, including crops, forests and algae, must grow in environments where the availability of light energy fluctuates dramatically. How photosynthesis maintains high efficiency despite such fluctuations in its energy source remains poorly understood. Here we show that Arabidopsis thaliana K(+) efflux antiporter (KEA3) is critical for high photosynthetic efficiency under fluctuating light. On a shift from dark to low light, or high to low light, kea3 mutants show prolonged dissipation of absorbed light energy as heat. KEA3 localizes to the thylakoid membrane, and allows proton efflux from the thylakoid lumen by proton/potassium antiport. KEA3's activity accelerates the downregulation of pH-dependent energy dissipation after transitions to low light, leading to faster recovery of high photosystem II quantum efficiency and increased CO2 assimilation. Our results reveal a mechanism that increases the efficiency of photosynthesis under fluctuating light.</p>

DOI10.1038/ncomms6439
Alternate JournalNat Commun
PubMed ID25451040
PubMed Central IDPMC4243252