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Updated: Aug 19, 2026

Using Changes in Leaf Transmission to Investigate Chloroplast Movement in Arabidopsis thaliana
Published on: July 14, 2021
Disequilibrium between chloroplast proton motive force and ATP levels in Arabidopsis
Gustaf E Degen1, Markus Schwarzländer2, Matthew P Johnson3
1Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Sheffield, UK. g.degen@sheffield.ac.uk.
Abstract:
Current dogma holds that CO2 fixation by photosynthesis requires additional ATP production via cyclic electron transfer, mediated by two distinct pathways involving the NADH dehydrogenase-like complex (NDH) and proton gradient regulation 5 protein (PGR5), to augment the ATP relative to NADPH produced by linear electron transfer. Here we use the MgATP2- fluorescent biosensor ATeam1.03-nD/nA and find that, while proton motive force in the Arabidopsis pgr5CAS and pgr5 ndho mutants is only 50-75% that of the wild type, chloroplast MgATP2- levels are unchanged. These data demonstrate that disequilibrium exists between the proton motive force and MgATP2- concentration in vivo, indicating that cyclic electron transfer is not required for ATP augmentation.
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