Depletion of stromal Pi induces high ‘energy‐dependent’ antenna exciton quenching (qE) by decreasing proton conductivity at CFO‐CF1 ATP synthase
- 7 November 2007
- journal article
- Published by Wiley in Plant, Cell & Environment
- Vol. 31 (2), 235-243
- https://doi.org/10.1111/j.1365-3040.2007.01753.x
Abstract
This work tests two models to account for the effects of depletion of stromal inorganic phosphate (P(i)), which results in down-regulation of light capture via the exciton quenching (q(E)) mechanism and has been proposed to act in feedback regulation of the light reactions. In both models, antenna down-regulation is activated by acidification of the lumen, despite the fact that linear electron flow (LEF) (and associated proton flux) is decreased upon P(i) depletion. In one model, an imbalance of ATP or NADPH activates cyclic electron transfer around photosystem I (CEF1), increasing proton influx to the lumen. In the second, the effective conductivity of the CF(O)-CF(1) ATP synthase to protons (g(H)(+)) is decreased, retarding proton efflux from the lumen. Sequestering of P(i) by mannose infiltration increased sensitivities of q(E) and pmf to LEF. The effects were attributable to decreases in g(H)(+), but not to CEF1 and were largely reversed by subsequent P(i) feeding. Rapid recovery of g(H)(+) in the dark suggested that dark-labile metabolic pools are responsible for regulation of the ATP synthase. Overall, these results support models where accumulation of Benson-Calvin cycle intermediates or lowering of stromal P(i) below its K(M)at the ATP synthase, retards proton efflux from the lumen, leading to build-up of pmf and subsequent down-regulation of photosynthetic light capture.Keywords
This publication has 46 references indexed in Scilit:
- Metabolism controls dimerization of the chloroplast FoF1ATP synthase inChlamydomonas reinhardtiiFEBS Letters, 2007
- Cyclic electron flow in C3 plantsBiochimica et Biophysica Acta (BBA) - Bioenergetics, 2006
- Is PsbS the site of non-photochemical quenching in photosynthesis?Journal of Experimental Botany, 2004
- Dimeric H+-ATP synthase in the chloroplast of Chlamydomonas reinhardtiiBiochimica et Biophysica Acta (BBA) - Bioenergetics, 2004
- Dynamic flexibility in the light reactions of photosynthesis governed by both electron and proton transfer reactionsTrends in Plant Science, 2004
- Post-translational regulation of nitrate reductase activity: a role for Ca2+ and 14-3-3 proteinsTrends in Plant Science, 1996
- The rate of ATP‐synthesis as a function of ΔpH and Δψ catalyzed by the active, reduced H+‐ATPase from chloroplastsFEBS Letters, 1991
- Control of the light‐harvesting function of chloroplast membranes by aggregation of the LHCII chlorophyll—protein complexFEBS Letters, 1991
- Activation of the chloroplast ATPase measured by the electrochromic change in leaves of intact plantsBiochimica et Biophysica Acta (BBA) - Bioenergetics, 1989
- Observations on the cytoplasmic and vacuolar orthophosphate pools in leaf tissues using in vivo 31P‐NMR spectroscopyFEBS Letters, 1989