Redox regulation of PGRL1 at the onset of low light intensity

Abstract

SUMMARY PGR5‐LIKE PHOTOSYNTHETIC PHENOTYPE1 (PGRL1) regulates photosystem I cyclic electron flow which transiently activates non‐photochemical quenching at the onset of light. Here, we show that a disulfide‐based mechanism of PGRL1 regulated this process in vivo at the onset of low light levels. We found that PGRL1 regulation depended on active formation of key regulatory disulfides in the dark, and that PGR5 was required for this activity. The disulfide state of PGRL1 was modulated in plants by counteracting reductive and oxidative components and reached a balanced state that depended on the light level. We propose that the redox regulation of PGRL1 fine‐tunes a timely activation of photosynthesis at the onset of low light.

Systematic monitoring of 2-Cys peroxiredoxin-derived redox signals unveiled its role in attenuating carbon assimilation rate

“…These results suggest that the availability of stromal NADPH governs the induction of photosynthetically-derived oxidative signals. The increasing recognition that oxidative signals play a dominant role in fine-tuning of metabolic activity under low-light conditions (Dangoor et al, 2012;Eliyahu et al, 2015;Vaseghi et al, 2018;Wolf et al, 2020) drove us to further investigate the sensitivity of the chl-roGFP2-PrxΔC R redox state to low-light intensity. To this end, plants were exposed to a gradual increase in light intensities, starting with ~22 µmol photons m −2 s −1 and increasing up to 330µmol photons m−2 s (Fig.…”

“…The increasing recognition that oxidative signals play a dominant role in fine-tuning of metabolic activity under low-light conditions (Dangoor et al, 2012;Eliyahu et al, 2015;Vaseghi et al, 2018;Wolf et al, 2020), drove us to further investigate the sensitivity of the chl-roGFP2-PrxΔCR redox state in the transition from dark to low light. To this end, we exposed dark-adapted chl-roGFP2-PrxΔCR and chl-roGFP2 plants to low light (~22 µmol photons m -2 s -1 ) for several hours.…”

Thiol Redox Regulation of Plant β-Carbonic Anhydrase

“…Another protein usage of the H + could occur in ATP synthesis and the CO 2 evades from the thylakoids as mentioned above. Redox regulation is well-established for processes in photosynthetic electron transport, e.g., thiol switching of F-ATP synthase to control photophosphorylation [53] and cyclic electron transport via disulfide reduction in proton gradient 5-like (PGR5-like) [54]. Therefore, redox regulation of CA may be another element in redox-dependent optimization of the photosynthetic performance in plants.…”

Dynamic Changes in Protein-Membrane Association for Regulating Photosynthetic Electron Transport

“…Furthermore, they reported the presence of PGRL1 together with FNR in high molecular weight fractions that did not contain PSI or Cyt b 6 f complex. In this context, it is interesting to mention that thioredoxin m forms a complex with PGRL1 [ 19 , 20 ], which itself contains redox-active cysteine residues [ 21 ]. The formation of a complex between reduced thioredoxin m and PGRL1 may inhibit cyclic electron flow by preventing the supercomplex formation required for cyclic flow.…”

“…The formation of a complex between reduced thioredoxin m and PGRL1 may inhibit cyclic electron flow by preventing the supercomplex formation required for cyclic flow. The work by Takahasi et al [ 18 ], and the reports on the interaction between thioredoxin m and PGRL1 [ 19 , 20 ], indicate that formation of supercomplexes in the stroma lamellae depends on the redox state of the plastoquinone pool, and on the general redox state of the chloroplast.…”