Complex Roles of PsbS and Xanthophylls in the Regulation of Nonphotochemical Quenching in Arabidopsis thaliana under Fluctuating Light

Photosynthetic organisms use various photoprotective mechanisms to dissipate excess photoexcitation as heat in a process called nonphotochemical quenching (NPQ). Regulation of NPQ allows for a rapid response to changes in light intensity and in vascular plants, is primarily triggered by a pH gradient across the thylakoid membrane (∆pH). The response is mediated by the PsbS protein and various xanthophylls. Time-correlated single-photon counting (TCSPC) measurements were performed on Arabidopsis thaliana to quantify the dependence of the response of NPQ to changes in light intensity on the presence and accumulation of zeaxanthin and lutein. Measurements were performed on WT and mutant plants deficient in one or both of the xanthophylls as well as a transgenic line that accumulates lutein via an engineered lutein epoxide cycle. Changes in the response of NPQ to light acclimation in WT and mutant plants were observed between two successive light acclimation cycles, suggesting that the character of the rapid and reversible response of NPQ in fully dark-acclimated plants is substantially different from in conditions plants are likely to experience caused by changes in light intensity during daylight. Mathematical models of the response of zeaxanthin- and lutein-dependent reversible NPQ were constructed that accurately describe the observed differences between the light acclimation periods. Finally, the WT response of NPQ was reconstructed from isolated components present in mutant plants with a single common scaling factor, which enabled deconvolution of the relative contributions of zeaxanthin- and lutein-dependent NPQ.

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Roles of the Cyclic Electron Flow Around PSI (CEF-PSI) and O2-Dependent Alternative Pathways in Regulation of the Photosynthetic Electron Flow in Short-Term Fluctuating Light in Arabidopsis thaliana

Plant and Cell Physiology ◽

10.1093/pcp/pcu033 ◽

2014 ◽

Vol 55 (5) ◽

pp. 990-1004 ◽

Cited By ~ 109

Author(s):

Masaru Kono ◽

Ko Noguchi ◽

Ichiro Terashima

Keyword(s):

Arabidopsis Thaliana ◽

Electron Flow ◽

Cyclic Electron Flow ◽

Short Term ◽

Alternative Pathways ◽

Photosynthetic Electron Flow ◽

Fluctuating Light

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The long-term response to fluctuating light quality is an important and distinct light acclimation mechanism that supports survival of Arabidopsis thaliana under low light conditions

Planta ◽

10.1007/s00425-008-0760-y ◽

2008 ◽

Vol 228 (4) ◽

pp. 573-587 ◽

Cited By ~ 47

Author(s):

Raik Wagner ◽

Lars Dietzel ◽

Katharina Bräutigam ◽

Wolfgang Fischer ◽

Thomas Pfannschmidt

Keyword(s):

Arabidopsis Thaliana ◽

Light Quality ◽

Light Acclimation ◽

Light Conditions ◽

Low Light ◽

Fluctuating Light ◽

Term Response

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Elevated CO2 Concentration Alters Photosynthetic Performances under Fluctuating Light in Arabidopsis thaliana

Cells ◽

10.3390/cells10092329 ◽

2021 ◽

Vol 10 (9) ◽

pp. 2329

Author(s):

Shun-Ling Tan ◽

Xing Huang ◽

Wei-Qi Li ◽

Shi-Bao Zhang ◽

Wei Huang

Keyword(s):

Arabidopsis Thaliana ◽

Elevated Co2 ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Photochemical Quenching ◽

Elevated Atmospheric Co2 ◽

Actinic Light ◽

Fluctuating Light ◽

Photosynthetic Performances ◽

Atmospheric Co2 Concentrations

In view of the current and expected future rise in atmospheric CO2 concentrations, we examined the effect of elevated CO2 on photoinhibition of photosystem I (PSI) under fluctuating light in Arabidopsis thaliana. At 400 ppm CO2, PSI showed a transient over-reduction within the first 30 s after transition from dark to actinic light. Under the same CO2 conditions, PSI was highly reduced after a transition from low to high light for 20 s. However, such PSI over-reduction greatly decreased when measured in 800 ppm CO2, indicating that elevated atmospheric CO2 facilitates the rapid oxidation of PSI under fluctuating light. Furthermore, after fluctuating light treatment, residual PSI activity was significantly higher in 800 ppm CO2 than in 400 ppm CO2, suggesting that elevated atmospheric CO2 mitigates PSI photoinhibition under fluctuating light. We further demonstrate that elevated CO2 does not affect PSI activity under fluctuating light via changes in non-photochemical quenching or cyclic electron transport, but rather from a rapid electron sink driven by CO2 fixation. Therefore, elevated CO2 mitigates PSI photoinhibition under fluctuating light at the acceptor rather than the donor side. Taken together, these observations indicate that elevated atmospheric CO2 can have large effects on thylakoid reactions under fluctuating light.

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The importance of chloroplast movement, nonphotochemical quenching, and electron transport rates in light acclimation and tolerance to high light in Arabidopsis thaliana

American Journal of Botany ◽

10.1002/ajb2.1378 ◽

2019 ◽

Vol 106 (11) ◽

pp. 1444-1453 ◽

Cited By ~ 4

Author(s):

Mia M. Howard ◽

Andrea Bae ◽

Martina Königer

Keyword(s):

Arabidopsis Thaliana ◽

Electron Transport ◽

Nonphotochemical Quenching ◽

High Light ◽

Light Acclimation ◽

Chloroplast Movement ◽

Electron Transport Rates

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The pathway of starch synthesis in Arabidopsis thaliana leaves

10.1101/2021.01.11.426159 ◽

2021 ◽

Cited By ~ 1

Author(s):

Maximilian M.F.F. Fünfgeld ◽

Wei Wang ◽

Hirofumi Ishihara ◽

Stéphanie Arrivault ◽

Regina Feil ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Sucrose Synthase ◽

Significant Contribution ◽

Starch Synthesis ◽

Classical Pathway ◽

Mesophyll Cells ◽

Fluctuating Light ◽

Leaf Sampling ◽

Transitory Starch ◽

Made In

AbstractMany plants accumulate transitory starch reserves in their leaves during the day to buffer their carbohydrate supply against fluctuating light conditions, and to provide carbon and energy for survival at night. It is universally accepted that transitory starch is synthesized from ADP-glucose (ADPG) in the chloroplasts. However, the consensus that ADPG is made in the chloroplasts by ADPG pyrophosphorylase has been challenged by a controversial proposal that ADPG is made primarily in the cytosol, probably by sucrose synthase (SUS), and then imported into the chloroplasts. To resolve this long-standing controversy, we critically re-examined the experimental evidence that appears to conflict with the consensus pathway. We show that when precautions are taken to avoid artefactual changes during leaf sampling, Arabidopsis thaliana mutants that lack SUS activity in mesophyll cells (quadruple sus1234) or have no SUS activity (sextuple sus123456) have wild-type levels of ADPG and starch, while ADPG is 20 times lower in the pgm and adg1 mutants that are blocked in the classical pathway of starch synthesis. We conclude that the ADPG needed for starch synthesis in leaves is synthesized primarily by ADPG pyrophosphorylase in the chloroplasts.Significance statementMutant analysis shows that sucrose synthase makes no significant contribution to transitory starch synthesis in Arabidopsis leaves, resolving a 20-year old controversy about one of the most important pathways of photosynthetic metabolism.

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Engineering the lutein epoxide cycle into Arabidopsis thaliana

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1704373114 ◽

2017 ◽

Vol 114 (33) ◽

pp. E7002-E7008 ◽

Cited By ~ 9

Author(s):

Lauriebeth Leonelli ◽

Matthew D. Brooks ◽

Krishna K. Niyogi

Keyword(s):

Arabidopsis Thaliana ◽

Photosystem Ii ◽

Plant Species ◽

Vascular Plants ◽

Photochemical Efficiency ◽

Nonphotochemical Quenching ◽

Reaction Centers ◽

Low Light ◽

Psii Efficiency ◽

Violaxanthin Deepoxidase

Although sunlight provides the energy necessary for plants to survive and grow, light can also damage reaction centers of photosystem II (PSII) and reduce photochemical efficiency. To prevent damage, plants possess photoprotective mechanisms that dissipate excess excitation. A subset of these mechanisms is collectively referred to as NPQ, or nonphotochemical quenching of chlorophyll a fluorescence. The regulation of NPQ is intrinsically linked to the cycling of xanthophylls that affects the kinetics and extent of the photoprotective response. The violaxanthin cycle (VAZ cycle) and the lutein epoxide cycle (LxL cycle) are two xanthophyll cycles found in vascular plants. The VAZ cycle has been studied extensively, owing in large part to its presence in model plant species where mutants are available to aid in its characterization. In contrast, the LxL cycle is not found in model plants, and its role in photosynthetic processes has been more difficult to define. To address this challenge, we introduced the LxL cycle into Arabidopsis thaliana and functionally isolated it from the VAZ cycle. Using these plant lines, we showed an increase in dark-acclimated PSII efficiency associated with Lx accumulation and demonstrated that violaxanthin deepoxidase is responsible for the light-driven deepoxidation of Lx. Conversion of Lx to L was reversible during periods of low light and occurred considerably faster than rates previously described in nonmodel species. Finally, we present clear evidence of the LxL cycle’s role in modulating a rapid component of NPQ that is necessary to prevent photoinhibition in excess light.

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