The Physiological Functionality of PGR5/PGRL1-Dependent Cyclic Electron Transport in Sustaining Photosynthesis

Ma, Mingzhu; Liu, Yifei; Bai, Chen; Yang, Yunhong; Sun, Zhenqiu; Zhang, Siwei; Han, Xianpei; Yong, Jean Wan Hong

doi:10.3389/fpls.2021.702196

Cited by 34 publications

(32 citation statements)

References 109 publications

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“…P700 redox was hardly changing, presumably, because its reduction and oxidation were, without the major CET pathway, balanced. Mingzhu Ma et al 80 noted that the PSI remains fully reduced under high light in the pgr5 mutant and our data suggest that this may remain valid even when the light oscillates.…”

Section: Light Modulationsupporting

confidence: 75%

Plants cope with fluctuating light by frequency-dependent non-photochemical quenching and cyclic electron transport

Niu

Lazár

Holzwarth

et al. 2022

Preprint

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Plants are often exposed in nature to light fluctuations with characteristic periods of several seconds to minutes. Photosynthetically active irradiance fluctuates typically in the range of several hundreds of micromol(photons).m-2.s-1. The photosynthetic regulatory networks that are necessary for minimizing damage by the dynamic load between redox reactions in fluctuating light are poorly understood. Arbitrary light fluctuations can be represented by a sum of harmonic oscillations and, to resolve the elemental components of any complex light patterns, we aimed at characterizing photosynthetic reactions in light that oscillated as an elemental sinus function. Chlorophyll fluorescence yield and optical transmission proxies of P700, plastocyanin, and ferredoxin were measured in Arabidopsis thaliana under oscillating light of various frequencies and amplitudes. The role of non-photochemical quenching (NPQ) and of cyclic electron transport around Photosystem I (CET) was studied by comparing the dynamics in wild-type plants with mutants that were deficient in NPQ (npq1 and npq4) or CET (crr2-2 and pgrl1ab). The study revealed a highly contrasting response in the mutants compared to wild type documenting relevance of non-photochemical quenching and cyclic electron transport for the functioning of plants in a dynamic light environment. The mutants deficient in the non-photochemical quenching constituents exhibited forced oscillations of much higher amplitude than those found in the wild types. The contrast was used to identify the range of frequencies (f < 1/60s) in which the non-photochemical quenching was highly effective. The frequency-domain analysis revealed complex resonance behaviors with the 1/30 s-1 and 1/60 s-1 frequencies that were absent in the npq4 mutant and reduced in the npq1 mutant. This contrast suggests an anomalous dynamic behavior of thylakoid acidification and PsbS-dependent feedback downregulation of Photosystem II light-harvesting at these frequencies. The mutants incapacitated in the cyclic electron transport exhibited a distinct dynamic response. The crr2-2 mutant lacks the activity of photosynthetic NADH dehydrogenase-like complex and typically exhibits wild-type-like induction during a dark-light transition and differs in the light-to-dark relaxation in the time domain. It showed a distinct dynamic signature in oscillating light that involved both rising and declining light phases. The pgrl1ab mutant exhibited a contrasting anomalous response to oscillating light, particularly in the redox reactions involving plastocyanin, P700, and ferredoxin. These findings thus suggest a crucial role of cyclic electron transport in the dynamic properties and regulation of the plants in fluctuating irradiance. The finding of contrasting frequency-dependent modes may explain the existence of multiple, seemingly redundant regulatory mechanisms, each presumably protecting the plant in a different frequency range. The study moreover documented that the harmonically oscillating light can serve, in addition to identifying the photosynthetic dynamics in natural fluctuating light, for revealing unique dynamic features in mutants, and, likely, for sensing plant stress. Furthermore, the sensing by harmonic forcing does not require dark-acclimation and may, thus, conveniently monitor the status of photosynthesis of plants in phenotyping platforms, in greenhouses, and in-field.

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Section: Light Modulationsupporting

confidence: 75%

Plants cope with fluctuating light by frequency-dependent non-photochemical quenching and cyclic electron transport

Niu

Lazár

Holzwarth

et al. 2022

Preprint

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“…In addition to NPQ, several alternative electron transfer (AET) routes become active in response to stress in order to prevent the LET chain from overreduction. To maintain an optimal ATP/NADPH ratio for metabolic processes under such conditions, electrons are rerouted from Fd back to the PQ pool potentially via the Proton Gradient Regulation 5 (PGR5)/PGR5‐like photosynthetic phenotype 1 (PGRL1) complex or the NADH dehydrogenase‐like (NDH) complex, thus driving cyclic electron transfer (CET) around PSI and sustaining ATP synthesis (Ma et al, 2021). The membrane‐embedded NDH‐1 complex not only reduces the PQ pool for CET with electrons deriving from NADPH via FNR and Fd (Mulo and Medina, 2017) but also transfers protons into the thylakoid lumen for activation of the ATP synthase (Peltier et al, 2016).…”

Section: The “Solar Panels” Of the Plant Cell—the Light Reactions Of ...mentioning

confidence: 99%

Here comes the sun: How optimization of photosynthetic light reactions can boost crop yields

Walter

Kromdijk

2022

JIPB

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“…Studies have demonstrated the importance of the cyclic electron transport (CET)-dependent proton motive force (pmf) under low light for ATP synthesis ( Walker et al, 2014 ). PGR5/PGRL1 and NDH can mediate CET processes in low light and facilitate CO 2 assimilation by supplying additional ATP ( Ma et al, 2021 ). Studies have also indicated that the PsbQ protein is required for photoautotrophic growth under low-light conditions ( Yi et al, 2006 ).…”

Section: Discussionmentioning

confidence: 99%

Comprehensive Effects of Flowering Locus T-Mediated Stem Growth in Tobacco

et al. 2022

Front. Plant Sci.

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In flowering plants, Flowering locus T (FT) encodes a major florigen. It is a key flowering hormone in controlling flowering time and has a wide range of effects on plant development. Although the mechanism by which FT promotes flowering is currently clearly understood, comprehensive effects of the FT gene on plant growth have not been evaluated. Therefore, the effects of FT on vegetative growth need to be explored for a complete understanding of the molecular functions of the FT gene. In this study, the Jatropha curcas L. FT gene was overexpressed in tobacco (JcFTOE) in order to discover multiple aspects and related mechanisms of how the FT gene affects plant development. In JcFTOE plants, root, stem, and leaf development was strongly affected. Stem tissues were selected for further transcriptome analysis. In JcFTOE plants, stem growth was affected because of changes in the nucleus, cytoplasm, and cell wall. In the nucleus of JcFTOE plants, the primary effect was to weaken all aspects of DNA replication, which ultimately affected the cell cycle and cell division. The number of stem cells decreased significantly in JcFTOE plants, which decreased the thickness and height of tobacco stems. In the cell wall of JcFTOE plants, hemicellulose and cellulose contents increased, with the increase in hemicellulose associated with up-regulation of xylan synthase-related genes expression. In the cytoplasm of JcFTOE plants, the primary effects were on biogenesis of ribonucleoprotein complexes, photosynthesis, carbohydrate biosynthesis, and the cytoskeleton. In addition, in the cytoplasm of JcFTOE plants, there were changes in certain factors of the core oscillator, expression of many light-harvesting chlorophyll a/b binding proteins was down-regulated, and expression of fructose 1,6-bisphosphatase genes was up-regulated to increase starch content in tobacco stems. Changes in the xylem and phloem of JcFTOE plants were also identified, and in particular, xylem development was affected by significant increases in expression of irregular xylem genes.

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The Physiological Functionality of PGR5/PGRL1-Dependent Cyclic Electron Transport in Sustaining Photosynthesis

Cited by 34 publications

References 109 publications

Plants cope with fluctuating light by frequency-dependent non-photochemical quenching and cyclic electron transport

Plants cope with fluctuating light by frequency-dependent non-photochemical quenching and cyclic electron transport

Here comes the sun: How optimization of photosynthetic light reactions can boost crop yields

Comprehensive Effects of Flowering Locus T-Mediated Stem Growth in Tobacco

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