scholarly journals Photosynthetic signalling during high light stress and recovery: targets and dynamics

2020 ◽  
Vol 375 (1801) ◽  
pp. 20190406 ◽  
Author(s):  
Peter J. Gollan ◽  
Eva-Mari Aro
Keyword(s):  
Gene Expression ◽  
Electron Transport ◽  
Redox Homeostasis ◽  
Light Stress ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
High Light ◽  
Abiotic Stress Response ◽  
High Light Stress ◽  
Retrograde Signalling

The photosynthetic apparatus is one of the major primary sensors of the plant's external environment. Changes in environmental conditions affect the balance between harvested light energy and the capacity to deal with excited electrons in the stroma, which alters the redox homeostasis of the photosynthetic electron transport chain. Disturbances to redox balance activate photosynthetic regulation mechanisms and trigger signalling cascades that can modify the transcription of nuclear genes. H 2 O 2 and oxylipins have been identified as especially prominent regulators of gene expression in response to excess light stress. This paper explores the hypothesis that photosynthetic imbalance triggers specific signals that target discrete gene profiles and biological processes. Analysis of the major retrograde signalling pathways engaged during high light stress and recovery demonstrates both specificity and overlap in gene targets. This work reveals distinct, time-resolved profiles of gene expression that suggest a regulatory interaction between rapidly activated abiotic stress response and induction of secondary metabolism and detoxification processes during recovery. The findings of this study show that photosynthetic electron transport provides a finely tuned sensor for detecting and responding to the environment through chloroplast retrograde signalling. This article is part of the theme issue ‘Retrograde signalling from endosymbiotic organelles’

Effect of High Light and High Light Stress on Composition, Function and Structure of the Photosynthetic Apparatus

1983 ◽  
pp. 353-370 ◽  
Author(s):  
H. K. Lichtenthaler ◽  
R. Burgstahler ◽  
C. Buschmann ◽  
D. Meier ◽  
U. Prenzel ◽  
...  
Keyword(s):  
Light Stress ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
High Light Stress

Strategies of light energy utilisation, dissipation and attenuation in sixco-occurring alpine heath species in Tasmania

2003 ◽  
Vol 30 (12) ◽  
pp. 1205 ◽  
Author(s):  
Erica L. Williams ◽  
Mark J. Hovenden ◽  
Dugald C. Close
Keyword(s):  
Light Stress ◽  
Photosynthetic Apparatus ◽  
Distinct Species ◽  
High Light ◽  
Light Energy ◽  
Shrub Species ◽  
High Light Stress ◽  
Thermal Energy Dissipation ◽  
Alpine Shrub ◽  
Cycle Dependent

Alpine environments are characterised by low temperatures and high light intensities. This combination leads to high light stress owing to the imbalance between light energy harvesting and its use in photochemistry. In extreme cases, high light stress can lead to the level of photo-oxidative damage exceeding the rate of repair to the photosynthetic apparatus. Plant species may vary in the mechanisms they use to prevent photodamage, but most comparisons are of geographically and ecologically distinct species. Differences in leaf colouration suggested that photoprotective strategies might differ among Tasmanian evergreen alpine shrub species. We compared chlorophyll fluorescence and leaf pigment composition in six co-occurring alpine shrub species on the summit of Mt Wellington, southern Tasmania, Australia, during spring and autumn. We found marked differences among species in light energy utilisation, attenuation and dissipation. Ozothamnus ledifolius maintained a large capacity for photosynthetic light utilisation and thus, had a low requirement for light dissipation. All five of the other species relied on xanthophyll-cycle-dependent thermal energy dissipation. In addition Epacris serpyllifolia, Richea sprengelioides and Leptospermum rupestre had foliar anthocyanins that would attenuate photosynthetically active light in the leaf. During spring, all species retained de-epoxidised xanthophylls through the night and the pre-dawn concentration of antheraxanthin and zeaxanthin was significantly correlated with reductions in pre-dawn Fv / Fm. We propose that these species use three photoprotective strategies to cope with the combination of high light and low temperature.

scholarly journals The Mitochondrial Respiratory Chain Maintains the Photosynthetic Electron Flow in Arabidopsis thaliana Leaves under High-Light Stress

2019 ◽  
Vol 61 (2) ◽  
pp. 283-295 ◽  
Author(s):  
Shoya Yamada ◽  
Hiroshi Ozaki ◽  
Ko Noguchi
Keyword(s):  
Arabidopsis Thaliana ◽  
Electron Transport ◽  
Respiratory Chain ◽  
Rate Constants ◽  
Electron Flow ◽  
Light Stress ◽  
Photosynthetic Electron Transport ◽  
Mitochondrial Respiratory Chain ◽  
High Light ◽  
Complex Iii

Abstract The plant respiratory chain includes the ATP-coupling cytochrome pathway (CP) and ATP-uncoupling alternative oxidase (AOX). Under high-light (HL) conditions, plants experience photoinhibition, leading to a damaged photosystem II (PSII). The respiratory chain is considered to affect PSII maintenance and photosynthetic electron transport under HL conditions. However, the underlying details remain unclear. In this study, we investigated the respiratory chain functions related to PSII maintenance and photosynthetic electron transport in plants exposed to HL stress. We measured the HL-induced decrease in the maximum quantum yield of PSII in the leaves of wild-type and AOX1a-knockout (aox1a) Arabidopsis thaliana plants in which CP was partially inhibited by a complex-III inhibitor. We also calculated PSII photodamage and repair rate constants. Both rate constants changed when CP was partially inhibited in aox1a plants, suggesting that the respiratory chain is related to both processes. Before HL stress, photosynthetic linear electron flow (LEF) decreased when CP was partially inhibited. After HL stress, aox1a in the presence of the CP inhibitor showed significantly decreased rates of LEF. The electron flow downstream from PSII and on the donor side of photosystem I may have been suppressed. The function of respiratory chain is required to maintain the optimal LEF as well as PSII maintenance especially under the HL stress.

scholarly journals Alterations in leaf photosynthetic electron transport in Welsh onion (Allium fistulosum L.) under different light intensity and soil water conditions

2019 ◽  
Author(s):  
Xuena Liu ◽  
Song Gao ◽  
Ying Liu ◽  
Kun Xu
Keyword(s):  
Drought Stress ◽  
Electron Transport ◽  
Light Stress ◽  
Photosynthetic Electron Transport ◽  
High Light ◽  
Stress Factors ◽  
Welsh Onion ◽  
Drought Treatment ◽  
Ojip Transient ◽  
Strong Light

Abstract Background: Welsh onions are often affected by stressful environments, such as high light and drought, during summer cultivation, which hinders their growth. To date, few studies have focused on leaf photosynthesis of Welsh onions during summer. We used carbon dioxide assimilation and OJIP transient and MR curves to analyze the photosynthetic characteristics of Welsh onions. Results: The results showed that strong light and drought could lead to a decrease in leaf pigment content. Simple high light stress caused a decrease in the net photosynthetic rate through stomatal limitation, while the simple drought treatment and the two stress factors combined caused a nonstomatal limitation. PSII energy distribution indicated that strong light and drought stress reduced the photochemical quantum efficiency of PSII. OJIP curve analysis showed that FO and FJ were increased, Fm was decreased, and a distinct K-phase was induced. In addition, OJIP parameters, including RC/CSO, TRO/ABS, ETO/TRO, and PIABS, were significantly reduced. MR analysis showed that strong light and drought stress blocked MR transients, leading to a gradual decrease in VPSI and VPSII-PSI. Conclusions: In general, the photosynthesis of Welsh onion was inhibited by high light and drought, which destroyed the receptor and donor side of PSII and reduced the electron transport capacity of PSII and PSI.

scholarly journals Interaction between photosynthetic electron transport and chloroplast sinks triggers protection and signalling important for plant productivity

2017 ◽  
Vol 372 (1730) ◽  
pp. 20160390 ◽  
Author(s):  
Peter J. Gollan ◽  
Yugo Lima-Melo ◽  
Arjun Tiwari ◽  
Mikko Tikkanen ◽  
Eva-Mari Aro
Keyword(s):  
Electron Transport ◽  
Carbon Fixation ◽  
Light Stress ◽  
Nuclear Gene ◽  
Photosynthetic Electron Transport ◽  
High Light ◽  
Crop Plants ◽  
Starch Accumulation ◽  
Nuclear Gene Expression ◽  
Photosynthetic Regulation

The photosynthetic light reactions provide energy that is consumed and stored in electron sinks, the products of photosynthesis. A balance between light reactions and electron consumption in the chloroplast is vital for plants, and is protected by several photosynthetic regulation mechanisms. Photosystem I (PSI) is particularly susceptible to photoinhibition when these factors become unbalanced, which can occur in low temperatures or in high light. In this study we used the pgr5 Arabidopsis mutant that lacks ΔpH-dependent regulation of photosynthetic electron transport as a model to study the consequences of PSI photoinhibition under high light. We found that PSI damage severely inhibits carbon fixation and starch accumulation, and attenuates enzymatic oxylipin synthesis and chloroplast regulation of nuclear gene expression after high light stress. This work shows that modifications to regulation of photosynthetic light reactions, which may be designed to improve yield in crop plants, can negatively impact metabolism and signalling, and thereby threaten plant growth and stress tolerance. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’.

scholarly journals Papain-like cysteine proteases are required for the regulation of photosynthetic gene expression and acclimation to high light stress

2021 ◽  
Vol 72 (9) ◽  
pp. 3441-3454
Author(s):  
Sarah Alomrani ◽  
Karl J Kunert ◽  
Christine H Foyer
Keyword(s):  
Gene Expression ◽  
Large Subunit ◽  
Light Stress ◽  
D1 Protein ◽  
Carbon Assimilation ◽  
Cysteine Proteases ◽  
High Light ◽  
High Light Stress ◽  
Photosynthetic Gene ◽  
Transgenic Lines

AbstractChloroplasts are considered to be devoid of cysteine proteases. Using transgenic Arabidopsis lines expressing the rice cystatin, oryzacystatin I (OC-I), in the chloroplasts (PC lines) or cytosol (CYS lines), we explored the hypothesis that cysteine proteases regulate photosynthesis. The CYS and PC lines flowered later than the wild type (WT) and accumulated more biomass after flowering. In contrast to the PC rosettes, which accumulated more leaf chlorophyll and carotenoid pigments than the WT, the CYS lines had lower amounts of leaf pigments. High-light-dependent decreases in photosynthetic carbon assimilation and the abundance of the Rubisco large subunit protein, the D1 protein, and the phosphorylated form of D1 proteins were attenuated in the CYS lines and reversed in the PC lines relative to the WT. However, the transgenic lines had higher amounts of LHC, rbcs, pasbA, and pasbD transcripts than the WT, and also showed modified chloroplast to nucleus signalling. We conclude that cysteine proteases accelerate the reconfiguration of the chloroplast proteome after flowering and in response to high-light stress. Inhibition of cysteine proteases, such as AtCEP1, slows chloroplast protein degradation and stimulates photosynthetic gene expression and chloroplast to nucleus signalling, enhancing stress tolerance traits.

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