scholarly journals NTRC Effects on Non-Photochemical Quenching Depends on PGR5

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 900
Author(s):  
Belen Naranjo ◽  
Jan-Ferdinand Penzler ◽  
Thilo Rühle ◽  
Dario Leister
Keyword(s):  
Steady State ◽  
Electron Flow ◽  
Thioredoxin Reductase ◽  
Energy Utilization ◽  
Photochemical Quenching ◽  
Additive Effects ◽  
Light Conditions ◽  
Fluctuating Light ◽  
Non Photochemical Quenching ◽  
Transient And Steady State

Non-photochemical quenching (NPQ) protects plants from the detrimental effects of excess light. NPQ is rapidly induced by the trans-thylakoid proton gradient during photosynthesis, which in turn requires PGR5/PGRL1-dependent cyclic electron flow (CEF). Thus, Arabidopsis thaliana plants lacking either protein cannot induce transient NPQ and die under fluctuating light conditions. Conversely, the NADPH-dependent thioredoxin reductase C (NTRC) is required for efficient energy utilization and plant growth, and in its absence, transient and steady-state NPQ is drastically increased. How NTRC influences NPQ and functionally interacts with CEF is unclear. Therefore, we generated the A. thaliana line pgr5 ntrc, and found that the inactivation of PGR5 suppresses the high transient and steady-state NPQ and impaired growth phenotypes observed in the ntrc mutant under short-day conditions. This implies that NTRC negatively influences PGR5 activity and, accordingly, the lack of NTRC is associated with decreased levels of PGR5, possibly pointing to a mechanism to restrict upregulation of PGR5 activity in the absence of NTRC. When exposed to high light intensities, pgr5 ntrc plants display extremely impaired photosynthesis and growth, indicating additive effects of lack of both proteins. Taken together, these findings suggest that the interplay between NTRC and PGR5 is relevant for photoprotection and that NTRC might regulate PGR5 activity.

Light Absorption and Partitioning in Response to Nitrogen in Apple Leaves

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 541a-541
Author(s):  
Lailiang Cheng ◽  
Leslie H. Fuchigami ◽  
Patrick J. Breen
Keyword(s):  
High Light ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Light Conditions ◽  
Psii Efficiency ◽  
Fluorescence Measurements ◽  
Free Radical Formation ◽  
Highly Correlated ◽  
Non Photochemical Quenching ◽  
Leaf N

Bench-grafted Fuji/M26 apple trees were fertigated with different concentrations of nitrogen by using a modified Hoagland solution for 6 weeks, resulting in a range of leaf N from 1.0 to 4.3 g·m–2. Over this range, leaf absorptance increased curvilinearly from 75% to 92.5%. Under high light conditions (1500 (mol·m–2·s–1), the amount of absorbed light in excess of that required to saturate CO2 assimilation decreased with increasing leaf N. Chlorophyll fluorescence measurements revealed that the maximum photosystem II (PSII) efficiency of dark-adapted leaves was relatively constant over the leaf N range except for a slight drop at the lower end. As leaf N increased, non-photochemical quenching under high light declined and there was a corresponding increase in the efficiency with which the absorbed photons were delivered to open PSII centers. Photochemical quenching coefficient decreased significantly at the lower end of the leaf N range. Actual PSII efficiency increased curvilinearly with increasing leaf N, and was highly correlated with light-saturated CO2 assimilation. The fraction of absorbed light potentially used for free radical formation was estimated to be about 10% regardless of the leaf N status. It was concluded that increased thermal dissipation protected leaves from photo-oxidation as leaf N declined.

The effect of fluctuating light on canopy photosynthesis: a focus on a chlorophyll-deficient Soybean mutant

2021 ◽  
Author(s):  
Nicole Salvatori
Keyword(s):  
Steady State ◽  
Dynamic Environment ◽  
Regulatory System ◽  
Total Carbon ◽  
Light Transmittance ◽  
Photochemical Quenching ◽  
Natural Environments ◽  
Deficient Mutant ◽  
Light Conditions ◽  
Variable Light

<p>In natural environments plants are subjected to variable light conditions and therefore need an efficient regulatory system to regulate photosynthesis and the downstream metabolism. Most of the measurements available are taken at steady state and at leaf level but those may overestimate total carbon uptake in a more dynamic environment. Furthermore, some plants may be more adapted than others to deal with light fluctuations and therefore is difficult to draw general conclusions. We then grew a commercial soybean variety and a chlorophyll deficient mutant in a recently developed growth chamber system (DYNAMISM) which allowed to obtain instantaneous gas exchange data at canopy level for several weeks. By doing so we could investigate both short term responses and long term adaptations to light dynamic conditions of the two varieties. At steady state, chlorophyll deficient crops are thought to have a similar or even a higher photosynthetic rate compared to the green wildtypes, enhanced by a higher light transmittance throughout the canopy. But little is known about how they respond to fluctuations in light. The two varieties were grown either in fluctuating (F) or non-fluctuating (NF) light conditions to evaluate how variable light would affect biomass accumulation. Two different light treatments were applied, low light (LL) and high light (HL) with different light intensities and amplitude of fluctuations. The LL treatment did not entail any difference among F and NF in both varieties. The chlorophyll-deficient mutant was instead found to be susceptible to the fluctuations of light in the HL treatment, by accumulating less biomass. It is hypothesised that this might be due to its longer non‐photochemical quenching relaxation time  in light transitions, but other acclimatation mechanisms need to be investigated.</p>

scholarly journals Growth under Fluctuating Light Reveals Large Trait Variation in a Panel of Arabidopsis Accessions

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 316 ◽  
Author(s):  
Elias Kaiser ◽  
Dirk Walther ◽  
Ute Armbruster
Keyword(s):  
Photosystem Ii ◽  
Chemical Potential ◽  
Genomic Variation ◽  
Operating Efficiency ◽  
Photochemical Quenching ◽  
Low Light ◽  
Trait Variation ◽  
Light Regimes ◽  
Fluctuating Light ◽  
Non Photochemical Quenching

The capacity of photoautotrophs to fix carbon depends on the efficiency of the conversion of light energy into chemical potential by photosynthesis. In nature, light input into photosynthesis can change very rapidly and dramatically. To analyze how genetic variation in Arabidopsis thaliana affects photosynthesis and growth under dynamic light conditions, 36 randomly chosen natural accessions were grown under uniform and fluctuating light intensities. After 14 days of growth under uniform or fluctuating light regimes, maximum photosystem II quantum efficiency (Fv/Fm) was determined, photosystem II operating efficiency (ΦPSII) and non-photochemical quenching (NPQ) were measured in low light, and projected leaf area (PLA) as well as the number of visible leaves were estimated. Our data show that ΦPSII and PLA were decreased and NPQ was increased, while Fv/Fm and number of visible leaves were unaffected, in most accessions grown under fluctuating compared to uniform light. There were large changes between accessions for most of these parameters, which, however, were not correlated with genomic variation. Fast growing accessions under uniform light showed the largest growth reductions under fluctuating light, which correlated strongly with a reduction in ΦPSII, suggesting that, under fluctuating light, photosynthesis controls growth and not vice versa.

scholarly journals Photosynthesis Regulation in Response to Fluctuating Light in the Secondary Endosymbiont Alga Nannochloropsis gaditana

2019 ◽  
Vol 61 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Alessandra Bellan ◽  
Francesca Bucci ◽  
Giorgio Perin ◽  
Alessandro Alboresi ◽  
Tomas Morosinotto
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Incident Light ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Nannochloropsis Gaditana ◽  
Fluctuating Light ◽  
Light Fluctuations

Abstract In nature, photosynthetic organisms are exposed to highly dynamic environmental conditions where the excitation energy and electron flow in the photosynthetic apparatus need to be continuously modulated. Fluctuations in incident light are particularly challenging because they drive oversaturation of photosynthesis with consequent oxidative stress and photoinhibition. Plants and algae have evolved several mechanisms to modulate their photosynthetic machinery to cope with light dynamics, such as thermal dissipation of excited chlorophyll states (non-photochemical quenching, NPQ) and regulation of electron transport. The regulatory mechanisms involved in the response to light dynamics have adapted during evolution, and exploring biodiversity is a valuable strategy for expanding our understanding of their biological roles. In this work, we investigated the response to fluctuating light in Nannochloropsis gaditana, a eukaryotic microalga of the phylum Heterokonta originating from a secondary endosymbiotic event. Nannochloropsis gaditana is negatively affected by light fluctuations, leading to large reductions in growth and photosynthetic electron transport. Exposure to light fluctuations specifically damages photosystem I, likely because of the ineffective regulation of electron transport in this species. The role of NPQ, also assessed using a mutant strain specifically depleted of this response, was instead found to be minor, especially in responding to the fastest light fluctuations.

Orange Carotenoid Protein (OCP): A Key Player in Non-photochemical Quenching of Cyanobacteria under Fluctuating Light Condition

2018 ◽  
Vol 4 (02) ◽  
pp. 35-40
Author(s):  
Yogesh Mishra ◽  
Akanksha Srivastava ◽  
Atul Tiwari ◽  
Raju Mondal ◽  
Sandhya Yadav ◽  
...  
Keyword(s):  
Active Form ◽  
Light Condition ◽  
High Irradiance ◽  
Water Soluble ◽  
Photochemical Quenching ◽  
Protective Mechanism ◽  
Terminal Domain ◽  
Fluctuating Light ◽  
Orange Carotenoid Protein ◽  
Non Photochemical Quenching

Fluctuating light condition poses major threat to photosynthetic organisms by evoking the production of reactive oxygen species (ROS). To endure the high irradiance level, plants and algae have evolved a photo-protective mechanism, referred as non-photochemical quenching (NPQ). This mechanism concerns with minimizing arrival of the excess excitation energy on reaction centers by dissipating surplus energy in form of harmless heat. Earlier cyanobacteria were not considered to capable of performing NPQ. Alternatively, state transition was supposed to be the major means that cyanobacteria preferably carried out to be protected under high light. Recently it was substantiated with evidence that these organisms can execute NPQ as a prominent photo-protective strategy. NPQ in cyanobacteria is mediated by a water soluble orange carotenoid protein (OCP) which is structurally and functionally modular. OCP consists of two domains (i) N-terminal domain (NTD) and (ii) C-terminal domain (CTD) with a single carotenoid as a chromophore spanning symmetrically in both domains. Blue-green or strong white light induces conversion of OCP from an inactive orange state (OCPO) to active red state (OCPR). Active form of OCP (OCPR) binds to core of light harvesting antenna complex, phycobilisome (PBS), where it quenches fluorescence and assists in dissipation of excess energy by non-radiative pathway. Prior to prevent wasteful quenching of fluorescence under light starvation, another protein named fluorescence recovery protein (FRP) partakes in decoupling OCPR from PBS and accelerates conversion of OCPR state back to OCPO state.

Cold-induced photoinhibition and foliar pigment dynamics of Eucalyptus nitens seedlings during establishment

2001 ◽  
Vol 28 (11) ◽  
pp. 1133 ◽  
Author(s):  
Dugald C. Close ◽  
Chris L. Beadle ◽  
Mark J. Hovenden
Keyword(s):  
Chlorophyll Fluorescence ◽  
Protein Complexes ◽  
Photochemical Quenching ◽  
Eucalyptus Nitens ◽  
Light Conditions ◽  
National Academy Of Sciences ◽  
Experimental Site ◽  
Chlorophyll Fluorescence Parameters ◽  
Non Photochemical Quenching ◽  
Academy Of Sciences

The effects of cold-induced photoinhibition on chlorophyll and carotenoid dynamics and xanthophyll cycling in Eucalyptus nitens (Deane and Maiden) Maiden were assessed between planting and 32 weeks after planting. The seedlings were fertilised or nutrient-deprived (non-fertilised) before planting and shaded or not shaded after planting. The experimental site was 700 m a.s.l., which is considered marginal for establishment of E. nitens plantations in Tasmania due to low mean annual minimum temperatures. Low temperature–high light conditions caused a reduction in variable to maximal chlorophyll fluorescence ratio (F v /F m ), which was more pronounced in non-fertilised than in fertilised seedlings. Shadecloth shelters alleviated this depression. Except in shaded fertilised seedlings, F v /F m did not recover to the level before planting until after 20 weeks. Total chlorophyll content was initially reduced in shaded treatments but subsequently increased with increasing temperatures and F v /F m. Total xanthophyll content and xanthophylls per unit chlorophyll remained relatively constant in fertilised seedlings but decreased in non-fertilised seedlings within 2 weeks after planting. Total xanthophyll and xanthophylls per unit chlorophyll subsequently recovered in non-shaded, non-fertilised seedlings with increasing temperatures and F v /F m. Diurnal [yield and non-photochemical quenching (NPQ) and seasonal (F v /F m) variation in chlorophyll fluorescence parameters were not reflected in xanthophyll cycling during the period of most severe photoinhibition. This result may indicate that chlorophyll–xanthophylls protein complexes form in winter-acclimated E. nitens foliage as have been demonstrated to occur in Eucalyptus pauciflora Sieb. ex Spreng. (Gilmore and Ball 2000, Proceedings of the National Academy of Sciences USA 97, 11098–11101).

scholarly journals FLUCTUATING-LIGHT-ACCLIMATION PROTEIN1, Conserved in Oxygenic Phototrophs, Regulates H+ Homeostasis and Non-Photochemical Quenching in Chloroplasts

2017 ◽  
Vol 58 (10) ◽  
pp. 1622-1630 ◽  
Author(s):  
Ryoichi Sato ◽  
Masaru Kono ◽  
Kyohei Harada ◽  
Hiroyuki Ohta ◽  
Shinichi Takaichi ◽  
...  
Keyword(s):  
Light Acclimation ◽  
Photochemical Quenching ◽  
Fluctuating Light ◽  
Non Photochemical Quenching ◽  
Oxygenic Phototrophs
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