scholarly journals Chloroplast thioredoxin systems dynamically regulate photosynthesis in plants

2019 ◽  
Vol 476 (7) ◽  
pp. 1159-1172 ◽  
Author(s):  
Lauri Nikkanen ◽  
Eevi Rintamäki
Keyword(s):  
Photosynthetic Efficiency ◽  
Carbon Fixation ◽  
Current Knowledge ◽  
Light Energy ◽  
Crop Fields ◽  
Plant Chloroplast ◽  
Regulation Mechanisms ◽  
Controlled Environments ◽  
Photosynthetic Reactions ◽  
Light Energy Conversion

Abstract Photosynthesis is a highly regulated process in photoautotrophic cells. The main goal of the regulation is to keep the basic photosynthetic reactions, i.e. capturing light energy, conversion into chemical energy and production of carbohydrates, in balance. The rationale behind the evolution of strong regulation mechanisms is to keep photosynthesis functional under all conditions encountered by sessile plants during their lifetimes. The regulatory mechanisms may, however, also impair photosynthetic efficiency by overriding the photosynthetic reactions in controlled environments like crop fields or bioreactors, where light energy could be used for production of sugars instead of dissipation as heat and down-regulation of carbon fixation. The plant chloroplast has a high number of regulatory proteins called thioredoxins (TRX), which control the function of chloroplasts from biogenesis and assembly of chloroplast machinery to light and carbon fixation reactions as well as photoprotective mechanisms. Here, we review the current knowledge of regulation of photosynthesis by chloroplast TRXs and assess the prospect of improving plant photosynthetic efficiency by modification of chloroplast thioredoxin systems.

scholarly journals Modeling indicates degradation of mRNA and protein as a potential regulation mechanisms during cold acclimation

2021 ◽  
Author(s):  
Maria Krantz ◽  
Julia Legen ◽  
Yang Gao ◽  
Reimo Zoschke ◽  
Christian Schmitz-Linneweber ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Temperature Acclimation ◽  
Ode Model ◽  
Future Directions ◽  
Chloroplast Gene Expression ◽  
Temperature Changes ◽  
Regulation Mechanisms ◽  
Photosynthetic Complexes ◽  
Photosynthetic Reactions ◽  
Account Temperature

AbstractPlants are constantly exposed to temperature fluctuations, which have direct effects on all cellular reactions because temperature influences reaction likelihood and speed. Chloroplasts are crucial to temperature acclimation responses of plants, due to their photosynthetic reactions whose products play a central role in plant metabolism. Consequently, chloroplasts serve as sensors of temperature changes and are simultaneously major targets of temperature acclimation. The core subunits of the complexes involved in the light reactions of photosynthesis are encoded in the chloroplast. As a result, it is assumed that temperature acclimation in plants requires regulatory responses in chloroplast gene expression and protein turnover. We conducted western blot experiments to assess changes in the accumulation of two photosynthetic complexes (PSII, and Cytb6f complex) and the ATP synthase in tobacco plants over two days of acclimation to low temperature. Surprisingly, the concentration of proteins within the chloroplast varied negligibly compared to controls. To explain this observation, we used a simplified Ordinary Differential Equation (ODE) model of transcription, translation, mRNA degradation and protein degradation to explain how the protein concentration can be kept constant. This model takes into account temperature effects on these processes. Through simulations of the ODE model, we show that mRNA and protein degradation are possible targets for control during temperature acclimation. Our model provides a basis for future directions in research and the analysis of future results.

scholarly journals Photosynthetic efficiency and production of cowpea cultivars under deficit irrigation

2018 ◽  
Vol 13 (5) ◽  
pp. 1 ◽  
Author(s):  
Alberto Soares de Melo ◽  
Allisson Rafael Ferreira da Silva ◽  
Alexson Filgueiras Dutra ◽  
Wellison Filgueiras Dutra ◽  
Marcos Eric Barbosa Brito ◽  
...  
Keyword(s):  
Water Deficit ◽  
Deficit Irrigation ◽  
Photosynthetic Efficiency ◽  
Arid Regions ◽  
Carbon Fixation ◽  
Management Strategies ◽  
Carbon Assimilation ◽  
Green Beans ◽  
Gas Exchanges ◽  
Cowpea Cultivars

Cowpea is a crop with great economic, social and food importance in semi-arid regions, but its production is drastically reduced by the water deficit in these regions, requiring better management strategies that allow the crop’s production. This study therefore aimed to evaluate the photosynthetic efficiency and production of cowpea cultivars under deficit irrigation replacement levels. The experiment tested three cowpea genotypes (G1 = ‘BRS Aracé’, G2 = ‘BR 17 Gurguéia’ and G3 = ‘BRS Marataoã’) and four irrigation depths (40, 60, 80 and 100% of ETc), resulting in a 3 x 4 factorial scheme, arranged in randomized complete blocks design with four replicates. During the experiment, the gas exchanges, chlorophyll a fluorescence and production of the cowpea genotypes under deficit irrigation were evaluated. Carbon fixation in the photosynthetic metabolism of cowpea plants was reduced by accentuated water deficit, regardless of the genotype. The low stress severity was indicated by the lack of effects on chlorophyll fluorescence, indicating that the reduction in the rate of carbon assimilation was due to the stomatal effects. The irrigation with 80% of ETc can be used in the cultivation of the respective cultivars, but with small losses in the production. Among the genotypes, ‘BRS Marataoã’ stands out with respect to yield, with higher values for weight of pods and green beans.

Optimizing molecule-like gold clusters for light energy conversion

2016 ◽  
Vol 4 (6) ◽  
pp. 2075-2081 ◽  
Author(s):  
Kevin G. Stamplecoskie ◽  
Abigail Swint
Keyword(s):  
Excited State ◽  
Energy Conversion ◽  
Metal Clusters ◽  
Light Harvesting ◽  
Photovoltaic Performance ◽  
Gold Clusters ◽  
Light Energy ◽  
Light Energy Conversion

As light harvesting materials, Au18SR14 metal clusters are highlighted for their favourable excited-state properties leading to better photovoltaic performance.

Porphyrin-Based Molecular Architectures for Light Energy Conversion

2007 ◽  
Vol 471 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Taku Hasobe ◽  
Hideyuki Murata ◽  
Shunichi Fukuzumi ◽  
Prashant V. Kamat
Keyword(s):  
Energy Conversion ◽  
Light Energy ◽  
Molecular Architectures ◽  
Light Energy Conversion
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