scholarly journals 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

2014 ◽  
Vol 55 (5) ◽  
pp. 990-1004 ◽  
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

scholarly journals ATP compartmentation in plastids and cytosol ofArabidopsis thalianarevealed by fluorescent protein sensing

2018 ◽  
Vol 115 (45) ◽  
pp. E10778-E10787 ◽  
Author(s):  
Chia Pao Voon ◽  
Xiaoqian Guan ◽  
Yuzhe Sun ◽  
Abira Sahu ◽  
May Ngor Chan ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Fluorescent Protein ◽  
Higher Plants ◽  
Electron Flow ◽  
Cyclic Electron Flow ◽  
Linear Electron ◽  
Protein Sensing ◽  
Atp Production ◽  
Respiratory Inhibitors ◽  
Sensor Protein

Matching ATP:NADPH provision and consumption in the chloroplast is a prerequisite for efficient photosynthesis. In terms of ATP:NADPH ratio, the amount of ATP generated from the linear electron flow does not meet the demand of the Calvin–Benson–Bassham (CBB) cycle. Several different mechanisms to increase ATP availability have evolved, including cyclic electron flow in higher plants and the direct import of mitochondrial-derived ATP in diatoms. By imaging a fluorescent ATP sensor protein expressed in livingArabidopsis thalianaseedlings, we found that MgATP2−concentrations were lower in the stroma of mature chloroplasts than in the cytosol, and exogenous ATP was able to enter chloroplasts isolated from 4- and 5-day-old seedlings, but not chloroplasts isolated from 10- or 20-day-old photosynthetic tissues. This observation is in line with the previous finding that the expression of chloroplast nucleotide transporters (NTTs) inArabidopsismesophyll is limited to very young seedlings. Employing a combination of photosynthetic and respiratory inhibitors with compartment-specific imaging of ATP, we corroborate the dependency of stromal ATP production on mitochondrial dissipation of photosynthetic reductant. Our data suggest that, during illumination, the provision and consumption of ATP:NADPH in chloroplasts can be balanced by exporting excess reductants rather than importing ATP from the cytosol.

Abolition of photosystem I cyclic electron flow in Arabidopsis thaliana following thermal-stress

2011 ◽  
Vol 49 (3) ◽  
pp. 235-243 ◽  
Author(s):  
Jemâa Essemine ◽  
Sridharan Govindachary ◽  
Saïda Ammar ◽  
Sadok Bouzid ◽  
Robert Carpentier
Keyword(s):  
Arabidopsis Thaliana ◽  
Thermal Stress ◽  
Photosystem I ◽  
Electron Flow ◽  
Cyclic Electron Flow

scholarly journals Photosynthesis acclimation under severely fluctuating light conditions allows faster growth of diatoms compared with dinoflagellates

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lu Zhou ◽  
Songcui Wu ◽  
Wenhui Gu ◽  
Lijun Wang ◽  
Jing Wang ◽  
...  
Keyword(s):  
Red Tide ◽  
Skeletonema Costatum ◽  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
Specific Inhibitor ◽  
Dynamic Environments ◽  
Thalassiosira Pseudonana ◽  
Light Conditions ◽  
Photosynthetic Electron Flow ◽  
Fluctuating Light

Abstract Background Diatoms contribute 20% of the global primary production and are adaptable in dynamic environments. Diatoms always bloom earlier in the annual phytoplankton succession instead of dinoflagellates. However, how diatoms acclimate to a dynamic environment, especially under changing light conditions, remains unclear. Results We compared the growth and photosynthesis under fluctuating light conditions of red tide diatom Skeletonema costatum, red tide dinoflagellate Amphidinium carterae, Prorocentrum donghaiense, Karenia mikimotoi, model diatom Phaeodactylum tricornutum, Thalassiosira pseudonana and model dinoflagellate Dinophycae Symbiodinium. Diatoms grew faster and maintained a consistently higher level of photosynthesis. Diatoms were sensitive to the specific inhibitor of Proton Gradient Regulation 5 (PGR5) depending photosynthetic electron flow, which is a crucial mechanism to protect their photosynthetic apparatus under fluctuating light. In contrast, the dinoflagellates were not sensitive to this inhibitor. Therefore, we investigate how PGR5 functions under light fluctuations in the model diatom P. tricornutum by knocking down and overexpressing PGR5. Overexpression of PGR5 reduced the photosystem I acceptor side limitation (Y (NA)) and increased growth rate under severely fluctuating light in contrast to the knockdown of PGR5. Conclusion Diatoms acclimatize to fluctuating light conditions better than dinoflagellates. PGR5 in diatoms can regulate their photosynthetic electron flow and accelerate their growth under severe light fluctuation, supporting fast biomass accumulation under dynamic environments in pioneer blooms.

Effect of short- and long-term phosphate stress on the non-phosphorylating pathway of mitochondrial electron transport in Arabidopsis thaliana

2010 ◽  
Vol 37 (5) ◽  
pp. 455 ◽  
Author(s):  
Vivek Vijayraghavan ◽  
Kathleen Soole
Keyword(s):  
Arabidopsis Thaliana ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Mitochondrial Electron Transport Chain ◽  
Short Term ◽  
Transport Chain ◽  
Short And Long Term ◽  
Pi Stress

Wild-type Arabidopsis thaliana L. seedlings generated in liquid culture were subjected to long- and short-term phosphate (Pi) stress to assess the response of the non-phosphorylating pathway of mitochondrial electron transport, comprising the internal (NDin) and external (NDex) non-phosphorylating NAD(P)H dehydrogenases and the alternative oxidase (AOX). Tissue Pi levels decreased but anthocyanin levels increased in both short- and long-term Pi stress. Oxidative damage was either lower or unchanged in response to short- and long-term Pi term stress. NDin and AOX capacity were elevated only in response to long-term Pi stress whereas NDex capacity was elevated only in response to short-term Pi stress. The only ND genes with elevated transcript levels in response to both short- and long-term Pi stress were Atnda2 (an NDin) and Atndb2 (an NDex). The binding site for PHR1, a transcription factor involved in the Pi stress response, was found in the promoter regions of Atnda2 and Atndb2. Results of this study indicate that a non-phosphorylating mitochondrial electron transport chain consisting of NDA2, NDB2 and AOX is synthesised to maintain respiratory electron flow through the mitochondrial electron transport chain during Pi stress.

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