scholarly journals Characterizing membrane anchoring of leaf-form ferredoxin-NADP+ oxidoreductase in rice

2021 ◽  
Author(s):  
xiaowen da ◽  
jiangfan guo ◽  
peng yan ◽  
Chao Yang ◽  
Hongfei Zhao ◽  
...  
Keyword(s):  
Thylakoid Membrane ◽  
Photosynthetic Electron Transport ◽  
Light Conditions ◽  
Membrane Anchor ◽  
Chloroplast Membranes ◽  
Leaf Form ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain ◽  
Chloroplast Stroma ◽  
Membrane Anchoring

Leaf-form ferredoxin-NADP+ oxidoreductases (LFNRs) function in the last step of the photosynthetic electron transport chain, exist as soluble proteins in the chloroplast stroma, and are weakly associated with thylakoids or tightly anchored to chloroplast membranes. Arabidopsis thaliana has two LFNRs, and the chloroplast proteins AtTROL (THYLAKOID RHODANESE-LIKE PROTEIN) and AtTIC62 (62-kDa SUBUNIT OF TRANSLOCON OF INNER CHLOROPLAST MEMBRANE) participate in anchoring AtLFNRs to the thylakoid membrane. By contrast, the membrane anchoring mechanism of rice (Oryza sativa) LFNRs has not been elucidated. Here, we investigated the membrane-anchoring mechanism of LFNRs and its physiological roles in rice. We characterized the rice protein OsTROL1 based on its homology to AtTROL and showed that OsTROL1 is also a thylakoid membrane anchor and its loss led to a compensatory increase in OsTIC62. Moreover, OsLFNR1 attachment through a membrane anchor depends on OsLFNR2, unlike their Arabidopsis counterparts. In addition, OsTIC62 was more highly expressed in rice under dark than under light conditions, consistent with the increased membrane binding of OsLFNR in the dark. Moreover, we observed reciprocal stabilization between OsLFNRs and their membrane anchors. Therefore, our study sheds light on the mechanisms anchoring LFNRs to membranes in rice and highlights differences with Arabidopsis

The Effect of Antibodies to Violaxanthin on Photosynthetic Electron Transport

1979 ◽  
Vol 34 (5-6) ◽  
pp. 427-430 ◽  
Author(s):  
Ursula Lehmann-Kirk ◽  
Georg H. Schmid ◽  
Alfons Radunz
Keyword(s):  
Electron Transport ◽  
Thylakoid Membrane ◽  
Specific Binding ◽  
Photosynthetic Electron Transport ◽  
Antigenic Determinants ◽  
Coombs Test ◽  
Diphenyl Carbazide ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain ◽  
Oxygen Evolving

Abstract An antiserum to violaxanthin in hibits photosynthetic electron transport between water, iodide or tetramethylbenzidine and various electron acceptors in chloroplasts from green tobacco (Nicotian a tabacum var. John William’s Broadleaf). However, electron transport from manganese or diphenyl-carbazide to these acceptors is not impaired. The typical photosystem I reaction from DPIP / ascorbate to anthraquinone-2-sulfonate in the presence of DCMU shows no inhibition. From this it is concluded that the effect of violaxanthin on the photosynthetic electron transport chain lies on the oxygen-evolving side of photosystem II before the site from which diphenylcarbazide or manganese donate electrons.In the presence of DCMU after preillumination we find an effect of the antiserum on fluorescence.The reaction of the antibodies to violaxanthin with stroma-freed chloroplasts depends on the condition of the thylakoid membrane. Chloroplasts which are still swellable react in a bivalent manner and are agglutinated. Non swellable chloroplasts react only in a monovalent manner. This specific binding was demonstrated by means of the Coombs-test.From these reactions it follows that the antigenic determinants of violaxanthin are accessible to the antibodies, hence, they must be located in the outer surface of the thylakoid membrane.

Formation mechanisms of superoxide radical and hydrogen peroxide in chloroplasts, and factors determining the signalling by hydrogen peroxide

2018 ◽  
Vol 45 (2) ◽  
pp. 102 ◽  
Author(s):  
Boris N. Ivanov ◽  
Maria M. Borisova-Mubarakshina ◽  
Marina A. Kozuleva
Keyword(s):  
Hydrogen Peroxide ◽  
Electron Transport ◽  
Thylakoid Membrane ◽  
Electron Transport Chain ◽  
Superoxide Radical ◽  
Photosynthetic Electron Transport ◽  
Formation Mechanisms ◽  
H2o2 Production ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

Reduction of O2 molecule to superoxide radical, O2•−, in the photosynthetic electron transport chain is the first step of hydrogen peroxide, H2O2, production in chloroplasts in the light. The mechanisms of O2 reduction by ferredoxin, by the components of the plastoquinone pool, and by the electron transfer cofactors in PSI are analysed. The data indicating that O2•− and H2O2 can be produced both outside and within thylakoid membrane are presented. The H2O2 production in the chloroplast stroma is described as a result of either dismutation of O2•− or its reduction by stromal reductants. Formation of H2O2 within thylakoid membrane in the reaction of O2•− with plastohydroquinone is examined. The significance of both ways of H2O2 formation for specificity of the signal being sent by photosynthetic electron transport chain to cell adaptation systems is discussed.

The atypical kinase ABC1K1 interacts with the EXECUTER pathway to promote chloroplast biogenesis.

2021 ◽  
Author(s):  
Joy Collombat ◽  
Thibaut Pralon ◽  
Jenny Pego Magalhaes ◽  
Sarah Rottet ◽  
Brigitte Ksas ◽  
...  
Keyword(s):  
Electron Transport Chain ◽  
Red Light ◽  
Photosynthetic Electron Transport ◽  
Chloroplast Biogenesis ◽  
Light Conditions ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain ◽  
Dependent Signal ◽  
Photosynthetic Mutants

Abstract Multiple chloroplast-to-nucleus signaling pathways contribute to the regulation of chloroplast biogenesis during plant greening. Here, we provide evidence for the direct implication of the atypical kinase ABC1K1. ABC1K1 is required for sufficient plastoquinone (PQ) allocation to the photosynthetic electron transport chain. Unexpectedly, mutation of abc1k1 suppresses greening and results in pale cotyledons under red light. This phenotype was not observed in other photosynthetic mutants and points to a specific signaling defect. Under red light, abc1k1 accumulated EXECUTER1 (EX1), a trigger of singlet oxygen (1O2) signaling. Consistent with the role of the FTSH metalloprotease in chloroplast biogenesis and EX1 degradation, the ftsh2 mutant var2, mimicked the greening defect of abc1k1 and accumulated EX1 under red light. We propose that this novel ABC1K1-dependent signal is required for chloroplast biogenesis to progress in challenging light conditions.

scholarly journals The Role of Selected Wavelengths of Light in the Activity of Photosystem II in Gloeobacter violaceus

2021 ◽  
Vol 22 (8) ◽  
pp. 4021
Author(s):  
Monika Kula-Maximenko ◽  
Kamil Jan Zieliński ◽  
Ireneusz Ślesak
Keyword(s):  
Photosystem Ii ◽  
Spectral Composition ◽  
Photosynthetic Electron Transport ◽  
Metabolic Energy ◽  
Light Conditions ◽  
Gloeobacter Violaceus ◽  
Transport Chain ◽  
Cyanobacterial Culture ◽  
Photosynthetic Antennas

Gloeobacter violaceus is a cyanobacteria species with a lack of thylakoids, while photosynthetic antennas, i.e., phycobilisomes (PBSs), photosystem II (PSII), and I (PSI), are located in the cytoplasmic membrane. We verified the hypothesis that blue–red (BR) light supplemented with a far-red (FR), ultraviolet A (UVA), and green (G) light can affect the photosynthetic electron transport chain in PSII and explain the differences in the growth of the G. violaceus culture. The cyanobacteria were cultured under different light conditions. The largest increase in G. violaceus biomass was observed only under BR + FR and BR + G light. Moreover, the shape of the G. violaceus cells was modified by the spectrum with the addition of G light. Furthermore, it was found that both the spectral composition of light and age of the cyanobacterial culture affect the different content of phycobiliproteins in the photosynthetic antennas (PBS). Most likely, in cells grown under light conditions with the addition of FR and G light, the average antenna size increased due to the inactivation of some reaction centers in PSII. Moreover, the role of PSI and gloeorhodopsin as supplementary sources of metabolic energy in the G. violaceus growth is discussed.

scholarly journals Effects of Different Planting Densities on Photosynthesis in Maize Determined via Prompt Fluorescence, Delayed Fluorescence and P700 Signals

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 276
Author(s):  
Wanying Chen ◽  
Bo Jia ◽  
Junyu Chen ◽  
Yujiao Feng ◽  
Yue Li ◽  
...  
Keyword(s):  
Electron Transport ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Electron Transport Chain ◽  
Plant Density ◽  
Photosynthetic Electron Transport ◽  
Planting Density ◽  
Strong Impact ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

The mutual shading among individual field-grown maize plants resulting from high planting density inevitably reduces leaf photosynthesis, while regulating the photosynthetic transport chain has a strong impact on photosynthesis. However, the effect of high planting density on the photosynthetic electron transport chain in maize currently remains unclear. In this study, we simultaneously measured prompt chlorophyll a fluorescence (PF), modulated 820 nm reflection (MR) and delayed chlorophyll a fluorescence (DF) in order to investigate the effect of high planting density on the photosynthetic electron transport chain in two maize hybrids widely grown in China. PF transients demonstrated a gradual reduction in their signal amplitude with increasing planting density. In addition, high planting density induced positive J-step and G-bands of the PF transients, reduced the values of PF parameters PIABS, RC/CSO, TRO/ABS, ETO/TRO and REO/ETO, and enhanced ABS/RC and N. MR kinetics showed an increase of their lowest point with increasing high planting density, and thus the values of MR parameters VPSI and VPSII-PSI were reduced. The shapes of DF induction and decay curves were changed by high planting density. In addition, high planting density reduced the values of DF parameters I1, I2, L1 and L2, and enhanced I2/I1. These results suggested that high planting density caused harm on multiple components of maize photosynthetic electron transport chain, including an inactivation of PSII RCs, a blocked electron transfer between QA and QB, a reduction in PSI oxidation and re-reduction activities, and an impaired PSI acceptor side. Moreover, a comparison between PSII and PSI activities demonstrated the greater effect of plant density on the former.

Rewiring photosynthesis: a photosystem I-hydrogenase chimera that makes H2in vivo

2020 ◽  
Vol 13 (9) ◽  
pp. 2903-2914 ◽  
Author(s):  
Andrey Kanygin ◽  
Yuval Milrad ◽  
Chandrasekhar Thummala ◽  
Kiera Reifschneider ◽  
Patricia Baker ◽  
...  
Keyword(s):  
Electron Transport ◽  
Hydrogen Production ◽  
Photosystem I ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

Photosystem I-hydrogenase chimera intercepts electron flow directly from the photosynthetic electron transport chain and directs it to hydrogen production.

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