scholarly journals The chloroplast NADH dehydrogenase-like complex influences the photosynthetic activity of the moss Physcomitrella patens

2020 ◽  
Vol 71 (18) ◽  
pp. 5538-5548
Author(s):  
Mattia Storti ◽  
Maria Paola Puggioni ◽  
Anna Segalla ◽  
Tomas Morosinotto ◽  
Alessandro Alboresi
Keyword(s):  
Electron Transport ◽  
Nadh Dehydrogenase ◽  
Photosynthetic Activity ◽  
Physcomitrella Patens ◽  
Physiological Role ◽  
Photosynthetic Performance ◽  
Plant Evolution ◽  
Cyclic Electron Transport ◽  
Double Knockout ◽  
Transport Pathway

Abstract Alternative electron pathways contribute to regulation of photosynthetic light reactions to adjust to metabolic demands in dynamic environments. The chloroplast NADH dehydrogenase-like (NDH) complex mediates the cyclic electron transport pathway around PSI in different cyanobacteria, algae, and plant species, but it is not fully conserved in all photosynthetic organisms. In order to assess how the physiological role of this complex changed during plant evolution, we isolated Physcomitrella patens lines knocked out for the NDHM gene that encodes a subunit fundamental for the activity of the complex. ndhm knockout mosses indicated high PSI acceptor side limitation upon abrupt changes in illumination. In P. patens, pseudo-cyclic electron transport mediated by flavodiiron proteins (FLVs) was also shown to prevent PSI over-reduction in plants exposed to light fluctuations. flva ndhm double knockout mosses had altered photosynthetic performance and growth defects under fluctuating light compared with the wild type and single knockout mutants. The results showed that while the contribution of NDH to electron transport is minor compared with FLV, NDH still participates in modulating photosynthetic activity, and it is critical to avoid PSI photoinhibition, especially when FLVs are inactive. The functional overlap between NDH- and FLV-dependent electron transport supports PSI activity and prevents its photoinhibition under light variations.

scholarly journals The activity of chloroplast NADH dehydrogenase-like complex influences the photosynthetic activity of the moss Physcomitrella patens

2020 ◽  
Author(s):  
Mattia Storti ◽  
Maria Paola Puggioni ◽  
Anna Segalla ◽  
Tomas Morosinotto ◽  
Alessandro Alboresi
Keyword(s):  
Electron Transport ◽  
Nadh Dehydrogenase ◽  
Molecular Mechanisms ◽  
Physcomitrella Patens ◽  
Physiological Role ◽  
Plant Evolution ◽  
Transport Systems ◽  
Photosynthetic Parameters ◽  
Transport Pathway ◽  
Strong Electron

ABSTRACTAlternative electron pathways contribute to the regulation of photosynthetic light reactions to meet metabolic demands in a dynamic environment. Understanding the molecular mechanisms of their activity is seminal to decipher their role in response to environmental cues and in plant adaptation. The chloroplast NADH dehydrogenase-like (NDH) complex mediates cyclic electron transport pathway around photosystem I (PSI) in different organisms like cyanobacteria, algae and various plant species but has a discontinuous distribution in the green lineage. In order to assess how its activity and physiological role changed during plant evolution, we isolated Physcomitrella patens lines knocked out of the gene NDHM which encodes for a subunit fundamental for the stability and activity of the whole complex. P. patens ndhm KO mosses showed high PSI acceptor side limitation upon illumination leading to PSI photoinhibition. Flavodiiron proteins (FLV) have similar and particularly important role in preventing PSI overreduction when plants are exposed to light fluctuations. The flva ndhm double KO mosses alteration in photosynthetic parameters leaded to a defect in plant growth under fluctuating light as compared to WT and single KO mutants. Results evidenced that, while FLV sustain strong electron transport after an abrupt change in light intensity, NDH contribution to electron transport is small. NDH still participate in modulating PSI activity and it is seminal to prevent PSI photoinhibition especially when FLV are inactive. In plants the functional overlap between NDH- and FLV-dependent electron transport systems sustains PSI activity and to prevent its photoinhibition.

scholarly journals The Physiological Functionality of PGR5/PGRL1-Dependent Cyclic Electron Transport in Sustaining Photosynthesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Mingzhu Ma ◽  
Yifei Liu ◽  
Chunming Bai ◽  
Yunhong Yang ◽  
Zhiyu Sun ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Nadh Dehydrogenase ◽  
Extreme Weather Events ◽  
Cyclic Electron Transport ◽  
Linear Electron ◽  
Transport Pathway ◽  
Biochemical Processes ◽  
Weather Events ◽  
Electron Transport Pathway

The cyclic electron transport (CET), after the linear electron transport (LET), is another important electron transport pathway during the light reactions of photosynthesis. The proton gradient regulation 5 (PGR5)/PRG5-like photosynthetic phenotype 1 (PGRL1) and the NADH dehydrogenase-like complex pathways are linked to the CET. Recently, the regulation of CET around photosystem I (PSI) has been recognized as crucial for photosynthesis and plant growth. Here, we summarized the main biochemical processes of the PGR5/PGRL1-dependent CET pathway and its physiological significance in protecting the photosystem II and PSI, ATP/NADPH ratio maintenance, and regulating the transitions between LET and CET in order to optimize photosynthesis when encountering unfavorable conditions. A better understanding of the PGR5/PGRL1-mediated CET during photosynthesis might provide novel strategies for improving crop yield in a world facing more extreme weather events with multiple stresses affecting the plants.

scholarly journals Regulation of electron transport is essential for photosystem I stability and plant growth

2019 ◽  
Author(s):  
Mattia Storti ◽  
Anna Segalla ◽  
Marco Mellon ◽  
Alessandro Alboresi ◽  
Tomas Morosinotto
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Nadh Dehydrogenase ◽  
Physcomitrella Patens ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Type I ◽  
Growth Reduction ◽  
Light Regimes ◽  
Photosynthetic Organisms

AbstractLife depends on the ability of photosynthetic organisms to exploit sunlight to fix carbon dioxide into biomass. Photosynthesis is modulated by pathways such as cyclic and pseudocyclic electron flow (CEF and PCEF). CEF transfers electrons from photosystem I to the plastoquinone pool according to two mechanisms, one dependent on proton gradient regulators (PGR5/PGRL1) and the other on the type I NADH dehydrogenase (NDH) complex. PCEF uses electrons from photosystem I to reduce oxygen; in several groups of photosynthetic organisms but not in angiosperms, it is sustained by flavodiiron proteins (FLVs). PGR5/PGRL1, NDH and FLVs are all active in the moss Physcomitrella patens, and mutants depleted in these proteins show phenotypes under specific light regimes. Here, we demonstrated that CEF and PCEF exhibit strong functional overlap and that when one protein component is depleted, the others can compensate for most of the missing activity. When multiple mechanisms are simultaneously inactivated, however, plants show damage to photosystem I and strong growth reduction, demonstrating that mechanisms for the modulation of photosynthetic electron transport are indispensable.

scholarly journals Inactivation of ycf33 Results in an Altered Cyclic Electron Transport Pathway Around Photosystem I in Synechocystis sp. PCC6803

2004 ◽  
Vol 45 (9) ◽  
pp. 1243-1251 ◽  
Author(s):  
Masako Ohtsuka ◽  
Junko Oyabu ◽  
Yasuhiro Kashino ◽  
Kazuhiko Satoh ◽  
Hiroyuki Koike
Keyword(s):  
Electron Transport ◽  
Photosystem I ◽  
Cyclic Electron Transport ◽  
Transport Pathway ◽  
Electron Transport Pathway ◽  
Synechocystis Sp

scholarly journals Novel Remote Sensing Index of Electron Transport Rate Predicts Primary Production and Crop Health in L. sativa and Z. mays

2020 ◽  
Vol 12 (11) ◽  
pp. 1718
Author(s):  
Oded Liran ◽  
Ofer M. Shir ◽  
Shai Levy ◽  
Ariel Grunfeld ◽  
Yuval Shelly
Keyword(s):  
Remote Sensing ◽  
Electron Transport ◽  
Light Intensity ◽  
Vegetation Index ◽  
Photosynthetic Activity ◽  
Electron Transport Rate ◽  
Photosynthetic Performance ◽  
Field Conditions ◽  
Transport Rate ◽  
Response Curves

Photosynthesis performance can be assessed quantitatively with light response curves. These curves record the Electron Transport Rate (ETR) as a function of light intensity. Then, statistical fit on these curves parameterize light use efficiency, maximum photosynthetic activity and the reaction of the apparatus to stress. While this technique is performed with portable fluorometers in field conditions, it is difficult to scale it to the canopy level. The Fraunhofer line discrimination technique, which detects fluorescence signals emitted during photosynthesis, is a promising method to assess photosynthetic performance of canopies. In this study, we define a remote sensing ETR index based on a combination of three parameters: sun-induced fluorescence, normalized differential vegetation index and light intensity. Two representatives of C3 and C4 photosynthesis, L. sativa and Z. mays, experienced a fertilization concentrations gradient. ETR increased with light intensity in both crops. In L. sativa, ETR assumed a linear relationship between the photosynthetic activity and light intensity, with a correlation of R2 = 0.99 to the portable fluorometer. Additional parametrization revealed a resilience of its reaction centers to photoinhibition in maximum light intensities. When Z. mays experienced open field conditions, ETR correlated with the plant’s status. While the results of this study are promising, the index still requires validation in terms of temporal track and spatial variability.

scholarly journals The Significance of Chloroplast NAD(P)H Dehydrogenase Complex and Its Dependent Cyclic Electron Transport in Photosynthesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Mingzhu Ma ◽  
Yifei Liu ◽  
Chunming Bai ◽  
Jean Wan Hong Yong
Keyword(s):  
Electron Transport ◽  
Growth And Development ◽  
Redox System ◽  
Thylakoid Membranes ◽  
Plant Evolution ◽  
Cyclic Electron Transport ◽  
Plant Growth And Development ◽  
Transport Pathways ◽  
Electron Transfer Chain ◽  
Transfer Chain

Chloroplast NAD(P)H dehydrogenase (NDH) complex, a multiple-subunit complex in the thylakoid membranes mediating cyclic electron transport, is one of the most important alternative electron transport pathways. It was identified to be essential for plant growth and development during stress periods in recent years. The NDH-mediated cyclic electron transport can restore the over-reduction in stroma, maintaining the balance of the redox system in the electron transfer chain and providing the extra ATP needed for the other biochemical reactions. In this review, we discuss the research history and the subunit composition of NDH. Specifically, the formation and significance of NDH-mediated cyclic electron transport are discussed from the perspective of plant evolution and physiological functionality of NDH facilitating plants’ adaptation to environmental stress. A better understanding of the NDH-mediated cyclic electron transport during photosynthesis may offer new approaches to improving crop yield.

scholarly journals Photosystem I cyclic electron flow via chloroplast NADH dehydrogenase-like complex performs a physiological role for photosynthesis at low light

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Wataru Yamori ◽  
Toshiharu Shikanai ◽  
Amane Makino
Keyword(s):  
Electron Transport ◽  
Light Intensity ◽  
Photosystem I ◽  
Nadh Dehydrogenase ◽  
Physiological Function ◽  
Electron Flow ◽  
Cyclic Electron Flow ◽  
Cyclic Electron Transport ◽  
Low Light ◽  
Ps I

Abstract Cyclic electron transport around photosystem I (PS I) was discovered more than a half-century ago and two pathways have been identified in angiosperms. Although substantial progress has been made in understanding the structure of the chloroplast NADH dehydrogenase-like (NDH) complex, which mediates one route of the cyclic electron transport pathways, its physiological function is not well understood. Most studies focused on the role of the NDH-dependent PS I cyclic electron transport in alleviation of oxidative damage in strong light. In contrast, here it is shown that impairment of NDH-dependent cyclic electron flow in rice specifically causes a reduction in the electron transport rate through PS I (ETR I) at low light intensity with a concomitant reduction in CO2 assimilation rate, plant biomass and importantly, grain production. There was no effect on PS II function at low or high light intensity. We propose a significant physiological function for the chloroplast NDH at low light intensities commonly experienced during the reproductive and ripening stages of rice cultivation that have adverse effects crop yield.

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