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 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 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.

Involvement of the Xanthophyll Cycle in Regulation of Cyclic Electron Flow around Photosystem II

1996 ◽  
Vol 51 (1-2) ◽  
pp. 47-52 ◽  
Author(s):  
W. I. Gruszecki ◽  
K. Strzałk ◽  
K.P. Bader ◽  
A. Radunz ◽  
G.H. Schmid
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Oxygen Evolution ◽  
Xanthophyll Cycle ◽  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Oxygen Evolution ◽  
Cyclic Electron Transport ◽  
Ps Ii ◽  
Low Levels

Abstract In our previous study (Gruszecki et al., 1995) we have postulated that the mechanism of cyclic electron transport around photosystem II, active under overexcitation of the photosynthetic apparatus by light is under control of the xanthophyll cycle. The combination of dif­ferent light quality and thylakoids having various levels of xanthophyll cycle pigments were applied to support this hypothesis. In the present work photosynthetic oxygen evolution from isolated tobacco chloroplasts was measured by means of mass spectrometry under conditions of high or low levels of violaxanthin, being transformed to zeaxanthin during dark incubation in an ascorbate containing buffer at pH 5.7. Analysis of oxygen evolution and of light-induced oxygen uptake indicate that the de-epoxidation of violaxanthin to zeaxanthin results in an increased cyclic electron transport around PS II, thus dimishing the vectorial electron flow from water. An effect similar to de-epoxidation was observed after incubation of thylakoid membranes with specific antibodies against violaxanthin.

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