Overproduction of PGR5 enhances the electron sink downstream of photosystem I in a C
            4
            plant,
            Flaveria bidentis

Youshi Tazoe; Noriko Ishikawa; Toshiharu Shikanai; Keiki Ishiyama; Daisuke Takagi; Amane Makino; Fumihiko Sato; Tsuyoshi Endo

doi:10.1111/tpj.14774

Overproduction of PGR5 enhances the electron sink downstream of photosystem I in a C 4 plant, Flaveria bidentis

The Plant Journal ◽

10.1111/tpj.14774 ◽

2020 ◽

Vol 103 (2) ◽

pp. 814-823 ◽

Cited By ~ 1

Author(s):

Youshi Tazoe ◽

Noriko Ishikawa ◽

Toshiharu Shikanai ◽

Keiki Ishiyama ◽

Daisuke Takagi ◽

...

Keyword(s):

Photosystem I ◽

Electron Sink ◽

Flaveria Bidentis

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Flavodiiron proteins act as safety valve for electrons in Physcomitrella patens

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1606685113 ◽

2016 ◽

Vol 113 (43) ◽

pp. 12322-12327 ◽

Cited By ~ 74

Author(s):

Caterina Gerotto ◽

Alessandro Alboresi ◽

Andrea Meneghesso ◽

Martina Jokel ◽

Marjaana Suorsa ◽

...

Keyword(s):

Electron Transport ◽

Photosystem I ◽

Physcomitrella Patens ◽

Safety Valve ◽

Cell Metabolism ◽

Photosynthetic Apparatus ◽

Photosynthetic Electron Transport ◽

Flowering Plants ◽

Knock Out ◽

Electron Sink

Photosynthetic organisms support cell metabolism by harvesting sunlight to fuel the photosynthetic electron transport. The flow of excitation energy and electrons in the photosynthetic apparatus needs to be continuously modulated to respond to dynamics of environmental conditions, and Flavodiiron (FLV) proteins are seminal components of this regulatory machinery in cyanobacteria. FLVs were lost during evolution by flowering plants, but are still present in nonvascular plants such as Physcomitrella patens. We generated P. patens mutants depleted in FLV proteins, showing their function as an electron sink downstream of photosystem I for the first seconds after a change in light intensity. flv knock-out plants showed impaired growth and photosystem I photoinhibition when exposed to fluctuating light, demonstrating FLV’s biological role as a safety valve from excess electrons on illumination changes. The lack of FLVs was partially compensated for by an increased cyclic electron transport, suggesting that in flowering plants, the FLV’s role was taken by other alternative electron routes.

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Providing an additional electron sink by the introduction of cyanobacterial flavodiirons enhances the growth of Arabidopsis thaliana in varying light

10.1101/2020.02.05.935346 ◽

2020 ◽

Cited By ~ 1

Author(s):

Suresh Tula ◽

Fahimeh Shahinnia ◽

Michael Melzer ◽

Twan Rutten ◽

Rodrigo Gómez ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Electron Transport ◽

Photosystem I ◽

Photosynthetic Electron Transport ◽

Photosynthetic Performance ◽

Growth Potential ◽

Photochemical Quenching ◽

Transport Chain ◽

Non Photochemical Quenching ◽

Electron Sink

AbstractThe ability of plants to maintain photosynthesis in a dynamically changing environment is of central importance for their growth. As their photosynthetic machinery typically cannot adapt rapidly to fluctuations in the intensity of radiation, the level of photosynthetic efficiency is not always optimal. Cyanobacteria, algae, non-vascular plants (mosses and liverworts) and gymnosperms all produce flavodiirons (Flvs), a class of proteins not represented in the angiosperms; these proteins act to mitigate the photoinhibition of photosystem I. Here, genes specifying two cyanobacterial Flvs have been expressed in the chloroplasts of Arabidopsis thaliana in an attempt to improve the robustness of Photosystem I (PSI). The expression of Flv1 and Flv3 together shown to enhance the efficiency of the utilization of light and to boost the plant’s capacity to accumulate biomass. Based on an assessment of the chlorophyll fluorescence in the transgenic plants, the implication was that photosynthetic activity (including electron transport flow and non-photochemical quenching during a dark-to-light transition) was initiated earlier in the transgenic than in wild type plants. The improved photosynthetic performance of the transgenics was accompanied by an increased production of ATP, an acceleration of carbohydrate metabolism and a more pronounced partitioning of sucrose into starch. The indications are that Flvs are able to establish an efficient electron sink downstream of PSI, thereby ensuring that the photosynthetic electron transport chain remains in a more oxidized state. The expression of Flvs in a plant acts to both protect photosynthesis and to control the ATP/NADPH ratio; together, their presence is beneficial for the plant’s growth potential.

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