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Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii

BACKGROUND: Proteasomes remove regulatory proteins in eukaryotic cells, and control a variety of plant processes. Proteasomes are localized to the cytosol and nuclear, but their role in plant biology has recently been extended to chloroplasts, where it regulates TOC complex. This is turn controls th...

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Autores principales: Mendoza, Felipe, Berry, Carson, Prestigiacomo, Laura, Van Hoewyk, Doug
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6958727/
https://www.ncbi.nlm.nih.gov/pubmed/31931713
http://dx.doi.org/10.1186/s12870-020-2236-6
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author Mendoza, Felipe
Berry, Carson
Prestigiacomo, Laura
Van Hoewyk, Doug
author_facet Mendoza, Felipe
Berry, Carson
Prestigiacomo, Laura
Van Hoewyk, Doug
author_sort Mendoza, Felipe
collection PubMed
description BACKGROUND: Proteasomes remove regulatory proteins in eukaryotic cells, and control a variety of plant processes. Proteasomes are localized to the cytosol and nuclear, but their role in plant biology has recently been extended to chloroplasts, where it regulates TOC complex. This is turn controls the import of nuclear-encoded chloroplastic proteins, which remodels the chloroplast proteome and facilitates proper developmental transitions. Proteasomal regulation of the TOC complex also alleviates stressors that generate reactive oxygen species. These recent advances motivated us to determine if proteasome inhibition rapidly alters photosynthetic processes stemming from photoinhibition induced by high light. RESULTS: The short-term effects of proteasome inhibition on photosystem II during light stress was measured in Chlamydomonas reinhardtii, which allowed the dual monitoring of both chlorophyll fluorescence and cell viability. After 48 h at low light, proteasome inhibition did not affect viability or photochemistiry, but decreased cell concentration and increased cell volume. Two hours of high light stress impaired the efficiency of photosystem II in proteasome-inhibited cells, as determined by a decrease in Fv/Fm and the electron transport rate. Elevated photoinhibition in proteasome inhibited cells was not caused by a decrease in cell viability or chlorophyll content. Recovery from photoinhibition was attenuated in MG132-treated cells, and suppressed growth of a reestablished culture. Proteasome inhibition decreased de novo protein synthesis, which possibly constrained the ability to remodel the plastid proteome, and thus hampering the ability to adjust to high light stress. CONCLUSION: The proteasome is implicated in protecting photosystem II from photoinhibition. In addition to high light stress, other stressors- including metals, drought, and salt- are also known to generate reactive oxygen species localized to the chloroplast. Therefore, proteasome maintenance in plants may help protect photosynthesis during abiotic stress, which could increase crop yield during adverse conditions.
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spelling pubmed-69587272020-01-17 Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii Mendoza, Felipe Berry, Carson Prestigiacomo, Laura Van Hoewyk, Doug BMC Plant Biol Research Article BACKGROUND: Proteasomes remove regulatory proteins in eukaryotic cells, and control a variety of plant processes. Proteasomes are localized to the cytosol and nuclear, but their role in plant biology has recently been extended to chloroplasts, where it regulates TOC complex. This is turn controls the import of nuclear-encoded chloroplastic proteins, which remodels the chloroplast proteome and facilitates proper developmental transitions. Proteasomal regulation of the TOC complex also alleviates stressors that generate reactive oxygen species. These recent advances motivated us to determine if proteasome inhibition rapidly alters photosynthetic processes stemming from photoinhibition induced by high light. RESULTS: The short-term effects of proteasome inhibition on photosystem II during light stress was measured in Chlamydomonas reinhardtii, which allowed the dual monitoring of both chlorophyll fluorescence and cell viability. After 48 h at low light, proteasome inhibition did not affect viability or photochemistiry, but decreased cell concentration and increased cell volume. Two hours of high light stress impaired the efficiency of photosystem II in proteasome-inhibited cells, as determined by a decrease in Fv/Fm and the electron transport rate. Elevated photoinhibition in proteasome inhibited cells was not caused by a decrease in cell viability or chlorophyll content. Recovery from photoinhibition was attenuated in MG132-treated cells, and suppressed growth of a reestablished culture. Proteasome inhibition decreased de novo protein synthesis, which possibly constrained the ability to remodel the plastid proteome, and thus hampering the ability to adjust to high light stress. CONCLUSION: The proteasome is implicated in protecting photosystem II from photoinhibition. In addition to high light stress, other stressors- including metals, drought, and salt- are also known to generate reactive oxygen species localized to the chloroplast. Therefore, proteasome maintenance in plants may help protect photosynthesis during abiotic stress, which could increase crop yield during adverse conditions. BioMed Central 2020-01-13 /pmc/articles/PMC6958727/ /pubmed/31931713 http://dx.doi.org/10.1186/s12870-020-2236-6 Text en © The Author(s). 2020 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Mendoza, Felipe
Berry, Carson
Prestigiacomo, Laura
Van Hoewyk, Doug
Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii
title Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii
title_full Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii
title_fullStr Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii
title_full_unstemmed Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii
title_short Proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in Chlamydomonas reinhardtii
title_sort proteasome inhibition rapidly exacerbates photoinhibition and impedes recovery during high light stress in chlamydomonas reinhardtii
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6958727/
https://www.ncbi.nlm.nih.gov/pubmed/31931713
http://dx.doi.org/10.1186/s12870-020-2236-6
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