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Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance

The activity of the protein kinase STN7, involved in phosphorylation of the light-harvesting complex II (LHCII) proteins, has been reported as being co-operatively regulated by the redox state of the plastoquinone pool and the ferredoxin–thioredoxin (Trx) system. The present study aims to investigat...

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Autores principales: Ancín, María, Fernández-San Millán, Alicia, Larraya, Luis, Morales, Fermín, Veramendi, Jon, Aranjuelo, Iker, Farran, Inmaculada
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6363096/
https://www.ncbi.nlm.nih.gov/pubmed/30476130
http://dx.doi.org/10.1093/jxb/ery415
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author Ancín, María
Fernández-San Millán, Alicia
Larraya, Luis
Morales, Fermín
Veramendi, Jon
Aranjuelo, Iker
Farran, Inmaculada
author_facet Ancín, María
Fernández-San Millán, Alicia
Larraya, Luis
Morales, Fermín
Veramendi, Jon
Aranjuelo, Iker
Farran, Inmaculada
author_sort Ancín, María
collection PubMed
description The activity of the protein kinase STN7, involved in phosphorylation of the light-harvesting complex II (LHCII) proteins, has been reported as being co-operatively regulated by the redox state of the plastoquinone pool and the ferredoxin–thioredoxin (Trx) system. The present study aims to investigate the role of plastid Trxs in STN7 regulation and their impact on photosynthesis. For this purpose, tobacco plants overexpressing Trx f or m from the plastid genome were characterized, demonstrating that only Trx m overexpression was associated with a complete loss of LHCII phosphorylation that did not correlate with decreased STN7 levels. The absence of phosphorylation in Trx m-overexpressing plants impeded migration of LHCII from PSII to PSI, with the concomitant loss of PSI–LHCII complex formation. Consequently, the thylakoid ultrastructure was altered, showing reduced grana stacking. Moreover, the electron transport rate was negatively affected, showing an impact on energy-demanding processes such as the Rubisco maximum carboxylation capacity and ribulose 1,5-bisphosphate regeneration rate values, which caused a strong depletion in net photosynthetic rates. Finally, tobacco plants overexpressing a Trx m mutant lacking the reactive redox site showed equivalent physiological performance to the wild type, indicating that the overexpressed Trx m deactivates STN7 in a redox-dependent way.
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spelling pubmed-63630962019-02-08 Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance Ancín, María Fernández-San Millán, Alicia Larraya, Luis Morales, Fermín Veramendi, Jon Aranjuelo, Iker Farran, Inmaculada J Exp Bot Research Papers The activity of the protein kinase STN7, involved in phosphorylation of the light-harvesting complex II (LHCII) proteins, has been reported as being co-operatively regulated by the redox state of the plastoquinone pool and the ferredoxin–thioredoxin (Trx) system. The present study aims to investigate the role of plastid Trxs in STN7 regulation and their impact on photosynthesis. For this purpose, tobacco plants overexpressing Trx f or m from the plastid genome were characterized, demonstrating that only Trx m overexpression was associated with a complete loss of LHCII phosphorylation that did not correlate with decreased STN7 levels. The absence of phosphorylation in Trx m-overexpressing plants impeded migration of LHCII from PSII to PSI, with the concomitant loss of PSI–LHCII complex formation. Consequently, the thylakoid ultrastructure was altered, showing reduced grana stacking. Moreover, the electron transport rate was negatively affected, showing an impact on energy-demanding processes such as the Rubisco maximum carboxylation capacity and ribulose 1,5-bisphosphate regeneration rate values, which caused a strong depletion in net photosynthetic rates. Finally, tobacco plants overexpressing a Trx m mutant lacking the reactive redox site showed equivalent physiological performance to the wild type, indicating that the overexpressed Trx m deactivates STN7 in a redox-dependent way. Oxford University Press 2019-01-30 2018-11-21 /pmc/articles/PMC6363096/ /pubmed/30476130 http://dx.doi.org/10.1093/jxb/ery415 Text en © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. http://creativecommons.org/licenses/by/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Papers
Ancín, María
Fernández-San Millán, Alicia
Larraya, Luis
Morales, Fermín
Veramendi, Jon
Aranjuelo, Iker
Farran, Inmaculada
Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance
title Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance
title_full Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance
title_fullStr Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance
title_full_unstemmed Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance
title_short Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance
title_sort overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase stn7 and alters photosynthetic performance
topic Research Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6363096/
https://www.ncbi.nlm.nih.gov/pubmed/30476130
http://dx.doi.org/10.1093/jxb/ery415
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