Overexpression of thioredoxin m in tobacco chloroplasts inhibits the protein kinase STN7 and alters photosynthetic performance
Fecha
2019Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Identificador del proyecto
ES/1PE/AGL2016-79868
Impacto
|
10.1093/jxb/ery415
Resumen
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 purpo ...
[++]
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. [--]
Materias
LHCII phosphorylation,
Nicotiana tabacum,
Photosynthesis,
Protein complex,
Thioredoxin,
Thylakoid membrane
Editor
Oxford University Press
Publicado en
Journal of Experimental Botany, Vol. 70, No. 3 pp. 1005–1016, 2019
Departamento
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua
Versión del editor
Entidades Financiadoras
This work was supported by the
Spanish Ministry of Science and Innovation (AGL2016-79868) and
from the Basque Government (UPV/EHU-GV IT-932-16). MA is a
holder of a PhD fellowship from the Spanish Ministry of Education
(FPU13/01675).