Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions

Autores
Bartoli, Carlos Guillermo; Gomez, Facundo Martin; Gergoff, Gustavo; Guiamet, Juan José; Puntarulo, Susana
Año de publicación
2005
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The aim of this study was to explore the role of the mitochondrial alternative oxidase (AOX) in the protection of photosynthesis during drought in wheat leaves. The relative water contents of water-replete and drought-exposed wheat plants were 97.2±0.3 and 75±2, respectively. Drought increased the amount of leaf AOX protein and also enhanced the rate of AOX-dependent O 2 uptake by the respiratory electron transport chain. The amount of the reduced, active form of the AOX protein was specifically increased by drought. The AOX inhibitor salicylhydroxamic acid (1 mM; SHAM) inhibited 70% of AOX activity in vivo in both water-replete and drought-exposed plants. Plants treated with SHAM were then exposed to low (100), high (350), or excess light (800 μmol photons m -2 s -1 ) for 90 min. SHAM did not modify chlorophyll a fluorescence quenching parameters in water-replete controls after any of these treatments. However, while the maximal quantum yield of photosystem II (PSII) electron transport (F v /F m ) was not affected by SHAM, the immediate quantum yield of PSII electron transport (Φ PSII ) and photochemical quenching (qP) were gradually reduced by increasing irradiance in SHAM-treated drought-exposed plants, the decrease being most pronounced at the highest irradiance. Non-photochemical quenching (NPO) reached near maximum levels in plants subjected to drought at high irradiance. However, a combination of drought and low light caused an intermediate increase in NPO, which attained higher values when AOX was inhibited. Taken together, these results show that up-regulation of the respiratory AOX pathway protects the photosynthetic electron transport chain from the harmful effects of excess light.
Instituto de Fisiología Vegetal
Materia
Ciencias Naturales
Alternative oxidase
Chlorophyll fluorescence
Drought
Photoprotection
Respiration
Wheat
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/83404
Acceder
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oai_identifier_str oai:sedici.unlp.edu.ar:10915/83404
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditionsBartoli, Carlos GuillermoGomez, Facundo MartinGergoff, GustavoGuiamet, Juan JoséPuntarulo, SusanaCiencias NaturalesAlternative oxidaseChlorophyll fluorescenceDroughtPhotoprotectionRespirationWheatThe aim of this study was to explore the role of the mitochondrial alternative oxidase (AOX) in the protection of photosynthesis during drought in wheat leaves. The relative water contents of water-replete and drought-exposed wheat plants were 97.2±0.3 and 75±2, respectively. Drought increased the amount of leaf AOX protein and also enhanced the rate of AOX-dependent O 2 uptake by the respiratory electron transport chain. The amount of the reduced, active form of the AOX protein was specifically increased by drought. The AOX inhibitor salicylhydroxamic acid (1 mM; SHAM) inhibited 70% of AOX activity in vivo in both water-replete and drought-exposed plants. Plants treated with SHAM were then exposed to low (100), high (350), or excess light (800 μmol photons m -2 s -1 ) for 90 min. SHAM did not modify chlorophyll a fluorescence quenching parameters in water-replete controls after any of these treatments. However, while the maximal quantum yield of photosystem II (PSII) electron transport (F v /F m ) was not affected by SHAM, the immediate quantum yield of PSII electron transport (Φ PSII ) and photochemical quenching (qP) were gradually reduced by increasing irradiance in SHAM-treated drought-exposed plants, the decrease being most pronounced at the highest irradiance. Non-photochemical quenching (NPO) reached near maximum levels in plants subjected to drought at high irradiance. However, a combination of drought and low light caused an intermediate increase in NPO, which attained higher values when AOX was inhibited. Taken together, these results show that up-regulation of the respiratory AOX pathway protects the photosynthetic electron transport chain from the harmful effects of excess light.Instituto de Fisiología Vegetal2005info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf1269-1276http://sedici.unlp.edu.ar/handle/10915/83404enginfo:eu-repo/semantics/altIdentifier/issn/0022-0957info:eu-repo/semantics/altIdentifier/doi/10.1093/jxb/eri111info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-10-22T16:56:37Zoai:sedici.unlp.edu.ar:10915/83404Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-10-22 16:56:38.217SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions
title Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions
spellingShingle Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions
Bartoli, Carlos Guillermo
Ciencias Naturales
Alternative oxidase
Chlorophyll fluorescence
Drought
Photoprotection
Respiration
Wheat
title_short Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions
title_full Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions
title_fullStr Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions
title_full_unstemmed Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions
title_sort Up-regulation of the mitochondrial alternative oxidase pathway enhances photosynthetic electron transport under drought conditions
dc.creator.none.fl_str_mv Bartoli, Carlos Guillermo
Gomez, Facundo Martin
Gergoff, Gustavo
Guiamet, Juan José
Puntarulo, Susana
author Bartoli, Carlos Guillermo
author_facet Bartoli, Carlos Guillermo
Gomez, Facundo Martin
Gergoff, Gustavo
Guiamet, Juan José
Puntarulo, Susana
author_role author
author2 Gomez, Facundo Martin
Gergoff, Gustavo
Guiamet, Juan José
Puntarulo, Susana
author2_role author
author
author
author
dc.subject.none.fl_str_mv Ciencias Naturales
Alternative oxidase
Chlorophyll fluorescence
Drought
Photoprotection
Respiration
Wheat
topic Ciencias Naturales
Alternative oxidase
Chlorophyll fluorescence
Drought
Photoprotection
Respiration
Wheat
dc.description.none.fl_txt_mv The aim of this study was to explore the role of the mitochondrial alternative oxidase (AOX) in the protection of photosynthesis during drought in wheat leaves. The relative water contents of water-replete and drought-exposed wheat plants were 97.2±0.3 and 75±2, respectively. Drought increased the amount of leaf AOX protein and also enhanced the rate of AOX-dependent O 2 uptake by the respiratory electron transport chain. The amount of the reduced, active form of the AOX protein was specifically increased by drought. The AOX inhibitor salicylhydroxamic acid (1 mM; SHAM) inhibited 70% of AOX activity in vivo in both water-replete and drought-exposed plants. Plants treated with SHAM were then exposed to low (100), high (350), or excess light (800 μmol photons m -2 s -1 ) for 90 min. SHAM did not modify chlorophyll a fluorescence quenching parameters in water-replete controls after any of these treatments. However, while the maximal quantum yield of photosystem II (PSII) electron transport (F v /F m ) was not affected by SHAM, the immediate quantum yield of PSII electron transport (Φ PSII ) and photochemical quenching (qP) were gradually reduced by increasing irradiance in SHAM-treated drought-exposed plants, the decrease being most pronounced at the highest irradiance. Non-photochemical quenching (NPO) reached near maximum levels in plants subjected to drought at high irradiance. However, a combination of drought and low light caused an intermediate increase in NPO, which attained higher values when AOX was inhibited. Taken together, these results show that up-regulation of the respiratory AOX pathway protects the photosynthetic electron transport chain from the harmful effects of excess light.
Instituto de Fisiología Vegetal
description The aim of this study was to explore the role of the mitochondrial alternative oxidase (AOX) in the protection of photosynthesis during drought in wheat leaves. The relative water contents of water-replete and drought-exposed wheat plants were 97.2±0.3 and 75±2, respectively. Drought increased the amount of leaf AOX protein and also enhanced the rate of AOX-dependent O 2 uptake by the respiratory electron transport chain. The amount of the reduced, active form of the AOX protein was specifically increased by drought. The AOX inhibitor salicylhydroxamic acid (1 mM; SHAM) inhibited 70% of AOX activity in vivo in both water-replete and drought-exposed plants. Plants treated with SHAM were then exposed to low (100), high (350), or excess light (800 μmol photons m -2 s -1 ) for 90 min. SHAM did not modify chlorophyll a fluorescence quenching parameters in water-replete controls after any of these treatments. However, while the maximal quantum yield of photosystem II (PSII) electron transport (F v /F m ) was not affected by SHAM, the immediate quantum yield of PSII electron transport (Φ PSII ) and photochemical quenching (qP) were gradually reduced by increasing irradiance in SHAM-treated drought-exposed plants, the decrease being most pronounced at the highest irradiance. Non-photochemical quenching (NPO) reached near maximum levels in plants subjected to drought at high irradiance. However, a combination of drought and low light caused an intermediate increase in NPO, which attained higher values when AOX was inhibited. Taken together, these results show that up-regulation of the respiratory AOX pathway protects the photosynthetic electron transport chain from the harmful effects of excess light.
publishDate 2005
dc.date.none.fl_str_mv 2005
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/83404
url http://sedici.unlp.edu.ar/handle/10915/83404
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0022-0957
info:eu-repo/semantics/altIdentifier/doi/10.1093/jxb/eri111
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
1269-1276
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
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reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
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repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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