'Senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves

Massive degradation of photosynthetic proteins is the hallmark of leaf senescence; however the mechanism involved in chloroplast protein breakdown is not completely understood. As small 'senescence-associated vacuoles' (SAVs) with intense proteolytic activity accumulate in senescing leaves...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Martínez, Dana Ethel, Costa, María Luján, Gomez, Facundo Martin, Otegui, Marisa, Guiamet, Juan José
Formato:	Articulo
Lenguaje:	Inglés
Publicado:	2008
Materias:	Ciencias Naturales Chloroplast breakdown Glutamine synthetase Proteolysis Rubisco Senescence-associated vacuoles Tobacco
Acceso en línea:	http://sedici.unlp.edu.ar/handle/10915/84235
Aporte de:	SEDICI (UNLP) de Universidad Nacional de La Plata

id	I19-R120-10915-84235
record_format	dspace
institution	Universidad Nacional de La Plata
institution_str	I-19
repository_str	R-120
collection	SEDICI (UNLP)
language	Inglés
topic	Ciencias Naturales Chloroplast breakdown Glutamine synthetase Proteolysis Rubisco Senescence-associated vacuoles Tobacco
spellingShingle	Ciencias Naturales Chloroplast breakdown Glutamine synthetase Proteolysis Rubisco Senescence-associated vacuoles Tobacco Martínez, Dana Ethel Costa, María Luján Gomez, Facundo Martin Otegui, Marisa Guiamet, Juan José 'Senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves
topic_facet	Ciencias Naturales Chloroplast breakdown Glutamine synthetase Proteolysis Rubisco Senescence-associated vacuoles Tobacco
description	Massive degradation of photosynthetic proteins is the hallmark of leaf senescence; however the mechanism involved in chloroplast protein breakdown is not completely understood. As small 'senescence-associated vacuoles' (SAVs) with intense proteolytic activity accumulate in senescing leaves of soybean and Arabidopsis, the main goal of this work was to determine whether SAVs are involved in the degradation of chloroplastic components. SAVs with protease activity were readily detected through confocal microscopy of naturally senescing leaves of tobacco (<i>Nicotiana tabacum</i> L.). In detached leaves incubated in darkness, acceleration of the chloroplast degradation rate by ethylene treatment correlated with a twofold increase in the number of SAVs per cell, compared to untreated leaves. In a tobacco line expressing GFP targeted to plastids, GFP was re-located to SAVs in senescing leaves. SAVs were isolated by sucrose density gradient centrifugation. Isolated SAVs contained chloroplast-targeted GFP and the chloroplast stromal proteins Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) and glutamine synthetase, but lacked the thylakoid proteins D1 and light-harvesting complex II of the photosystem II reaction center and photosystem II antenna, respectively. In SAVs incubated at 30°C, there was a steady decrease in Rubisco levels, which was completely abolished by addition of protease inhibitors. These results indicate that SAVs are involved in degradation of the soluble photosynthetic proteins of the chloroplast stroma during senescence of leaves.
format	Articulo Articulo
author	Martínez, Dana Ethel Costa, María Luján Gomez, Facundo Martin Otegui, Marisa Guiamet, Juan José
author_facet	Martínez, Dana Ethel Costa, María Luján Gomez, Facundo Martin Otegui, Marisa Guiamet, Juan José
author_sort	Martínez, Dana Ethel
title	'Senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves
title_short	'Senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves
title_full	'Senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves
title_fullStr	'Senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves
title_full_unstemmed	'Senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves
title_sort	'senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves
publishDate	2008
url	http://sedici.unlp.edu.ar/handle/10915/84235
work_keys_str_mv	AT martinezdanaethel senescenceassociatedvacuolesareinvolvedinthedegradationofchloroplastproteinsintobaccoleaves AT costamarialujan senescenceassociatedvacuolesareinvolvedinthedegradationofchloroplastproteinsintobaccoleaves AT gomezfacundomartin senescenceassociatedvacuolesareinvolvedinthedegradationofchloroplastproteinsintobaccoleaves AT oteguimarisa senescenceassociatedvacuolesareinvolvedinthedegradationofchloroplastproteinsintobaccoleaves AT guiametjuanjose senescenceassociatedvacuolesareinvolvedinthedegradationofchloroplastproteinsintobaccoleaves
bdutipo_str	Repositorios
_version_	1764820488515747841

'Senescence-associated vacuoles' are involved in the degradation of chloroplast proteins in tobacco leaves

Ejemplares similares