Ascorbate content of wheat leaves is not determined by maximal L-galactono-1,4-lactone dehydrogenase (GalLDH) activity under drought stress

Although ascorbic acid (AA) is a high-abundance metabolite, relatively little is known about the factors controlling its accumulation in leaves. To address this issue, we examined the role of l-galactono-1,4-lactone dehydrogenase (GalLDH), the enzyme which catalyses the last step of this pathway, in...

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Autores principales: Bartoli, Carlos Guillermo, Guiamet, Juan José, Kiddle, Guy, Pastori, Gabriela M., Di Cagno, Raffaella, Theodoulou, Frederica L., Foyer, Christine H.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2005
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/83152
Aporte de:
id I19-R120-10915-83152
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
Ascorbic acid
Dehydroascorbate
Drought
L-galactono-1,4-lactone
L-galactono-1,4-lactone dehydrogenase
Mitochondria
Oxidative damage
Redox regulation
Wheat
spellingShingle Ciencias Naturales
Ascorbic acid
Dehydroascorbate
Drought
L-galactono-1,4-lactone
L-galactono-1,4-lactone dehydrogenase
Mitochondria
Oxidative damage
Redox regulation
Wheat
Bartoli, Carlos Guillermo
Guiamet, Juan José
Kiddle, Guy
Pastori, Gabriela M.
Di Cagno, Raffaella
Theodoulou, Frederica L.
Foyer, Christine H.
Ascorbate content of wheat leaves is not determined by maximal L-galactono-1,4-lactone dehydrogenase (GalLDH) activity under drought stress
topic_facet Ciencias Naturales
Ascorbic acid
Dehydroascorbate
Drought
L-galactono-1,4-lactone
L-galactono-1,4-lactone dehydrogenase
Mitochondria
Oxidative damage
Redox regulation
Wheat
description Although ascorbic acid (AA) is a high-abundance metabolite, relatively little is known about the factors controlling its accumulation in leaves. To address this issue, we examined the role of l-galactono-1,4-lactone dehydrogenase (GalLDH), the enzyme which catalyses the last step of this pathway, in the control of AA content under optimal and stress conditions. In a range of species, no clear relationship between AA content and leaf GalLDH protein and activity was found under optimal growth conditions. To explore the effect of drought stress on GalLDH activity and protein content, wheat (Triticum aestivum L.) was selected for detailed analysis, using two cultivars that differ in their constitutive AA level. In well-watered plants, the AA content of cv Buck Chambergo (BCH) was over twice that of cv Cooperativa Maipún (CM) but dehydroascorbic acid content was similar in both cv. In agreement with this, dehydroascorbate reductase and glutathione reductase activities were higher in cv BCH than in cv CM, indicating a higher capacity for AA regeneration. Neither leaf DHA content nor activities of AA regenerating enzymes were modified by drought. Although drought caused a substantial increase in GalLDH protein and activity in the low AA cv CM, this treatment had no effect on these parameters in cv BCH. Notably, leaf AA content was unaffected by drought in either cv. These results suggest that GalLDH protein and activity cannot be used as an indicator for changes in the capacity for ascorbate biosynthesis and that AA biosynthesis is constrained by other factors under stress. This can be explained by the importance of regeneration in maintaining AA levels and possibly also by redox regulation of GalLDH.
format Articulo
Articulo
author Bartoli, Carlos Guillermo
Guiamet, Juan José
Kiddle, Guy
Pastori, Gabriela M.
Di Cagno, Raffaella
Theodoulou, Frederica L.
Foyer, Christine H.
author_facet Bartoli, Carlos Guillermo
Guiamet, Juan José
Kiddle, Guy
Pastori, Gabriela M.
Di Cagno, Raffaella
Theodoulou, Frederica L.
Foyer, Christine H.
author_sort Bartoli, Carlos Guillermo
title Ascorbate content of wheat leaves is not determined by maximal L-galactono-1,4-lactone dehydrogenase (GalLDH) activity under drought stress
title_short Ascorbate content of wheat leaves is not determined by maximal L-galactono-1,4-lactone dehydrogenase (GalLDH) activity under drought stress
title_full Ascorbate content of wheat leaves is not determined by maximal L-galactono-1,4-lactone dehydrogenase (GalLDH) activity under drought stress
title_fullStr Ascorbate content of wheat leaves is not determined by maximal L-galactono-1,4-lactone dehydrogenase (GalLDH) activity under drought stress
title_full_unstemmed Ascorbate content of wheat leaves is not determined by maximal L-galactono-1,4-lactone dehydrogenase (GalLDH) activity under drought stress
title_sort ascorbate content of wheat leaves is not determined by maximal l-galactono-1,4-lactone dehydrogenase (galldh) activity under drought stress
publishDate 2005
url http://sedici.unlp.edu.ar/handle/10915/83152
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