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Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
agricultural and biological sciences
GDP-d-mannose 3,5-epimerase (GME) plays a key role at the intersection of ascorbate and non-cellulosic cell-wall biosynthesis in tomato
Plant Journal, Volume 60, No. 3, Year 2009
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Description
The GDP-d-mannose 3,5-epimerase (GME, EC 5.1.3.18), which converts GDP-d-mannose to GDP-l-galactose, is generally considered to be a central enzyme of the major ascorbate biosynthesis pathway in higher plants, but experimental evidence for its role in planta is lacking. Using transgenic tomato lines that were RNAi-silenced for GME, we confirmed that GME does indeed play a key role in the regulation of ascorbate biosynthesis in plants. In addition, the transgenic tomato lines exhibited growth defects affecting both cell division and cell expansion. A further remarkable feature of the transgenic plants was their fragility and loss of fruit firmness. Analysis of the cell-wall composition of leaves and developing fruit revealed that the cell-wall monosaccharide content was altered in the transgenic lines, especially those directly linked to GME activity, such as mannose and galactose. In agreement with this, immunocytochemical analyses showed an increase of mannan labelling in stem and fruit walls and of rhamnogalacturonan labelling in the stem alone. The results of MALDI-TOF fingerprinting of mannanase cleavage products of the cell wall suggested synthesis of specific mannan structures with modified degrees of substitution by acetate in the transgenic lines. When considered together, these findings indicate an intimate linkage between ascorbate and non-cellulosic cell-wall polysaccharide biosynthesis in plants, a fact that helps to explain the common factors in seemingly unrelated traits such as fruit firmness and ascorbate content. © 2009 Blackwell Publishing Ltd.
Authors & Co-Authors
Gilbert, Louise
France, Bordeaux
Université de Bordeaux
Alhagdow, Moftah
France, Bordeaux
Université de Bordeaux
Libya, Tripoli
University of Tripoli
Nunes-Nesi, Adriano
Germany, Potsdam
Max Planck Institute of Molecular Plant Physiology
Quemener, Bernard
France, Nantes
Biopolymères, Interactions Assemblages Bia
Guillon, Fabienne
France, Nantes
Biopolymères, Interactions Assemblages Bia
Bouchet, Brigitte
France, Nantes
Biopolymères, Interactions Assemblages Bia
Faurobert, Mireille
France, Montfavet
Génétique et Amélioration Des Fruits et Légumes Gafl
Gouble, Barbara
France, Avignon
Centre de Recherche Inrae Provence-alpes-côte D’azur
Page, David
France, Avignon
Centre de Recherche Inrae Provence-alpes-côte D’azur
Garcia, Virginie
France, Bordeaux
Université de Bordeaux
Petit, Johann
France, Bordeaux
Université de Bordeaux
Stevens, Rebecca G.
France, Montfavet
Génétique et Amélioration Des Fruits et Légumes Gafl
Causse, Mathilde A.
France, Montfavet
Génétique et Amélioration Des Fruits et Légumes Gafl
Fernie, Alisdair Robert
Germany, Potsdam
Max Planck Institute of Molecular Plant Physiology
Lahaye, Marc
France, Nantes
Biopolymères, Interactions Assemblages Bia
Rothan, Christophe
France, Bordeaux
Université de Bordeaux
Baldet, Pierre
France, Bordeaux
Université de Bordeaux
Statistics
Citations: 198
Authors: 17
Affiliations: 6
Identifiers
Doi:
10.1111/j.1365-313X.2009.03972.x
ISSN:
09607412
e-ISSN:
1365313X