Multi-regulated GDP-l-galactose phosphorylase calls the tune in ascorbate biosynthesis
2024
Baldet, Pierre | Mori, Kentaro | Prigent, Sylvain | Decros, Guillaume | Beauvoit, Bertrand | Colombié, Sophie | Pétriacq, Pierre | Gibon, Yves | Biologie du fruit et pathologie (BFP) ; Université de Bordeaux (UB)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Plateforme Bordeaux Metabolome ; Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-MetaboHUB-Bordeaux ; MetaboHUB-MetaboHUB | Université de Bordeaux (UB) | MetaboHUB-Bordeaux ; MetaboHUB | MetaboHUB | This work was supported by the Plant Biology and Breeding Division of INRAE, LIA FreQUenCE INRAE-Tsukuba University (2020–2024) and GPR Bordeaux Plant Sciences in the framework of the IdEX Bordeaux University ‘Investments for the Future’ program.
International audience
显示更多 [+] 显示较少 [-]英语. Ascorbate is involved in numerous vital processes, in particular in response to abiotic but also biotic stresses whose frequency and amplitude increase with climate change. Ascorbate levels vary greatly depending on species, tissues, or stages of development, but also in response to stress. Since its discovery, the ascorbate biosynthetic pathway has been intensely studied and it appears that GDP-l-galactose phosphorylase (GGP) is the enzyme with the greatest role in the control of ascorbate biosynthesis. Like other enzymes of this pathway, its expression is induced by various environmental and also developmental factors. Although mRNAs encoding it are among the most abundant in the transcriptome, the protein is only present in very small quantities. In fact, GGP translation is repressed by a negative feedback mechanism involving a small open reading frame located upstream of the coding sequence (uORF). Moreover, its activity is inhibited by a PAS/LOV type photoreceptor, the action of which is counteracted by blue light. Consequently, this multi-level regulation of GGP would allow fine control of ascorbate synthesis. Indeed, experiments varying the expression of GGP have shown that it plays a central role in response to stress. This new understanding will be useful for developing varieties adapted to future environmental conditions.
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