Spatial organization of the vindoline biosynthetic pathway in Catharanthus roseus.

Détails

ID Serval
serval:BIB_009368257D5D
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Spatial organization of the vindoline biosynthetic pathway in Catharanthus roseus.
Périodique
Journal of plant physiology
Auteur(s)
Guirimand G., Guihur A., Poutrain P., Héricourt F., Mahroug S., St-Pierre B., Burlat V., Courdavault V.
ISSN
1618-1328 (Electronic)
ISSN-L
0176-1617
Statut éditorial
Publié
Date de publication
15/04/2011
Peer-reviewed
Oui
Volume
168
Numéro
6
Pages
549-557
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Résumé
Vindoline constitutes the main terpenoid indole alkaloid accumulated in leaves of Catharanthus roseus, and four genes involved in its biosynthesis have been identified. However, the spatial organization of the tabersonine-to-vindoline biosynthetic pathway is still incomplete. To pursue the characterization of this six-step conversion, we illustrated, with in situ hybridization, that the transcripts of the second biosynthetic enzyme, 16-hydroxytabersonine 16-O-methyltransferase (16OMT), are specifically localized to the aerial organ epidermis. At the subcellular level, by combining GFP imaging, bimolecular fluorescence complementation assays and yeast two-hybrid analysis, we established that the first biosynthetic enzyme, tabersonine 16-hydroxylase (T16H), is anchored to the ER as a monomer via a putative N-terminal helix that we cloned using a PCR approach. We also showed that 16OMT homodimerizes in the cytoplasm, allowing its exclusion from the nucleus and thus facilitating the uptake of T16H conversion product, although no T16H/16OMT interactions occur. Moreover, the two last biosynthetic enzymes, desacetoxyvindoline-4-hydroxylase (D4H) and deacetylvindoline-4-O-acetyltransferase (DAT), were shown to operate as monomers that reside in the nucleocytoplasmic compartment following passive diffusion to the nucleus allowed by the protein size. No D4H/DAT interactions were detected, suggesting the absence of metabolic channeling in the vindoline biosynthetic pathway. Finally, these results highlight the importance of the inter- and intracellular translocations of intermediates during the vindoline biosynthesis and their potential regulatory role.
Mots-clé
Acetyltransferases/genetics, Acetyltransferases/metabolism, Biosynthetic Pathways, Catharanthus/chemistry, Catharanthus/cytology, Catharanthus/enzymology, Catharanthus/metabolism, Cloning, Molecular, Cytosol/enzymology, Cytosol/metabolism, Endoplasmic Reticulum/enzymology, Endoplasmic Reticulum/metabolism, Gene Expression Regulation, Plant, Indole Alkaloids/metabolism, Methyltransferases/genetics, Methyltransferases/metabolism, Mixed Function Oxygenases/genetics, Mixed Function Oxygenases/metabolism, Molecular Sequence Data, Plant Epidermis/enzymology, Plant Epidermis/metabolism, Plant Leaves/cytology, Plant Leaves/enzymology, Plant Leaves/metabolism, Plant Proteins/genetics, Plant Proteins/metabolism, Quinolines/metabolism, Secologanin Tryptamine Alkaloids/metabolism, Vinblastine/analogs & derivatives, Vinblastine/biosynthesis, Vinblastine/metabolism
Pubmed
Web of science
Création de la notice
06/12/2018 15:26
Dernière modification de la notice
21/08/2019 6:32
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