Spatial organization of the vindoline biosynthetic pathway in Catharanthus roseus.

Details

Serval ID
serval:BIB_009368257D5D
Type
Article: article from journal or magazin.
Collection
Publications
Title
Spatial organization of the vindoline biosynthetic pathway in Catharanthus roseus.
Journal
Journal of plant physiology
Author(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
Publication state
Published
Issued date
15/04/2011
Peer-reviewed
Oui
Volume
168
Number
6
Pages
549-557
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Abstract
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.
Keywords
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
Create date
06/12/2018 14:26
Last modification date
21/08/2019 5:32
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