Cellular and Subcellular Compartmentation of the 2C-Methyl-D-Erythritol 4-Phosphate Pathway in the Madagascar Periwinkle

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Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_6A5B661B067D
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Cellular and Subcellular Compartmentation of the 2C-Methyl-D-Erythritol 4-Phosphate Pathway in the Madagascar Periwinkle
Journal
Plants
Author(s)
Guirimand Grégory, Guihur Anthony, Perello Catalina, Phillips Michael, Mahroug Samira, Oudin Audrey, Dugé de Bernonville Thomas, Besseau Sébastien, Lanoue Arnaud, Giglioli-Guivarc'h Nathalie, Papon Nicolas, St-Pierre Benoit, Rodríguez-Concepcíon Manuel, Burlat Vincent, Courdavault Vincent
ISSN
2223-7747
Publication state
Published
Issued date
07/04/2020
Volume
9
Number
4
Pages
E462
Language
english
Abstract
The Madagascar periwinkle (Catharanthus roseus) synthesizes the highly valuable monoterpene indole alkaloids (MIAs) through a long metabolic route initiated by the 2C-methyl-D-erythritol 4-phosphate (MEP) pathway. In leaves, a complex compartmentation of the MIA biosynthetic pathway occurs at both the cellular and subcellular levels, notably for some gene products of the MEP pathway. To get a complete overview of the pathway organization, we cloned four genes encoding missing enzymes involved in the MEP pathway before conducting a systematic analysis of transcript distribution and protein subcellular localization. RNA in situ hybridization revealed that all MEP pathway genes were coordinately and mainly expressed in internal phloem-associated parenchyma of young leaves, reinforcing the role of this tissue in MIA biosynthesis. At the subcellular level, transient cell transformation and expression of fluorescent protein fusions showed that all MEP pathway enzymes were targeted to plastids. Surprisingly, two isoforms of 1-deoxy-D-xylulose 5-phosphate synthase and 1-deoxy-D-xylulose 5-phosphate reductoisomerase initially exhibited an artifactual aggregated pattern of localization due to high protein accumulation. Immunogold combined with transmission electron microscopy, transient transformations performed with a low amount of transforming DNA and fusion/deletion experiments established that both enzymes were rather diffuse in stroma and stromules of plastids as also observed for the last six enzymes of the pathway. Taken together, these results provide new insights into a potential role of stromules in enhancing MIA precursor exchange with other cell compartments to favor metabolic fluxes towards the MIA biosynthesis.
Keywords
2C-methyl-D-erythritol 4-phosphate pathway, compartmentation, Catharanthus roseus, stromules, GFP imaging, localization artifact, alkaloids
Pubmed
Open Access
Yes
Create date
17/04/2020 14:22
Last modification date
30/07/2020 6:21
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