Sphingolipids involvement in plant endomembrane differentiation: the BY2 case

Authors

  • Anne Aubert,

    1. Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355/IFR87, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), 91198, Gif-sur-Yvette Cedex, France
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    • These authors have equally contributed to this work.

  • Jessica Marion,

    1. Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355/IFR87, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), 91198, Gif-sur-Yvette Cedex, France
    2. Pôle de Biologie Cellulaire, Imagif, Centre de Recherche de Gif, (FRC3115), CNRS, IFR 87, 91198, Gif-sur-Yvette Cedex, France
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    • These authors have equally contributed to this work.

  • Claire Boulogne,

    1. Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355/IFR87, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), 91198, Gif-sur-Yvette Cedex, France
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  • Mickael Bourge,

    1. Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355/IFR87, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), 91198, Gif-sur-Yvette Cedex, France
    2. Pôle de Biologie Cellulaire, Imagif, Centre de Recherche de Gif, (FRC3115), CNRS, IFR 87, 91198, Gif-sur-Yvette Cedex, France
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  • Susana Abreu,

    1. Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355/IFR87, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), 91198, Gif-sur-Yvette Cedex, France
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  • Yannick Bellec,

    1. Institut Jean-Pierre Bourgin, unité mixte de recherche 1318, INRA-AgroParisTech, Centre de Versailles-Grignon, 78026 Versailles cedex, France
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  • Jean-Denis Faure,

    1. Institut Jean-Pierre Bourgin, unité mixte de recherche 1318, INRA-AgroParisTech, Centre de Versailles-Grignon, 78026 Versailles cedex, France
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  • Béatrice Satiat-Jeunemaitre

    Corresponding author
    1. Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355/IFR87, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), 91198, Gif-sur-Yvette Cedex, France
    2. Pôle de Biologie Cellulaire, Imagif, Centre de Recherche de Gif, (FRC3115), CNRS, IFR 87, 91198, Gif-sur-Yvette Cedex, France
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(fax +33 (0)1 69 82 3355; e-mail bsj@isv.cnrs-gif.fr).

Summary

Sphingolipids play an essential role in the functioning of the secretory pathway in eukaryotic organisms. Their importance in the functional organization of plant cells has not been studied in any detail before. The sphingolipid synthesis inhibitor fumonisin B1 (FB1), a mycotoxin acting as a specific inhibitor of ceramide synthase, was tested for its effects on cell growth, cell polarity, cell shape, cell cycle and on the ultrastructure of BY2 cells. We used cell lines expressing different GFP-tagged markers for plant cell compartments, as well as a Golgi marker fused to the photoconvertible protein Kaede. Light and electron microscopy, combined with flow cytometry, were applied to analyse the morphodynamics and architecture of compartments of the secretory pathway. The results indicate that FB1 treatment had severe effects on cell growth and cell shape, and induced a delay in cell division processes. The cell changes were accompanied by the formation of the endoplasmic reticulum (ER)-derived tubular aggregates (FB1-induced compartments), together with an inhibition of cargo transport from the ER to the Golgi apparatus. A change in polar localization of the auxin transporter PIN1 was also observed, but endocytic processes were little affected. Electron microscopy studies confirmed that molecular FB1 targets were distinct from brefeldin A (BFA) targets. We propose that the reported effects of inhibition of ceramide biosynthesis reflect the importance of sphingolipids during cell growth and establishment of cell polarity in higher plant cells, notably through their contribution to the functional organization of the ER or its differentiation into distinct compartments.

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