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Nat Plants. 2019 Jun;5(6):604-615. doi: 10.1038/s41477-019-0429-5. Epub 2019 Jun 10.

Sphingolipid biosynthesis modulates plasmodesmal ultrastructure and phloem unloading.

Author information

1
The Sainsbury Laboratory, University of Cambridge, Cambridge, UK.
2
Helsinki Institute of Life Science/Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
3
Department of Biotechnology, Indian Institute of Technology, Roorkee, India.
4
Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, Villenave d'Ornon, France.
5
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
6
Laboratoire de Biophysique Moléculaire aux Interfaces, TERRA Research Centre, GX ABT, Université de Liège, Gembloux, Belgium.
7
Bordeaux Imaging Centre, Plant Imaging Platform, UMS 3420, INRA-CNRS-INSERM, University of Bordeaux, Villenave-d'Ornon, France.
8
Department of Horticulture, Faculty of Agriculture and Natural Resources, Persian Gulf University, Bushehr, Iran.
9
Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
10
Biosciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
11
Joint Bioenergy Institute, Emeryville, CA, USA.
12
School of Biological Sciences, Washington State University, Pullman, WA, USA.
13
Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA.
14
Laboratoire de Biogenèse Membranaire, UMR 5200, CNRS, Université de Bordeaux, Villenave d'Ornon, France. emmanuelle.bayer@u-bordeaux.fr.
15
The Sainsbury Laboratory, University of Cambridge, Cambridge, UK. yrjo.helariutta@slcu.cam.ac.uk.
16
Helsinki Institute of Life Science/Institute of Biotechnology, University of Helsinki, Helsinki, Finland. yrjo.helariutta@slcu.cam.ac.uk.

Abstract

During phloem unloading, multiple cell-to-cell transport events move organic substances to the root meristem. Although the primary unloading event from the sieve elements to the phloem pole pericycle has been characterized to some extent, little is known about post-sieve element unloading. Here, we report a novel gene, PHLOEM UNLOADING MODULATOR (PLM), in the absence of which plasmodesmata-mediated symplastic transport through the phloem pole pericycle-endodermis interface is specifically enhanced. Increased unloading is attributable to a defect in the formation of the endoplasmic reticulum-plasma membrane tethers during plasmodesmal morphogenesis, resulting in the majority of pores lacking a visible cytoplasmic sleeve. PLM encodes a putative enzyme required for the biosynthesis of sphingolipids with very-long-chain fatty acid. Taken together, our results indicate that post-sieve element unloading involves sphingolipid metabolism, which affects plasmodesmal ultrastructure. They also raise the question of how and why plasmodesmata with no cytoplasmic sleeve facilitate molecular trafficking.

Comment in

PMID:
31182845
PMCID:
PMC6565433
[Available on 2019-12-10]
DOI:
10.1038/s41477-019-0429-5
[Indexed for MEDLINE]
Free PMC Article

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