ABCG transporters export cutin precursors for the formation of the plant cuticle

Carolina Elejalde-Palmett; Ignacio Martinez San Segundo; Imène Garroum; Laurence Charrier; Damien De Bellis; Antonio Mucciolo; Aurore Guerault; Jie Liu; Viktoria Zeisler-Diehl; Asaph Aharoni; Lukas Schreiber; Bénédicte Bakan; Mads H Clausen; Markus Geisler; Christiane Nawrath

doi:10.1016/j.cub.2021.02.056

ABCG transporters export cutin precursors for the formation of the plant cuticle

Curr Biol. 2021 May 24;31(10):2111-2123.e9. doi: 10.1016/j.cub.2021.02.056. Epub 2021 Mar 22.

Authors

Affiliations

¹ Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland.
² Center for Nanomedicine and Theranostics, Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
³ Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland.
⁴ Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland; Electron Microscopy Facility, University of Lausanne, 1015 Lausanne, Switzerland.
⁵ Electron Microscopy Facility, University of Lausanne, 1015 Lausanne, Switzerland.
⁶ Institute of Cellular and Molecular Botany, University of Bonn, 53115 Bonn, Germany.
⁷ Department of Plant Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
⁸ INRAE, Biopolymers Interactions Assemblies UR1268, 44316 Nantes Cedex 3, France.
⁹ Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland. Electronic address: christiane.nawrath@unil.ch.

PMID: 33756108
DOI: 10.1016/j.cub.2021.02.056

Abstract

The plant cuticle is deposited on the surface of primary plant organs, such as leaves, fruits, and floral organs, forming a diffusion barrier and protecting the plant against various abiotic and biotic stresses. Cutin, the structural polyester of the plant cuticle, is synthesized in the apoplast. Plasma-membrane-localized ATP-binding cassette (ABC) transporters of the G family have been hypothesized to export cutin precursors. Here, we characterize SlABCG42 of tomato representing an ortholog of AtABCG32 in Arabidopsis. SlABCG42 expression in Arabidopsis complements the cuticular deficiencies of the Arabidopsis pec1/abcg32 mutant. RNAi-dependent downregulation of both tomato genes encoding proteins highly homologous to AtABCG32 (SlABCG36 and SlABCG42) leads to reduced cutin deposition and formation of a thinner cuticle in tomato fruits. By using a tobacco (Nicotiana benthamiana) protoplast system, we show that AtABCG32 and SlABCG42 have an export activity for 10,16-dihydroxy hexadecanoyl-2-glycerol, a cutin precursor in vivo. Interestingly, also free ω-hydroxy hexadecanoic acid as well as hexadecanedioic acid were exported, furthering the research on the identification of cutin precursors in vivo and the respective mechanisms of their integration into the cutin polymer.

Keywords: ABC transporter; Arabidopsis; acyl lipid; cuticle; cutin; diffusion barrier; plasma membrane; tomato; transport; wax.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

ATP Binding Cassette Transporter, Subfamily G* / genetics
ATP Binding Cassette Transporter, Subfamily G* / metabolism
Arabidopsis / genetics
Arabidopsis / metabolism
Arabidopsis Proteins
Gene Expression Regulation, Plant
Membrane Lipids
Nicotiana / metabolism
Plant Epidermis*
Plant Leaves / metabolism
Plant Proteins* / genetics
Plant Proteins* / metabolism
Solanum lycopersicum* / genetics
Solanum lycopersicum* / metabolism

Substances

ABCG32 protein, Arabidopsis
ATP Binding Cassette Transporter, Subfamily G
Arabidopsis Proteins
Membrane Lipids
Plant Proteins
cutin