title: Ester Cross-Link Profiling of the Cutin Polymer of Wild-Type and Cutin Synthase Tomato Mutants Highlights Different Mechanisms of Polymerization.
abstract: Cuticle function is closely related to the structure of the cutin polymer. However, the structure and formation of this hydrophobic polyester of glycerol and hydroxy/epoxy fatty acids has not been fully resolved. An apoplastic GDSL-lipase known as CUTIN SYNTHASE1 (CUS1) is required for cutin deposition in tomato (Solanum lycopersicum) fruit exocarp. In vitro, CUS1 catalyzes the self-transesterification of 2-monoacylglycerol of 9(10),16-dihydroxyhexadecanoic acid, the major tomato cutin monomer. This reaction releases glycerol and leads to the formation of oligomers with the secondary hydroxyl group remaining nonesterified. To check this mechanism in planta, a benzyl etherification of nonesterified hydroxyl groups of glycerol and hydroxy fatty acids was performed within cutin. Remarkably, in addition to a significant decrease in cutin deposition, mid-chain hydroxyl esterification of the dihydroxyhexadecanoic acid was affected in tomato RNA interference and ethyl methanesulfonate-cus1 mutants. Furthermore, in these mutants, the esterification of both sn-1,3 and sn-2 positions of glycerol was impacted, and their cutin contained a higher molar glycerol-to-dihydroxyhexadecanoic acid ratio. Therefore, in planta, CUS1 can catalyze the esterification of both primary and secondary alcohol groups of cutin monomers, and another enzymatic or nonenzymatic mechanism of polymerization may coexist with CUS1-catalyzed polymerization. This mechanism is poorly efficient with secondary alcohol groups and produces polyesters with lower molecular size. Confocal Raman imaging of benzyl etherified cutins showed that the polymerization is heterogenous at the fruit surface. Finally, by comparing tomato mutants either affected or not in cutin polymerization, we concluded that the level of cutin cross-linking had no significant impact on water permeance.
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Glenn
authors.initials: G
authors.lastname: Philippe
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Cédric
authors.initials: C
authors.lastname: Gaillard
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Johann
authors.initials: J
authors.lastname: Petit
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Nathalie
authors.initials: N
authors.lastname: Geneix
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Michèle
authors.initials: M
authors.lastname: Dalgalarrondo
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Cécile
authors.initials: C
authors.lastname: Bres
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Mauxion
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Rochus
authors.initials: R
authors.lastname: Franke
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Christophe
authors.initials: C
authors.lastname: Rothan
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Lukas
authors.identifier: http://orcid.org/0000-0001-7003-9929
authors.initials: L
authors.lastname: Schreiber
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.).
authors.forename: Didier
authors.initials: D
authors.lastname: Marion
authors.affiliation: Institut National de la Recherche Agronomique, Research Unit Biopolymers Interactions Assemblies, BP71627 44316, Nantes cedex 3, France (G.P., C.G., N.G., M.D., D.M., B.B.);Institut National de la Recherche Agronomique, University of Bordeaux, Unité Mixte de Recherche 1332 Fruit Biology and Pathology, 33140 Villenave d'Ornon, France (J.P., C.B., J.-P.M., C.R.); andInstitute of Cellular and Molecular Botany, University of Bonn, D-53115 Bonn, Germany (R.F., L.S.) benedicte.bakan@nantes.inra.fr.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Bakan
mesh_terms: D004951:Esterification; D004952:Esters / Q000737:chemistry; D005020:Ethyl Methanesulfonate / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry; D005638:Fruit / Q000201:enzymology / Q000235:genetics; D005990:Glycerol / Q000737:chemistry; D008049:Lipase / Q000235:genetics / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics; D008563:Membrane Lipids / Q000737:chemistry* / Q000378:metabolism; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011091:Polyesters / Q000737:chemistry; D058105:Polymerization; D011108:Polymers / Q000737:chemistry
chemical_list: D004952:Esters; D005227:Fatty Acids; D008563:Membrane Lipids; D010940:Plant Proteins; D011091:Polyesters; D011108:Polymers; C000521:cutin; D005020:Ethyl Methanesulfonate; D008049:Lipase; D005990:Glycerol