title: Remodeling of pectin and hemicelluloses in tomato pericarp during fruit growth.
abstract: Tomato fruit texture depends on histology and cell wall architecture, both under genetic and developmental controls. If ripening related cell wall modifications have been well documented with regard to softening, little is known about cell wall construction during early fruit development. Identification of key events and their kinetics with regard to tissue architecture and cell wall development can provide new insights on early phases of texture elaboration. In this study, changes in pectin and hemicellulose chemical characteristics and location were investigated in the pericarp tissue of tomato (Solanum lycopersicon var Levovil) at four stages of development (7, 14 and 21day after anthesis (DPA) and mature green stages). Analysis of cell wall composition and polysaccharide structure revealed that both are continuously modified during fruit development. At early stages, the relative high rhamnose content in cell walls indicates a high synthesis of rhamnogalacturonan I next to homogalacturonan. Fine tuning of rhamnogalacturonan I side chains appears to occur from the cell expansion phase until prior to the mature green stage. Cell wall polysaccharide remodelling also concerns xyloglucans and (galacto)glucomannans, the major hemicelluloses in tomato cell walls. In situ localization of cell wall polysaccharides in pericarp tissue revealed non-ramified RG-I rich pectin and XyG at cellular junctions and in the middle lamella of young fruit. Blocks of non-methyl esterified homogalacturonan are detected as soon as 14 DPA in the mesocarp and remained restricted to cell corner and middle lamella whatever the stages. These results point to new questions about the role of pectin RGI and XyG in cell adhesion and its maintenance during cell expansion.
authors.affiliation: INRA, UR1268 Biopolymères, Interactions et Assemblages, BP 71627, F-44316 Nantes, France.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Guillon
authors.affiliation: INRA, UR1268 Biopolymères, Interactions et Assemblages, BP 71627, F-44316 Nantes, France.
authors.forename: Adeline
authors.initials: A
authors.lastname: Moïse
authors.affiliation: INRA, UR1268 Biopolymères, Interactions et Assemblages, BP 71627, F-44316 Nantes, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Quemener
authors.affiliation: INRA, UR1268 Biopolymères, Interactions et Assemblages, BP 71627, F-44316 Nantes, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Bouchet
authors.affiliation: INRA, UR1268 Biopolymères, Interactions et Assemblages, BP 71627, F-44316 Nantes, France.
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Devaux
authors.affiliation: INRA, UR1268 Biopolymères, Interactions et Assemblages, BP 71627, F-44316 Nantes, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Alvarado
authors.affiliation: INRA, UR1268 Biopolymères, Interactions et Assemblages, BP 71627, F-44316 Nantes, France. Electronic address: marc.lahaye@inra.fr.
authors.forename: Marc
authors.initials: M
authors.lastname: Lahaye
mesh_terms: D002473:Cell Wall / Q000378:metabolism; D000939:Epitopes / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005638:Fruit / Q000033:anatomy & histology* / Q000166:cytology / Q000254:growth & development* / Q000648:ultrastructure; D005936:Glucans / Q000378:metabolism; D018551:Solanum lycopersicum / Q000033:anatomy & histology* / Q000166:cytology / Q000378:metabolism*; D009929:Organ Size; D010368:Pectins / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014990:Xylans / Q000378:metabolism
chemical_list: D000939:Epitopes; D005936:Glucans; D011134:Polysaccharides; D014990:Xylans; C029353:xyloglucan; C007916:hemicellulose; D010368:Pectins; C003181:polygalacturonic acid
keywords: Cell wall; Electron microscopy; Fruit development; Immunocytochemistry; Mass spectrometry; Solanum lycopersicum