title: The auxin Sl-IAA17 transcriptional repressor controls fruit size via the regulation of endoreduplication-related cell expansion.
abstract: Auxin is known to regulate cell division and cell elongation, thus controlling plant growth and development. Part of the auxin signaling pathway depends on the fine-tuned degradation of the auxin/indole acetic acid (Aux/IAA) transcriptional repressors. Recent evidence indicates that Aux/IAA proteins play a role in fruit development in tomato (Solanum lycopersicum Mill.), a model species for fleshy fruit development. We report here on the functional characterization of Sl-IAA17 during tomato fruit development. Silencing of Sl-IAA17 by an RNA interference (RNAi) strategy resulted in the production of larger fruit than the wild type. Histological analyses of the fruit organ and tissues demonstrated that this phenotype was associated with a thicker pericarp, rather than larger locules and/or a larger number of seeds. Microscopic analysis demonstrated that the higher pericarp thickness in Sl-IAA17 RNAi fruits was not due to a larger number of cells, but to the increase in cell size. Finally, we observed that the cell expansion in the transgenic fruits is tightly coupled with higher ploidy levels than in the wild type, suggesting a stimulation of the endoreduplication process. In conclusion, this work provides new insights into the function of the Aux/IAA pathway in fleshy fruit development, especially fruit size and cell size determination in tomato.
authors.affiliation: Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France.
authors.forename: Liyan
authors.initials: L
authors.lastname: Su
authors.affiliation: Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France.
authors.forename: Carole
authors.initials: C
authors.lastname: Bassa
authors.affiliation: Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France.
authors.forename: Corinne
authors.initials: C
authors.lastname: Audran
authors.affiliation: Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Mila
authors.affiliation: INRA, UMR990 Génomique et Biotechnologie des Fruits, 24 Chemin de Borde Rouge, CS 52627, F-31326 Castanet-Tolosan, France INRA, UMR1332 Biologie du Fruit et Pathologie, CS 20032, F-33882 Villenave d'Ornon, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Cheniclet
authors.affiliation: INRA, UMR990 Génomique et Biotechnologie des Fruits, 24 Chemin de Borde Rouge, CS 52627, F-31326 Castanet-Tolosan, France INRA, UMR1332 Biologie du Fruit et Pathologie, CS 20032, F-33882 Villenave d'Ornon, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Chevalier
authors.affiliation: Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France.
authors.forename: Mondher
authors.initials: M
authors.lastname: Bouzayen
authors.affiliation: Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Roustan
authors.affiliation: Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France Université de Toulouse, INP-ENSA Toulouse, UMR990 Génomique et Biotechnologie des Fruits, Avenue de l'Agrobiopole, CS 32607, F-31326 Castanet-Tolosan, France chervin@ensat.fr.
authors.forename: Christian
authors.initials: C
authors.lastname: Chervin
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D062951:Endoreduplication; D005638:Fruit / Q000166:cytology* / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D007210:Indoleacetic Acids / Q000378:metabolism; D018551:Solanum lycopersicum / Q000033:anatomy & histology / Q000166:cytology / Q000254:growth & development*; D009929:Organ Size; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011123:Polyploidy; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010940:Plant Proteins; D012097:Repressor Proteins
keywords: Aux/IAA; Auxin; Cell expansion; Endoreduplication; Fruit development; Tomato