title: Elucidating the functional role of endoreduplication in tomato fruit development.
abstract: BACKGROUND
  Endoreduplication is the major source of endopolyploidy in higher plants. The process of endoreduplication results from the ability of cells to modify their classical cell cycle into a partial cell cycle where DNA synthesis occurs independently from mitosis. Despite the ubiquitous occurrence of the phenomenon in eukaryotic cells, the physiological meaning of endoreduplication remains vague, although several roles during plant development have been proposed, mostly related to cell differentiation and cell size determination.
  
  
  METHODS
  Here recent advances in the knowledge of endoreduplication and fruit organogenesis are reviewed, focusing on tomato (Solanum lycopersicum) as a model, and the functional analyses of endoreduplication-associated regulatory genes in tomato fruit are described.
  
  
  CONCLUSIONS
  The cyclin-dependent kinase inhibitory kinase WEE1 and the anaphase promoting complex activator CCS52A both participate in the control of cell size and the endoreduplication process driving cell expansion during early fruit development in tomato. Moreover the fruit-specific functional analysis of the tomato CDK inhibitor KRP1 reveals that cell size and fruit size determination can be uncoupled from DNA ploidy levels, indicating that endoreduplication acts rather as a limiting factor for cell growth. The overall functional data contribute to unravelling the physiological role of endoreduplication in growth induction of fleshy fruits.
authors.affiliation: Institut National de la Recherche Agronomique, Université de Bordeaux, Unité Mixte de Recherche 619 sur la Biologie du Fruit, Villenave d'Ornon Cedex, France. chevalie@bordeaux.inra.fr
authors.forename: Christian
authors.initials: C
authors.lastname: Chevalier
authors.forename: Mehdi
authors.initials: M
authors.lastname: Nafati
authors.forename: Elodie
authors.initials: E
authors.lastname: Mathieu-Rivet
authors.forename: Matthieu
authors.initials: M
authors.lastname: Bourdon
authors.forename: Nathalie
authors.initials: N
authors.lastname: Frangne
authors.forename: Catherine
authors.initials: C
authors.lastname: Cheniclet
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Renaudin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Gévaudant
authors.forename: Michel
authors.initials: M
authors.lastname: Hernould
mesh_terms: D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D005638:Fruit / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D020440:Gene Duplication / Q000235:genetics*; D018551:Solanum lycopersicum / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D008954:Models, Biological
chemical_list: D018844:Cyclin-Dependent Kinases