title: In vitro auxin treatment promotes cell division and delays endoreduplication in developing seeds of the model legume species Medicago truncatula.
abstract: The role of auxins in the morphogenesis of immature seeds of Medicago truncatula was studied, focusing on the transition from the embryo cell division phase to seed maturation. We analyzed seed development in vitro, by flow cytometry, and through the determination of the kinetics of seed fresh weight and size. Thus, seeds were harvested at 8, 10 and 12 days after pollination and cultured in vitro on a medium either without auxin or supplemented with indole-3-butyric acid (IBA) or naphthalene acetic acid (NAA) at 1 mg l(-1). All parameters studied were determined every 2 days from the start of in vitro culture. The results showed that both auxins increased the weight and size of seeds with NAA having a stronger effect than IBA. We further demonstrated that the auxin treatments modulate the transition between mitotic cycles and endocycles in M. truncatula developing seed by favoring sustained cell divisions while simultaneously prolonging endoreduplication, which is known to be the cytogenetical imprint of the transition from the cell division phase to the storage protein accumulation phase during seed development.
authors.affiliation: INRA CR de Dijon, UMR1347 Agroécologie, BP 86510, F-21065, Dijon Cedex, France.
authors.forename: Rana M
authors.initials: RM
authors.lastname: Atif
authors.forename: Florian
authors.initials: F
authors.lastname: Boulisset
authors.forename: Catherine
authors.initials: C
authors.lastname: Conreux
authors.forename: Richard
authors.initials: R
authors.lastname: Thompson
authors.forename: Sergio J
authors.initials: SJ
authors.lastname: Ochatt
mesh_terms: D018533:Biomass; D002455:Cell Division / Q000187:drug effects*; D062951:Endoreduplication / Q000187:drug effects*; D005434:Flow Cytometry; D007210:Indoleacetic Acids / Q000494:pharmacology*; D046913:Medicago truncatula / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development*; D008954:Models, Biological; D012639:Seeds / Q000166:cytology* / Q000187:drug effects / Q000235:genetics / Q000254:growth & development
chemical_list: D007210:Indoleacetic Acids