title: Role of reactive oxygen species in the regulation of Arabidopsis seed dormancy.
abstract: Freshly harvested seeds of Arabidopsis thaliana, Columbia (Col) accession were dormant when imbibed at 25°C in the dark. Their dormancy was alleviated by continuous light during imbibition or by 5 weeks of storage at 20°C (after-ripening). We investigated the possible role of reactive oxygen species (ROS) in the regulation of Col seed dormancy. After 24 h of imbibition at 25°C, non-dormant seeds produced more ROS than dormant seeds, and their catalase activity was lower. In situ ROS localization revealed that germination was associated with an accumulation of superoxide and hydrogen peroxide in the radicle. ROS production was temporally and spatially regulated: ROS were first localized within the cytoplasm upon imbibition of non-dormant seeds, then in the nucleus and finally in the cell wall, which suggests that ROS play different roles during germination. Imbibition of dormant and non-dormant seeds in the presence of ROS scavengers or donors, which inhibited or stimulated germination, respectively, confirmed the role of ROS in germination. Freshly harvested seeds of the mutants defective in catalase (cat2-1) and vitamin E (vte1-1) did not display dormancy; however, seeds of the NADPH oxidase mutants (rbohD) were deeply dormant. Expression of a set of genes related to dormancy upon imbibition in the cat2-1 and vet1-1 seeds revealed that their non-dormant phenotype was probably not related to ABA or gibberellin metabolism, but suggested that ROS could trigger germination through gibberellin signaling activation.
authors.affiliation: UR5 EAC7180 CNRS, Université Pierre et Marie Curie-Paris 6, Paris, France.
authors.forename: Juliette
authors.initials: J
authors.lastname: Leymarie
authors.forename: Giedré
authors.initials: G
authors.lastname: Vitkauskaité
authors.forename: Hai Ha
authors.initials: HH
authors.lastname: Hoang
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Gendreau
authors.forename: Virginie
authors.initials: V
authors.lastname: Chazoule
authors.forename: Patrice
authors.initials: P
authors.lastname: Meimoun
authors.forename: Françoise
authors.initials: F
authors.lastname: Corbineau
authors.forename: Hayat
authors.initials: H
authors.lastname: El-Maarouf-Bouteau
authors.forename: Christophe
authors.initials: C
authors.lastname: Bailly
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D060146:Ecotype; D016166:Free Radical Scavengers / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D005980:Glutathione Reductase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D057445:Plant Dormancy / Q000187:drug effects / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012639:Seeds / Q000187:drug effects / Q000235:genetics; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D013481:Superoxides; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase