title: Contribution of gibberellin deactivation by AtGA2ox2 to the suppression of germination of dark-imbibed Arabidopsis thaliana seeds.
abstract: Gibberellin levels in imbibed Arabidopsis thaliana seeds are regulated by light via phytochrome, presumably through regulation of gibberellin biosynthesis genes, AtGA3ox1 and AtGA3ox2, and a deactivation gene, AtGA2ox2. Here, we show that a loss-of-function ga2ox2 mutation causes an increase in GA(4) levels and partly suppresses the germination inability during dark imbibition after inactivation of phytochrome. Experiments using 2,2-dimethylGA(4), a GA(4) analog resistant to gibberellin 2-oxidase, in combination with ga2ox2 mutant seeds suggest that the efficiency of deactivation of exogenous GA(4) by AtGA2ox2 is dependent on light conditions, which partly explains phytochrome-mediated changes in gibberellin effectiveness (sensitivity) found in previous studies.
authors.affiliation: RIKEN Plant Science Center, Suehiro-cho 1-7-22, Tsurumi-ku, Yokohama, Kanagawa, 230-0045 Japan.
authors.forename: Yukika
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Noriko
authors.initials: N
authors.lastname: Takeda-Kamiya
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hanada
authors.forename: Mikihiro
authors.initials: M
authors.lastname: Ogawa
authors.forename: Ayuko
authors.initials: A
authors.lastname: Kuwahara
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Seo
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kamiya
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Yamaguchi
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D003624:Darkness; D017343:Genes, Plant; D018525:Germination; D005875:Gibberellins / Q000378:metabolism* / Q000494:pharmacology; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype
chemical_list: D005875:Gibberellins; D006899:Mixed Function Oxygenases; C121463:gibberellin 2-dioxygenase