Takeda-Kamiya Noriko Hanada Atsushi 17289793 Kamiya Yuji Yamauchi Yukika Yamaguchi Shinjiro 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. Kuwahara Ayuko Ogawa Mikihiro 2007 Mar 3 Yamauchi Yukika et al. 2007 Mar. Plant Cell Physiol. 48(3):555-61. 48 Contribution of gibberellin deactivation by AtGA2ox2 to the suppression of germination of dark-imbibed Arabidopsis thaliana seeds. Seo Mitsunori 555-61