title: BEN1, a gene encoding a dihydroflavonol 4-reductase (DFR)-like protein, regulates the levels of brassinosteroids in Arabidopsis thaliana.
abstract: The ben1-1D (bri1-5 enhanced 1-1dominant) mutant was identified via an activation-tagging screen for bri1-5 extragenic modifiers. bri1-5 is a weak mutant allele of the brassinosteroid receptor gene, BRI1. Overexpression of BEN1 greatly enhances the defective phenotypes of bri1-5 plants. Removal of BEN1 by gene disruption in a Col-0 wild-type background, on the other hand, promotes the elongation of organs. Because BEN1 encodes a novel protein homologous to dihydroflavonol 4-reductase (DFR) and anthocyanidin reductase (BAN), BEN1 is probably involved in a brassinosteroid metabolic pathway. Analyses of brassinosteroid profiles demonstrated that BEN1 is indeed responsible for regulating the levels of several brassinosteroids, including typhasterol, castasterone and brassinolide. In vivo feeding and in vitro biochemical assays suggest that BEN1 is probably involved in a new mechanism to regulate brassinosteroid levels. These results provide additional insight into the regulatory mechanisms of bioactive brassinosteroids.
authors.affiliation: Department of Botany and Microbiology, University of Oklahoma, OK 73019, USA.
authors.forename: Tong
authors.initials: T
authors.lastname: Yuan
authors.forename: Shozo
authors.initials: S
authors.lastname: Fujioka
authors.forename: Suguru
authors.initials: S
authors.lastname: Takatsuto
authors.forename: Shogo
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Gou
authors.forename: Kai
authors.initials: K
authors.lastname: He
authors.forename: Scott D
authors.initials: SD
authors.lastname: Russell
authors.forename: Jia
authors.initials: J
authors.lastname: Li
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D015536:Down-Regulation; D035264:Flowers / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008027:Light; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000378:metabolism; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism; D013256:Steroids / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D013256:Steroids; D000429:Alcohol Oxidoreductases; C523325:BEN1 protein, Arabidopsis