title: Involvement of auxin dynamics in hypergravity-induced promotion of lignin-related gene expression in Arabidopsis inflorescence stems.
abstract: Recent studies have shown that hypergravity enhances lignification through up-regulation of the expression of lignin biosynthesis-related genes, although its hormonal signalling mechanism is unknown. The effects of hypergravity on auxin dynamics were examined using Arabidopsis plants that were transformed with the auxin reporter gene construct DR5::GUS. Hypergravity treatment at 300 g significantly increased β-glucuronidase activity in inflorescence stems of DR5::GUS plants, indicating that endogenous auxin accumulation was enhanced by hypergravity treatment. The hypergravity-related increased expression levels of both DR5::GUS and lignin biosynthesis-related genes in inflorescence stems were suppressed after disbudding, indicating that the increased expression of lignin biosynthesis-related genes is dependent on an increase in auxin influx from the shoot apex.
authors.affiliation: Department of Biology, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tamaoki
authors.forename: Ichirou
authors.initials: I
authors.lastname: Karahara
authors.forename: Takumi
authors.initials: T
authors.lastname: Nishiuchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Wakasugi
authors.forename: Kyoji
authors.initials: K
authors.lastname: Yamada
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Kamisaka
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D056626:Inflorescence / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism*
chemical_list: D007210:Indoleacetic Acids; D008031:Lignin