title: Regulation of auxin homeostasis and gradients in Arabidopsis roots through the formation of the indole-3-acetic acid catabolite 2-oxindole-3-acetic acid.
abstract: The native auxin, indole-3-acetic acid (IAA), is a major regulator of plant growth and development. Its nonuniform distribution between cells and tissues underlies the spatiotemporal coordination of many developmental events and responses to environmental stimuli. The regulation of auxin gradients and the formation of auxin maxima/minima most likely involve the regulation of both metabolic and transport processes. In this article, we have demonstrated that 2-oxindole-3-acetic acid (oxIAA) is a major primary IAA catabolite formed in Arabidopsis thaliana root tissues. OxIAA had little biological activity and was formed rapidly and irreversibly in response to increases in auxin levels. We further showed that there is cell type-specific regulation of oxIAA levels in the Arabidopsis root apex. We propose that oxIAA is an important element in the regulation of output from auxin gradients and, therefore, in the regulation of auxin homeostasis and response mechanisms.
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umea, Sweden.
authors.forename: Ales
authors.initials: A
authors.lastname: Pencík
authors.forename: Biljana
authors.initials: B
authors.lastname: Simonovik
authors.forename: Sara V
authors.initials: SV
authors.lastname: Petersson
authors.forename: Eva
authors.initials: E
authors.lastname: Henyková
authors.forename: Sibu
authors.initials: S
authors.lastname: Simon
authors.forename: Kathleen
authors.initials: K
authors.lastname: Greenham
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Mariusz
authors.initials: M
authors.lastname: Kowalczyk
authors.forename: Mark
authors.initials: M
authors.lastname: Estelle
authors.forename: Eva
authors.initials: E
authors.lastname: Zazímalová
authors.forename: Ondrej
authors.initials: O
authors.lastname: Novák
authors.forename: Göran
authors.initials: G
authors.lastname: Sandberg
authors.forename: Karin
authors.initials: K
authors.lastname: Ljung
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D002478:Cells, Cultured; D006706:Homeostasis; D007210:Indoleacetic Acids / Q000378:metabolism*; D009154:Mutation; D000078183:Oxindoles; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development*; D036226:Seedlings / Q000254:growth & development; D014026:Nicotiana / Q000166:cytology / Q000254:growth & development
chemical_list: D007210:Indoleacetic Acids; D000078183:Oxindoles; D010937:Plant Growth Regulators; C003013:2-oxindole-3-acetic acid