title: Abscisic acid is a negative regulator of root gravitropism in Arabidopsis thaliana.
abstract: The plant hormone abscisic acid (ABA) plays a role in root gravitropism and has led to an intense debate over whether ABA acts similar to auxin by translating the gravitational signal into directional root growth. While tremendous advances have been made in the past two decades in establishing the role of auxin in root gravitropism, little progress has been made in characterizing the role of ABA in this response. In fact, roots of plants that have undetectable levels of ABA and that display a normal gravitropic response have raised some serious doubts about whether ABA plays any role in root gravitropism. Here, we show strong evidence that ABA plays a role opposite to that of auxin and that it is a negative regulator of the gravitropic response of Arabidopsis roots.
authors.affiliation: School of Biotechnology, Kangwon National University, Chuncheon, Gangwon, South Korea.
authors.forename: Woong
authors.initials: W
authors.lastname: Han
authors.forename: Honglin
authors.initials: H
authors.lastname: Rong
authors.forename: Hanma
authors.initials: H
authors.lastname: Zhang
authors.forename: Myeong-Hyeon
authors.initials: MH
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D001692:Biological Transport / Q000235:genetics; D018522:Gravitropism / Q000187:drug effects / Q000502:physiology*; D007210:Indoleacetic Acids / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D009154:Mutation; D010797:Phthalimides / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology / Q000502:physiology*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*
chemical_list: D007210:Indoleacetic Acids; D010797:Phthalimides; D010937:Plant Growth Regulators; C002687:alpha-naphthylphthalamic acid; D000040:Abscisic Acid