title: A role for the root cap in root branching revealed by the non-auxin probe naxillin.
abstract: The acquisition of water and nutrients by plant roots is a fundamental aspect of agriculture and strongly depends on root architecture. Root branching and expansion of the root system is achieved through the development of lateral roots and is to a large extent controlled by the plant hormone auxin. However, the pleiotropic effects of auxin or auxin-like molecules on root systems complicate the study of lateral root development. Here we describe a small-molecule screen in Arabidopsis thaliana that identified naxillin as what is to our knowledge the first non-auxin-like molecule that promotes root branching. By using naxillin as a chemical tool, we identified a new function for root cap-specific conversion of the auxin precursor indole-3-butyric acid into the active auxin indole-3-acetic acid and uncovered the involvement of the root cap in root branching. Delivery of an auxin precursor in peripheral tissues such as the root cap might represent an important mechanism shaping root architecture.
authors.affiliation: Department of Plant Systems Biology, VIB, Gent, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: De Rybel
authors.forename: Dominique
authors.initials: D
authors.lastname: Audenaert
authors.forename: Wei
authors.initials: W
authors.lastname: Xuan
authors.forename: Paul
authors.initials: P
authors.lastname: Overvoorde
authors.forename: Lucia C
authors.initials: LC
authors.lastname: Strader
authors.forename: Stefan
authors.initials: S
authors.lastname: Kepinski
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hoye
authors.forename: Ronald
authors.initials: R
authors.lastname: Brisbois
authors.forename: Boris
authors.initials: B
authors.lastname: Parizot
authors.forename: Steffen
authors.initials: S
authors.lastname: Vanneste
authors.forename: Xing
authors.initials: X
authors.lastname: Liu
authors.forename: Alison
authors.initials: A
authors.lastname: Gilday
authors.forename: Ian A
authors.initials: IA
authors.lastname: Graham
authors.forename: Long
authors.initials: L
authors.lastname: Nguyen
authors.forename: Leentje
authors.initials: L
authors.lastname: Jansen
authors.forename: Maria Fransiska
authors.initials: MF
authors.lastname: Njo
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
authors.forename: Bonnie
authors.initials: B
authors.lastname: Bartel
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
mesh_terms: D017360:Arabidopsis / Q000254:growth & development*; D007210:Indoleacetic Acids / Q000378:metabolism; D010940:Plant Proteins / Q000502:physiology*; D018517:Plant Roots / Q000254:growth & development*; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; D012333:RNA, Messenger