title: D'orenone blocks polarized tip growth of root hairs by interfering with the PIN2-mediated auxin transport network in the root apex.
abstract: The C(18) ketone (5E,7E)-6-methyl-8-(2,6,6-trimethylcyclohex-1-enyl)octa-5,7-dien-2-one (D'orenone) has been postulated to be an early cleavage product of beta-carotene en route to trisporic acids; these act as morphogenetic factors during the sexual reproduction of zygomycetes. Here we report that D'orenone blocks the highly polarized tip growth of root hairs, causing tip growth to stop completely within a few minutes. Importantly, external auxin reverses the effects of D'orenone on root hairs. Further analysis revealed that D'orenone lowers the auxin concentration in trichoblasts via PIN2-mediated auxin efflux to below the critical levels essential for root hair growth. D'orenone specifically increases PIN2 protein abundance without affecting PIN2 transcripts, and the PIN2 expression domain enlarges and shifts basipetally, resulting in more active auxin transport. The observation that D'orenone does not interfere with the root hair growth in roots of null mutant lines provides additional evidence that PIN2 is its specific target.
authors.affiliation: Rheinische Friedrich-Wilhelms-Universität Bonn, Zellbiologie der Pflanzen, Bonn, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schlicht
authors.forename: Olga
authors.initials: O
authors.lastname: Samajová
authors.forename: Doreen
authors.initials: D
authors.lastname: Schachtschabel
authors.forename: Stefano
authors.initials: S
authors.lastname: Mancuso
authors.forename: Diedrik
authors.initials: D
authors.lastname: Menzel
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Boland
authors.forename: Frantisek
authors.initials: F
authors.lastname: Baluska
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000502:physiology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D007659:Ketones / Q000494:pharmacology*; D018518:Plant Root Cap / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D035321:Telomeric Repeat Binding Protein 1 / Q000187:drug effects / Q000502:physiology
chemical_list: D007210:Indoleacetic Acids; D007659:Ketones; D035321:Telomeric Repeat Binding Protein 1; D004121:Dimethyl Sulfoxide