title: Synthesis and biological evaluation of novel azole derivatives as selective potent inhibitors of brassinosteroid biosynthesis.
abstract: Brassinosteroids (BRs) are phytohormones that control several important agronomic traits, such as flowering, plant architecture, seed yield, and stress tolerance. To manipulate the BR levels in plant tissues using specific inhibitors of BR biosynthesis, a series of novel azole derivatives were synthesized and their inhibitory activity on BR biosynthesis was investigated. Structure-activity relationship studies revealed that 2RS, 4RS-1-[4-(2-allyloxyphenoxymethyl)-2-(4-chlorophenyl)-[1,3]dioxolan-2-ylmethyl]-1H-[1,2,4]triazole (G(2)) is a highly selective inhibitor of BR biosynthesis, with an IC(50) value of approximately 46 ± 2 nM, which is the most potent BR biosynthesis inhibitor observed to date. Use of gibberellin (GA) biosynthesis mutants and BR signaling mutants to analyze the mechanism of action of this synthetic series indicated that the primary site of action is BR biosynthesis. Experiments feeding BR biosynthesis intermediates to chemically treated Arabidopsis seedlings suggested that the target sites of this synthetic series are CYP90s, which are responsible for the C-22 and/or C-23 hydroxylation of campesterol.
authors.affiliation: Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, 241-438, Shimoshinjo Nakano, Akita 010-0195, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yamada
authors.forename: Osamu
authors.initials: O
authors.lastname: Yajima
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yoshizawa
authors.forename: Keimei
authors.initials: K
authors.lastname: Oh
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism; D001393:Azoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D060406:Brassinosteroids / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D015394:Molecular Structure
chemical_list: D001393:Azoles; D060406:Brassinosteroids