title: Fenarimol, a Pyrimidine-Type Fungicide, Inhibits Brassinosteroid Biosynthesis.
abstract: The plant steroid hormone brassinosteroids (BRs) are important signal mediators that regulate broad aspects of plant growth and development. With the discovery of brassinoazole (Brz), the first specific inhibitor of BR biosynthesis, several triazole-type BR biosynthesis inhibitors have been developed. In this article, we report that fenarimol (FM), a pyrimidine-type fungicide, exhibits potent inhibitory activity against BR biosynthesis. FM induces dwarfism and the open cotyledon phenotype of Arabidopsis seedlings in the dark. The IC50 value for FM to inhibit stem elongation of Arabidopsis seedlings grown in the dark was approximately 1.8 ± 0.2 μM. FM-induced dwarfism of Arabidopsis seedlings could be restored by brassinolide (BL) but not by gibberellin (GA). Assessment of the target site of FM in BR biosynthesis by feeding BR biosynthesis intermediates indicated that FM interferes with the side chain hydroxylation of BR biosynthesis from campestanol to teasterone. Determination of the binding affinity of FM to purified recombinant CYP90D1 indicated that FM induced a typical type II binding spectrum with a Kd value of approximately 0.79 μM. Quantitative real-time PCR analysis of the expression level of the BR responsive gene in Arabidopsis seedlings indicated that FM induces the BR deficiency in Arabidopsis.
authors.affiliation: Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, 241-438, Shimoshinjo Nakano, Akita 010-0195, Japan. jmwang@akita-pu.ac.jp.
authors.forename: Keimei
authors.initials: K
authors.lastname: Oh
authors.affiliation: Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, 241-438, Shimoshinjo Nakano, Akita 010-0195, Japan. tmatsumoto@affrc.go.jp.|National Agricultural Research Center, National Agriculture and Food Research Organization, 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8666, Japan. tmatsumoto@affrc.go.jp.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan. ayamagam@riken.jp.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Yamagami
authors.affiliation: Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, 241-438, Shimoshinjo Nakano, Akita 010-0195, Japan. M16G027@akita-pu.ac.jp.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Hoshi
authors.affiliation: Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan. tnakano@riken.jp.|CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan. tnakano@riken.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakano
authors.affiliation: Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, 241-438, Shimoshinjo Nakano, Akita 010-0195, Japan. yyoshizawak@akita-pu.ac.jp.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yoshizawa
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology* / Q000633:toxicity; D017360:Arabidopsis / Q000187:drug effects* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism; D060406:Brassinosteroids / Q000096:biosynthesis*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D011485:Protein Binding; D011743:Pyrimidines / Q000494:pharmacology* / Q000633:toxicity; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development
chemical_list: D000935:Antifungal Agents; D029681:Arabidopsis Proteins; D060406:Brassinosteroids; D011743:Pyrimidines; D003577:Cytochrome P-450 Enzyme System; C500774:cytochrome P-450 90D1, Arabidopsis; C033789:fenarimol
keywords: brassinosteroid biosynthesis inhibitor; fenarimol; plant growth regulation; plant hormone