title: Does the brassinosteroid signal pathway in photomorphogenesis overlap with the gravitropic response caused by auxin?
abstract: Brassinosteroid (BR) and auxin co-regulate plant growth in a process termed cross-talking. Based on the assumption that their signal transductions are partially shared, inhibitory chemicals for both signal transductions were screened from a commercially available library. A chemical designated as NJ15 (ethyl 2-[5-(3,5-dichlorophenyl)-1,2,3,4-tetrazole-2-yl]acetate) diminished the growth promotion of both adzuki bean epicotyls and Arabidopsis seedlings, by the application of either BR or auxin. To understand its target site(s), bioassays with a high dependence on the signal transduction of either BR (BR-signaling) or auxin (AX-signaling) were performed. NJ15 inhibited the photomorphogenesis of Arabidopsis seedlings grown in the dark, which mainly depends on BR-signaling, while NJ15 also inhibited their gravitropic responses mainly depending on AX-signaling. On the study for the structure-activity relationships of NJ15 analogs, they showed strong correlations on the inhibitory profiles between BR- and AX-signalings. These correlations imply that NJ15 targets the downstream pathway after the integration of BR- and AX-signals.
authors.affiliation: a Department of Applied Biological Chemistry , The University of Tokyo , Tokyo , Japan.
authors.forename: Naiyanate
authors.initials: N
authors.lastname: Jaroensanti
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Yoon
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakai
authors.forename: Ikuya
authors.initials: I
authors.lastname: Shirai
authors.forename: Masato
authors.initials: M
authors.lastname: Otani
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Ken-Ichiro
authors.initials: K
authors.lastname: Hayashi
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nakajima
authors.forename: Tadao
authors.initials: T
authors.lastname: Asami
mesh_terms: D000085:Acetates / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics; D060406:Brassinosteroids / Q000378:metabolism / Q000494:pharmacology; D003624:Darkness; D007887:Fabaceae / Q000187:drug effects* / Q000254:growth & development; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology*; D008027:Light; D009154:Mutation; D017440:Photoperiod; D015398:Signal Transduction / Q000187:drug effects; D054852:Small Molecule Libraries / Q000494:pharmacology*; D013777:Tetrazoles / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000085:Acetates; D029681:Arabidopsis Proteins; D060406:Brassinosteroids; C511864:GIL1 protein, Arabidopsis; D007210:Indoleacetic Acids; D054852:Small Molecule Libraries; D013777:Tetrazoles
keywords: auxin; brassinosteroid; gravitropic response; inhibitor; photomorphogenesis