title: Auxin signaling through SCFTIR1/AFBsmediates feedback regulation of IAA biosynthesis.
abstract: We previously reported that exogenous application of auxin to Arabidopsis seedlings resulted in downregulation of indole-3-acetic acid (IAA) biosynthesis genes in a feedback manner. In this study, we investigated the involvement of the SCFTIR1/AFB-mediated signaling pathway in feedback regulation of the indole-3-pyruvic acid-mediated auxin biosynthesis pathway in Arabidopsis. Application of PEO-IAA, an inhibitor of the IAA signal transduction pathway, to wild-type seedlings resulted in increased endogenous IAA levels in roots. Endogenous IAA levels in the auxin-signaling mutants axr2-1, axr3-3, and tir1-1afb1-1afb2-1afb3-1 also increased. Furthermore, YUCCA (YUC) gene expression was repressed in response to auxin treatment, and expression of YUC7 and YUC8 increased in response to PEO-IAA treatment. YUC genes were also induced in auxin-signaling mutants but repressed in TIR1-overexpression lines. These observations suggest that the endogenous IAA levels are regulated by auxin biosynthesis in a feedback manner, and the Aux/IAA and SCFTIR1/AFB-mediated auxin-signaling pathway regulates the expression of YUC genes.
authors.affiliation: a Kihara Institute for Biological Research, Yokohama City University , Yokohama , Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Takato
authors.affiliation: a Kihara Institute for Biological Research, Yokohama City University , Yokohama , Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kakei
authors.affiliation: a Kihara Institute for Biological Research, Yokohama City University , Yokohama , Japan.|b RIKEN CSRS , Yokohama , Japan.
authors.forename: Marie
authors.initials: M
authors.lastname: Mitsui
authors.affiliation: a Kihara Institute for Biological Research, Yokohama City University , Yokohama , Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Ishida
authors.affiliation: a Kihara Institute for Biological Research, Yokohama City University , Yokohama , Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: a Kihara Institute for Biological Research, Yokohama City University , Yokohama , Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Yamazaki
authors.affiliation: c Department of Biochemistry , Okayama University of Science , Okayama , Japan.
authors.forename: Ken-Ichiro
authors.initials: KI
authors.lastname: Hayashi
authors.affiliation: d NARO/WARC , Zentsuji , Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ishii
authors.affiliation: a Kihara Institute for Biological Research, Yokohama City University , Yokohama , Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: d NARO/WARC , Zentsuji , Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Soeno
authors.affiliation: a Kihara Institute for Biological Research, Yokohama City University , Yokohama , Japan.|b RIKEN CSRS , Yokohama , Japan.
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Shimada
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D025461:Feedback, Physiological; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D007211:Indoles / Q000378:metabolism* / Q000494:pharmacology; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors
chemical_list: C000603490:AFB2 protein, Arabidopsis; C000596911:AFB3 protein, Arabidopsis; C110728:AXR3 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D044783:F-Box Proteins; D007210:Indoleacetic Acids; D007211:Indoles; D009687:Nuclear Proteins; D010937:Plant Growth Regulators; D011956:Receptors, Cell Surface; C501405:TIR1 protein, Arabidopsis; D014157:Transcription Factors; C000597137:auxin-responsive protein IAA7, Arabidopsis; C008122:indol-3-yl pyruvic acid; C030737:indoleacetic acid; D006899:Mixed Function Oxygenases; C585335:YUCCA8 protein, Arabidopsis; D010105:Oxygenases; C422746:YUC protein, Arabidopsis
keywords: Arabidopsis; auxin; feedback-regulation