title: SMALL ORGAN SIZE 1 and SMALL ORGAN SIZE 2/DWARF AND LOW-TILLERING Form a Complex to Integrate Auxin and Brassinosteroid Signaling in Rice.
abstract: Although auxin and brassinosteroid (BR) synergistically control various plant responses, the molecular mechanism underlying the auxin-BR crosstalk is not well understood. We previously identified SMOS1, an auxin-regulated APETALA2-type transcription factor, as the causal gene of the small organ size 1 (smos1) mutant that is characterized by a decreased final size of various organs in rice. In this study, we identified another smos mutant, smos2, which shows the phenotype indistinguishable from smos1. SMOS2 was identical to the previously reported DWARF AND LOW-TILLERING (DLT), which encodes a GRAS protein involved in BR signaling. SMOS1 and SMOS2/DLT physically interact to cooperatively enhance transcriptional transactivation activity in yeast and in rice nuclei. Consistently, the expression of OsPHI-1, a direct target of SMOS1, is upregulated only when SMOS1 and SMOS2/DLT proteins are both present in rice cells. Taken together, our results suggest that SMOS1 and SMOS2/DLT form a keystone complex on auxin-BR signaling crosstalk in rice.
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan. Electronic address: khirano@nuagr1.agr.nagoya-u.ac.jp.
authors.forename: Ko
authors.initials: K
authors.lastname: Hirano
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Aya
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Kawamura
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Tokunori
authors.initials: T
authors.lastname: Hobo
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Kanna
authors.initials: K
authors.lastname: Sato-Izawa
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Hidemi
authors.initials: H
authors.lastname: Kitano
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan. Electronic address: mueguchi@nuagr1.agr.nagoya-u.ac.jp.
authors.forename: Miyako
authors.initials: M
authors.lastname: Ueguchi-Tanaka
authors.affiliation: Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Matsuoka
mesh_terms: D060406:Brassinosteroids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D060406:Brassinosteroids; D007210:Indoleacetic Acids; D010940:Plant Proteins; D014157:Transcription Factors
keywords: auxin; brassinosteroid; crosstalk; rice; transcription factor