title: A noncanonical auxin-sensing mechanism is required for organ morphogenesis in Arabidopsis.
abstract: Tissue patterning in multicellular organisms is the output of precise spatio-temporal regulation of gene expression coupled with changes in hormone dynamics. In plants, the hormone auxin regulates growth and development at every stage of a plant's life cycle. Auxin signaling occurs through binding of the auxin molecule to a TIR1/AFB F-box ubiquitin ligase, allowing interaction with Aux/IAA transcriptional repressor proteins. These are subsequently ubiquitinated and degraded via the 26S proteasome, leading to derepression of auxin response factors (ARFs). How auxin is able to elicit such a diverse range of developmental responses through a single signaling module has not yet been resolved. Here we present an alternative auxin-sensing mechanism in which the ARF ARF3/ETTIN controls gene expression through interactions with process-specific transcription factors. This noncanonical hormone-sensing mechanism exhibits strong preference for the naturally occurring auxin indole 3-acetic acid (IAA) and is important for coordinating growth and patterning in diverse developmental contexts such as gynoecium morphogenesis, lateral root emergence, ovule development, and primary branch formation. Disrupting this IAA-sensing ability induces morphological aberrations with consequences for plant fitness. Therefore, our findings introduce a novel transcription factor-based mechanism of hormone perception in plants.
authors.affiliation: Department of Crop Genetics, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Sara
authors.initials: S
authors.lastname: Simonini
authors.affiliation: Department of Crop Genetics, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Joyita
authors.initials: J
authors.lastname: Deb
authors.affiliation: Department of Crop Genetics, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Laila
authors.initials: L
authors.lastname: Moubayidin
authors.affiliation: Department of Crop Genetics, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Pauline
authors.initials: P
authors.lastname: Stephenson
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom.
authors.forename: Manoj
authors.initials: M
authors.lastname: Valluru
authors.affiliation: Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, the Netherlands.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Freire-Rios
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom.
authors.forename: Karim
authors.initials: K
authors.lastname: Sorefan
authors.affiliation: Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, the Netherlands.
authors.forename: Dolf
authors.initials: D
authors.lastname: Weijers
authors.affiliation: Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria.
authors.forename: Jiří
authors.initials: J
authors.lastname: Friml
authors.affiliation: Department of Crop Genetics, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Lars
authors.identifier: http://orcid.org/0000-0002-8497-7657
authors.initials: L
authors.lastname: Østergaard
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D044783:F-Box Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D007210:Indoleacetic Acids / Q000378:metabolism*; D009024:Morphogenesis / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C109765:ETT protein, Arabidopsis; D044783:F-Box Proteins; D007210:Indoleacetic Acids; D009687:Nuclear Proteins; D011956:Receptors, Cell Surface; C501405:TIR1 protein, Arabidopsis; D014157:Transcription Factors; D017346:Protein Serine-Threonine Kinases
keywords: Arabidopsis; ETTIN; IAA; auxin signaling; plant development; transcription factor complex