A noncanonical auxin sensing mechanism is required for organ morphogenesis in arabidopsis Journal Article

Author(s): Simonini, Sara; Deb, Joyita; Moubayidin, Laila; Stephenson, Pauline; Valluru, Manoj; Freire-Rios, Alejandra; Sorefan, Karim; Weijers, Dolf; Friml, Jiří; Östergaard, Lars Jørgen
Article Title: A noncanonical auxin sensing mechanism is required for organ morphogenesis in arabidopsis
Affiliation IST Austria
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 hormonesensing 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. © 2016 Simonini et al.
Keywords: Arabidopsis; Plant development; Auxin signaling; IAA; ETTIN; Transcription factor complex
Journal Title: Genes and Development
Volume: 30
Issue 20
ISSN: 1549-5477
Publisher: Cold Spring Harbor Laboratory Press  
Date Published: 2016-10-15
Start Page: 2286
End Page: 2296
DOI: 10.1101/gad.285361.116
Notes: We thank Norwich Research Park Bioimaging, Grant Calder, Roy Dunford, Caroline Smith, Paul Thomas, and Mark Youles for technical support; Charlie Scutt, Alejandro Ferrando, and George Lomonossoff for plasmids; Toshiro Ito for seeds; Brendan Davies and Barry Causier for the REGIA library; and Mark Buttner, Simona Masiero, Fabio Rossi, Doris Wagner, and Jun Xiao for help and material. We are also grateful to Stefano Bencivenga, Marie Brüser, Friederike Jantzen, Lukasz Langowski, Xinran Li, and Nicola Stacey for discussions and helpful comments on the manuscript. This work was supported by grants BB/M004112/1 and BB/I017232/1 (Crop Improvement Research Club) to L.Ø. from the Biotechnological and Biological Sciences Research Council, and Institute Strategic Programme grant (BB/J004553/ 1) to the John Innes Centre. S.S., J.D., and L.Ø conceived the ex- periments.
Open access: yes (repository)