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

Sara Simonini, Joyita Deb, Laila Moubayidin, Pauline Stephenson, Manoj Valluru, Alejandra Freire-Rios, Karim Sorefan, Dolf Weijers, Jiří Friml, Lars Østergaard*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

55 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)2286-2296
JournalGenes and Development
Issue number20
Publication statusPublished - 2016


  • Arabidopsis
  • Auxin signaling
  • IAA
  • Plant development
  • Transcription factor complex

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    Simonini, S., Deb, J., Moubayidin, L., Stephenson, P., Valluru, M., Freire-Rios, A., Sorefan, K., Weijers, D., Friml, J., & Østergaard, L. (2016). A noncanonical auxin-sensing mechanism is required for organ morphogenesis in arabidopsis. Genes and Development, 30(20), 2286-2296. https://doi.org/10.1101/gad.285361.116