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Updated: Jul 7, 2026

A Method for Characterizing Embryogenesis in Arabidopsis
Published on: August 4, 2017
TOPLESS mediates auxin-dependent transcriptional repression during Arabidopsis embryogenesis
Heidi Szemenyei1, Mike Hannon, Jeff A Long
1Plant Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
Abstract:
The transcriptional response to auxin is critical for root and vascular development during Arabidopsis embryogenesis. Auxin induces the degradation of AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) transcriptional repressors, freeing their binding partners, the AUXIN RESPONSE FACTOR (ARF) proteins, which can activate transcription of auxin response genes. We show that TOPLESS (TPL) can physically interact with IAA12/BODENLOS (IAA12/BDL) through an ETHYLENE RESPONSE FACTOR (ERF)-associated amphiphilic repression (EAR) motif. TPL can repress transcription in vivo and is required for IAA12/BDL repressive activity. In addition, tpl-1 can suppress the patterning defects of the bdl-1 mutant. Direct interaction between TPL and ARF5/MONOPTEROS, which is regulated by IAA12/BDL, results in a loss-of-function arf5/mp phenotype. These observations show that TPL is a transcriptional co-repressor and further our understanding of how auxin regulates transcription during plant development.
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