The plant hormone auxin promotes the degradation of inhibitors of ARF transcription factors to control plant development, but the role of auxin in patterning has been unclear. The ARF protein MONOPTEROS is shown to induce both its own expression and that of its inhibitor, with auxin acting as a threshold-specific trigger to switch this feedback system to MONOPTEROS accumulation.
- Steffen Lau
- Ive De Smet
- Gerd Jürgens
