PSB Seminar Prof Jiri Friml on Thursday, December 15 at 11 am

11:00 - 12:30

Jozef Schell seminar room

“Auxin signaling: more than we could ever imagine”

The plant hormone auxin is a versatile intercellular signal influencing virtually all aspects of plant life. It has a unique ability to be directionally transported within tissues forming local auxin maxima or gradients that are central to many developmental processes mediated by auxin. One of the key roles of auxin is adaptation of plant growth to gravity, where shoots bend up and roots down. This paradox is based on opposite responses of these organs to the phytohormone auxin, which promotes cell expansion in shoots, while inhibiting it in roots via an unclear signalling pathway and yet unknown downstream cellular mechanism.
The well-established canonical auxin signalling involving the TIR1/AFB auxin receptors, Aux/IAA repressors and ARF transcription factors acts in nucleus and mediates gene transcription. However, auxin also triggers cellular responses within seconds or minutes, too fast to rely on transcription. Part of the rapid responses is mediated by the non-transcriptional branch of the TIR1/AFB signalling, but others involve a yet completely unknown mechanism.
Here Prof Jiri Friml will present new and surprising insights into the mechanism of auxin signalling including an ultrafast auxin-triggered protein phosphorylation response and previously unsuspected aspects of TIR1/AFB auxin perception and downstream signalling.

Keywords: Auxin, Arabidopsis, root gravitropism, TIR1/AFB signalling

Acknowledgements: Prof Jiri Friml gratefully acknowledges all present and past members of the Friml group and their excellent collaborators.

Invited by Prof Dirk Inzé and Prof Daniël Van Damme