Seminars

Organogenesis in plants is based on precise cell fate determination of undifferentiated cells, which are derived from stem cells that reside in meristems. Cell fate determination depends on the position of a cell within the plant body. A number of mechanisms provide positional information to cells or cell populations: (1) plant hormones like auxin establish gradients or local concentration   maxima;
(2) secreted ligands and membrane associated receptors enables cell-cell signalling between adjacent cell layers; (3) transcription factors can act non-cell autonomously to integrate cellular responses, and (4) long range communication takes place by transport of signals between cells through plasmodesmata.
Our current understanding is that these mechanisms act in a concerted manner to govern plant development. I will report on our most recent results on receptor kinase signalling pathways that control the growth and maintenance of meristems, and specifically regulate the patterning of ovules that give rise to the seeds after successful fertilization. Using a toolbox of fluorescence imaging techniques in planta, we studied the dynamics of receptor assembly into larger complexes at distinct regions of the plasmamembranes upon the perception of their specific ligands.
Furthermore, we found that alterations of receptor expression levels of the ligands can have profound developmental consequences. I will also attempt to link aspects of peptide-receptor and hormonal signalling pathways.