Seminar Josep Vilarrasa-Blasi (Stanford University, USA) 7th of May 16:00
Maintenance of water homeostasis is a fundamental cellular process required by all living organisms. While osmo-signaling pathways have been defined in bacteria, yeast and animals, how plants orchestrate adaptive responses remains at its infancy. We leverage Chlamydomonas reinhardtii as a simplified plant model system to dissect the osmotic signaling response through transcriptomics, phosphoproteomics and functional genomics. Overlap of these approaches revealed a core osmotic pathway across life kingdoms and the contribution of different cellular organelles to the osmotic response within the green lineage. Characterization of Arabidopsis thaliana homologous mutants disclosed different spatiotemporal modes of root cell death upon an osmotic challenge. The analysis of actin dynamics upon osmotic stress revealed that cells undergoing growth cessation exhibit massive changes in actin organization. Overall, we established a new model system to study osmoregulation within the green lineage and uncovered a new role for actin in controlling plant survival upon osmotic stress.