Abstract - The root of Arabidopsis thaliana is an excellent model for studying cell differentiation in plants. In this organ, cell types are arranged in stereotypic concentric layers around a central vascular bundle. Numerous morphological and genetic studies have demonstrated that each cell type is generated by a specific stem cell population maintained near the tip, in a region called meristem. Within the cell lineages, with each new stem cell division, cells are displaced upwards and differentiate, thereby creating a longitudinal developmental trajectory where the spatial arrangement of cells recapitulates the temporal dynamics of differentiation.

While transcriptional characterisation of root cell populations have originally focused on the analysis of bulk sorted lineages, the recent development of single-cell technologies has allowed a more precise investigation of the spatio-temporal diversity of cellular states. We have undertaken deep characterization of the root transcriptome at single cell resolution and combined it with spatial mapping to identify rare, transient, and unpredicted cell states. The reconstruction of developmental trajectories for distinct cell lineages and their associated co-expression networks revealed unexpected topologies and shed light on the different layers of regulation of cellular identities in the root during development.

Biography - Marina obtained her PhD from the Ecole Normale Supérieure in Lyon, France. She worked with Teva Vernoux on the role of auxin and its signalling pathway in plant architecture, and contributed to the development of fluorescent sensors to monitor auxin levels in vivo. She then started her postdoctoral studies at the University of Western Australia, in the laboratory of Prof. Ryan Lister, where she is making use of state-of-the-art single-cell technologies to explore various aspects of plant development.