To understand the progression from stem cells to differentiated tissues we are exploiting the simplifying aspects of root development. We have profiled mRNA and small RNAs for all cell types and developmental stages within the Arabidopsis root. We are developing new experimental, analytical and imaging methods to identify networks functioning within different cell types and developmental stages under normal laboratory conditions and under abiotic and biotic stress. We have uncovered a clock-like process responsible for the positioning of lateral roots along the root primary axis. Two sets of genes were identified that oscillate in opposite phases at the root tip and are involved in the production of prebranch sites, locations of future lateral roots. Finally, we are analyzing the dynamics of growth of physical root networks using novel non-invasive imaging methods and developing mathematical descriptors of root system architecture.

This work is supported by grants from the NIH, NSF and DARPA.