Systems biology of stomatal development  
There are many outstanding questions about how cells transit through the stomatal development pathway and how the individual genes we have identified fit into a regulatory hierarchy.  Many of these questions can only be answered by understanding at a global scale what happens at each cell state transition. For example, what is the inventory of genes required to make a meristemoid? Which are required to be a meristemoid?  What are the direct targets of each of the stomatal bHLHs?  How can expression of such similar transcription factors generate such different outcomes?

Generating a map of stomatal lineage cells by FACs sorting
Based on the pioneering work of Ken Birnbaum and Phillip Benfey using FACS-based sorting of GFP-positive cells to create an atlas of “cell type specific” information from roots, we have begun to use stomatal lineage GFP markers to sort stomatal lineage cells.  Our goal is to identify the transcriptome of each of the major stomatal lineage cell types. Later we aim to use this system in combination with mutants and environmental perturbations to assay their consequences in a cell-type specific manner.

Markers of stomatal lineage for use in FACS-sorting experiments.  In the bottom panels are examples of cells sorted using FAMA::GFP. The cells in the red box are GMCs (those cells expressing FAMA) that can be sorted away from the bulk population.

Funding by NIH, NSF