As the interface between plants and the environment, the leaf epidermis provides the first layer of protection against dehydration (drought), UV and pathogen attacks through highly coordinated and functionally specialized cells in epidermis, such as stomata, pavement cells and trichomes. Stomata, microscopic pores in the epidermis, function as valves to mediate the exchange of CO2 entering and water exiting the leaf through transpiration. Modulation of stomatal numbers could enhance drought tolerance of plants. More than half of Arabidopsis leaf epidermal cells are made through stomatal development. In stomatal development, asymmetric cell divisions produce meristemoids (red), precursors of stomatal guard cells, and stomatal lineage ground cells (SLGCs, blue) which may become pavement cells, or reinitiate asymmetric divisions to produce more stomata. How to maintain the multipotency in SLGCs? What drives a cell to exit from a proliferative state to a differentiation state? What is the developmental cue to specify the cell fates in the leaf epidermis? The mechanism remains unclear.   

By combining FACS-sorting, single cell sequencing, transcriptome analysis, molecular and cell biology approaches, we aim to identify factors in leaf epidermal development. Understanding the key players controlling this developmental plasticity could potentially generate the desired leaf epidermis for plants to resist the effects of climate change.

(A and B) vst triple mutant is shorter and more erect compared to WT. (C and D) There are excessive cell divisions and paired stomata in vst triple mutant (Ho et. al. 2016).