I am interested in the mechanisms underlying how cells become polar and how tissue-specific factors and hormones regulate gene expression in plants. Protonemal cells of the moss (Physcomitrella patens) are being used as models to study intracellular polarity (Fig. 1). Both moss and Arabidopsis are the systems for analyzing tissue-specific gene expression via the phytohormone abscisic acid (ABA), and, for understanding the evolution of the desiccation tolerance mechanism during seed development (Fig.2).

Complementing moss polarity mutants and generating insertion and activation tagged moss lines are in progress to identify genes that play a role in polarity. Also, a more targeted approach, to disrupt genes involved in cytoskeletal (i.e. actin) dynamics, is underway utilizing RNAi, as well as specific gene knock-outs and gene replacement by homologous recombination.

Projects on gene regulation during seed maturation are focused on the regulatory protein ABI3 (VP1) from Arabidopsis (maize) and its target genes such as Em. The studies are designed to determine the spectrum of embryonic genes under control of ABA and/or ABI3 during seed maturation and whether any can be activated by ABI3 in non-embryonic cells/tissues. Although moss lacks seeds, it does possess an ABA signaling pathway (Fig.3), as well as desiccation- tolerance processes. We are using a comparative genomics approach to determine he evolution of the ABA pathway and its relationship to desiccation tolerance in moss and seed development in Arabidopsis. Agilent microarrays for moss and Arabidopsis are being utilized to characterize this gene regulatory network. To learn more visit the Research page.