Abstract
Plants have evolved unique systems for plant body formation. Plant vascular development is a paradigm of plant body formation. This process includes the regulation of stem cell fates, differentiation of various types of vascular cells, and cell-cell communication between vascular cells. To understand vascular development, we have established a few culture systems including Zinnia xylogenic cell culture in which mesophyll cells differentiate into tracheary elements (TEs) and an Arabidopsis xylogenic culture. Using these cultures and microarray systems, we have revealed gene expression profiles associated with vascular development. Based on these analyses, we discovered two novel master regulators of TE differentiation, VND6 and VND7. To understand cell-cell communication among vascular cells to form a well-organized tissue, we searched extracellular factors that affect vascular development, using the Zinnia culture. As a result, we discovered novel factors; TE differentiation-promoting and inhibiting factors, xylogen and TDIF, respectively. The analysis of in vivo function of these novel factors in Arabidopsis casted a new light on understanding of vascular development.
