Expression data from Arabidopsis suspension cells overexpressing VND6 and SND1

Xylem consists of three types of cells: vessel cells, also referred to as tracheary elements (TEs), parenchyma cells, and fiber cells. TE differentiation includes two essential processes, programmed cell death (PCD) and secondary cell wall formation. These two processes are tightly coupled. However, little is known about the molecular mechanism of their gene regulation. Here, we show that VASCULAR-RELATED NAC-DOMAIN 6 (VND6), a master regulator of TEs, regulates these processes in a coordinated manner. We first identified specific genes downstream of VND6 by comparing them with those of SECONDARY WALL-ASSOCIATES NAC DOMAIN PROTEIN1 (SND1), a master regulator of xylem fiber cells, with transformed suspension culture cells in microarray experiments. We used three types of Arabidopsis cultured cells: wild type cells, estrogen-inducible VND6 transformed cells, estrogen-inducible SND1 cells. To examine the initial molecular events induced by VND6 and SND1, we sampled three types of cells at 0h and 12h after the addition of estrogen with triplicates.