Description
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.