Analysis of procambial /cambial maintenance in vascular tissues

 

 

 

 

 

 

 

 

 

Procambium / cambium is crucial for vascular development. These tissues compose the vascular meristem. Stem cells in the vascular meristem proliferate and differentiate to produce new vascular tissues. It is considered that this process is rigidly regulated by intercellular signal transduction. Recent researches revealed that TDIF (TRACHEARY ELEMENT DIFFERENTIATION INHIBITORY FACTOR), a small peptide secreted from phloem tissue, is involved in this regulation. TDIF belongs to CLE (CLAVATA3/EMBRYO SURROUNDING REGION-RELATED) family. Through TDR (TDIF-RECEPTOR), it promotes proliferation of stem cells and also inhibits differentiation of stem cells into xylem tissue. In these two effects of TDIF, stem cell proliferation depends on WOX4 (WUSCHEL-related HOMEOBOX 4). WOX4 is a putative transcriptional factor and it suggests that stem cell proliferation is regulated by WOX4-mediated expression of downstream genes.