Plant-specific cell-cell signaling
Plant cells are not able to change their position and orientation, because they are interconnected by rigid cell walls. Therefore, formation of correct tissue patterns relies on a mechanism that determine the fate of each cell depending on its position. What makes such developmental process possible?
For cells to know their positions in organ primordia, they need to communicate each other. Cells exchange "positional cues" to decide their cell fate. The theory of position-dependent cell fate determination is the basic principle of plant development.
Cell-cell communication is usually mediated by ligand-receptor pathways, which are seen in both plants and animals. However, recent studies revealed the existence of a plant-specific cell-cell communication mechanism.
It has been known that plant cells are connected with small tunnels across the cell walls, termed the plasmodesmata (PD). Since PDs serve as a channel for viral spreading, PDs have been studied mostly by plant pathologists. However, as PDs became recognized as essential channels to transmit developmental signals, developmental biologists are now interested in the regulation of PD functions.