Plasmodesmata and phloem-based trafficking of macromolecules

Plant cell fate specification, responses to stimuli, and developmental coordination at multicellular level are achieved by cell-to-cell communication. Plasmodesmata (PD), cytoplasmic nanochannels interconnecting neighboring cells, sophisticate such communication by regulating exchange of molecules. The composition, organization, and architecture of these interconnecting channels have emerged, and several models are available. PD play as major gatekeepers of signaling macromolecules such as proteins and/or RNAs and establish domains of symplasmically connected cells either to facilitate or restrict the transport of such signaling molecules. This chapter is dedicated for those who seek insightful review through supporting evidence on intercellular trafficking of a range of endogenous proteins and their updated non-cell-autonomous protein pathway (NCAPP) machinery/components taking care, together, of plant development.