Plasmodesmata: Cell-Cell Channels in Plants
Yoselin Benitez Alfonso, Laurence Cantrill and David Jackson
Plasmodesmata (PD) permit diffusion of small metabolites and proteins, as well as active
trafficking of specific RNAs and proteins. Their structure and distribution vary according
to species, cell type, physiological function and stage of development.
Two mechanisms for PD trafficking have been described: targeted and nontargeted. Transgenic plants expressing cytoplasmic GFP (Green Fluorescent Protein), illustrate nontargeted transport, as GFP moves freely between immature cells by diffusion. The transport through PD of viral proteins is the most studied example of targeted movement.
PD are also involved in the regulation of cell fate and development, as PD transport of transcription factors and RNAs, which act as short and long distance signals, has also been reported.
Cell-cell communication is highly regulated by developmental and environmental factors. Blocking or selective occlusion of PD has been reported during stomatal development, regeneration of plant tissues, embryogenesis, phloem development and reproductive development.
Here we review current models of PD structure and function, though many of their molecular components are still unknown.