Lights at the end of the tunnel: new views of plasmodesmal structure and function

▶ Proteomic analyses have identified PD localized proteins that control PD permeability. ▶ Imaging studies have unraveled PD dynamics and biogenesis. ▶ New developments highlight the dynamic role of callose in modulating PD permeability. ▶ More developmental regulators, including small RNAs, are found to be mobile. Plasmodesmata (PDs), tiny channels connecting neighboring plant cells, play big roles in the transport of metabolites, viral movement, cell fate specification and development. Many recent studies are opening our eyes to the composition and formation of PDs, as well as the function and regulation of trafficking through them. Both proteomic and genetic approaches have revealed the central importance of callose in modulating PD connectivity. Moreover, many new developmental regulators, including transcription factors as well as small RNAs (sRNAs), have been found to be mobile and essential for specifying cell fate and tissue patterning.