Plasmodesmata are important channels that facilitate intercellular communication. However, neither the conservation nor diversification of plasmodesmata among plants has been thoroughly explored. In this issue, Hsu et al. demonstrate that the structure of plasmodesmata in the model liverwort, Marchantia polymorpha, progresses from simple to complex, and that the accumulation of callose (β-1,3-glucan) at plasmodesmata is a conserved feature. Furthermore, they observe that plasmodesmata permeability may be subject to stage-specific or tissue-specific regulation.
The cover image shows the accumulation of callose at plasmodesmata in a Marchantia polymorpha gemma directly picked from the gemma cup. The gemma was submerged in Aniline Blue staining solution and imaged under a confocal microscope. The discontinuous signals indicate the positions of plasmodesmata on cell walls between most cells.