Beyond the pore: Conceptual advances on plasmodesmata

Plasmodesmata (PD) are membrane-lined cytoplasmic bridges that connect plant cells and control intercellular exchange. PD operate as dynamic regulatory systems integrating developmental, environmental and immune signals to modulate cell-cell communication. Recent advances have begun to redefine PD at multiple levels. Structural approaches now provide first insights into PD molecular organisation, while a conceptual shift places PD as specialised membrane contact sites where endoplasmic reticulum-plasma membrane junctions contribute to transport regulation alongside cell wall remodelling. Recent work has also re-opened the question of transport selectivity with emerging roles for charge and nanoscale confinement. Here, we review these advances, focusing on PD molecular architecture, and newly emerging transport mechanisms.