Plasmodesmata‐located proteins: The molecular hubs in noncell‐autonomous immunity

Abstract Plasmodesmata (PD) are unique connection structures between plant cells that play a key role in the transportation of signal molecules and metabolites. In noncell‐autonomous immunity, PD function as battlegrounds against intruders, including viral, fungal and bacterial pathogens. Recent studies have demonstrated that a variety of proteins, including catalytic enzymes involved in callose metabolism, callose‐binding proteins, receptor kinases, lipid‐associated proteins, and tether proteins, serve as critical molecular hubs in plant defense responses by facilitating the closure of PD. Here, we present a comprehensive overview of the regulation mechanisms of PD‐related proteins in the process of plant disease resistance. Moreover, we discuss the challenges currently encountered in PD regulation and highlight critical questions for future investigation. Addressing these issues will further enhance our understanding of intercellular communication in plant defense system and promote its application in agriculture.