PDLP5, a plasmodesmata permeability regulator, can traffic between plant cells

Plasmodesmata (PD) are membranous nanopores that connect the cytoplasm of neighboring plant cells and enable the cell-to-cell trafficking of nutrients and macromolecules, as well as invading viruses. PD plays a critical role in regulating intercellular communication, contributing to plant development, environmental responses, and interactions with viral pathogens. The PD proteome includes two major types of functional proteins, PD callose binding proteins (PDCBs) and PD-located proteins (PDLPs), involved in manipulating the size of PD pores. Most studies of PDCBs and PDLPs focused on their effects on the PD transport of different cargo molecules; yet, whether these PD proteins themselves have the capacity for cell-to-cell movement remains largely obscure. Here, we addressed this question by demonstrating that PDLP5, but not PDLP1 and PDLP2, can move efficiently from cell to cell in Nicotiana benthamiana and that this movement involves the native transmembrane domain of PDLP5. These observations would be useful for a better understanding of the complexity of the PDLP5 protein function during the processes of PD transport.