Modulates cell-to-cell trafficking. (Microbial infection) Interacts with Grapevine fanleaf virus (GFLV) 2B-MP. Co-localizes with the Grapevine fanleaf virus (GFLV) 2B-MP at the base of tubules within modified plasmodesmata. Highly expressed in inflorescence pedacel and shoot apex. Expressed in the outermost L1 layer of the shoot apical meristem and in the epidermis of bulging floral primordia. Within the L1, expression was restricted to the peripheral zone (at protein level). Expression in the epidermis of floral primordia changes through development from being weakly expressed in the youngest the floral organs, with possibly a stronger expression on the abaxial side (P1, P2 stage) to being relatively strongly expressed in both the adaxial and abaxial epidermis at later stages. Both pdlp2 and pdlp3, and pdlp1 and pdlp3 double mutants show altered protein diffusion (measured using GFP). In pdlp1, pdlp2 and pdlp3 triple mutant there is inhibition of GFLV 2BMP tubule formation. Virus cell-to-cell movement is negatively affected. There is a 22% reduction in mean surface area of infection foci by GFLV and an approximately 12 h delay in long distance movement in comparison to wild-type plants. There is also a systemic delay in Cauliflower mosaic virus (CaMV) spread. Belongs to the cysteine-rich repeat secretory protein family. Plasmodesmata-located proteins (PDLD) subfamily. PDLPs were initially named Cysteine-rich secretory proteins based on a classification work that failed to predict the transmembrane region at the C-terminus (PubMed:11402176). However, it was later shown that PDLPs are membrane proteins.