Plasmodesmata (PD) are nano-scaled membrane-lined channels PD that span the thick cell wall of virtually all plant cells, establishing both cytoplasmic and membrane continuity throughout the entire plant body (Fig.1). In recent years, PD have emerged as key elements of the cell-to-cell communication machinery and as such have been implicated in processes guaranteeing the collaborative functioning of the cells, and controlled developmental events. Plant viruses but also fungus can exploit PD transport machinery to establish infection and the emerging view is that PD may well represent a consensus target for pathogens and constitute key element in defence signalling and plant development. Understanding of how PD dictate cellular connectivity is dependent on comprehensive knowledge of the composition of PD and functional characterization of their constituents. Although some progress has been made in the identification of PD proteins, the role played by major membrane constituents, e.g. the lipids, remains totally uncovered. Yet PD are primarily membranous structures, defined by specialised membrane domains of the endoplasmic reticulum (desmotubule) and the plasma membrane (PD-PM) and the majority of identified PD proteins are membrane-associated. Research in biological membrane over the last decade has unequivocally demonstrated that lipids are functional units that can modulates membrane organisation and cellular function. Just as proteins, lipids are likely to be key elements of PD specialised membrane domains and as such contribute to proper functionality at PD. In line with that recent data suggests that the PM domain lining PD may share similar properties to membrane rafts, high ordered sterol- and sphingolipid-enriched nanodomains of the PM involved in signalling, protein targeting and lateral segregation of membrane constituents. Hence, several raft markers have been shown not only to localise to microdomains at the PM per se but also accumulates at PD. Moreover recent data suggest that rafts could play a central role in the control of viral cell-to-cell spray through the PD channels. Altogether, this raises questions about the lipidic nature of the PD-PM. Do rafts contribute to the PD-PM? What is the role of lipids in defining PD membrane structurally and functionally? The CONNECT project concentrates on the functional relationship that may exist between PD and rafts, as well as the implication of lipids in PD function and structure. Using suspension-cultured cells, to isolate pure PD, we propose for the first time to analyse the lipid composition of these unique membrane structures. Coupling lipidomic, biochemical approaches, spectrometric analyses as well as high-resolution microscopy we would like to establish whether or not raft-like domains are enriched at PD. Is the specialised PD-PM domain sharing properties similar to rafts; i.e. highly organised and enriched in sterols and sphingolipids? Is lipid segregation along PD-PM fundamental for proper PD function? In particular the role of lipids in PD targeting will be investigated by modifying their sterol composition. Last we propose to examine the involvement of rafts in the control of Potato virus X movement via PD. In particular, we make the hypothesis that rafts may be involved in the control of PD permeability and that raft aggregation occurs around PD during viral infection.