IMMUNOLOGICAL DETECTION OF THE 8K PROTEIN OF POTATO-VIRUS-X (PVX) IN CELL-WALLS OF PVX-INFECTED TOBACCO AND TRANSGENIC POTATO

Open reading frame 4 (ORF4) of the potato virus X (PVX) genome encodes an 8K protein which is a part of the ''triple gene block'' and is kno wn to play a role in the cell-to-cell movement of the virus in infecte d plants. To locate the 8K protein and further elucidate the mechanism of cell-to-cell transport of PVX, antibodies were raised against the 8K protein and used to localize this protein in PVX-infected tobacco a nd in transgenic potato plants expressing the 8K protein both by subce llular fractionation and by immunolabeling with colloidal gold. The re sults indicated that the 8K protein was localized to the cell wall.