MOVEMENT PROTEIN-DERIVED RESISTANCE TO TRIPLE GENE BLOCK-CONTAINING PLANT-VIRUSES

Two mutant potato virus X (PVX) movement protein (MP) genes (m12K-Sal and m12K-Kpn) were obtained by inserting specific linkers at the bound ary between the N-terminal hydrophobic and putative transmembrane segm ent, and the central invariant hydrophilic region of the respective 12 kDa, 12 K, triple gene block (TGB) protein. Several transgenic potato lines which expressed m12K-Sal or m12K-Kpn to different degrees were resistant to infection by PVX, potato aucuba mosaic potexvirus and the carlaviruses potato virus M and S over a wide range of inoculum conce ntrations (3-300 mu g/ml). However, they were not resistant to potato virus Y, which lacks a TGB protein. We suggest that the resistance of m 12K-Sal and m 12K-Kpn transgenic potato lines is MP-derived and not RNA-mediated.