Alfalfa Mosaic Virus Movement Protein Induces Tubules in Plant Protoplasts

The alfalfa mosaic virus (AlMV) movement protein (MP) was fused with the green fluorescence protein (GFP). The MP-GFP fusion was transiently expressed in protoplasts prepared from Nicotiana tabacum, resulting in the production of long, extending, tubular structures protruding from the protoplast surface. Deletions of MP amino acids 1 to 77, 84 to 142, or 226 to 300 all affected tubule formation. Hence, the AlMV MP is solely required for the induction of the tubular structures, and the results suggest that AlMV may move from cell to cell via tubules.