Abstract
Electron-microscopic evidence is presented for the infection of isolated tomato-fruit locule tissue protoplasts by tobacco mosaic virus. Uptake of tobacco mosaic virus by pinocytosis into vesicles in the cytoplasm was observed. Following the disappearance of virus from pinocytic vesicles and the regeneration of these isolated proplasts into cells the virus appeared in the cytoplasm in aggregates characteristic of tobacco mosaic virus infection in these cells. Adequate removal of ribonucleases and purification of the pectinase enzyme employed for the isolation of protoplasts was essential for the establishment of infection.