Mosaic symptoms on tobacco mosaic virus (TMV)-infected tobacco leaves consist of dark-green and light-green areas. Infectivity tests and electron microscopy so far reported have shown that TMV concentration is high in the light-green areas and low in the dark green areas1,2,3,4,5). It was also reported that the dark-green areas were resistant to re inoculation with TMV3,5). These results suggest that certain cells are infected with TMV whereas others contain little or no virus in the dark-green areas. In this study we attempted to isolate
