FIG. 4.

Time course analysis of expanding PVX infection foci, measured by using GFP as a visual marker to count the number of infected epidermal cells across an infection focus. The average diameters of 10 infection foci on an inoculated leaf of nontransgenic (○), TGB200 (•), and TGB600 (▵) tobacco plants were measured at 3, 5, and 7 dpi. Dotted lines in two panels indicate the cell-to-cell movement of wild-type PVX.GFP, while solid lines indicate the cell-to-cell movement of the mutant viruses named in each panel.