Figure 4

GFP expression with differing subgenomic promoters and rescue by gene silencing suppressor coexpression. (a) 4 dpi and (b) 8 dpi. In both panels, the top row show fluorescence from N. benthamiana agroinoculated with FECT/GFP but without p19 silencing suppressor and the bottom row shows leaves co-agroinoculation of FECT/GFP and 35S/p19. Only a small number of very faint fluorescent spots were found in FECT22 and FECT40 leaves at 4 dpi (a), and this fluorescence disappeared by 8 dpi (b). However, a vigorous fluorescence occurred with the addition of 35S/p19. FECT0 plants did not fluoresce even in the presence of 35S/p19. (c) FECT40/GFP was co-agroinoculated with 35S/p19 onto N. benthamiana and samples were taken each day of the time course and protein extracted by grinding and centrifugation. Lanes: M, protein marker; 0, protein extract from uninoculated leaf; 2 to 7, extracts from FECT agroinfiltrated leaves, 2 to 7 dpi, respectively. (d) Western blot of GFP expression at 7 dpi. Lanes: 1, 0.2 μg GFP standard (E. coli generated); 2, FECT/GFP + 35S/p19 in N. benthamiana; 3, 35S/p19 alone in N. benthamiana.