FIG. 5.

Accumulation of TRV siRNAs and viral TRV RNAs in Arabidopsis rdr mutants. RNA gel blot analysis of TRV siRNAs (A) and genomic (g) and subgenomic (sg) TRV RNAs (B) from inflorescence tissue of wild-type and single, double, and triple rdr Arabidopsis mutants infected with TRV. Duplicate samples were analyzed using a radiolabeled probe specific for the 3′ UTR of TRV. The relative accumulations (RA) of TRV siRNAs were calculated from band intensities and are indicated below the siRNA bands. Band intensities in tissue from wild-type-inoculated plants with the highest hybridization signal were normalized to 1.0. Composite images from single blots are shown. Figure content is as described in the legend of Fig. 2. (C) Spatial distribution profile of TRV1-derived siRNAs in Arabidospsis rdr mutants. Histograms represent the percentage of siRNA accumulation in each PCR fragment relative to the total accumulation in all the fragments, as determined for Fig. 3 and 4, using double and triple rdr mutants infected with TRV. Mean values and standard deviations from three independent experiments are shown. Figure content is as described in the legend of Fig. 3. dpi, days postinoculation; GUS, β-glucoronidase; rdr1/6, rdr1 rdr6; rdr2/6, rdr2 rdr6, rdr1/2/6, rd1 rdr2 rdr6.