FIG 6.

Agroexpression of AGO1, AGO2, AGO4, and AGO5, but not of AGO7 or of GUS, attenuates viroid accumulation. (A and B) Northern blot hybridizations with a full-length radiolabeled riboprobe for detecting PSTVd plus strands of total RNAs from halos of mock- and PSTVd-inoculated N. benthamiana agroinfiltrated with cultures of A. tumefaciens with binary plasmids for expressing HA-tagged AGO1 (A, lanes 1, 4, and 5), AGO2 (A, lanes 6 and 7), AGO4 (B, lanes 1, 4, 5, and 6), AGO5 (B, lanes 7, 8, and 9), AGO7 (A, lanes 8 and 9, and B, lanes 10 and 11), and GUS (A and B, lanes 2 and 3). Mock inoculations were performed as indicated in the legend to Fig. 3. Total RNAs, extracted 2 days after agroinfiltration, were separated by denaturing PAGE in 5% gels, and equal loading was assessed by the intensity of tRNA after staining with ethidium bromide. Western blot analyses of total proteins from halos were carried out with the anti-HA monoclonal antibody following protein separation by PAGE in 4 to 12% gels; equal loading was assessed by the intensity of the large subunit of RubisCO after staining with Ponceau S. In all cases, samples were processed 2 days after agroinfiltration of plants that were PSTVd infected, or mock inoculated, 8 days before.