Figure 1.

RDR6-dependent RNA silencing driven by PVX. A, Leaves of GFP and GFP/rdr6i plants systemically infected with PVX:00 or PVX:P (21 dpi) visualized under UV light. B, Accumulation of GFP mRNA, PVX:P genomic RNA (gRNA), and asP siRNAs assessed by northern-blot analyses using probes specific for the GF and P regions (see Fig. 2C). C, Wild-type (WT) and rdr6i plants systemically infected with PVX:PDS (21 dpi). D, Accumulation of PDS mRNA assessed by semiquantitative RT-PCR followed by Southern blotting with amplification of actin used as a control for quantification. PVX:PDS gRNA and asPDS and sPDS siRNAs were assessed by northern blot analysis. Ethidium bromide-stained rRNAs are shown as loading controls, and positions of 24- and 21-nt size markers are indicated.