AGO4 and infection: (C) Percentage of methylated cytosines in the intergenic region (IR) of TYLCV in systemic infection assays with TYLCV wild-type or V2 null mutant (TYLCV-V2null) in AGO4-silenced (TRV-NbAGO4) or control (TRV-EV) N. benthamiana plants at 3 weeks post-inoculation (wpi), as detected by bisulfite sequencing.