FIG 4.

CLCuMuV V2 suppresses TGS in plants. (A) 16c-TGS plants were agroinfected with PVX-HA-V2 or PVX-HA-nLUC. Photographs were taken under white light or UV light at 9 days postinfiltration (dpi). An HA-tagged N-terminal fragment of the firefly luciferase (HA-nLUC) was used as a negative control. (B) RT-qPCR analysis of relative GFP mRNA levels in 16c-TGS plants infected with PVX-HA-V2 or PVX-HA-nLUC. The asterisks indicate significant differences (*, P < 0.05; **, P < 0.01; [Student’s t test]). The bars represent means ± SD. Data were obtained from three independent experiments. (C) Immunoblot assay of GFP protein using anti-GFP antibody in 16c-TGS plants infected with PVX-HA-V2 or PVX-HA-nLUC. RuBisCO was stained with Ponceau Red as a loading control. (D) Percentage of methylated cytosine in CaMV 35S promoter sites in 16c-TGS or 16c-TGS plants infected with PVX-V2 and PVX-HA-nLUC. The histogram represents the proportions of methylated cytosine residues in different sequence groups. The asterisks indicate significant differences (*, P < 0.05; **, P < 0.01 [Student’s t test]). (E) Detection of V2 protein in transgenic plants by immunoblotting. V2 protein was immunoblotted using an anti-V2 antibody. RuBisCO was stained with Ponceau Red as a loading control. (F) Percentage of cytosine methylation of N. benthamiana transposons Tnt1 and TE1 in 35S:HA-V2 transgenic or mock plants. The histogram represents the proportions of methylated cytosines in different sequence groups. The asterisks indicate significant differences (*, P < 0.05; **, P < 0.01 [Student’s t test]). The bars represent means ± SD. Data were obtained from three independent experiments.