Silencing of TCTP gene inhibited PVY infection in N. benthamiana. A) The phenotype of N. benthamiana plants infected with TRV-NbTCTP or TRV-GUS was photographed at 12 dpi. B) The relative expression levels of NbTCTP in TRV-NbTCTP–inoculated and mock-inoculated N. benthamiana plants were determined through RT-qPCR. The data represented the means ± Sd from 3 biological replicates and 3 technical replicates. Statistical significance between the 2 treatments was determined using Duncan's multiple-range test. Different letters represented significant differences (P < 0.05). C) Western blot analysis of the TCTP accumulation levels in N. benthamiana plants systematically infected with TRV-NbTCTP or TRV-GUS at 12 dpi using a TCTP-specific antibody. The Rubisco large subunit protein was used as a loading control. Protein band intensities were measured using the ImageJ software. Numbers indicated the accumulation levels of TCTP normalized to Rubisco staining. D) Incidence of plants with GFP fluorescence at various days post PVY-GFP inoculation. The error bars represented the means ± Sd from 3 independent experiments and each treatment had 10 plants. E) The phenotype of PVY-GFP in TCTP-silenced and mock-inoculated N. benthamiana plants. The plants were photographed under UV illumination at 4 d post PVY-GFP inoculation. The GFP fluorescence intensity derived from PVY-GFP as shown in dotted rectangle regions was measured using the ImageJ software. The bar graphs represented the means ± Sd (n = 10). Statistical significance between the 2 treatments was determined using Duncan's multiple-range test. Different letters represented significant differences (P < 0.05). F) The accumulation levels of PVY-GFP in the TCTP-silenced and mock-inoculated N. benthamiana plants at 4 dpi. The Rubisco large subunit protein was used as a loading control. Band intensities were measured using the ImageJ software. Numbers indicated the accumulation levels of PVY CP normalized to Rubisco staining. G) Accumulation levels of PVY-GFP replicon (referred to as PVYrep-GFP thereafter) genomic (+) and minus-strand (−) RNAs in the TRV-NbTCTP–inoculated or the TRV-GUS–inoculated plants were determined through RT-qPCR. The error bars represented the means ± Sd from 3 biological replicates and 3 technical replicates. Statistical significance between the 2 treatments was determined using Duncan's multiple-range test. Different letters represented significant differences (P < 0.05). H) The phenotype of PVY-GFP in N. tabacum TCTP-knockdown (NtTCTP-KD) and overexpression (NtTCTP-OE) transgenic lines. The plants were photographed under UV illumination at 5 d post PVY-GFP inoculation. I and J) The protein levels of TCTP in the transgenic N. tabacum plants, and the accumulation levels of CP in the leaves systematically infected with PVY-GFP were determined through Western blot assay using a TCTP-specific or CP-specific antibody. The Rubisco large subunit protein was used as a loading control. Protein band intensities were measured using the ImageJ software. Numbers indicated the accumulation levels of TCTP and PVY CP normalized to Rubisco staining, and the WT band in each was set to 1. The experiments were repeated 3 times independently.