(K) A proposed model illustrating how the E3 ligase NbHRD1 negatively regulates viral infection in plants. Plant viruses with a TGB, BNYVV and PVX, as models, infect N. benthamiana plants, inducing the expression of NbHRD1 interacts with TGB movement proteins of BNYVV and PVX in the ER membrane. NbHRD1 triggers the ubiquitination and 26S proteasome-mediated degradation of TGB proteins, thereby suppressing viral movement to inhibit virus infection.

In (D), (G), and (J), EF1α served as an internal reference. The GFP gene was used as the indicator of viral RNA accumulation. Values are means ± SDs of three independent repeats. ^∗∗p < 0.01; ^∗∗∗p < 0.001; ^∗∗∗∗p < 0.0001; ns, not significant (Student’s t test).