Infectivity and symptoms induced by MYVV together with MYVB or MYVBΔUTR. (A) Symptoms induced by infectious clones of MYVV plus MYVB or MYVBΔUTR on N. benthamiana plants at 30 dpi. (B) Southern blot analysis of viral and betasatellite DNAs in inoculated N. benthamiana plants. Nucleic acids were extracted from upper leaves of plants infected with MYVV and MYVB (lanes 1–3), MYVV and MYVBΔUTR (lanes 4–6). Blots were probed with the CP gene sequence of MYVV (top) or full-length of MYVB (bottom). The positions of single-stranded DNA (SS) forms are indicated. The lower panel represents an ethidium bromide-stained gel of DNA samples as a loading control. (C) Densitometric quantification of band intensities. The value obtained from MYVV plus MYVB was arbitrarily assigned as 100%. Standard deviation values are based on three independent experiments.