Figure 4.

Phenotypic responses of soybean L800 (Rsv1) to biolistic inoculation with the infectious cDNA clones of avirulent Soybean mosaic virus (SMV) strain N (SMV‐N) and two SMV‐N‐derived virulent derivatives harbouring a parallel mutation in polyprotein codon 947 located in the P3 cistron. It should be noted that alanine (Ala) (A) to threonine (Thr) (T) substitution at position 947 leads to alteration in the overlapping PIPO codon (C30Y), whereas replacement with valine (Val) (V), instead of Thr, does not. This demonstrates that the determinant of virulence on L800 (Rsv1) resides on P3 and not the overlapping pipo‐encoded protein. Plants were photographed at 14 days post‐inoculation.