Abstract Potyviruses possess one positive-sense single-stranded RNA genome mainly with polyprotein processing as their gene expression strategy. The resulting polyproteins are proteolytically processed by three virus-encoded proteases into 11 or 12 mature proteins. One of such, 6-kDa peptide 1 (6K1), is an understudied viral factor. Its function in viral infection remains largely mysterious. This study is to reveal part of its roles by using pepper veinal mottle virus (PVMV) as a model virus.
