The influence of the N- and C- terminal modifications of Potato virus X coat protein on virus properties

The Potato virus X (PVX)-based vector was used for the construction of N- and C-terminally modified PVX coat protein (XCP) chimeras. N-terminal XCP modifications do not influence the viral life cycle, whereas the simple XCP C-terminal fusion impedes the viral replication. We designed several C-terminally modified XCP chimeras and tested their viabilities in various Nicotiana benthamiana genotypes. Our results showed the negative impact of 3'-terminal modification of XCP on the chimera's life cycle. To ensure chimeric constructs stability, the second copy of the last 60 nucleotides of XCP followed by the 3'-untranslated region (UTR) was added downstream of the recombinant sequence. Simultaneously, the first copy of the last 60 nucleotides of XCP was mutated in order to prevent recombination between the two identical sequences. The movement protein of Tobacco mosaic virus expressed in transgenic N. benthamiana plants positively affected the cell-to-cell spread of C-terminally modified XCP chimeras.