Rice yellow mottle virus is a suitable amplicon vector an efficient production of an anti-leishmianiasis vaccine in Nicotiana benthamiana leaves.

The suitability of rice yellow mottle virus RYMV as a gene expression vector in plant was assessed using a construct carrying promastigote surface antigen (PSA) C-terminal coding sequence of the parasite protozoan Leishmania. RYMV ORF1 encoding P1 protein has been deleted from the RYMV native genome. The C-terminal PSA gene was substituted for the viral coat protein. PSA is present at the surface of the parasite and displays vaccine properties against canine and human leishmaniosis. RYMV-based vector allowed PSA expression in Nicotiana benthamiana. Q-pcr analysis showed that chimeric RYMV carrying PSA gene is able to replicate in N. benthamiana leaves. P19 silencing suppressor in combination with the lacked viral vector ORF encoding RYMV Coat Protein (CP) enhanced significantly RYMV tool replication in N. benthamiana. RYMV CP played a key role on viral RNA stabilization and acts as a weak silencing suppressor. The original RYMV-based expression vector allowed PSA protein expression enhancement in N. benthamiana without any symptoms. RYMV-based vector could be suitable for functional genomic studies in monocots by VIGS (Viral Induced Gene Silencing) technology.