Genomic characterization of grapevine viruses N and O: novel vitiviruses from South Africa

A survey was performed on a Vitis cultivar collection in Stellenbosch, South Africa. Metaviromes were generated for each cultivar, using an RNAtag-seq workflow. Analysis of assembled contigs indicated the presence of two putatively novel members of the genus Vitivirus, provisionally named "grapevine virus N" (GVN) and "grapevine virus O" (GVO). Comparisons of amino acid sequences showed that GVN and GVO are most closely related to grapevine virus G and grapevine virus E, respectively. The incidence of these novel viruses within the sampling site was low, with GVO and GVN associated with only five and two cultivars, respectively, of the 229 sampled.