P-464 - A novel virus from Japanese holly fern

Japanese holly fern (JHF; Cyrtomium falcatum), a plant native to eastern Asia, India, southern Africa and Hawaii, is popular as a ground covering or border edging ornamental plant in the southern US. This plant is susceptible to infections by Japanese holly fern mottle virus (JHFMoV; family Mayoviridae, genus Pteridovirus) displaying yellow mottle, mosaics,  and, in some cases, reduced growth. In this study we characterized a new virus in several symptomatic fern plants purchased in a local retail store. Molecular characterization started by extraction, purification and analyses of double stranded RNAs (dsRNAs) to be used as a template for Illumina-based pair-end high throughput sequencing. HTS obtained contigs were subjected to RACE experiments to obtain complete genome sequences. Analyses of HTS data revealed that JHF plants were coinfected by JHFMoV and an additional virus related, but distinct from current members of the family Virgaviridae. Its genome consist of two molecules of polycistronic RNAs encoding for several proteins with roles in virus replication, movement and particle formation. The relatedness of the virus to virgavirids was demonstrated by transmission electron microscope observation of rigid rod particles in partially purified preparations from infected JHF plants. However, clear differences in genomic organization, distinct phylogeny of viral proteins and other data generated in this study strongly suggest that this virus, for which we propose name Japanese holly fern virus A (JHFVA), is a member of a new genus in the family Virgaviridae.