A new Polerovirus species in plants from the Asparagaceae family defined by its RNA-silencing repressor protein P0

To contribute to the discovery of the global virome, we explored plants from an urban botanic garden in the Netherlands for new and variant plant viruses. Analyzing RNA from 25 plants from the Asparagaceae family with both RNA-seq, as well as smallRNA-seq revealed in six plants the presence of a variant Polerovirus from the Solemoviridae family that shows an overall RNA-sequence identity of 93% to the known Ornithogalum Virus 5 (OV-5). Amino acid sequence comparison of the complex set of proteins produced by the new virus revealed that all but Protein-0, showed high similarity (> 91%) with those of the OV-5 virus. The similarity between the new P0 protein and the OV-5 P0 protein, however, was for all variants less than 83%, well below the ICTV species protein-based demarcation criterium. Hence, we named the new virus Asparagaceae Polerovirus 1 (AspPolV-1).