Family: Fimoviridae

Genus: Emaravirus

Distinguishing features

Since only one genus is currently recognized, the genus description corresponds to that of the family description.

Species demarcation criteria

Species in the genus have previously been demarcated based upon the amino acid sequence of relevant gene products of RNA1 (RNA-directed RNA polymerase, RdRP), RNA2 (glycoprotein precursor, GP), and RNA3 (nucleocapsid protein, NP) differing by more than 25%.

However, these criteria are not consistent with the current species; viruses that would not be classified into different species using the 25% cutoff are aspen mosaic-associated virus (AsMaV) and Pistacia virus B (PiVB) (RNA1: 23.7%), pigeonpea sterility mosaic virus 2 (PPSMV2) and Pueraria lobata-associated emaravirus (PloaEV) (RNA1: 23.4%), ash shoestring-associated virus (ASaV) and Actinidia virus 2 (AcV2) (RNA1: 22.1%), PPSMV2 and fig mosaic virus (FMV) (RNA3: 20.0%); PPSMV2 and AcV2 (RNA3: 24.1%), PloaEV and FMV (RNA3: 22.6%), and PloaEV and AcV2 (RNA3: 25.0%). Accordingly, the threshold for species demarcation has been lowered to 20%. The remaining inconsistencies [e.g., PPSMV2 and PloaEV (RNA3: 18.5%)] can be solved by including MP among the gene products used in comparisons and adding the requirement that at least two of the four proteins differ by more than 20%.

Based on the above considerations, the species demarcation criteria for emaraviruses are as follows: species in the genus are demarcated on the basis that the amino acid sequences of at least two of the gene products of RNA1 (RNA-directed RNA polymerase, RdRP), RNA2 (glycoprotein precursor, GP), RNA3 (nucleocapsid protein, NP) and RNA4 (movement protein, MP) differ by more than 20%.