New features in the genus Ilarvirus revealed by the nucleotide sequence of Fragaria chiloensis latent virus

Fragaria chiloensis latent virus (FClLV), a member of the genus Ilarvirus was first identified in the early 1990s. Double-stranded RNA was extracted from FClLV infected plants and cloned. The complete nucleotide sequence of the virus has been elucidated. RNA 1 encodes a protein with methyltransferase and helicase enzymatic motifs while RNA 2 encodes the viral RNA dependent RNA polymerase and an ORF, that shares no homology with other Ilarvirus genes. RNA 3 codes for movement and coat proteins and an additional ORF, making FClLV possibly the first Ilarvirus encoding a third protein in RNA 3. Phylogenetic analysis reveals that FClLV is most closely related to Prune dwarf virus, the type member of subgroup 4 of the Ilarvirus genus. FClLV is also closely related to Alfalfa mosaic virus (AlMV), a virus that shares many properties with ilarviruses. We propose the reclassification of AlMV as a member of the Ilarvirus genus instead of being a member of a distinct genus.