Identification and characterization of blueberry latent spherical virus, a new member of subgroup C in the genus Nepovirus

A new member of the genus Nepovirus was isolated from blueberry in Japan. The virus was associated with latent infection of blueberry trees and provisionally named blueberry latent spherical virus (BLSV). BLSV was found to have isometric particles approximately 30 nm in diameter, which were composed of a single coat protein (CP) of 55 kDa. The viral genome consisted of two positive-sense single-stranded RNA species (RNA1 and RNA2), which were 7,960 and 6,344 nucleotides (nt) long, respectively. The organization of RNA1 and RNA2 was similar to that of nepoviruses. The 3′ non-coding regions of RNA1 and RNA2 were 1,379 nt and 1,392 nt long, respectively. The amino acid sequences of the BLSV polymerase and CP shared the highest amino acid sequence similarities with those of the subgroup C nepoviruses (57% and 43%, respectively). Additionally, the BLSV genome, in contrast to other nepovirus genomes, was predicted to encode a serine protease.