Five isolates of a new member of the family Closteroviridae, tentatively named blackcurrant leafroll-associated virus 1 (BcLRaV-1), were identified in the currant. The 17-kb-long genome codes for 10 putative proteins. The replication-associated polyprotein has several functional domains, including papain-like proteases, methyltransferase, Zemlya, helicase, and RNA-dependent RNA polymerase. Additional open reading frames code for a small protein predicted to integrate into the host cell wall, a heat-shock protein 70 homolog, a heat-shock protein 90 homolog, two coat proteins, and three proteins of unknown functions. Phylogenetic analysis showed that BcLRaV-1 is related to members of the genus Closterovirus, whereas recombination analysis provided evidence of intraspecies recombination.

A novel virus with distinct genome features was discovered by high throughput sequencing in a symptomatic blackcurrant plant. The virus, tentatively named Ribes americanum virus A (RAVA), has distinct genome organization and molecular features bridging genera in the order Tymovirales. The genome consists of 7106 nucleotides excluding the poly(A) tail. Five open reading frames were identified, with the first encoding a putative viral replicase with methyl transferase (MTR), AlkB, helicase, and RNA dependent RNA polymerase (RdRp) domains. The genome organization downstream of the replicase resembles that of members of the order Tymovirales with an unconventional triple gene block (TGB) movement protein arrangement with none of the other four putative proteins exhibiting significant homology to viral proteins. Phylogenetic analysis using replicase conserved motifs loosely placed RAVA within the Betaflexiviridae. Data strongly suggest that RAVA is a novel virus that should be classified as a species in a new genus in the Betaflexiviridae or a new family within the order Tymovirales.

Five isolates of a new putative member of the genus Closterovirus, tentatively named blackcurrant leafroll associated virus 1 (BcLRaV-1), were identified in currant. The 17 kb long genome of BcLRaV-1 contained 10 open reading frames (ORFs). The replication associated polyprotein has two papain-like leader proteases, a methyltransferase, a helicase and an RNA-dependent RNA polymerase domain. Additional ORFs coded for heat shock protein 70 homolog, heat shock protein 90 homolog, two divergent copies of coat protein, and three accessory proteins without identifiable functions. Phylogenetic analysis showed that BcLRaV-1 is related to members of the genus Closterovirus and recombination analysis of the isolates showed clear evidences of intraspecies recombination.