The genus Socyvirus includes a single species represented by soybean cyst nematode virus 1 (SbCNV1) (Bekal et al., 2011). Phylogenetic analysis using a conserved region of the RNA-dependent RNA polymerase (RdRP) region of the large (L) protein places SbCNV1 in a separate clade to the nyaviruses.
Non-segmented, negative-sense RNA genome of 11,359 nucleotides, assembled from a nematode transcriptome (Bekal et al., 2011).
Based on the genome organization, five structural proteins: nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G) and large protein (L).
Genome organization and replication
The SbCNV1 genome contains five ORFs in anti-genomic sense in the order 3′-N–P–M–G–L-5′, whereas nyaviruses genomes contain one additional ORF (IV) between the N and G coding sequences. Transcription initiation motifs upstream of the ORFs are not conserved between SbCNV1 and nyaviruses.
SbCNV1 was isolated from a plant parasitic nematode (Heterodera glycines Ichinohe, 1952).
Species demarcation criteria
There is only one species in the genus; species demarcation criteria have not been defined.