Family: Botourmiaviridae

Genus: Betarhizoulivirus

Distinguishing features

Betarhizouliviruses have a mono-segmented genome, infect fungi, and are phylogenetically distinct from other botourmiaviruses.

Virion

No true virions are associated with betarhizouliviruses since their genomes have no capsid protein gene.

Genome organization and replication

The Rhizoctonia solani ourmia-like virus 5 (RsOLV5) genome is a (+) RNA molecule of 5 234 nucleotides with 55% GC content. The complete genome sequence has a 5′ non-coding region (NCR) of 919 nt and a 3′ NCR of 202 nt. The virus genome contains a single open reading frame from positions 920 to 5 032, predicted to encode a polypeptide of 1 370 amino acids (153.22 kDa) that has similarity to the RNA-directed RNA polymerase (RdRP) of the rhizouliviruses (Picarelli et al., 2019). 

Biology

RsOLV5 infects the plant pathogenic fungus Rhizoctonia solani (Picarelli et al., 2019). 

Species demarcation criteria

There is only one species in the genus. Members of distinct species in the genus are expected to have amino acid sequence identities of their putative RdRP proteins of less than 90%.