Genus: Sclerodarnavirus

Genus: Sclerodarnavirus

Distinguishing features

There is a single species in the genus, Sclerotinia sclerotiorum debilitation-associated RNA virus represented by Sclerotinia sclerotiorum debilitation-associated RNA virus, a capsid-less mycovirus. Despite the lack of capsid, phylogenetic analysis of the replication-associated protein (Rep) places it within the Alphaflexiviridae family (Xie et al., 2006).

Virion 

Morphology

None.

Physicochemical and physical properties

No information.

Nucleic acid

A single linear molecule of positive-sense RNA of 5470 nt with a polyadenylated tract at the 3′-terminus (Figure 1.Sclerodarnavirus).

Proteins

No information available.

Carbohydrates

Not applicable.

Genome organization and replication

There is a single ORF encoding a Rep protein of 193 kDa (Figure 1.Sclerodarnavirus).

Figure 1.Sclerodarnavirus. Sclerotinia sclerotiorum debilitation-associated RNA virus genome organization. Mtr, methyltransferase; Hel, helicase; RdRP, RNA-directed RNA polymerase.

Biology

Sclerotinia sclerotiorum debilitation-associated RNA virus was discovered in the plant pathogenic fungus Sclerotinia sclerotiorum and appears to cause debilitation (hypovirulence).

Derivation of names

Sclerodarna: from Sclerotinia sclerotiorum debilitation-associated RNA virus, the type species of the genus.

Species demarcation criteria

Since there is currently only a single species in the genus, species demarcation criteria are not yet defined, but , as delineated for other genera in the family, members of distinct species may have less than 72% nt identity (or 80% aa identity) between Rep genes.

Member species

Exemplar isolate of the species
SpeciesVirus nameIsolateAccession numberRefSeq numberAvailable sequenceVirus Abbrev.
Sclerotinia sclerotiorum debilitation-associated RNA virusSclerotinia sclerotiorum debilitation-associated RNA virusChinaAY147260NC_007415Complete genomeSsDRV

Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.