title: A novel putative virus of Gremmeniella abietina type B (Ascomycota: Helotiaceae) has a composite genome with endornavirus affinities.
abstract: Ascospore and mycelial isolates of Gremmeniella abietina type B were found to contain three different dsRNA molecules with approximate lengths of 11, 5 and 3 kb. The 11 kb dsRNA encoded the genome of a putative virus and is named Gremmeniella abietina type B RNA virus XL (GaBRV-XL). GaBRV-XL probably exists in an unencapsulated state. We identified two distinct dsRNAs (10 374 and 10 375 bp) of GaBRV-XL, both of which coded for the same putative polyprotein (3249 amino acids) and contained four regions similar to putative viral methyltransferases, DExH box helicases, viral RNA helicase 1 and RNA-dependent RNA polymerases. While a cysteine-rich region with several CxCC motifs in GaBRV-XL was similar to that of putative endornaviruses, cluster analyses of conserved regions revealed GaBRV-XL to be distinct from a broad range of viral taxa but most closely related to Discula destructiva virus 3. Collectively, these findings suggest that GaBRV-XL represents a novel virus group related to endornaviruses.
authors.affiliation: Finnish Forest Research Institute, Vantaa Research Unit, Jokiniemenkuja 1, PO Box 18, FI-01301 Vantaa, Finland. Tero.Tuomivirta@metla.fi
authors.forename: Tero T
authors.initials: TT
authors.lastname: Tuomivirta
authors.forename: Juha
authors.initials: J
authors.lastname: Kaitera
authors.forename: Jarkko
authors.initials: J
authors.lastname: Hantula
mesh_terms: D001203:Ascomycota / Q000821:virology*; D016679:Genome, Viral; D008969:Molecular Sequence Data; D010802:Phylogeny; D012328:RNA Viruses / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*