title: Characterisation of a novel hypovirus from Sclerotinia sclerotiorum potentially representing a new genus within the Hypoviridae.
abstract: A novel mycovirus tentatively assigned the name Sclerotinia sclerotiorum hypovirus 2 (SsHV2/5472) was detected in the phytopathogenic fungus Sclerotinia sclerotiorum. The genome is 14581 nucleotides (nts) long, excluding the poly (A) tail. A papain-like cysteine protease (Pro), an RNA-dependent RNA polymerase (RdRp) and a helicase (Hel) domain were detected in the polyprotein. Phylogenetic analysis based on multiple alignments of the aa sequence of the polyprotein placed it in a distinct clade from Alphahypovirus and Betahypovirus. The distinct aa sequence plus the fact that SsHV2/5472 possesses the longest reported genome for a hypovirus, suggests that SsHV2/5472 may represent a new genus in the family Hypoviridae. Eliminating SsHV2/5472 from S. sclerotiorum significantly increased the virulence of the protoplast virus-free derivative 5472-P5, although SsHV/5472-containing isolates showed significant variation in their virulence. In addition, membrane-bound vesicles (25-50 nm) were observed in ultrathin mycelial sections of SsHV2/5472 containing isolates but not in SsHV2/5472-free isolate.
authors.affiliation: School of Biological Sciences, The University of Auckland, PO Box 92019, Auckland 1010, New Zealand. Electronic address: mkha201@aucklanduni.ac.nz.
authors.forename: Mahmoud E
authors.initials: ME
authors.lastname: Khalifa
authors.affiliation: School of Biological Sciences, The University of Auckland, PO Box 92019, Auckland 1010, New Zealand.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Pearson
mesh_terms: D000595:Amino Acid Sequence; D001203:Ascomycota / Q000821:virology*; D001483:Base Sequence; D016679:Genome, Viral; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D012328:RNA Viruses / Q000737:chemistry / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D014764:Viral Proteins
keywords: Hypoviridae; Hypovirus; Mycovirus; Sclerotinia sclerotiorum; dsRNA