Molecular characterization of dsRNA segments 2 and 5 and electron microscopy of a novel reovirus from a hypovirulent isolate, W370, of the plant pathogen Rosellinia necatrix

• Published in: Journal of general virology Vol. 84; no. 9; pp. 2431 - 2437
• Main Authors: Wei, C.Z, Osaki, H, Iwanami, T, Matsumoto, N, Ohtsu, Y
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01.09.2003
• Subjects: Amino Acid Sequence; Ascomycota - pathogenicity; Ascomycota - virology; biological control agents; double-stranded RNA; dsRNA viruses; Microscopy, Electron; Molecular Sequence Data; Molecular Weight; mycoviruses; nucleotide sequences; Open Reading Frames; Reoviridae - classification; Reoviridae - genetics; Reoviridae - ultrastructure; RNA, Double-Stranded; RNA, Viral - genetics; Rosellinia anti-rot virus; Rosellinia necatrix; Sequence Alignment; Terminology as Topic; Viral Proteins - chemistry; Viral Proteins - genetics
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.19098-0

1 National Institute of Fruit Tree Science, Fujimoto, Tsukuba 305-8605, Japan 2 National Institute for Agro-Environmental Sciences, Kan-nondai, Tsukuba 305-8604, Japan Correspondence Chuan Zhao Wei chenwei{at}vesta.ocn.ne.jp A hypovirulent isolate, W370, of the white root rot fungus Rosellinia necatrix has previously been shown to harbour 12 dsRNA segments. In this study, complete nucleotide sequences of segments 2 and 5 of W370 dsRNAs were determined. The nucleotide sequence of genome segment 2 was 3773 bases long with a single long open reading frame (ORF) encoding 1226 amino acid residues with a predicted molecular mass of approximately 138·5 kDa. The nucleotide sequence of segment 5 was 2089 bases long with a single long ORF, whose deduced polypeptide contained 646 amino acid residues with a predicted molecular mass of about 72 kDa. Comparative analysis showed that the deduced protein sequence of segment 2 had significant homology with the putative VP2 of Colorado tick fever virus (CTFV) and European Eyach virus (EYAV) in the genus Coltivirus , but the deduced protein sequence of segment 5 had no similarity with other virus proteins. Double-shelled spherical particles approximately 80 nm in diameter associated with W370 dsRNAs were observed in a preparation from the mycelial tissue of isolate W370. The results demonstrated that the virus associated with W370 dsRNAs is a novel reovirus of the family Reoviridae . The virus was named Rosellinia anti-rot virus (RArV). The GenBank accession numbers of the sequences reported in this paper are AB098022 (segment 2) and AB098023 (segment 5). Present address: National Agricultural Research Center for Kyushu Okinawa Region, Suya 2421, Nishigoshi, Kumamoto 861-1192, Japan.