Three unrelated viruses occur in a single isolate of Gremmeniella abietina var. abietina type A.
Five enclosed double-stranded RNA (dsRNA) bands in electrophoresis, probably of viral origin, were found from a single isolate (SurS4) of Gremmeniella abietina var. abietina type A. Analysis of the dsRNAs revealed that they represented three different viruses, named as Gremmeniella abietina mitochondrial RNA virus S2 (GaMRV-S2), Gremmeniella abietina RNA virus MS2 (GaRV-MS2) and Gremmeniella abietina RNA virus L2 (GaRV-L2). The genome of GaMRV-S2 was 2587 base pairs (bp) long and had a very low GC content (31%). Sequence variations occurred at both ends. The genome coded for a putative RNA-dependent RNA polymerase (RdRp) under a mitochondrial translation code. The GaRV-MS2 genome was composed of three dsRNA molecules (1781 bp, 1586 bp and 1186 bp). They coded for a putative RdRp, a coat protein (CP) and a protein with an unknown function, respectively. The GaRV-L2 genome was 5129 bp long and contained two ORFs. The 5'-proximal ORF coded for a putative CP, whereas the 3'-proximal ORF encoded for a putative RdRp. The buoyant density of GaRV-MS2 and GaRV-L2 were 1.37 and 1.42 g/ml, respectively. GaMRV-S2, GaRV-MS2 and GaRV-L2 were closely related to the previously described viruses GaMRV-S1, GaRV-MS1 and GaRV-L1, respectively, and are putative members of the genera Mitovirus, Partitivirus and Totivirus, respectively. This is the first report on the occurrence of viruses of all these different genera in a single fungal isolate.
Tuomivirta
Tero T
TT
Finnish Forest Research Institute, P.O. Box 18, 01301 Vantaa, Finland. Tero.Tuomivirta@metla.fi
Hantula
Jarkko
J
D000595:Amino Acid Sequence; D001203:Ascomycota / Q000821:virology*; D036022:Capsid Proteins / Q000235:genetics; D002499:Centrifugation, Density Gradient; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011110:Polymorphism, Genetic; D012328:RNA Viruses / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D012330:RNA, Double-Stranded / Q000235:genetics / Q000302:isolation & purification; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D019197:Totivirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D014764:Viral Proteins / Q000235:genetics
D036022:Capsid Proteins; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D014764:Viral Proteins; D012324:RNA-Dependent RNA Polymerase