Double-stranded RNA viruses were detected in virulent strains of Rhizoctonia solani. The virus particles were 33 nm in diameter, contained two or three major segments of dsRNA (mol. wt. 1.6 × 106, 1.45 × 106 and 1.25 × 106), had a density of 1.34 g/ml and had an estimated sedimentation coefficient of 161S. The major coat protein had a mol. wt. of 46000. An RNA-dependent RNA polymerase activity was associated with the viral capsids. Native hypovirulent strains of R. solani were devoid of these viruses and attenuation of virulent strains to hypovirulence appeared to be correlated with the loss of some or all of the segments of dsRNA. Transmission of dsRNA from a virulent to a hypovirulent strain by heterokaryon formation was associated with the transmission of virulence.
BakerK. F.1970; Types of Rhizoctonia diseases and their occurrence. In Rhizoctonia solani: Biology and Pathology pp 125–148 Edited by
ParmeterJ. R.
Los Angeles: University of California Press;
BozarthR. F.1979; The physico-chemical properties of mycoviruses. In Viruses and Plasmids in Fungi pp 43–91 Edited by
LemkeP. A.
New York: Marcel Dekker;
BuckK. W.1979; Replication of double-stranded RNA mycoviruses. In Viruses and Plasmids in Fungi pp 94–162 Edited by
LemkeP. A.
New York: Marcel Dekker;
BuckK. W.,
RomanosM. A.,
McfaddenJ. J. P.,
RawlinsonC. J.1981; In vitro transcription of double-stranded RNA by virion-associated RNA polymerase of viruses fromGaeumannomyces graminis. Journal of General Virology 57:157–168
FieldJ. F.,
BruennJ. A.,
ChangT. H.,
PinhasiO.,
KoltinY.1983; TwoUstilago maydis viral dsRNAs of different size code for the same product. Nucleic Acids Research 11:2765–2778
FranklinR. M.1966; Purification and properties of the replicative intermediate of the RNA bacteriophage R17. Proceedings of the National Academy of Sciences, U,. S,. A 55:1504–1511
GhabrialS. A.,
MernaughR. L.1983; Biology and transmission ofHelminthosporium vidoriae mycoviruses. In Double-Stranded RNA Viruses pp 441–449 Edited by
CompansR. W.,
BishopD. H. L.
New York: Elsevier;
HashibaT.,
HommaY.,
HyakumachiM.,
MatsudaI.1984; Isolation of a DNA plasmid in the fungusRhizoctonia solani. Journal of General Microbiology 130:2067–2070
MartiniG.,
GrimaldiG.,
GuardiolaI.1978; Extrachromosomal DNA in phytopathogenic fungi. In Genetic Engineering pp 197–200 Edited by
BoyerH. W.,
NicosiaS.
Amsterdam:: Elsevier/North-Holland;
NeffN. F.,
ThomasJ. F.,
GrisafiP.,
BotsteinD.1983; Isolation of theβ-tubulin gene from yeast and demonstration of its essential functionin vivo. Cell 33:211–219
RawlinsonC. J.,
HornbyC. J.,
PearsonV.,
CarpenterJ. M.1973; Virus-like particles in take all fungusGaeumannomyces graminis. Annals of Applied Biology 74:197–209
van AlfenN. K.1982; Biology and potential for disease control of hypovirulent strains ofEndothia parasitica. Annual Review of Phytopathology 20:349–362
van AlfenN. K.,
HansenD. R.1983; Hypovirulence: a unique phenotypic expression of dsRNA in a pathogenic fungus. In Double-Stranded RNA Viruses pp 463–467 Edited by
CompansR. W.,
BishopD. H. L.
New York: Elsevier;
ZanzingerD. H.,
BandyB. P.,
TavantzisS. M.1984; High frequency of finding double-stranded RNA in naturally occurring isolates ofRhizoctonia solani. Journal of General Virology 65:1601–1605