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Double-stranded RNA elements in the root rot fungus Heterobasidion annosum

Ihrmark, Katarina (2001). Double-stranded RNA elements in the root rot fungus Heterobasidion annosum. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Silvestria, 1401-6230 ; 210
ISBN 91-576-6094-8
[Doctoral thesis]

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This thesis comprises studies concerning the potential of using double-stranded RNA (dsRNA) mycoviruses as biological control agents against Heterobasidion annosum, a pathogen that causes root and butt rot in conifers. A large number of H. annosum isolates of various origin have been screened for the presence of dsRNA and it was found that dsRNA elements are present in a low proportion of isolates from most forest sites affected by H. unnosum. The highest proportion, up to 25%, of dsRNA infected isolates were found in localities heavily infected with H. unnosum. Sequence information indicates that the dsRNA elements in H. annosum belong to the virus family Partitiviridae. Studies on transmission of dsRNA in H. annosum indicated that horizontal transmission between vegetative cells occurs readily in this species and that anastomoses that allow dsRNA to transfer occur between both homo- and heterokaryotic mycelia, and also between isolates from different intersterility groups. Vertical transmission into spores was less efficient, particularly into conidiospores. It was concluded that conidia are not important for the spread of dsRNA in H. annosum, while basidiospores transmit dsFNA efficiently enough to be of importance for the spread of dsRNA. There was little difference in virulence between dsRNA infected and dsRNA free H. annosum isolates of the same genotype in virulence tests on ten-day-old seedlings of pine and spruce. Moreover, the virulence of the fungus was not affected when dsRNA was transferred from isolates of the S intersterility group to a P isolate. In conclusion, the present work indicates that partitivirus-like dsRNA elements cannot be used as biocontrol agents against H. annosum, since they do not cause hypovirulence in this species. However, the ease with which dsRNA was transmitted between incompatible isolates shows promise that deleterious mycoviruses have a potential as biocontrol agents in H. annosum, although the low transmission rate of dsRNA into conidia poses a potential problem concerning application of such a biocontrol age

Authors/Creators:Ihrmark, Katarina
Title:Double-stranded RNA elements in the root rot fungus Heterobasidion annosum
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Silvestria
Year of publishing :January 2001
Number of Pages:36
ALLI. Ihrmark, K., Zheng, J., Stenstrom, E. & Stenlid, J. 2001. Presence of double- stranded RNA in Heterobasidion annosum. Forest pathology 31. In press. 11. Ihrmark, K., Johannesson, H., Stenstrom, E. & Stenlid, J. Transmission of double-stranded RNA in Heterobasidion annosum. Submitted. 111. Ihrmark, K., Stenstrom, E. & Stenlid, J. Double-stranded RNA transmission through basidiospores of Heterobasidion annosum. Submitted. IV. Ihrmark, K., Stenstrom, E. & Stenlid, J. Virulence and double-stranded RNA in Heterobasidion annosum. Submitte
Place of Publication:Uppsala
ISBN for printed version:91-576-6094-8
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:H Protection of plants and stored products > H20 Plant diseases
Subjects:Not in use, please see Agris categories
Agrovoc terms:biological control, boreal forests, fungal diseases, heterobasidion annosum, plant viruses, root rots, heterobasidion annosum
Keywords:Basidiomycota, boreal forest, fungal viruses, biological control, partitiviruses
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ID Code:4
Department:(S) > Institutionen för skoglig mykologi och patologi
Deposited By: Staff Epsilon
Deposited On:03 May 2002 00:00
Metadata Last Modified:02 Dec 2014 10:01

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