AUTHOR=Sutela Suvi , Piri Tuula , Vainio Eeva J. 

TITLE=Discovery and Community Dynamics of Novel ssRNA Mycoviruses in the Conifer Pathogen Heterobasidion parviporum

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.770787

DOI=10.3389/fmicb.2021.770787

ISSN=1664-302X

ABSTRACT=<p><italic>Heterobasidion</italic> species are highly destructive basidiomycetous conifer pathogens of the Boreal forest region. Earlier studies have revealed dsRNA virus infections of families <italic>Curvulaviridae</italic> and <italic>Partitiviridae</italic> in <italic>Heterobasidion</italic> strains, and small RNA deep sequencing has also identified infections of <italic>Mitoviridae</italic> members in these fungi. In this study, the virome of <italic>Heterobasidion parviporum</italic> was examined for the first time by RNA-Seq using total RNA depleted of rRNA. This method successfully revealed new viruses representing two established (+)ssRNA virus families not found earlier in <italic>Heterobasidion</italic>: <italic>Narnaviridae</italic> and <italic>Botourmiaviridae</italic>. In addition, we identified the presence of a recently described virus group tentatively named “ambiviruses” in <italic>H. parviporum</italic>. The <italic>H. parviporum</italic> isolates included in the study originated from experimental forest sites located within 0.7 km range from each other, and a population analysis including 43 isolates was conducted at one of the experimental plots to establish the prevalence of the newly identified viruses in clonally spreading <italic>H. parviporum</italic> individuals. Our results indicate that viral infections are considerably more diverse and common among <italic>Heterobasidion</italic> isolates than known earlier and include ssRNA viruses with high prevalence and interspecies variation.</p>