Complex transmission of partiti-, ambi- and ourmiaviruses in the forest pathogen Heterobasidion parviporum.

Utilizing Heterobasidion partitivirus 13 strain an1 (HetPV13-an1) and 15 strain pa1 (HetPV15-pa1) in co-infection is considered a potential biocontrol approach against Heterobasidion root and butt rot. Both partitiviruses mediate debilitating effects in most Heterobasidion host isolates and are generally transmitted efficiently between host strains. In this investigation, we conducted transmission experiments in the laboratory (in vitro) using several H.

Virus transmission frequencies in the pine root rot pathogen Heterobasidion annosum.

The combined use of Heterobasidion partitiviruses 13 and 15 (HetPV13-an1 and HetPV15-pa1) is considered a promising biocontrol approach against Heterobasidion root and butt rot. In a previous study, the transmission frequency of HetPV15-pa1 was found to be higher from a double partitivirus-infected donor than from a single partitivirus-infected donor. In this study, we included a wider array of recipient isolates to assess whether the phenomenon is widespread across different host strains and conducted transmission experiments on artificial media (in vitro) using a total of 45 different H.

Diversity and impact of single-stranded RNA viruses in Czech populations.

comprises some of the most devastating pathogens of conifers. Exploring virocontrol as a potential strategy to mitigate economic losses caused by these fungi holds promise for the future. In this study, we conducted a comprehensive screening for viruses in 98 .

Efficacy of Biological and Chemical Control Agents against Spore Infections of Norway Spruce and Scots Pine Stumps on Drained Peatland.

Treatment of conifer stumps with a control agent effectively prevents spore infections in summer cuttings and protects the residual stand and the next tree generation from damage caused by Heterobasidion root rot. Thus far, stump treatment experiments have been carried out in mineral soils, and no information is available on the efficacy of stump treatment agents in boreal peatland conditions. In the present study, biological and chemical control agents ( and urea, respectively) were tested in Scots pine and Norway spruce stands subjected to thinning, cap cutting, and clearcutting on drained peatland in Central Finland.

Bunyaviruses Affect Growth, Sporulation, and Elicitin Production in .

is an important oomycetous plant pathogen with numerous host plant species, including garden strawberry ( × ) and silver birch (). also hosts mycoviruses, but their phenotypic effects on the host oomycete have not been studied earlier. In the present study, we tested polyethylene glycol (PEG)-induced water stress for virus curing and created an isogenic virus-free isolate for testing viral effects in pair with the original isolate.

Phenotypic Recovery of a Isolate Infected by a Debilitation-Associated Virus Is Related to Altered Host Gene Expression and Reduced Virus Titer.

The fungal genus includes forest pathogenic species hosting a diverse group of partitiviruses. They include the host debilitating Heterobasidion partitivirus 13 strain an1 (HetPV13-an1), which was originally observed in a slowly growing strain 94233. In this study, a relatively fast-growing sector strain 94233-RC3 was isolated from a highly debilitated mycelial culture of 94233, and its gene expression and virus transcript quantities as well as the genomic sequence of HetPV13-an1 were examined.

RNA-Dependent RNA Polymerase from Heterobasidion RNA Virus 6 Is an Active Replicase In Vitro.

Heterobasidion RNA virus 6 (HetRV6) is a double-stranded (ds)RNA mycovirus and a member of the recently established genus within the family . The purpose of the study was to determine the biochemical requirements for RNA synthesis catalyzed by HetRV6 RNA-dependent RNA polymerase (RdRp). HetRV6 RdRp was expressed in and isolated to near homogeneity using liquid chromatography.

Viral diversity in Phytophthora cactorum population infecting strawberry.

Eighty-eight Phytophthora cactorum strains isolated from crown or leather rot of strawberry in 1971-2019 were screened for viruses using RNA-seq and RT-PCR. Remarkably, all but one isolate were virus-infected, most of them harbouring more than one virus of different genera or species. The most common virus occurring in 94% of the isolates was the Phytophthora cactorum RNA virus 1 (PcRV1) resembling members of Totiviridae.

Role and function of Chondrostereum purpureum in biocontrol of trees.

A decay fungus, Chondrostereum purpureum (Pers. Ex Fr.) Pouzar, has been investigated in Europe, Northern America and New Zealand for its ability to decay hardwood stumps and thus prevent sprouting.

Rainstorm effects on the biocontrol efficacy of the decay fungus Chondrostereum purpureum against birch sprouting in boreal forests.

In forest regeneration areas, alongside roads and railways, under electric power lines and above gas pipe lines, there is a need for regular sprout control. A biocontrol method against broadleaved sprouting with formulations including the decay fungus Chondrostereum purpureum (Pers. Ex Fr.

Multiple virus infections on Heterobasidion sp.

Heterobasidion viruses have previously been shown to affect each other's transmission and phenotypic effects on their hosts in a complex way. In this work, Heterobasidion parviporum strains hosting five coinfecting viruses simultaneously were constructed and used as donors in transmission experiments. They showed that viruses move more frequently between the mycelia of the same species than between the mycelia of H.

Alphapartitiviruses of Wood Decay Fungi Affect Each Other's Transmission and Host Growth.

spp. root rot fungi are highly destructive forest pathogens of the northern boreal forests, and are known to host a diverse community of partitiviruses. The transmission of these mycoviruses occurs horizontally among host strains via mycelial anastomoses.

Description, Distribution, and Relevance of Viruses of the Forest Pathogen .

The European race of the ascomycetous species (Lagerberg) Morelet includes causal agents of shoot blight and stem canker of several conifers in Europe and North America, which are known to host a diverse virome. GaRV6 is the latest and sixth mycovirus species reported within . Before its description, one victorivirus and one gammapartitivirus species were described in biotype A, two mitoviruses in both biotypes A and B and a betaendornavirus in biotype B.

Cadophora margaritata sp. nov. and other fungi associated with the longhorn beetles Anoplophora glabripennis and Saperda carcharias in Finland.

Symbiosis with microbes is crucial for survival and development of wood-inhabiting longhorn beetles (Coleoptera: Cerambycidae). Thus, knowledge of the endemic fungal associates of insects would facilitate risk assessment in cases where a new invasive pest occupies the same ecological niche. However, the diversity of fungi associated with insects remains poorly understood.

Interfertility and genetic variability among European and North American isolates of the basidiomycete fungus Chondrostereum purpureum.

The conspecificity of Finnish and western Canadian isolates of the decay fungus Chondrostereum purpureum was investigated by several approaches, including the assessment of genetic variability, mating and progeny analysis, and the analysis of selected phenotypic traits. Eight second-generation single spore strains per fungal isolate pairing were investigated with specific genetic markers developed for both Finnish and Canadian parental isolates. Tests of linkage disequilibrium were used to analyze whether these markers assorted independently among single spore strains.

Characterization of small RNAs originating from mitoviruses infecting the conifer pathogen Fusarium circinatum.

Deep sequencing of small RNAs has proved effective in the diagnosis of mycovirus infections. In this study, the presence of mycoviruses in ten isolates of the phytopathogenic fungus Fusarium circinatum was investigated by high-throughput sequencing (HTS) of small RNAs. The contigs resulting from de novo assembly of the reads were aligned to viral genome sequences.

Heterobasidion Partitivirus 13 Mediates Severe Growth Debilitation and Major Alterations in the Gene Expression of a Fungal Forest Pathogen.

The fungal genus includes some of the most devastating conifer pathogens in the boreal forest region. In this study, we showed that the alphapartitivirus Heterobasidion partitivirus 13 from (HetPV13-an1) is the main causal agent of severe phenotypic debilitation in the host fungus. Based on RNA sequencing using isogenic virus-infected and cured fungal strains, HetPV13-an1 affected the transcription of 683 genes, of which 60% were downregulated and 40% upregulated.

Looking for relationships between the populations of Dothistroma septosporum in northern Europe and Asia.

Dothistroma septosporum, a notorious pine needle pathogen with an unknown historical geographic origin and poorly known distribution pathways, is nowadays found almost in all areas inhabited by pines (Pinus spp.). The main aim of this study was to determine the relationship between North European and East Asian populations.

Distribution of Viruses Inhabiting Heterobasidion annosum in a Pine-Dominated Forest Plot in Southern Finland.

We investigated the diversity and spatial distribution of viruses infecting strains of the root rot fungus Heterobasidion annosum collected from pine stumps at a heavily infected forest site. Four different partitiviruses were detected in 14 H. annosum isolates at the study site, constituting approximately 29% of all Heterobasidion isolates investigated (N = 48).

Occurrence of similar mycoviruses in pathogenic, saprotrophic and mycorrhizal fungi inhabiting the same forest stand.

Fungal viruses (mycoviruses) are considered to be highly host specific, but phylogenetic analysis supports the occasional occurrence of horizontal transmission between species. We used an extensive sampling strategy to investigate whether similar viruses occur in more than one fungal species of the same forest habitat. Mycelial samples were collected from in-growth mesh bags (N = 259), fruiting bodies (N = 173) and cultured isolates (N = 68) at a forest site where the spatial distribution of viral infections in clonal individuals of the wood decay fungus Heterobasidion parviporum was mapped in detail earlier.

Tree invasions and biosecurity: eco-evolutionary dynamics of hitchhiking fungi.

When non-native plants reach novel environments, they typically arrive with hidden microbiomes. In general, most of these hitchhikers remain on their co-evolved hosts, some contribute to the invasiveness of their hosts, and a small number can undergo host shifts and move onto native hosts. Invasion success can vary depending upon the different categories of fungal associates.

The efficacy of six elite isolates of the fungus Chondrostereum purpureum against the sprouting of European aspen.

The sprouting of broad-leaved trees after cutting is problematic in forest regeneration areas, along roads and railways, under electric power and above gas pipe lines. In Finland, one of the most difficult species to control in these areas is the European aspen (Populus tremula), which produces both stump sprouts and root suckers after saplings have been cut. In this study, we investigated whether a decay fungus of broad-leaved trees, Chondrostereum purpureum, could be used as a biological control agent against aspen sprouting.

Taxonomy, biogeography and importance of Heterobasidion viruses.

The genus Heterobasidion consists of several species of necrotrophic and saprotrophic fungi, and includes some of the most detrimental organisms in boreal conifer forests. These fungi host a widespread and diverse mycovirus community composed of more than 16 species of Partitiviridae, a species of Narnaviridae and one taxonomically unassigned virus related to the Curvularia thermal tolerance virus. These viruses are able to cross species borders, co-infect single host strains and cause phenotypic changes in their hosts.