Browsing by Subject "Narnaviridae"

Understanding the biomes and niches within forest ecosystems is key to maintaining and predicting micro-organism led processes, such as, nutrient recycling and disease proliferation. Insect-vectored fungi occupy the tree bark biosphere as incidental associates. Also, more selective transmission of fungi is seen via the beetle’s specialised structure called the mycangium. Mites carried by these insects, have also been described to vector fungi. Within these fungi are mycoviruses that express cryptic, beneficial, or detrimental effects to the host. The positive and negative effects on fungal host phenotypes encourage investigations into unknown virospheres. A study into the distribution of mycoviruses within bark-beetle vectored fungi in Finnish forests has yet to be carried out. The master’s thesis work continued an evaluation of viromes from 52 forest, bark-beetle vectored, fungal isolates transformed into 4 RNA libraries via high throughput sequencing platforming, using Illumina chemistry. Scots pine, Pinus sylvestris, and Norway spruce, Picea abies, logs were sampled. A further 31 fungal isolates were screened, via RT-PCR, for 22 putative viral sequences recovered from the RNA libraries. Patterns in viral sequence host range, co-infectivity and similarities between viral sequences were investigated. The viral sequences described in this study were unique to the databases searched against and could be looked at when maintaining the Finnish forest ecosystem. It was shown that positive-sense ssRNA viruses could play a major role in the virome of bark-beetle vectored fungi as 77.3 % of viral sequences described were classified as so. Mitovirus infections were most frequent across the two forests and, the interspecies-infective Ophiostomatoid mitovirus 2 strain was seen to infect at least four species, across two fungal genera. The description of Kuraishia capsulata narna-like virus 1 showing RNA dependent RNA polymerases (RdRp) across 2 genomes segments, supports current growing evidence, which in turn could contribute to the new classification of viruses within the Narnaviridae family.