Aspergillus fumigatus mycovirus causes mild hypervirulent effect on pathogenicity when tested on Galleria mellonella

Abstract

Mycoviruses are a specific group of viruses that naturally infect and replicate in fungi. The importance of mycoviruses was revealed after their effects were identified not only in economically important fungi but also in the human pathogenic fungus Aspergillus fumigatus. The latter was shown recently to harbor at least three different types of mycoviruses including a chrysovirus, a partitivirus and an as yet uncharacterized virus. Assessment of virulence in the presence and absence of mycoviruses in A. fumigatus is pivotal to understanding its pathogenicity. Here, we have investigated, for the first time, the effects of mycoviruses on the pathogenicity of A. fumigatus as assessed using larvae of the greater wax moth Galleria mellonella. In order to observe the effects of mycoviruses on pathogenicity, G. mellonella were injected with virus-free and virus-infected isolates of A. fumigatus and post-infection survival times were analyzed along with the fungal burden. Neither chrysovirus nor partitivirus infection affected fungal pathogenicity when survival rates were assessed which, for the chrysovirus, agreed with a previous study on murine pathogenicity. However statistically significant differences were observed in survival rates and fungal burden in the presence of the uncharacterized A78 virus. Here we show, for the first time, the effects of a partitivirus and an uncharacterized A78 virus on the pathogenicity of A. fumigatus.

Using a Novel Partitivirus in Pseudogymnoascus destructans to Understand the Epidemiology of White-Nose Syndrome

“…Similarly, a high level of virulence was reported in the presence of a six kbp mycoviral dsRNA in Nectria radicicola , the causal fungus of ginger root rot [28]. The opportunistic fungal pathogen, Aspergillus fumigatus causing lung disease in immunocompromised humans and animals also exhibited hypervirulence in the presence of the uncharacterized A78 mycovirus [29]. We have not explored the roles of PdPV-pa in WNS in the present study, but some indirect evidence, including the difficulties in curing the fungus of PdPV-pa, the stability of the virus after numerous generations of laboratory cultures, the changes in pigmentation and the significantly reduced production of conidia in the virus-free isolate indicate close biological relationships between the fungus and the virus; hence future investigation on potential biological effects of PdPV-pa will be important.…”

A novel mycovirus from Aspergillus fumigatus contains four unique dsRNAs as its genome and is infectious as dsRNA

“…Student's t test was used to analyze all of the data for significant differences in growth rate and biomass production. G. mellonella infectivity assays, fungal burden assays, and statistical analyses were performed as described by Özkan and Coutts (16). All experiments were performed in triplicate.…”

“…Apart from a minor reduction in the intensity of blue green pigmentation in AfuNK125, there were no significant differences in phenotype, growth rates, or biomass between A. fumigatus Af293 and AfuNK125 in either medium. Additionally, the greater wax moth Galleria mellonella infection model was used to compare the virulence of A. fumigatus Af293 and AfuNK125 as described previously (16). Statistically significant differences in the survival rates of G. mellonella larvae infected with Af293 and AfuNK125 (Fig.…”

Investigation of mycoviruses in endophytic and phytopathogenic strains of Colletotrichum from different hosts

“…In recent years, the number of studies regarding mycoviruses in phytopathogenic fungi has increased considerably Zhong et al, 2014;Özkan and Coutts, 2015;Shang et al, 2015). The frequency of mycovirus strains in Colletotrichum from different plant hosts as detected by mycoviral dsRNA herein was low (1/26; 3.85%).…”