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Virulence in an insect model differs between mating types in Aspergillus fumigatus
Manjinder S Cheema1, Julian K Christians
1Simon Fraser University, Biological Sciences, Burnaby, British Columbia, Canada.
Abstract:
Aspergillus fumigatus is an opportunistic fungal pathogen that has recently been found to undergo sexual reproduction. Previous work suggested that invasiveness differs between mating types, and in the present study we tested whether virulence differs between mating types in an in vivo model, i.e., larvae of the wax moth Galleria mellonella. We measured virulence of 20 A. fumigatus isolates; three MAT1-1 isolates of environmental origin, five MAT1-1 isolates of clinical origin, seven MAT1-2 isolates of environmental origin and five MAT1-2 isolates of clinical origin. For each isolate, we measured virulence in six replicates and for each replicate, conidia were grown, harvested, and counted independently, and 2,500 colony forming units were injected into each of 10 G. mellonella larvae. Virulence differed between mating types, with lower survival in larvae injected with MAT1-1 isolates. Virulence also differed between clinical and environmental isolates, but surprisingly larvae injected with environmental isolates had lower survival. Identification of the mechanisms underlying variation in virulence may identify novel targets for the treatment of Aspergillus infections.
Insights
Aspergillus fumigatus mating types influence virulence. MAT1-1 strains showed lower virulence in a wax moth model, suggesting mating type impacts fungal infection severity.
Area of Science:
- Mycology
- Infectious Diseases
- Pathogen Biology
Background:
- Aspergillus fumigatus, an opportunistic fungal pathogen, exhibits sexual reproduction.
- Previous research indicated mating type-dependent differences in invasiveness.
- The impact of mating types on virulence remained largely unexplored.
Purpose of the Study:
- To investigate whether mating types of Aspergillus fumigatus influence virulence.
- To compare the virulence of MAT1-1 and MAT1-2 mating types in an in vivo model.
- To assess differences in virulence between clinical and environmental isolates.
Main Methods:
- Virulence of 20 Aspergillus fumigatus isolates (MAT1-1 and MAT1-2, clinical and environmental) was assessed.
- The wax moth Galleria mellonella served as an in vivo model.
- Larvae were injected with 2,500 conidia per replicate, with virulence measured by larval survival.
Main Results:
- Significant differences in virulence were observed between Aspergillus fumigatus mating types.
- Larvae infected with MAT1-1 isolates exhibited lower survival rates compared to MAT1-2 isolates.
- Environmental isolates unexpectedly showed lower survival rates in larvae compared to clinical isolates.
Conclusions:
- Aspergillus fumigatus mating type is a determinant of virulence.
- MAT1-1 strains are less virulent in the Galleria mellonella model.
- Understanding virulence variation mechanisms may reveal new therapeutic targets for Aspergillus infections.
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