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Double-stranded RNA in the entomopathogenic fungus metarhizium flavoviride
M K Martins1, M C Furlaneto, D R Sosa-Gomez
1Centro de Ciências Biológicas, Universidade Estadual de Londrina, P.O. Box 6001, CEP: 86051-970, Londrina - PR, Brazil.
Abstract:
Bands of dsRNA were detected in five out of seven isolates of the entomopathogenic fungus Metarhizium flavoviride. The identity of these bands was proven by RNase and S1-nuclease treatments. The transference of dsRNA between isolates (from CG291 to CG442) was successfully carried out through forced heterokaryons. Isogenic strains, with or without dsRNA, were submitted to virulence tests against the grasshopper Rhammatocerus schistocercoides. In contrast to what has been found in some phytopathogenic fungi, these dsRNA fragments did not cause hypovirulence to M. flavoviride.
Insights
Double-stranded RNA (dsRNA) was found in Metarhizium flavoviride isolates but did not reduce fungal virulence against grasshoppers. This contrasts with findings in plant-pathogenic fungi, suggesting dsRNA may not impact this entomopathogenic fungus.
Area of Science:
- Mycology
- Molecular Biology
- Entomology
Background:
- Entomopathogenic fungi like Metarhizium flavoviride are crucial for biological pest control.
- Double-stranded RNA (dsRNA) has been linked to hypovirulence in some plant-pathogenic fungi.
- The presence and effect of dsRNA in M. flavoviride isolates were previously uncharacterized.
Purpose of the Study:
- To detect and characterize dsRNA in Metarhizium flavoviride.
- To investigate the potential for dsRNA transfer between fungal isolates.
- To determine the impact of dsRNA on the virulence of M. flavoviride against grasshoppers.
Main Methods:
- Detection of dsRNA using nuclease treatments (RNase, S1-nuclease).
- dsRNA transfer via forced heterokaryons between M. flavoviride isolates.
- Virulence assays using isogenic strains (with and without dsRNA) against Rhammatocerus schistocercoides.
Main Results:
- dsRNA bands were identified in 5 out of 7 M. flavoviride isolates.
- dsRNA was successfully transferred between isolates.
- Isogenic strains containing dsRNA did not exhibit reduced virulence against the target grasshopper.
Conclusions:
- dsRNA is present in some M. flavoviride isolates.
- dsRNA can be transferred between fungal isolates.
- Unlike in phytopathogenic fungi, dsRNA does not appear to induce hypovirulence in this entomopathogenic fungus.