Double-stranded RNA in the entomopathogenic fungus Metarhizium flavoviride

Bands of dsRNA were detected in five out of seven isolates of the entomopat hogenic fungus Metarhizium favourite . The identity of these bands was prov en by RNase and S1-nuclease treatments. The transference of dsRNA between i solates (from CG291 to CG442) was successfully carried out through forced h eterokaryons. Isogenic strains, with or without dsRNA, were submitted to vi rulence tests against the grasshopper Rhammatocerus schistocercoides. In co ntrast to what has been found in some phytopathogenic fungi, these dsRNA fr agments did not cause hypovirulence to M. flavoviride .