RT-PCR detection of dsRNAs associated with La France disease of the cultivated mushroom Agaricus bisporus (Lange) Imbach.

A reverse transcription-polymerase chain reaction assay (RT-PCR) is described for the detection of double-stranded RNA (dsRNA) molecules (M1, M2, and L3) associated with La France disease of the cultivated mushroom Agaricus bisporus. RT-PCR was faster and more sensitive than current methods used to detect dsRNA, such as dsRNA extraction and analysis by electrophoresis. Another major advantage of RT-PCR was the detection of M1 dsRNA in rapidly prepared homogenates of sporophores and spawn, and in compost before sporophore production. The early detection of La France disease by RT-PCR will enable implementation of control measures by growers that may reduce losses in production time associated with a disease outbreak. Sequence analysis of dsRNA molecules in two Australian isolates showed that M1 was more conserved than M2 or L3 dsRNA.