In vitro transcription of the double-stranded RNA genome of maize rough dwarf virus (Reoviridae).

An RNA-dependent RNA polymerase associated with particles of maize rough dwarf virus, a Fijivirus, was characterized using two in vitro assays differing in their energy regeneration systems. Optimum reaction rates occurred at pH 8-0 to 8.5 at 20 °C. The presence of virus and Mn 2+ or Mg 2+ was essential for enzyme activity; Mn 2+ stimulated more incorporation events than Mg z+, at optimum concentrations of 2 to 4 mM and 4 mM, respectively. Incorporation was not affected by (alfa)-amanitin, actinomycin D or rifampicin. The products synthesized in vitro were single-stranded RNAs which hybridized specifically with the double stranded genomic RNAs of the template virus, but not with genomic RNAs of five other reoviruses. The in vitro transcripts were also used to detect maize rough dwarf virus RNA in plants and in vector insects.