In vitro transcription by RNA polymerase associated with rice gall dwarf virus

1 Institute for Biological Science, The University of Tsukuba, Sakura-mura, Ibaraki 305 and 2 Institute for Plant Virus Research, Tsukuba Science City, Yatabe, Ibaraki 305, Japan An RNA-dependent polymerase associated with rice gall dwarf virus (RGDV), a new Phytoreovirus, was characterized. Optimum polymerase activity was found between pH 8.0 and 8.5 at 25°C. Mg 2+ was essential for the activity, the optimum concentration being 2 m M . Mn 2+ could replace Mg 2+ . The RNA products synthesized in vitro hybridized with RGDV RNA, but not with RNA of rice dwarf virus which is in the same subgroup of plant reoviruses. Electrophoretic analysis of the products showed at least nine bands, the sizes of which are discussed. Keywords: RGDV, RNA polymerase, dsRNA Received 2 August 1983; accepted 7 November 1983.