Chromatographic studies of RNA synthesis in tobacco leaf tissues infected with tobacco mosaic virus

Abstract

RNA synthesis in tobacco leaf tissues infected with tobacco mosaic virus (TMV) was investigated by chromatography with methylated albumin kieselguhr columns. When the relative rates of host- and TMV-RNA synthesis in the infected tissues were compared by exposing the tissues to P 32 for 30–60 minutes at different times after inoculation, there were observed distinctive changes in the pattern of RNA synthesis in the infected leaf tissues as infection time elapsed. Although, at earlier stages of infection, there was an increase of host-RNA synthesis which seemed to be induced by virus infection, it was less at later times. The relative rate of TMV-RNA synthesis was highest at 48 hours after inoculation. Both host- and TMV-RNA synthesis continued at 96 hours after inoculation, though lower. In the infected leaf tissues treated with actinomycin D and labeled with P 32 or both P 32 and tritiated guanosine, host-RNA synthesis was markedly suppressed whereas TMV-RNA synthesis was not. This result confirms previously reported suggestions that TMV-RNA synthesis is independent of host DNA.