Lack of Temperature Sensitivity of RNA-dependent RNA Polymerases Isolated from Tobacco Plants Infected with ts Mutants of Alfalfa Mosaic Virus

Enzyme activities of particulate and solubilized RNA-dependent RNA polymerase preparations from tobacco plants infected with 10 ts mutants of alfalfa mosaic virus (AMV), having their mutations in each of the three parts of the virus genome, were found to behave similarly with respect to temperature as compared to preparations obtained from plants infected with wild type AMV or from uninfected plants. Thus it is very unlikely that a virus-specific protein is involved in these in vitro RNA polymerase activities.