Reserach Notes A Single Amino Acid Change in Tobacco Mosaic Virus Replicase Prevents Symptom Production. Dennis J. Lewandowski. Department of Plant Pathology, University of California, Riverside 92521 U.S.A. William O. Dawson. Department of Plant Pathology, University of California, Riverside 92521 U.S.A. MPMI 6:157-160. Accepted 28 September 1992. Copyright 1993 The American Phytopathological Society.

A tobacco mosaic tobamovirus (TMV) mutant that produced a symptomless systemic infection in tobacco and other plants was found to have a single nucleotide change resulting in an amino acid substitution in both the 126- and 183-kDa proteins. Virus accumulation was reduced in both inoculated and systemically infected leaves of tobacco relative to TMV U1.