Abstract
Antiserum raised against purified potato yellow dwarf virus (PYDV) reacted specifically with all five viral structural proteins in immunoblots and also with ultrathin sections of infected tobacco cells. In these sections viral proteins were detected with gold-labelled anti-IgG antibodies and gold particles were predominantly located over the nucleoplasm and over PYDV virus particles either at the periphery of nuclei or in the cytoplasm. Control sections of uninfected or healthy cells were not labelled. The results suggest that the nucleoplasm is the only site of accumulation of PYDV structural proteins.