CHARACTERIZATION OF A POTYVIRUS INFECTING SUNFLOWER IN ARGENTINA

A virus causing chlorotic mottling symptoms on sunflower was found in various locations in Argentina. Symptoms were small chlorotic spots, y ellow blotches on leaves, and plant stunting. Virus transmission effic iency by mechanical inoculation was 73 to 100%, and by Myzus persicae was 31 to 49%. The host range included members of the Amaranthaceae, A steraceae. Chenopodiaceae, and Solanaceae families. Electron microscop y of leaf dips from infected plants revealed flexuous particles 17 nm wide and 770 nm long. Cytoplasmic laminar aggregates and pinwheel incl usions were observed in ultrathin sections. Purified virus preparation s analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresi s resolved a capsid protein of 33 kDa. A monoclonal antibody to aphid- transmitted potyviruses reacted with the capsid protein of this virus. In dot blot immunoassays, a polyclonal antiserum (early bleeding) rea cted with infected sunflowers and weakly with Bidens mottle potyvirus, but not with either maize dwarf mosaic potyvirus or potato virus Y. T he evidence suggests that a potyvirus is infecting sunflower, and a pa rtial characterization of the causal agent is reported.