Purification, Electron Microscopy, and Serology of Dioscorea Latent Virus

A virus latent in yam species Dioscorea floribunda and D. composita (DLV) was purified by use of powdered activated charcoal and magnesium-treated bentonite to clarify extracted Dioscorea leaf sap. The virus produced a single band in sucrose-density gradients. Antisera produced in a rabbit reached a titer of 1:16,000. Purified DLV did not react with antiscra to any of 25 rod-shaped viruses. Myzus persicae (Sulzer), the green peach aphid, did not transmit DLV from infected Dioscorea plants. Seventy-four percent of the particles measured 395-445 nm. Inoculated D. floribunda seedlings showed no symptoms, but the virus was observed in dip preparations from systemically infected growth. DLV occurred in combination with a second virus that was aphid-transmissible and which incited green banding symptoms.