Purification and Some Properties of an Isolate of Beet Yellows Virus from Ukraine

A purification procedure, which yielded up to 15–30 mg of beet yellows virus (BYV) per 100 g of infected Tetragonia expansa leaves, has been developed. The procedure included sap clarification with Triton X‐100, and two cycles of ultracentrifugation through sucrose cushion, which contained PEG‐6000 and NaCl. A specific antiserum was prepared, and BYV infection was successfully detected by the double‐antibody sandwich (DAS) ELISA in infected sugar beet leaves and roots diluted up to 1 × 105 and 1 × 104, respectively. The virus concentration was demonstrated to decrease in infected sugar beet roots slowly during 7 months, thus allowing successful diagnosis of planting material in winter storage. BYV presence in Myzus persicae aphids was also reliably detectable using the DAS‐ELISA. In a competitive DAS‐ELISA test, the Ukraine and the British BYV isolates were found serologically indistinguishable.