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A filamentous virus isolated from a sugar-beet plant showing systemic mosaic collected in South Kazakhstan was identified as an isolate of beet mosaic virus (BMV-K). BMV-K was transmitted by the green peach aphid Myzus persicae in a non-persistent manner, and by sap inoculation to 11 out of 19 species from seven families tested. The virus could not be transmitted to Nicotina tabacum, N. debneyi, N. glutinosa and N. clevelandii, either mechanically or with M. persicae. The thermal inactivation point of BMV-K in sugar-beet sap was 55–60 C, dilution end point 1:1000 and longevity in vitro 2 days at 20 C. A purification procedure produced 1.5–3 mg of purified virus from 100 g of infected Stellaria media plants. Purified virus contained a single protein species of molecular weight 34 700 Da. In ELISA tests. BMV-K reacted positively with BMV-specific antisera obtained from Japan. Germany and Portugal. By competitive DAS-ELISA, the virus isolate was shown to be closely serologically related to all the three isolates of BMV, and very distantly related to bean yellow mosaic and soybean mosaic viruses. [ABSTRACT FROM AUTHOR]

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 X 105 and 1 X 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. [ABSTRACT FROM AUTHOR]