PRESERVATION OF PURIFIED PEANUT STRIPE AND TURNIP MOSAIC POTYVIRUSES BY FREEZING AND FREEZE-DRYING

During storage at -20 degrees C of purified preparations of peanut str ipe and turnip mosaic potyviruses, infectivity of intact particles and RNA extracted from preserved preparations decreased. This decrease ca n be attributed to several factors such as virus aggregation and alter ations of the nucleic acids and coat proteins. However, the addition t o the preparations of 0.5% peptone or 1% sucrose permitted a high leve l of infectivity to be retained for extended periods. Freeze-drying le d to aggregation of the particles and in a marked decrease of infectiv ity. Virus aggregation and RNA degradation were suppressed by the addi tion of protectants such as 0.5% lysine. Results suggest that other po tyviruses may be well preserved under similar conditions.