EFFECT OF PROTECTANTS IN L-DRYING ON THE CONFORMATION AND INFECTIVITYOF RICE DWARF PHYTOREOVIRUS

Purified rice dwarf phytoreovirus preparations, after rehydration foll owing drying without freezing (L-drying) and sucrose density gradient centrifugation, sedimented to the same position as untreated controls. Upon storage at 65 degrees C, virion conformation in L-dried preparat ions supplemented with 1% sucrose was maintained better than without a dditives. Moreover, during storage for 6 years at -70 degrees C, infec tivity of L-dried preparations from crude extracts of infected rice pl ants containing 5% sucrose was higher than controls based on the numbe r of count of infected foci on cell monolayers and transmission to ric e seedlings by leafhopper of the vector Nephotettix cincticeps, which had been injected with such extracts.