ACCUMULATION OF DIFFERENT TYPES OF RASPBERRY RINGSPOT NEPOVIRUS PARTICLE IN INFECTED NICOTIANA PROTOPLASTS

Nicotiana tabacum protoplasts inoculated with raspberry ringspot virus accumulated top component (T), middle component (M) and bottom component (B) particles progressively from about 20 h post-infection (p.i.) until at least 73 h p.i.; the ratio between the amounts of T and B particles changed little during the multiplication cycle of the virus. In contrast, in raspberry ringspot virus-infected N. clevelandii protoplasts although the accumulation of T particles continued up to at least 91 h p.i., the accumulation of B and M particles decreased greatly or ceased after about 60 h p.i. In either species of protoplast there was no evidence that T particles arose from B or M particles although some physical treatments did cause an apparent loss of nucleic acid from B and M particles.