This study has three primary objectives: l) to continue studies on the structure and organization of the RNA of sonchus yellow net virus (SYNV), a plant rhabdovirus; 2) to infect tobacco protoplasts with SYNV so that kinetics and subcellular location of the viral specific RNAs and proteins can be investigated during synchronous replication; and 3) to isolate a transcriptase from infected protoplasts. Completion of objective l will provide a precise description of the genome of a plant rhabdovirus that can be used to compare its structure, function, and evolution with related animal rhabdoviruses. Infection of protoplasts with SYNV (Objective 2) will allow analysis of the kinetics of synthesis of SYNV RNAs and proteins at defined stages of replication and will permit investigation of their association with host polypeptides and cytopathic structures that appear during infection. Isolation of a transcriptase complex (Objective 3) from infected protoplasts will facilitate in vitro studies of the functions of viral specific components and the requirement for host factors during transcription of messenger RNAs and replication of SYNV RNA.
