Identification and characterization of pseudo-recombinants of red clover mottle comovirus.

cDNA clones specific for the two genomic RNAs of strain O of the comovirus red clover mottle virus (RCMV) were constructed. Using these clones, in conjunction with clones specific for RNAs of RCMV strain S, local lesion isolates containing reciprocal pseudo-recombinants between strains S and O were identified. Investigation of the biological properties of these pseudo-recombinants showed that the ability of RCMV to infect Chenopodium quinoa is determined by B RNA. The results also suggest that both RNAs are involved in symptom formation in Pisum sativum. Analysis of the strain O clones enabled the sequences at the 3' ends of both genomic RNAs of strain O to be determined. Comparison of these sequences with the corresponding region of the strain S RNAs suggests that the 3' terminal sequences critical for replicase recognition may lie somewhat upstream of the poly(A) tract.