A 1.9 Kilobase Homology in the 3'-terminal Regions of RNA-1 and RNA-2 of Tomato Ringspot Virus

Summary Double-stranded cDNA copies of RNA-1 and RNA-2 of tomato ringspot virus were cloned into pUC9. Comparison of restriction enzyme maps of eight clones indicated that 1.9 kb at the 3′ termini of RNA-1 and RNA-2 were similar. Five of these clones were used in Northern hybridization analyses and found to contain sequences either unique to RNA-1 or RNA-2, or common to RNA-1 and RNA-2. Southern blot analyses using clones derived from RNA-1 and RNA-2 confirmed that there is a 1.9 kb nucleotide sequence homology at the 3′ termini. A sequence homology of this magnitude has not been reported previously for other plant viruses with multipartite ssRNA genomes.