Coat protein gene and 3'-noncoding region of a new Korean isolate of cymbidium mosaic virus.

A new Korean isolate of cymbidium mosaic virus (denoted as CymMV-K2), a member of potexviruses, was identified and isolated from a Korean cultivar of Cymbidium species When the nucleotide sequence of the 3'-terminal region of the viral RNA was compared with those of the corresponding regions of two Singaporean isolates (denoted as CymMV-S1 and CymMV-S2) and a Korean isolate (denoted as CymMV-K1), the nucleotide sequence of the coat protein gene of CymMV-K2 was highly homologous to other cymbidium mozaic viruses (92.9%-96.7% homology). The coat protein of CymMV-K2 and CymMV-S2 consists of 223 amino acids, while the coat protein of CymMV-K1 and CymMV-S1 consists of 220 amino acids. This difference was caused by deletions of 5 nucleotides in the coat protein open reading frame (ORF) of CymMV-S1 and CymMV-K1, when compared with CymMV-K2 and CymMV-S2. These deletions result in changes of the deduced amino acid sequence and the length of the coat protein. The 3'-noncoding region of the CymMV-K2, which contains sequences involved in the replication and polyadenylation of viral RNA, was compared with those of other cymbidium mosaic viruses. No canonical polyadenylation signal was found in the 3'-noncoding region of CymMV-K2, whereas in other CymMVs AAUAAA boxes, are present at the end of RNA with their AAA portions as the first A residue of the poly(A) tail.