Sequence analysis of the coat protein and 3'-noncoding region for Korean and other strains of sweet potato feathery mottle virus.

The 3'-terminal regions of the genomic RNAs of two Korean isolates of sweet potato feathery mottle potyvirus (SPFMV) were cloned and their nucleotide sequences of full-length coat protein (CP) gene and 3' noncoding region (NCR) were determined. The CP of the two Korean isolates contained 315 amino acid residues. The CP cistron sequences of the Korean isolates exhibit 72.7% to 98.7% nucleotide sequence identity and 79.9% to 99.0% amino acid identity when compared with those of 8 other known SPFMV strains. Pairwise comparison revealed sequence similarities of 47.4% to 62.1% at the nucleotide level, and 48.6% to 70.2% at the amino acid level between SPFMV and 21 other potyviruses. SPFMV CP has extensive amino acid sequence similarity to the other members of the genus Potyvirus throughout its central and C-terminal regions. The 3' NCR of the SPFMV showed 42.5% to 99.1% nucleotide sequence identities among the strains. The 3' NCR of SPFMV revealed 19.9% to 63.6% sequence similarities to those of 21 other potyviruses. These results support the assignment of SPFMV as a distinct member of the genus Potyvirus of the family Potyviridae.