Nucleotide sequence analysis of RNA-2 of a flat apple isolate of Cherry rasp leaf virus with regions showing greater identity to animal picornaviruses than to related plant viruses.

Abstract

RNA-2 of a flat apple isolate of Cherry rasp leaf virus (CRLV-FA) appears to consist of 3274 nucleotides, excluding a 3' poly (A) tail. The data supports re-classification of CRLV in a new genus in the family Comoviridae. A single open reading frame (ORF) encoding a putative 108 kDa polyprotein was identified. Potential protease cleavage sites were identified which would result in the production of a putative movement protein (41 kDa), and 3 capsid protein subunits (24, 20, and 22 kDa, respectively). A 5'-UTR and 3'-UTR were identified, 248 nt and 146 nt long, respectively. The genome organisation of CRLV-FA RNA-2 is similar to that of Apple latent spherical virus (ALSV) RNA-2, a new member of the family Comoviridae. The Vp25 amino acid sequences were unique to CRLV-FA and ALSV (54% identity), with no relationship identified to any other virus. CRLV-FA Vp20 and Vp24 amino acid sequences were closely related to ALSV (59 and 65%, respectively) but the only other relationships identified were with a range of animal ssRNA positive-strand viruses.