Nucleotide sequence and genome organisation of cherry mottle leaf virus and its relationship to members of the Trichovirus genus

The nucleotide sequence of cherry mottle leaf virus (CMLV) was determined and compared to sequences of a number of plant viruses including the type member of the Trichovirus genus (apple chlorotic leafspot virus, ACLSV), and members of the Vitivirus genus including grapevine virus B, (GVB). The CMLV genome was determined to consist of 8003 nt excluding the poly(A) tail at the 3' end of the genome. The overall A+U content of CMLV genomic RNA was 59.1%, which is similar to ACLSV, but significantly different from GVB. Four putative open reading frames were identified (ORFs 1, 2, 3, and 4) encoding proteins of M-r, 215.8 kDa, 47 kDa, 21.6 kDa, and 15.3 kDa, respectively. This differs from ACLSV which has 3 ORFS, and GVB which has 5 ORFs. Protein database searches showed no matches of CMLV ORF4 with ACLSV sequences, but found similarities between ORF4 of CMLV and ORF5 of GVB, suggesting that this may be a nucleic acid-binding protein. CMLV and ACLSV formed a common virus clade in phylogenetic analysis of the coat protein amino acid sequence and except for CMLV's ORF4, these viruses show high levels of similarity throughout the genome. CMLV appears to be a member of the Trichovirus genus.