MOLECULAR ANALYSIS OF THE COMPLETE GENOME SEQUENCE OF A TOBACCO ETCH VIRUS ISOLATE FROM CHINA

摘要

An isolate of Tobacco etch virus (TEV-Shaanxi) induces systemic mosaic and necrotic lines or etching in N. Tabacum and is transmitted by M. persicae more efficiently than A. gossypii. The complete genome of TEV-Shaanxi consists of 9,494 nucleotides, excluding the 3' poly (A) tail. It contains a single large open reading frame (ORF) coding for a polyprotein of 3,054 amino acids, with an AUG start codon and a UGA stop codon. The polyprotein encodes 10 proteins (P1, HC-Pro, P3, 6K1, CI, 6K2, NIa-VPg, NIa-Pro, NIb and CP), whose putative cleavage sites were identified by comparison with sequences of other known potyviruses. The identities of the 10 proteins of TEV-Shaanxi with other members of the genus Potyvirus were 30.5-62.7% and 29.4-68.8% at the nucleotide and amino acid levels, respectively. A short internal open reading frame, PIPO, was also highly conserved. TEV isolates whose sequences are available cluster into two groups which correspond with their host of origin.