The complete genomic sequence of a novel member of the genus Caulimovirus isolated from Dregea volubilis.

A novel caulimovirus was identified from diseased leaves of Dregea volubilis exhibiting yellowing and vein-associated chlorosis in Yuanjiang County, Yunnan Province, China. The virus was tentatively named Dregea volubilis caulimovirus 1 (DVCaV1). The complete genome sequence of DVCaV1, determined by de novo assembly of high-throughput sequencing data, comprises 8,160 bp of circular double-stranded DNA containing two intergenic regions and seven open reading frames (ORFs). These ORFs encode (in order) a movement protein (MP), an aphid transmission factor (ATF), a virion-associated protein (VAP), a coat protein (CP), a polymerase polyprotein (Pol, containing protease, reverse transcriptase, and RNase H domains), a transactivator/viroplasmin (TAV) protein, and a hypothetical protein of unknown function. Sequence comparisons revealed the highest nucleotide similarity with strawberry vein banding virus (SVBV; NC_001725). Phylogenetic analysis confirmed DVCaV1 as a member of the genus Caulimovirus, with SVBV as its closest known relative. According to current ICTV species demarcation criteria for the genus Caulimovirus (host range and > 20% nucleotide sequence divergence in the polymerase region), DVCaV1 represents a novel species. This is, to our knowledge, the first report of a caulimovirus detected in naturally symptomatic Dregea volubilis.