Identification and genetic characterization of a new totivirus from Bursera graveolens in western Ecuador

Abstract

Abstract The complete genomic sequence of a previously uncharacterized virus provisionally named Bursera graveolens totivirus 1 (BgTV-1) was obtained from Bursera graveolens (Kunth) Triana & Planch., a tree known as “palo santo” in Ecuador. The BgTV-1 genome is monopartite double-stranded RNA (dsRNA) and 4,794 nucleotides (nt) long (GenBank accession number ON988291). Phylogenetic analysis of the capsid protein (CP) and RNA-dependent-RNA-polymerase (RdRp) placed BgTV-1 in a clade with other plant-associated totiviruses. Amino acid (aa) sequence comparisons of BgTV-1 putative proteins showed the highest identities to those of taro-associated totivirus L (QFS21890.1-QFS21891.1) and Panax notoginseng virus A (YP_009225664.1- YP_009225665.1) with 51.4% and 49.8%, for the CP, and 56.4% and 55.2% for the RdRp, respectively. BgTV-1 was not detected in any of the two endophytic fungi grown in BgTV-1-positive B. graveolens leaves, suggesting a plant totivirus. Based on distinct host and low aa identities between the CP of BgTV-1 and counterparts from closest relatives, the virus described in this study should be assigned as a new member of the genus Totivirus.