The genome sequence of Dioscorea bacilliform TR virus, a member of the genus Badnavirus infecting Dioscorea spp., sheds light on the possible function of endogenous Dioscorea bacilliform viruses

The complete genome sequence of Dioscorea bacilliform TR virus (DBTRV) was determined. The closest relatives of DBTRV are Dioscorea bacilliform AL virus (DBALV) and Dioscorea bacilliform RT virus 1 (DBRTV1). Specific primers were designed and used to determine the prevalence of DBTRV in a yam germplasm collection. It was found that this virus infects Dioscorea alata and D. trifida plants in Guadeloupe and French Guyana. DTRBV was not detected in any of the tested D. cayenensis-rotundata accessions. In silico analysis provided evidence for the presence of DBTRV-like endogenous sequences in the genome of D. cayenensis-rotundata, pointing to a possible role of these sequences in antiviral defense.