Complete genome sequences of newly discovered Dioscorea bacilliform AL virus and Dioscorea bacilliform SN virus isolates from Dioscorea bulbifera L. in northeastern Brazil

To assess the DNA virome associated with air yam ( Dioscorea bulbifera L.), leaf samples were collected from plants displaying virus-like symptoms in northeastern Brazil in 2021. Total DNA preparations from PCR positive samples (n = 3) were used as template for viral genome amplification via rolling circle amplification and subjected to high-throughput sequencing. Three Illumina-based full-length badnaviral genomes were recovered from 980 to 30,668 reads and a coverage depth of 33 to 963x. The new genomes ranged from 7,208 to 7,420 bp in size and showed typical badnaviral genomic organization with three main open reading frames (ORFs 1–3). Based on pairwise nucleotide identity using the reverse transcriptase (RT) and ribonuclease H (RNase H) sequences, the newly discovered isolates were identified as dioscorea bacilliform AL virus (DBALV; n = 1) and dioscorea bacilliform SN virus (DBSNV; n = 2), at 85.1–86.6 and 82.2–83.9%, respectively. At least two recombination events were predicted in the DBSNV-DBH isolate, with DBALV- and DBSNV-like sequences identified as putative parents. To our knowledge, these are the first complete genome sequences of yam-infecting badnaviruses described in Brazil.