Genetic Diversity Analysis of Badnaviruses Infecting Banana in Burkina Faso

Badnaviruses are serious plant pararetroviruses affecting banana and causes serious economic losses to banana production worldwide. This study aims to examine the variability of BSV and SCBV nature infecting banana in Burkina Faso. Polymerase Chain Reaction (PCR) used the Badna FP/RP specific primers for the RT/RNase H regions present in badnaviruses. The PCR yielded about 579 bp amplicons from banana infected by BSV and SCBV. The 38 BSV isolates recorded low nucleotide identity ranging from 58.9% - 98.1%. Based on percentage nucleotide sequence identity and phylogenetic analyse, BSV isolates were categorized into four groups: 1, 2, 3 and 4. Group 4 shared 76.9% - 100% identity with BSOL species. However, Groups 1 and 3 recorded a low identity ranging, from 76.8% - 79.2%, 68.8% - 79.7% with BSCV, and 72.8% - 79.0% between Group 2 and BSOLV. Groups 1, 2 and 3 were assigned to a potentially new BSV species. The two SCBV isolates recorded a low nucleotide identity of 68% among themselves indicating high diversity. In addition, SCBV_Cd and SCBV_CE showed high nucleotide identity 91.3% and 58.7% with SCBV_C and SCBV, when they were compared to all published SCBV genotypes. In addition, phylogenetic analysis revealed the segregation of SCBV isolates into two genotypes, SCBV_Cd in C and SCBV_CE segregated in a new genotype namely Z. Recombination analyses showed weak signatures of recombination among some of the BSV and SCBV sequences.