Identification and molecular characterization of <i>Taro bacilliform virus</i> and <i> Taro bacilliform <scp>CH</scp> virus </i> from East Africa

Taro ( Colocasia esculenta ) and tannia ( Xanthosoma sp.) are important root crops cultivated mainly by small‐scale farmers in sub‐Saharan Africa and the South Pacific. Viruses are known to be one of the most important constraints to production, with infections resulting in severe yield reduction. In 2014 and 2015, surveys were conducted in Ethiopia, Kenya, Tanzania and Uganda to determine the identity of viruses infecting taro in East Africa. Screening of 392 samples collected from the region using degenerate badnavirus primers revealed an incidence of 58–74% among the four countries surveyed, with sequence analysis identifying both Taro bacilliform virus (Ta BV ) and Taro bacilliform CH virus (Ta BCHV ). Ta BCHV was identified from all four countries while Ta BV was identified in all except Ethiopia. Full‐length sequences from representative Ta BV and Ta BCHV isolates showed that the genome organization of Ta BV isolates from East Africa was consistent with previous reports while Ta BCHV isolates from East Africa were found to encode only four ORF s, distinct from a previous report from China. Phylogenetic analysis showed that all East African Ta BV isolates form a single subgroup within known Ta BV isolates, while Ta BCHV isolates form at least two distinct subgroups. To the authors' knowledge, this is the first report describing the occurrence and genome organization of Ta BV and Ta BCHV isolates from East Africa and the first full‐length sequence of the two viruses from tannia.