## 3 Results
### Analysis of the BBTV S-DNA Sequences  
The nucleotide identities between the 40 isolates collected in Mozambique (Table 3) and the isolates available in GenBank (Table 2) showed that this gene is highly conserved, with more than 50% of the isolates having 100% identity, and the lowest identity was 98%. When compared to the GenBank isolates, the lowest identities observed (92-93%) occurred with isolates MT433376 and MT433375 from Indonesia, KM607468 from Taiwan, KM607469 from the Philippines, KM607536 and AF238876 from China and AB078023 from Japan. The highest identities occurred with isolates JQ820467 from Rwanda, KM607470 from Egypt, KM607505 from the Democratic Republic of Congo (DRC) and JF75980 and JQ820455 from Malawi, all from the African continent, although from different geographical regions. Only Malawi is found in the surrounding region, bordering western Mozambique. These isolates present in the African continent probably had a common geographical origin. The amino acid identities observed among the Mozambique isolates were similar, with only seven isolates varying between 96 and 99% and the others showing 100% identity. When compared to isolates from GenBank, in addition to the higher identities already specified above, they also showed high identities with isolates from South and South-east Asia and the South Pacific: MK140621 from Pakistan, AB252642 from Myanmar and KM607584 from Tonga. Notably, isolates BBTV_172_F11 from Mozambique and AB078023 from Japan showed 98% and 93% nucleotide identity, respectively, when compared to the other isolates. The amino acid identity of the Mozambique isolate and Japanese isolate presented identities between 95 and 98%, indicating that the substitutions were of a synonymous type. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Group \({}^{*}\)**} & \multicolumn{3}{c}{**S-DNA**} \\ \cline{2-4}  & **Origin** & **GenBank** & **Reference** \\ \hline PIO & **Malawi** & JF755980 & [8] \\ SEA & Myanmar & AB252642 & [25] \\ SEA & China & KM607536 & [29] \\ SEA & Taiwan & KM607468 & [29] \\ SEA & Philippines & KM607469 & [29] \\ PIO & Egypt & KM607471 & [29] \\ PIO & Egypt & KM607470 & [29] \\ PIO & **Tonga** & KM607584 & [29] \\ PIO & Tonga & KM607550 & [29] \\ PIO & **DRC** & KM607505 & [29] \\ PIO & Australia & KM607489 & [29] \\ PIO & **Burundi** & KM607456 & [29] \\ OutGR & Malaysia & NC. -010316 & [30] \\ PIO & **Rwanda** & JQ820467 & [31] \\ SEA & **Malawi** & JQ820455 & [31] \\ SEA & China & AF238876 & [32] \\ SEA & Japan & AB078023 & [33] \\ SEA & Indonesia & MT433375 & [34] \\ SEA & Indonesia & MT433376 & [34] \\ SEA & Myanmar & AB252644 & [35] \\ PIO & Pakistan & MK140621 & [36] \\ \hline \hline \end{tabular} \({}^{*}\)PIO group according to R-DNA analysis, SSA countries in bold.  
\end{table} 
Table 2: Cont. Figures 3 and 4 illustrate the phylogenetic trees constructed based on the nucleotide and amino acid sequences, respectively, of the S-DNA. There was a clear subdivision of isolates into two clades, one with isolates from China, Japan, the Philippines, Taiwan and Indonesia and one with Mozambique isolates and the remaining isolates from GenBank. The Mozambique isolates were grouped into the same clade as the isolates from Myanmar, Malawi, Rwanda and the DRC. Although isolates from Myanmar, Australia, Burundi, Egypt, Tonga, Pakistan and China were grouped in the same clade as the Mozambique isolates, they occupied different subclades. In the tree constructed based on amino acid sequences, in addition to the isolates from Malawi and Rwanda, the isolates from Myanmar, Pakistan, Tonga and Egypt were also grouped with the Mozambique isolates. This must have occurred because the nucleotide substitutions are synonymous. In this tree, some isolates moved and occupied other subclades.