Fig. 2.

Maximum-likelihood phylogenetic tree based on near full-length 16S rRNA gene sequences of 25 Bradyrhizobium strains isolated from root nodules of cowpea and 17 species type strain sequences from the public databases. The tree is rooted with a further public database sequence of a type strain of a species of the genus Rhizobium. The statistical branch support values were obtained by bootstrap analysis (>50%) of 1000 resampled datasets. The strain identifiers indicate the geographical origin (K: Kilifi, M: Mbeere agroecological region). The strains 1–15 are from cultivated sites and the strains 16–20 from uncultivated sites. The sequence accession numbers are given in parentheses and the scale bar indicates the percentage of nucleotide substitutions. The colour coding follows that used in the dendrogram of Fig. 1.