1. Figure S5. A maximum-likelihood phylogeny based on nodA nucleotide data for Burkholderia isolates included in this study. Similar groupings were generated following BI analysis of the data. Statistical support of  60% for ML bootstrap (BS) and  0.60 BI posterior probability (PP) are indicated at the branches in the order PP/BS. Isolate/strain designations are followed by host name and geographic origin. Indigenous host names are abbreviated as explained in Table S1. Beta-rhizobial isolates from South Africa are indicated in green (and those from this study is in bold), while those from other regions appear in red. The scale bar indicates the number of nucleotide substitutions per site. The tree is rooted to the outgroup taxa Rhizobium gallicum and Ensifer arboris. The evolutionary model used for this dataset is GTR+I+G. Similar groupings were obtained using Bayesian Inferences analysis of the data (i.e., model = GTR+I; generations = ; burnin = 2000).

2. South Africa Other Beta- rhizobia RAU2f H. coluteoides
RAU2k H. coluteoides
RAU2l H. coluteoides
RAU2i H. coluteoides
WC7.3a P. calyptrata
RAU2h H. coluteoides
CB2 C. buxifolia
Cses4 C. sessiliflora
UCT30 C. sessiliflora
WC7.3c P. calyptrata
WC7.3f P. calyptrata
CS2 C. subternata
RAU2b H. coluteoides
RAU2d2 H. coluteoides
Kb2 V. oroboides
Clong1 C. longifolia
CI1 C. intermedia
RAU2c H. coluteoides
UCT71 C. glabra
RAU2d H. coluteoides
RAU2g H. coluteoides
UCT34 C. glabra
UCT43 C. meyeriana
UCT56 C. meyeriana
CM1 C. maculata
Cpub6 C. pubescens
RAU6.4a H. oxalidifolius
Burkholderia sp. WSM3937 Rhynchosia ferulifolia
Burkholderia sp. WSM3930 Rhynchosia ferulifolia
Kb6 V. oroboides
WK1.1m H. sophoroides
WK1.1k H. sophoroides
WK1.1j H. sophoroides
WK1.1h H. sophoroides
HC1.1bh H. sophoroides
WK1.1f H. sophoroides
WK1.1i H. sophoroides
WK1.1g H. sophoroides
WK1.1a H. sophoroides
WK1.1d H. sophoroides
HC1.1a2 H. sophoroides
HC1.1be H. sophoroides
Burkholderia tuberum Cyclopia spp. (STM678T)
UCT2 C. genistoides
WC7.3b P. calyptrata
HC1.1bb H. sophoroides
WK1.1c H. sophoroides
HC1.1bc H. sophoroides
WC7.3d P. calyptrata
HC1.1ba H. sophoroides
HC1.1a3 H. sophoroides
HC1.1a1 H. sophoroides
Burkholderia sp. WSM3602 Lessertia herbacea
HC1.1bd H. sophoroides
UCT70 C. maculata
RAU6.4f H. oxalidifolius
Kb14 V. oroboides
Kb15 V. oroboides
HC6.4b H. oxalidifolius
Clong3 C. longifolia
UCT31 C. sessiliflora
Kb13 V. oroboides
Kb12 V. oroboides
RAU6.4b H. oxalidifolius
Kb16 V. oroboides
RAU2j H. coluteoides
WC7.3g P. calyptrata
RAU6.4d H. oxalidifolius
Kb1A V. oroboides
CI2 C. intermedia
CI3 C. intermedia
Methylobacterium nodulans Crotalaria podocarpa Senegal (ORS2060T ; AM712915)
Bradyrhizobium iriomotense Entada koshunensis Japan (EK05T; AB300999)
Bradyrhizobium elkanii Glycine max USA (USDA76T; AM117554)
Bradyrhizobium japonicum Glycine max Japan (USDA 6T; AM117545)
Mesorhizobium ciceri Cicer arietinum Spain (UPM-Ca7T; AJ300247)
Burkholderia tuberum strain STM6020 Mimosa pudica French Guiana
Burkholderia tuberum strain STM3638 Mimosa pudica French Guiana
Burkholderia tuberum strain STM3649 Mimosa pudica French Guiana
Burkholderia sp. mpa6.4 Mimosa pigra Australia
Burkholderia mimosarum Mimosa pigra Taiwan (PAS44T)
Burkholderia caribensis Mimosa diplotricha Taiwan
(TJ182)
Cupriavidus taiwanensis Mimosa pudica Taiwan
(PAS15; AY752964)
Burkholderia sp. mpud4.5 Mimosa pudica Panama
Burkholderia sp. mpud5.2 Mimosa pudica Panama
Burkholderia diazotrophica Mimosa candollei Brazil (LMG26031T)
Burkholderia phymatum Machaerium lunatum French Guiana (LMG21445T)
Rhizobium gallicum Phaseolus vulgaris France (R602spT; AJ300236)
Ensifer arboris Prosopis chilensis Sudan (HAMBI1552T; Z95234)
1.00/100
1.00/72
1.00/89
1.00/82
1.00/66
1.00/86
1.00/84
- /61
0.84/73
0.86/79
1.00/92
1.00/96
0.95/81
1.00/95
- /79
1.00/79
0.97/76
1.00/94
0.99/69
0.99/72
0.84/60
1.00/93
0.1
1.00/ -
0.99/ -
0.67/ -
0.98/ -
0.74/ -
0.92/ -
0.69/ -
0.97/ -
0.81/ -
0.89/ -
0.94/ -
South Africa
Other
Beta-
rhizobia