Twenty years of paradigm-breaking studies of taxonomy and symbiotic nitrogen fixation by beta-rhizobia, and indication of Brazil as a hotspot of Paraburkholderia diversity

Delineation of Paraburkholderia tuberum sensu stricto and description of Paraburkholderia podalyriae sp. nov. nodulating the South African legume Podalyria calyptrata

“…These distribution patterns are similar to those reported previously [16,17,30,63,64], and reflects the two centres of nodulating Paraburkholderia diversity in South Africa and South and Central America [15,16,46,65]. Accordingly, the symbiotic loci of these continentally separated groups of rhizobia were acquired independently, early during the evolution of Paraburkholderia species in the respective centres [31,91,92].…”

“…ginsengisoli within the broader Paraburkholderia phylogeny [13]. During their subsequent divergence, the rhizobial Paraburkholderia species could thus have acquired their nodulation abilities via independent horizontal transfer events [31,91,92], as evident from nodulating gene phylogenies showing distinct continental patterns [64]. Our future research will seek to investigate the plausibility of this and hypotheses for explaining the geographic distribution of P. podalyriae sp.…”

“…For example, the two South and Central American species nodulate diverse mimosoid legumes (mainly Mimosa species), but some also nodulate the promiscuous papilionoids Phaseolus vulgaris and Ma. atropurpureum that are both native to the region [74,90,91,92]. It is also likely that these rhizobial species are capable of nodulating Calliandra species, as Paraburkholderia symbionts of this legume genus can nodulate the South America native species Mimosa pudica and carry nod genes that are closely related to those of Mimosa symbionts [102,116].…”

“…Therefore, further development of the Paraburkholderia sv. system would undoubtedly complement taxonomic studies and improve our understanding of the functional diversity and ecology of these bacteria [91,92].…”

High-Throughput Absolute Quantification Sequencing Reveals that a Combination of Leguminous Shrubs Is Effective in Driving Soil Bacterial Diversity During the Process of Desertification Reversal

“…Acidobacteria are widely distributed bacteria with high variation and high abundance in low organic C environments [ 34 ]. Proteobacteria is a phylum of gram-negative bacteria, and some α- or β-Proteobacteria can also grow in low nutrient environments, inducing N fixation and forming symbionts with plants [ 56 , 60 ]. Proteobacteria was one of the most important phyla in the leguminous shrub plantation in the present research.…”