Genome analysis of two free-living, non-diazotrophic Bradyrhizobium isolates from contrasting soils. Comparison of two free-living Bradyrhizobium genomes

The bacterial genus Bradyrhizobium is biologically important within soils, with different representatives found to perform a wide range of biochemical functions including photosynthesis, nitrogen fixation through symbioses, denitrification and aromatic compound degradation. Some phenotypes have been found to be non-symbiotic and have either never acquired, or lost the ability to form nodules and are assumed to have different roles in soil. Bradyrhizobium-like species have been shown by many metagenomic studies on soil to be one of the most abundant and active groups. One grassland and one bare fallow Bradyrhizobium isolate were chosen to have their genome sequenced using Ion Torrent and Illumina sequencing platforms. The genomes were assembled using SOAPdenovo2 and manually curated using Geneious. The genomes show distinct genomic differences. Differences between the genomes have been assessed in order to establish the different functions these isolates are able to perform to give clues to their role in the community.