Genome sequences of Bradyrhizobium. Bradyrhizobium

Rhizobia are one of the most effective bioinoculants, because they form root nodules in leguminous plants and symbiotically supply fixed nitrogen to the host plant. In particular, Bradyrhizobium has been use as microbial inoculants for soybean cultivation in many countries. We have constructed a mixture of bradyrhizobial strains isolated from various soils with a view to develop a bradyrhizobial inoculum that overcomes the competition problem. Their effectiveness is not only symbiotic nitrogen fixation, but also reduction of N2O (Greenhouse gas) emitted from the soybean root systems during the late soybean growth period. Bradyrhizobial strains were obtained as follows. Briefly, each nodule harvested from soybean was surface sterilized, crushed, and spread to HM or other media solidified with agar, and single colonies were obtained by several purification steps.