Enrichment for Hydrogen-Oxidizing Acinetobacter spp. in the Rhizosphere of Hydrogen-Evolving Soybean Root Nodules

摘要

Field soybean plants were inoculated with Hup⁺ wild-type or H2 uptake-negative (Hup⁻) mutants of Bradyrhizobium japonicum. For two consecutive summers we found an enrichment for acinetobacters associated with the surfaces of the H2-evolving nodules. Soybean root nodules that evolved H2 had up to 12 times more Acinetobacter spp. bacteria associated with their surfaces than did nodules incapable of evolving H2. All of the newly isolated strains identified as Acinetobacter obtained from the surfaces of root nodules, as well as known established Acinetobacter strains, were capable of oxidizing H2, a property not previously described for this alkane-degrading soil bacterium.