Effect of Legume Nodule Hydrogen Uptake Status on Hydrogen-Oxidizing Rhizobacteria and the Rotation of Crops

Abstract

This study evaluates the effect of the uptake hydrogenase (HUP) status on symbiosis on crop rotation. Two isogenetic strains of Bradyrhizobium japonicus, JH and JH47, were used to inoculate soybean plants in field trials. The two strains only differ in that the JH47 strain has a Tn5 insert in the hydrogenase gene to make it HUP-. Results showed that inoculation of hydrogen-oxidizing bacteria from soil adjacent to HUP- nodules significantly promoted root elongation of young spring wheat seedlings. Very likely, any rhizobacteria that can reduce ethylene prodn. in roots should also be plant growth-promoting rhizobacteria. Another interesting activity of these hydrogen-oxidizing bacteria is degrading N-acyl homoserine-lactone, which is a quorum-sensing signal and a key regulator of the community behavior of many proteobacteria. [on SciFinder(R)]