Hydrogen Uptake (HUP) Activity of Rhizobium japonicum from Major U.S. Soybean Production Areas

Abstract

The purpose of these experiments was to determine the distribution of the hydrogen uptake (Hup) system among Rhizobium japonicum isolated from major soybean production areas of the USA. Soybean nodules were collected from approximately 100 different locations during the 1979 and 1980 growing seasons. The major conclusion is that a majority (> 75 %) of the Rhizobium japonicum strains isolated from major soybean producing areas are missing H2 uptake activity. The role of the H2 uptake system in energy efficiency of nitrogen fixation is discussed.