Deoxyribonucleic Acid Homology Among Bacillus polymyxa, Bacillus macerans, Bacillus azotofixans, and Other Nitrogen-Fixing Bacillus Strains

Abstract

DNA homology experiments were performed among representative strains of B. polymyxa, B. macerans and B. azotofixans and other N2-fixing Bacillus strains identified as B. polymyxa-like. All B. azotofixans strains showed < 20% homology when B. polymyxa or B. macerans was used as a probe. The range of homology among B. azotofixans strains (strain P3L-5T [T = type strain] was used as the probe) varied from 54-100%, indicating that these strains comprise a relatively homogeneous species. Strain Hino appears to be a variant of B. azotofixans because it exhibited only 28-44% homology with this species. Strains P3L-2, CR5D-16, and CR5D-23 showed less than 20% homology with B. polymyxa, B. macerans and B. azotofixans, indicating that these strains do not belong to these species. Additional data will be necessary to fully clarify the taxonomy of these N2-fixing Bacillus strains.