FIG. 1.

Southern hybridization of DNAs from P. azotofixans strains isolated from maize planted in Cerrado and Várzea soils with the following probes: nifKDH from K. pneumoniae or part of nifH from P. azotofixans (A) and the 0.58-kb fragment from P. azotofixans C3L4 (B). Only one representative strain of each major group is presented here. Lanes: 1, pattern of 1-kb ladder (Gibco BRL); 2, pattern observed in 58.7% of strains from Cerrado soil and 26.7% of strains from Várzea soil; 3, pattern observed in 41.3% of strains from Cerrado soil and 26.7% of strains from Várzea soil; 4, pattern observed in 100% of strains from Cerrado soil and 58.3% of strains from Várzea soil.