DNA RELATEDNESS OF BACILLUS-BREVIS MIGULA 1900 STRAINS AND PROPOSAL OF BACILLUS-AGRI SP-NOV, NOM REV, AND BACILLUS-CENTROSPORUS SP-NOV, NOM REV

Studies were carried out to determine the underlying reasons for the phenotypic heterogeneity of Bacillus brevis Migula 1900. DNA reassociation measurements demonstrated that 31 of 37 strains segregated into seven groups of genetically related organisms. The members of the seven groups were not related genetically to selected presently recognized Bacillus species that are strictly aerobic and form oval spores. The results of the DNA relatedness studies and phenotypic comparisons suggested that two of these groups have not been described previously and that the five other groups probably represent previously, but inadequately, described species. Two of the five groups are proposed as new species and are given the revived names Bacillus agri and Bacillus centrosporus. Thus, the phenotypic heterogeneity of B. brevis sensu lato results from the inclusion of genetically unrelated organisms in the taxon and not from the inherent variability of genetically related strains.