Genome analysis of five soil bacterial isolates named formerly Enterobacter agglomerans

The genomes of five nitrogen-fixing strains isolated from the vicinity of Bayreuth and named formerly Enterobacter agglomerans were studied and compared with the genomes of several Rahnella aquatilis strains as well as with one Pantoea agglomerans and one Ent. agglomerans reference strains, obtained from different world collections; they all were previously assumed to be related to this group of natural isolates.
By using the infrequently cutting restriction endonuclease XbaI , highly chracteristic fingerprints were obtained for each of the studied strains except two Ent. agglomerans isolates which had identical fingerprints. By hybridization of the resulting individual PFGE-fingerprints with a rDNA probe, containing the rrnB ribosomal RNA operon of Escherichia coli , the relationship between the analysed strains was studied. It was shown that the natural isolates are very closely related to the type strain of R. aquatilis —ATCC 33071. The genome sizes of all studied strains were estimated to be between 4.4 and 5.8 Mb on the basis of the lengths of their Xba I fragments. By a modification of the PFGE technique it was shown that the analysed strains harbour one to three large and extra large plasmids with sizes in the range 90 to 608 kb.