Identification of strains assigned to the genus Gluconobacter Asai 1935 based on the sequence and the restriction analyses of the 16S-23S rDNA internal transcribed spacer regions

Thirteen reference strains, including the type strains of the type species of the genus Gluconobacter, Giuconobacter oxydans (NBRC 14819(T)), Gluconobacter cerinus (NBRC 3267(T)), and Gluconobacter frateurii (IFO 3264(T)) were examined for their species identification based on the sequence and the restriction analyses of the 16S-23S rDNA internal transcribed spacer (ITS) regions. A phylogenetic tree constructed by the neighbor-joining method represented three clusters corresponding respectively to the three species, G. oxydans, G. cerinus, and G. frateurii. The type strain of Gluconobacter asaii (NBRC 3276(T)), which is a junior subjective synonym of G. cerinus, was included completely in the G. cerinus cluster. Several restriction endonucleases discriminating the three species from one another were selected by computer analyses: Bsp1286l, Mboll, Sapl, Bpu10l, Earl, BsiHKAl, and Fatl. On digestion of the PCR products with restriction endonucleases Bsp1286l and Mboll, all the restriction patterns coincided with those of the type strains of the three species except for strain NBRC 3251. This strain gave a different pattern from the type strain of G. frateurii, when digested with Moll. However, strain 3251 was included phylogenetically in the G. frateurii cluster. All the reference strains were thus identified at the species level by the sequence and the restriction analyses of the 16S-23S rDNA ITS regions.