Transfer of Erwinia ananas (synonym, Erwinia uredovora) and Erwinia stewartii to the genus Pantoea emend. as Pantoea ananas (Serrano 1928) comb. nov. and Pantoea stewartii (Smith 1898) comb. nov., respectively, and description of Pantoea stewartii subsp. indologenes subsp. nov.
Eight E. stewartii strains, 11 E. ananas strains and 7 E. uredovora strains, as well as 9 phenotypically similar E. herbicola strains and Enterobacter agglomerans LMG 5342, were compared by examining electropherograms prepared from their soluble proteins and were grouped into 9 protein electrophoretic groups. The levels of DNA relatedness among these electrophoretic groups were determined spectrophotometrically from the renaturation rates at 74°C of the DNAs of 13 selected strains. The representatives from 5 protein electrophoretic groups, including E. ananas LMG 2665T (T = type strain) and E. uredovora LMG 2667T, exhibited 76 to 100% DNA binding to each other and constituted DNA hybridization group 2665. All E. stewartii strains (including LMG 2715T) were electrophoretically very similar; representatives of this species exhibited 93 to 99% DNA binding to each other and constituted DNA hybridization subgroup 2715. The strains belonging to the remaining 3 protein electrophoretic groups exhibited 94 to 96% DNA binding to each other and formed DNA hybridization subgroup 2632. The latter 2 subgroups were 60 to 83% (average, 73%) interrelated and exhibited 30 to 39% DNA binding group 2665. It is proposed that E. ananas and E. uredovora should be united in a single species, which should be classified in the genus Pantoea as Pantoea ananas (Serrano 1928) comb. nov.; its type strain is strain LMG 2665 (=NCPPB 1846). This species also includes DNA hybridization group VI of Brenner et al. (International Journal of Systematic Bacteriology (1984) 34,45-55). The transfer of E. stewartii to the genus Pantoea and the creation of 2 separate subspecies within Pantoea stewartii (Smith 1898) comb. nov. are also proposed. Pantoea stewartii subsp. stewartii (Smith 1898) comb. nov. (synonym, Erwinia stewartii) contains the strains belonging to subgroup 2715, and its type strain is strain LMG 2715 (=NCPPB 2295); and Pantoea stewartii subsp. indologenes subsp. nov. contains the strains belonging to subgroup 2632, and its type strain is strain LMG 2632 (=NCPPB 2280). As determined by principle-component analysis of the cellular fatty acid compositions, P. ananas, P. stewartii subsp. stewartii and P. stewartii subsp. indologenes are separated from each other mainly by differences in the relative contents of cis-9-hexadecenoic acid (C16:1 cis 9), cyclo-heptadecanoic acid (C17:0 cyclo), and straight-chain octodecenoic acids (C18:1). P. stewartii subsp. stewartii can also be differentiated from P. ananas and P. stewartii subsp. indologenes by its inability to produce indole, to utilize citrate, to grow on cis-aconitate, and to form acid from 7 carbohydrates. P. stewartii subsp. indologenes can also be separated from P. ananas by its ability to form acid from sorbitol and α-methyl-smallcap˜D-mannoside. Descriptions of P. ananas and P. stewartii and its 2 subspecies are given, and the description of the genus Pantoea is emended.