Four bacterial strains, A-IN1
T, A-TC2
T, E-TC7
T, and K-TC2
T, isolated from soil-borne nematodes of the species
Oscheius tipulae and
Acrobeloides bodenheimeri, were found to represent new species of the genera
Acinetobacter,
Alcaligenes,
Enterobacter, and
Kaistia, respectively. In this study, we described these new species using a polyphasic taxonomic approach that included whole-genome and whole-proteome phylogenomic reconstructions, core genome sequence comparisons, and phenotypic characterization. Phylogenomic reconstructions using whole-genome and whole-proteome sequences show that A-IN1
T is closely related to
Acinetobacter guillouiae DSM 590
T and to
Acinetobacter bereziniae LMG 1003
T. The dDDH values between A-IN1
T and these latest strains are 25.1 and 39.6%, respectively, which are below the 70% divergence threshold for prokaryotic species delineation. A-TC2
T is closely related to
Alcaligenes faecalis subsp.
faecalis DSM 30030
T and to
Alcaligenes faecalis subsp.
phenolicus DSM 16503
T. The dDDH values between A-TC2
T and these latest strains are 47.0 and 66.3%, respectively. In addition, the dDDH values between
Alcaligenes faecalis subsp.
faecalis DSM 30030
T,
Alcaligenes faecalis subsp.
phenolicus DSM 16503
T, and
Alcaligenes faecalis subsp.
parafaecalis are always lower than 70%, demonstrating that the three strains represent species within the genus
Alcaligenes rather than subspecies within
Alcaligenes faecalis. E-TC7
T is closely related to
Enterobacter kobei DSM 13645
T,
Enterobacter chuandaensis 090028
T, and to
Enterobacter bugandensis STN0717-56
T. The dDDH values between E-TC7
T and these strains are 43.5, 42.9, and 63.7%, respectively. K-TC2
T is closely related to
Kaistia terrae DSM 21341
T and to
Kaistia defluvii JCM 18034
T. The dDDH values between these strains are 29.2 and 30.7%, respectively. Several biochemical tests allow to differentiate the type strains of the newly described species from the type strains of their more closely related species. Based on the results of this polyphasic taxonomic approach, the following new species are proposed:
Acinetobacter nematophilus sp. nov. with A-IN1
T (=CCM 9231
T =CCOS 2018
T) as the type strain,
Alcaligenes nematophilus sp. nov. with A-TC2
T (=CCM 9230
T =CCOS 2017
T) as the type strain,
Enterobacter nematophilus sp. nov. with E-TC7
T (=CCM 9232
T =CCOS 2020
T) as the type strain, and
Kaistia nematophila sp. nov. with K-TC2
T (=CCM 9239
T =CCOS 2022
T) as the type strain. In addition, we propose the elevation of
Alcaligenes faecalis subsp.
faecalis,
Alcaligenes faecalis subsp.
parafaecalis, and
Alcaligenes faecalis subsp.
phenolicus to the species level. Therefore, we propose the creation of
Alcaligenes parafaecalis sp. nov. with DSM 13975
T as the type strain, and
Alcaligenes phenolicus sp. nov. with DSM 16503
T as the type strain. Our study contributes to a better understanding of the biodiversity and phylogenetic relationships of bacteria associated with soil-borne nematodes.
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