Description of Pseudomonas stagnisoli sp. nov. and Pseudomonas cimarronensis sp. nov., isolated from freshwater sediments

A polyphasic taxonomic approach was employed to characterize two novel strains, P3C3^T and MAC6^T, isolated from sediments of the Innovation Way Drive Pond (Stillwater, OK) and the Cimarron River (Perkins, OK), respectively. Both strains were strictly aerobic, Gram-stain-negative, rod-shaped, motile and non-spore-forming bacteria. Strain P3C3^T grew optimally at 35 °C, pH 6.0 and 0.5% (v/w) NaCl, while strain MAC6^T grew optimally at 30 °C, pH 6.0 and 4.0% (v/w) NaCl. Based on 16S rRNA gene sequence similarity, P3C3^T was most closely related to <i>Pseudomonas alcaligenes</i> (98.3%), whereas MAC6^T was most closely related to <i>Pseudomonas anguilliseptica</i> (98.6%). Phylogenetic analysis using the 16S rRNA gene and whole-genome phylogenomic analysis indicated that P3C3^T and MAC6^T formed distinct branches within the <i>Pseudomonas</i> genus. Additionally, overall genomic-based relatedness indices demonstrated that P3C3^T and MAC6^T and the type strains of close relatives shared average nucleotide identity and digital DNA-DNA hybridization values <95% and <70%, respectively, which are below the currently accepted thresholds for species-level delineation. The genomes of strains P3C3^T and MAC6^T were 4.3 and 4.2 Mbp, respectively, with G+C contents of 64.5 and 60.5 mol%. Based on polyphasic taxonomic criteria, P3C3^T and MAC6^T represent two novel species within the genus <i>Pseudomonas</i>, for which the names <i>Pseudomonas stagnisoli</i> and <i>Pseudomonas cimarronensis</i> sp. nov. are proposed. The type strains are P3C3^T (=CCM 9468^T=CECT 31230^T=DSM 119661^T) and MAC6^T (=CCM 9470^T=CCUG 78313^T=CECT 31231^T), respectively.