Pseudomonas vesperimontis sp. nov. and Pseudomonas viridinivis sp. nov., isolated from temporary meltwater ponds and green snow in the Thala Hills Oasis, Antarctica

Three strains of Gram-negative, cold-adapted, aerobic bacteria were isolated on the coast of the Alasheyev Bight in the area of the Vecherniy region, the Thala Hills Oasis, Enderby Land, East Antarctica. Strains TMP9^T and TMP25 were isolated from temporary meltwater ponds, while strain G.S.17^T was obtained from a sample of green snow. Strains TMP9^T and TMP25 were motile rods, catalase-negative and oxidase-positive, while G.S.17^T was rod-shaped and exhibited motility, but was catalase- and oxidase-positive. TMP9^T and TMP25 grew at 4-25 °C, pH 5.5-9.0 and tolerated up to 4.5% NaCl. G.S.17^T grew at 4-28 °C, pH 5.0-8.5 and NaCl concentration up to 3.0%. The 16S rRNA gene sequence analysis placed all strains within the genus <i>Pseudomonas</i>: strains TMP9^T and TMP25 are closely related to <i>Pseudomonas peli</i> DSM 17833^Т (99.5% identity), and the strain G.S.17^T exhibits the highest similarity to <i>Pseudomonas rossensis</i> P2663^T (99.1% identity). Whole-genome comparisons using average nucleotide identity suggested that strains TMP9^T and TMP25 represent a novel species within the genus <i>Pseudomonas</i>, which is most closely related to <i>Pseudomonas guineae</i> LMG 24016^T (83.3%). Strain G.S.17^T also represents a novel species within the genus <i>Pseudomonas</i> and is most closely related to <i>Pseudomonas caspiana</i> FBF102^T (80.5%). The predominant cellular fatty acids of strains TMP9^T, TMP25 and G.S.17^T were cis-9-hexadecenoic, hexadecanoic and trans-9-octadecenoic acids. Physiological and biochemical tests, as well as genomic analysis results, clearly differentiated strains TMP9^T, TMP25 and G.S.17^T from type strains of closely related species. Thus, according to the data obtained, two novel species within the genus <i>Pseudomonas</i> are proposed: <i>Pseudomonas vesperimontis</i> sp. nov. (type strain TMP9^T=BIM B-1560^T=VKM B-3887^T) and <i>Pseudomonas viridinivis</i> sp. nov. (type strain G.S.17^T=BIM B-1635^T=VKM B-3888^T).