Halomonas populi sp. nov. isolated from Populus euphratica

Three yellow-pigmented, Gram-stain-negative, aerobic, motile by flagella and rod-shaped strains, designated as MC T , PC and RC, were isolated from stems of Populus euphratica . Growth of those three strains occurs at 4–40 °C, pH 6.0–10.0 and with 0.5–18.0% (w/v) NaCl. Respiratory quinones contained ubiquinone-9 and ubiquione-8 as major and minor components, respectively. Major fatty acids (> 10%) were summed feature 8 (C 18:1 ω 6 c and/or C 18:1 ω 7 c ), summed feature 3 (C 16:1 ω 6 c and/or C 16:1 ω 7 c ) and C 16:0 . Polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified phospholipids, one unidentified aminolipid, one unidentified glycolipid and four unidentified lipids. Strains MC T , PC and RC shared pairwise 16S rRNA gene sequence similarities of 99.9–100.0%, and showed higher similarities of 98.4–98.5% with Halomonas songnenensis NEAU-ST10-39 T and 98.3–98.4% with Halomonas nanhaiensis YIM M 13059 T than to other Halomonas type strains. Genomic comparisons revealed that those three strains had the pan-genome consisting of 4446 orthologous clusters, among which 676 orthologous clusters were absent in other Halomonas type strains. Phylogenomic tree indicated that strains MC T , PC and RC formed an independently stable clade with Halomonas nanhaiensis YIM M 13059 T and Halomonas songnenensis NEAU-ST10-39 T . The average nucleotide identity and digital DNA–DNA hybridization values between those three strains and other Halomonas type strains were < 89.9% and < 39.3%, respectively. Based upon phenotypic, chemotaxonomic, phylogenetic and genomic results, strains MC T , PC and RC represent a novel species in the genus Halomonas , for which the name Halomonas populi sp. nov. is proposed. The type strain is MC T (= JCM 33545 T = MCCC 1K03942 T ).