Thermomonas flagellata sp. nov. and Thermomonas alba sp. nov., two novel members of the phylum Pseudomonadota isolated from hot spring sediments

Two novel species, designated strains SYSU G04041 T and SYSU G04536 T , were isolated from hot spring sediments collected in Yunnan, PR China. Phenotypic and chemotaxonomic analyses, and whole-genome sequencing were used to determine the taxonomic positions of the candidate strains. Phylogenetic analysis using 16S rRNA gene sequence indicated that strain SYSU G04041 T showed the highest sequence similarity to Thermomonas haemolytica A50-7-3 T (97.5 %), and SYSU G04536 T showed the highest sequence similarity to Thermomonas hydrothermalis SGM-6 T (98.2 %). The strains could be differentiated from other species of the genus Thermomonas by their distinct phenotypic and genotypic characteristics. Cells of strains SYSU G04041 T and SYSU G04536 T were aerobic, motile and Gram-stain-negative. Growth both occurred optimally at 45 °C and pH 7.0 for SYSU G04041 T and SYSU G04536 T . In addition, the predominant respiratory quinone in both isolates was ubiquinone Q-8. The major fatty acids (>10 %) of strain SYSU G04041 T were C 16 : 0 , iso-C 15 : 0 and iso-C 16 : 0 , while the major fatty acids (>10 %) of strain SYSU G04536 T were iso-C 15 : 0 and iso-C 16 : 0 . The main detected polar lipids in strains SYSU G04041 T and SYSU G04536 T included phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The G+C contents of the genomic DNA of strains SYSU G04041 T and SYSU G04536 T based on draft genomic sequences were 72.5 and 68.3 %, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strains SYSU G04041 T and SYSU G04536 T represent two novel species of the genus Thermomonas , for which the names Thermomonas flagellata sp. nov. and Thermomonas alba sp. nov. are proposed, with the type strains SYSU G04041 T (=CGMCC 1.19366 T =KCTC 92228 T ) and SYSU G04536 T (=CGMCC 1.19367 T =KCTC 82839 T ), respectively.