Work

Genomic insights into the genus Halalkalibacter and proposal of two novel Halalkalibacter species, Halalkalibacter haasae sp. nov., and Halalkalibacter salibacillus sp. nov

Year: 2026

Type: article

Abstract: Background The present study aimed to investigate the genomic insights into the genus Halalkalibacter and evaluate the taxonomic positions of haloalkaliphilic strains HAAS-P013 T and HAAS-P014 T , isolated from saline-alkali soil using a polyphasic approach. Results Strains HAAS-P013 T and HAAS-P014 T were Gram-positive, aerobic, motile, and rod-shaped. Phylogenetic and 16S rRNA gene sequence analyses assigned both strains to the genus Halalkalibacter . Strain HAAS-P013 T grew at 12-45 °C (optimum at 32 °C), pH 6.0–11.0 (optimum at pH 10.0) and demonstrates tolerance to NaCl concentration up to 15% (w/v), while strain HAAS-P014 T grew at 12–45 °C (optimum at 37 °C), pH 7.0–11.0 (optimum at pH 10.0) and could tolerate NaCl up to 20% (w/v). Both strains consist of meso- 2,6-diaminopimelic acid, MK-6 and MK-7 as menaquinones, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified lipid as polar lipids, and anteiso-C 15:0 and C 16:0 as dominant fatty acids. Strain HAAS-P013 T contained two unidentified phospholipids in addition to the above polar lipids, whereas strain HAAS-P014 T contained one unidentified phospholipid. The genomic analysis of strains HAAS-P013ᵀ and HAAS-P014ᵀ showed the presence of multiple genes potentially involved in osmotic and alkaline stress responses. The average nucleotide identity/digital DNA-DNA hybridization values among strains HAAS-P013 T , HAAS-P014 T , and other Halalkalibacter species were below the threshold values (95-96/70%) for species delineation. Conclusions Based on the above results, the strains HAAS-P013 T and HAAS-P014 T represent two novel species of the genus Halalkalibacter , for which the names Halalkalibacter haasae sp. nov., and Halalkalibacter salibacillus sp. nov., are proposed. The type strains are HAAS-P013 T ( = KCTC 43869 T = GDMCC 1.6158 T ) and HAAS-P014 T ( = KCTC 43870 T = GDMCC 1.6094 T ).

Source: BMC Microbiology

DOI: 10.1186/s12866-026-05785-z