Mongoliitalea daihaiensis sp. nov., isolated from Daihai Lake in Inner Mongolia

Abstract

A novel Gram-negative strain, designated X100-76^T, was isolated from Daihai Lake in Inner Mongolia, Republic of China. The strain was non-motile, non-spore-forming, long-rod-shaped, oxidase positive and catalase positive. Colonies incubated at 33 °C on 2216 marine agar medium for 3 days were circular, smooth, transparent, convex with clear edges, orange-red in colour and approximately 1.0 mm in diameter. Growth occurred at pH 6.5-12 (optimum pH 7.5), in 0-5.0% (w/v) NaCl (optimum 1.5%, w/v) and at 4-40 °C (optimum 28-33 °C). Phylogenetic analysis based on 16S rRNA gene sequences showed that X100-76^T belongs to the genus Mongoliitalea and is most closely related to Mongoliitalea lutea MIM18^T with 98.3% sequence similarity. The total genome size of X100-76^T was 4,816,617 bp with a G + C content of 39.6%. The digital DNA-DNA hybridization and average nucleotide identity values between strain X100-76^T and M. lutea MIM18^T were both below the recommended cut-off values. Chemotaxonomic analysis revealed iso-C_15:0, Sum Feature 4 (anteiso-C_17:1 B and/or iso-C_17:1 I), C_15:1ω6c, Sum Feature 9 (C_16:0 10-methyl and/or iso-C_17:1ω9c), C_16:0 and iso-C_15:1 G as the major fatty acids, menaquinone MK-7 as the major isoprenoid quinone, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol as the major cellular polar lipids. The results of polyphasic analysis demonstrated that X100-76^T represents a novel species within the genus Mongoliitalea, for which the name Mongoliitalea daihaiensis sp. nov. is proposed. The type strain is X100-76^T (= CGMCC 1.18762^T = KCTC 82458^T).

Keywords: Daihai Lake; Lake water; Mongoliitalea daihaiensis; Polyphasic taxonomy.