Flavihumibacter fluminis sp. nov. and Flavihumibacter rivuli sp. nov., isolated from a freshwater stream

초록

Two Gram-stain-positive, aerobic, chemoheterotrophic, non-motile, rod-shaped, and yellow-pigmented bacterial strains, designated IMCC34837(T) and IMCC34838(T), were isolated from a freshwater stream. Results of 16S rRNA gene-based phylogenetic analyses showed that strains IMCC34837(T) and IMCC34838(T) shared 96.3% sequence similarity and were most closely related to Flavihumibacter profundi Chu64-6-1(T) (99.6%) and Flavihumibacter cheonanensis WS16(T) (96.4%), respectively. Complete whole-genome sequences of strains IMCC34837(T) and IMCC34838(T) were 5.0 Mbp and 4.3 Mbp of genome size with 44.5% and 47.9% of DNA G + C contents, respectively. Average nucleotide identity (ANI) and digital DNA- DNA hybridization (dDDH) values between the two strains were 70.0% and 17.9%, repectively, revealing that they are independent species. The two strains showed <= 75.2% ANI and <= 19.3% dDDH values to each closely related species of the genus Flavihumibacter, indicating that the two strains represent each novel species. Major fatty acid constituents of strain IMCC34837(T) were iso-C-15:0, iso-C-15:1 G and anteiso-C-15:0 and those of strain IMCC34838(T) were iso-C-15:0 and iso-C-15:1 G. The predominant isoprenoid quinone detected in both strains was menaquinone-7 (MK-7). Major polar lipids of both strains were phosphatidylethanolamine, aminolipids, and glycolipids. Based on the phylogenetic and phenotypic characterization, strains IMCC34837(T) and IMCC34838(T) were considered to represent two novel species within the genus Flavihumibacter, for which the names Flavihumibacter fluminis sp. nov. and Flavihumibacter rivuli sp. nov. are proposed with IMCC34837(T) (= KACC 21752(T) = NBRC 115292(T)) and IMCC34838(T) (= KACC 21753(T) = NBRC 115293(T)) as the type strains, respectively.

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