Niabella beijingensis sp. nov. and Thermomonas beijingensis sp. nov., two bacteria from constructed wetland

Abstract

Two Gram-stain-negative, aerobic, non-motile and rod-shaped bacterial strains designated 3A5MI-3^T and RSS-23^T were isolated from the Dragon-shaped Wetland System in Beijing Olympic Park, PR China. Strain 3A5MI-3^T grew at 15–45 °C, pH 5.0–9.0 and with 0–2 % NaCl (w/v), and strain RSS-23^T grew at 15-40 ^oC, pH 5.5–9.0 and with 0–1 % NaCl (w/v). Phylogenetic analyses of 16S rRNA gene sequences revealed that strains 3A5MI-3^T and RSS-23^T were members of Bacteroidetes and Proteobacteria , respectively. Phylogenetically closest relatives of strains 3A5MI-3^T and RSS-23^T were Niabella pedocola R384^T and Thermomonas aquatica SY21^T, respectively. The cells of strain 3A5MI-3^T contained menaquinone MK-7 and phosphatidylethanolamine, and the major cellular fatty acids were composed of iso-C_{15 : 0}, iso-C_{15 : 1} ω6c and/or iso-C_{15 : 1} ω7c, iso-C_{17 : 0} 3-OH, C_{16 : 0} and summed feature 3 (C_{16 : 1} ω7c/C_{16 : 1} ω6c). Strain RSS-23^T contained ubiquinone Q-8 and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unknown phospholipids and an unknown lipid, and its major cellular fatty acids were iso-C_{15 : 0}, iso-C_{17 : 1} ω9c, iso-C_{11 : 0} 3-OH and summed feature 3 (C_{16 : 1} ω7c/C_{16 : 1} ω6c). DNA sequencing resulted in 6.59 Mb for the strain 3A5MI-3^T genome and 2.79 Mb for the strain RSS-23^T genome. The calculated G+C molar contents for strains 3A5MI-3^T and RSS-23^T were 47.07 and 61.21 mol%, respectively. According to phenotypic and phylogenetic characteristics, strains 3A5MI-3^T and RSS-23^T represent novel species of the genera Niabella and Thermomonas for which the names Niabella beijingensis sp. nov. and Thermomonas beijingensis sp. nov. are proposed. The type strain for N. beijingensis sp. nov. is 3A5MI-3^T (=CGMCC 1.17737^T=KCTC 82817^T). The type strain for T. beijingensis sp. nov. is RSS-23^T (=CGMCC 1.17738^T=KCTC 82820^T).

Keywords: CGMCC 1.17737T=KCTC 82817T; CGMCC 1.17738T=KCTC 82820T; Niabella beijingensis sp. nov.; Thermomonas beijingensis sp. nov.; strain 3A5MI-3T; strain RSS-23T.

Fig. 1.

Neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, showing the phylogenetic position of strains 3A5MI-3^T (a) and RSS-23^T (b) among closely related taxa. GenBank accession numbers are given in parentheses. Numbers at nodes indicate the percentage of 1000 bootstrap replicates yielding this topology; only values >50 % are shown. Filled circles indicate nodes recovered by all three treeing methods (neighbour-joining, maximum-likelihood and maximum-parsimony). Chitinophaga pinensis NBRC 18968^T and Citrobacter bitternis SKKU-TP7^T were used as outgroups.

Fig. 2.

Phylogenomic trees of strains 3A5MI-3^T (a) and RSS-23^T (b). GenBank accession numbers are given in parentheses. We performed genome sequencing of Niabella pedocola JCM31011^T and the sequence was deposited in the GenBank/EMBL/DDBJ with the accession number JAJNEC000000000. Chitinophaga pinensis DSM 2588^T (=NBRC 18968^T) and Citrobacter braakii CDC 80-58^T (=SKKU-TP7^T) were used as outgroups.