Taxonomic, genomic, and ecological insights into a novel Flavobacteriaceae strain from coastal tidal flats

BACKGROUND

Tidal flats are vital coastal ecosystems that play a significant role in organic carbon accumulation and biogeochemical cycles. Members of the family Flavobacteriaceae is known for its ability to degrade complex organic matter, including polysaccharides. However, the ecological roles and metabolic capabilities of Flavobacteriaceae in tidal flat environments remain underexplored.

RESULTS

In this study, we isolated and characterized a novel bacterium, strain NBU2967T, from the tidal flats of Meishan Island in the East China Sea. Phylogenetic and genomic analyses identified this strain as a new genus and species within the family Flavobacteriaceae, for which we propose the name Meishania litoralis gen. nov., sp. nov. Comprehensive polyphasic characterization, including morphological, physiological, chemotaxonomic, and genomic analyses, confirmed its distinct taxonomic status. Genomic analysis revealed a diverse set of carbohydrate-active enzymes (CAZymes), along with multiple metabolic pathways associated with carbon and sulfur cycling, highlighting the strain's potential adaptation to organic-rich marine environments. Comparative genomic and pangenome analyses further demonstrated significant genetic divergence from related taxa. Environmental distribution data revealed that the newly proposed genus Meishania is widely distributed across global marine ecosystems.

CONCLUSIONS

We isolated and characterized a novel bacterium, designated NBU2967T (= KCTC 82912 T = MCCC 1K06391T), for which we propose the name Meishania litoralis gen. nov., sp. nov. This strain is classified as a new genus within the family Flavobacteriaceae. The strain's ability to process both carbon and sulfur compounds underscores its ecological significance in marine ecosystems. These findings provide novel insights into the ecological functions of the family Flavobacteriaceae in coastal tidal flats environments and enhance our understanding of microbial-mediated degradation and transformation of chemical compounds in dynamic coastal ecosystems.

Comprehensive genomic and phenotypic characterization of thermophilic bacterium Sinimarinibacterium thermocellulolyticum sp. nov. HSW-8T, a cellulase-producing bacterium isolated from hot spring water in South Korea

A thermophilic cellulase-producing bacterium, strain HSW-8T, isolated from hot spring waters in South Korea, was subjected to a taxonomic analysis. Cells of strain HSW-8T were gram-stain-negative, facultatively anaerobic, rod-shaped, with optimum growth at 45 °C, pH 7.0, in the presence of 0% (w/v) NaCl. Strain HSW-8T showed the highest 16S rRNA gene sequence similarity to Sinimarinibacterium flocculans NH6-24T (97.52%), followed by Fontimonas thermophila DSM 23609T (96.97%), Solimonas flava CW-KD 4T (95.24%), and Solimonas variicoloris DSM 15731T (95.18%). Based on 16S rRNA phylogeny, strain HSW-8T is phylogenetically closely related to Fontimonas thermophila DSM 23609T and Sinimarinibacterium flocculans DSM 104150T and could be distinguished from the type species based on their phenotypic properties. The genome length of strain HSW-8T was 3.32 Mbp with a 67.33% G + C content. The average nucleotide identity and digital DNA-DNA hybridization values between strain HSW-8T and its closely related type strains were 75.4-83.2 and 20.2-26.2%, respectively. Summed feature 8 (C18:1ω7c and/or C18:1ω6c), C16:0, and iso-C16:0 identified the major fatty acids (> 10%). Phosphatidylglycerol and phosphatidylethanolamine were demonstrated as the major polar lipids while the respiratory quinone is ubiquinone-8. Strain HSW-8T exhibited multiple adaptations for survival at high temperatures, including diverse potential motility mechanisms and toxin-antitoxin systems, as evidenced by both phenotypic characteristics and genomic analysis. Based on genotypic and phenotypic features, strain HSW-8T (= KCTC 92765T = GDMCC 1.4313T) represents a novel Sinimarinibacterium species, in which the name Sinimarinibacterium thermocellulolyticum sp. nov. is proposed.

Denitrificimonas halotolerans sp. nov., a novel species isolated from UASB sludge treating landfill leachate

A Gram-stain-negative, facultative anaerobe, rod-shaped strain JX-1T was isolated from UASB sludge treating landfill leachate in Wuhan, China. The isolate is capable of growing under conditions of pH 6.0-11.0 (optimum, pH 7.0-8.0), temperature 4-42 ℃ (optimum, 20-30 ℃), 0-8.0% (w/v) NaCl (optimum, 5.0%), and ammonia nitrogen concentration of 200-5000 mg/L (optimum, 500 mg/L) on LB plates. The microorganism can utilize malic acid, D-galactose, L-rhamnose, inosine, and L-glutamic acid as carbon sources, but does not reduce nitrates and nitrites. The major fatty acids are C18:1ω7c/C18:1ω6c, iso-C15:0, and anteiso-C15:0. The respiratory quinones are Q9 (91.92%) and Q8 (8.08%). Polar lipids include aminolipid, aminophospholipid, diphosphatidylglycerol, glycolipid, phosphatidylethanolamine, phosphatidylglycerol, and phospholipid. Compared with other strains, strain JX-1T and Denitrificimonas caeni HY-14T have the highest values in terms of 16S rRNA gene sequence similarity (96.79%), average nucleotide identity (ANI; 76.06%), and average amino acid identity (AAI; 78.89%). Its digital DNA-DNA hybridization (dDDH) result is 20.3%. The genome of strain JX-1T, with a size of 2.78 Mb and 46.12 mol% G + C content, lacks genes for denitrification and dissimilatory nitrate reduction to ammonium (DNRA), but contains genes for ectoine synthesis as a secondary metabolite. The results of this polyphasic study allow genotypic and phenotypic differentiation of the analysed strain from the closest related species and confirm that the strain represents a novel species within the genus Denitrificimonas, for which the name Denitrificimonas halotolerans sp. nov. is proposed with JX-1T (= MCCC 1K08958T = KCTC 8395T) as the type strain.

Marinicella meishanensis sp. nov., a novel Marinicella member isolated from coastal mudflat sediment of Meishan Islandin the East China Sea

A Gram-negative, rod-shaped, non-motile and strictly aerobic strain, designated NBU2979T, was isolated from a coastal mudflat located on Meishan Island in the East China Sea. Strain NBU2979T grew optimally at 32 °C, with 2.0 % NaCl (w/v) and at pH 7.0-7.5. The predominant fatty acid (>10 %) was iso-C15 : 0. The major polar lipids included phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidyldimethylethanolamine, phosphatidylcholine, an unidentified glycolipid, two unidentified aminophospholipids, an unidentified phospholipid and an unidentified lipid. The only respiratory quinone was ubiquinone-8. Comparative analysis of 16S rRNA gene sequences showed that strain NBU2979T exhibited highest similarity to Marinicella sediminis F2T (98.0 %), Marinicella marina S1101T (97.5 %), Marinicella litoralis KMM 3900T (96.6 %), Marinicella rhabdoformis 3539T (95.5 %), Marinicella pacifica sw153T (95.2 %) and Marinicella gelatinilytica S6413T (94.9 %). Phylogenetic analyses indicated that strain NBU2979T clustered with the genus Marinicella and was closely related to strain M. sediminis F2T. The average nucleotide identity and digital DNA-DNA hybridization values between strain NBU2979T and related species of genus Marinicella were well below the threshold limit for prokaryotic species delineation. The DNA G+C content of strain NBU2979T was 51.6 mol%. Based on its phenotypic, chemotaxonomic and genotypic data, strain NBU2979T (=KCTC 82911T=MCCC 1K06402T) is considered to be a representative of a novel species in the genus Marinicella, for which the name Marinicella meishanensis sp. nov. is proposed.

Tessaracoccus caeni sp. nov., a novel member of Propionibacteriaceae isolated from activated sludge in Hefei, PR China

A floc-forming bacterial strain, designated HF-7T, was isolated from the activated sludge of an industrial wastewater treatment plant in Hefei, PR China. Cells of this strain were Gram-stain-positive, catalase- and oxidase-negative, facultatively anaerobic, and rod-shaped. Growth occurred at 20-42 °C (optimum, 28 °C), at pH 5.5-10.5 (optimum, pH 7.5) and with 0-8.0 % (w/v) NaCl (optimum, 1 %). The major fatty acid was anteiso-C15 : 0. The polar lipid profile contained phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol. The DNA G+C content was 67 mol% from whole genomic sequence analysis. Based on the results of 16S rRNA gene sequence analysis, this strain should be assigned to the genus Tessaracoccus and is closely related to Tessaracoccus arenae CAU 1319T (95.87 % similarity), Tessaracoccus lapidicaptus IPBSL-7T (95.19 %) and Tessaracoccus bendigoensis Ben 106T (94.63 %) but separated from them by large distances in different phylogenetic trees. Based on whole genome analysis, the orthologous average nucleotide identity and in silico DNA-DNA hybridization values against two of the closest relatives were 75.21-76.50 % and 14.2-24.4 %, respectively. The phylogenetic, genotypic, phenotypic and chemotaxonomic data demonstrated that strain HF-7T could be distinguished from its phylogenetically related species and represents a novel species within the genus Tessaracoccus, for which the name Tessaracoccus caeni sp. nov. is proposed. The type strain is HF-7T (=KCTC 49959T=CCTCC AB 2023019T).

Muricauda meishanensis sp. nov., a facultative anaerobic bacterium belonging to the family Flavobacteriaceae isolated from marine sediment in the East China Sea

A facultative anaerobic, Gram-strain-negative, rod-shaped bacterium (strain NBU2970T) was isolated by using modified ichip in situ cultivation from a marine sediment sample collected from Meishan Island in the East China Sea. Strain NBU2970T grew optimally at 37 °C, with a NaCl concentration of 2.0 % (w/v) and at pH 7.0. The 16S rRNA gene sequence analyses revealed that strain NBU2970T represents a novel species with the genus Muricauda, sharing highest sequence identities with Muricauda beolgyonensis BB-My12T (96.1 %), Muricauda alvinocaridis SCR12T (96.0 %), Muricauda taeanensis 105T (96.0 %) and Muricauda ruestringensis B1T (95.6 %). Phylogenetic analyses also indicated that strain NBU2970T clustered with the genus Muricauda and was closely related to M. beolgyonensis BB-My12T and M. ruestringensis B1T. The draft genome sequence of strain NBU2970T was composed of six contigs with a size of 3.2 Mbp, containing 3045 protein-coding genes and 38 RNA genes. The DNA G+C content was 43.8 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain NBU2970T and related species of the genus Muricauda were well below the threshold limit for prokaryotic species delineation. The major cellular fatty acids were iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH. The only respiratory quinone was MK-6. The major polar lipid was phosphatidylethanolamine. Based on its phenotypic, chemotaxonomic and genotypic data, strain NBU2970T is considered to be a representative of a novel species in the genus Muricauda, for which the name Muricauda meishanensis sp. nov. is proposed. The type strain is NBU2970T (=KCTC 82915T=MCCC 1K06394T).

Pontibacter liquoris sp. nov. and Pontibacter vulgaris sp. nov., two novel bacteria isolated from the pit mud of Chinese liquor

Two pink-pigmented bacterial strains, designated NBU2971^T and NBU2972^T, were isolated from the pit mud of a Chinese liquor. Phylogenetic analyses based on 16S rRNA gene sequences suggested that strains NBU2971^T and NBU2972^T formed a distinct lineage within the family Hymenobacteraceae and were closely related to members of the genus Pontibacter. 16S rRNA gene sequences revealed that strain NBU2971^T showed highest similarity of 97.9 % to Pontibacter arcticus 2b14^T, and strain NBU2972^T showed the highest similarity of 96.9 % to Pontibacter deserti JC215^T. The 16S rRNA gene sequence similarity, average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two novel strains were 95.2, 73.8 and 19.6 %, respectively, suggesting that they represent different species. The ANI and dDDH values between two novel strains and related species of genus Pontibacter were well below the threshold limit for prokaryotic species delineation. The genomic DNA G+C contents of strains NBU2971^T and NBU2972^T were 51.3 and 44.5 mol%, respectively. The major cellular fatty acids of the two novel strains were iso-C_15 : 0 and summed feature 4 (iso-C_17 : 1 I and/or anteiso-C_17 : 1 B). The major polar lipid of both novel strains was phosphatidylethanolamine. The only respiratory quinone was MK-7. Combining results of phenotypic, chemotaxonomic and genotypic data, strains NBU2971^T and NBU2972^T are considered to be two representatives in the genus Pontibacter, which the name Pontibacter liquoris sp. nov. and Pontibacter vulgaris sp. nov. are proposed. The type strains of the new species are NBU2971^T (=KCTC 82916^T=MCCC 1K06395^T) and NBU2972^T (=KCTC 82917^T=MCCC 1K06396^T), respectively.

Oricola nitratireducens sp. nov., a novel nitrate reducing bacterium isolated from marine sediment in East China Sea

A novel strain designated NBU1457^T, was isolated from marine sediment sampled on Meishan Island located in the East China Sea. Cells of strain NBU1457^T was Gram-negative, facultatively anaerobic, non-motile and ovoid-shaped. Strain NBU1457^T grew optimally at 37 °C, NaCl concentration of 2.0-3.0% (w/v) and pH 6.5-7.5. Catalase and oxidase activities, urease, nitrate reduction and H₂S production were positive. Indole production, methyl red reaction, hydrolysis of starch, gelatin, casein, Tweens 20, 40, 60 and 80 were negative. Comparative analysis of the 16S rRNA gene sequence showed highest similarities to the species with validated name Oricola thermophila MEBiC13590^T (98.8%), Oricola cellulosilytica CC-AMH-0 ^T (97.9%) and Oricola indica JL-62 ^T (97.9%). Phylogenetic analyses indicated that strain NBU1457^T clustered with the genus Oricola and closely related to strains Oricola thermophila MEBiC13590^T, Oricola cellulosilytica CC-AMH-0 ^T and Oricola indica JL-62 ^T. The average nucleotide identity and digital DNA-DNA hybridization values between strain NBU1457^T and related species of genus Oricola were well below the threshold limit for prokaryotic species delineation. The DNA G + C content was 63.2%. The major cellular fatty acid was summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylmonomethylethanolamine, sulfoquinovosyldiacylglycerol and phosphatidylglycerol. The only respiratory quinone was ubiquinone-10 (Q-10). Combining results of our phenotypic, chemotaxonomic and genotypic data, strain NBU1457^T is considered to be a representative in the genus Oricola, which the name Oricola nitratireducens sp. nov. is proposed. The type strain of the new species is NBU1457^T (= KCTC 82225 ^T = MCCC 1K04764^T).

Phylogenomics and molecular marker-based analyses of the order Nevskiales: Proposal for the creation of Steroidobacterales ord. nov. and Peristeroidobacter gen. nov

The order Nevskiales, class Gammaproteobacteria, encompasses four families Algiphilaceae, Salinisphaeraceae, Nevskiaceae, and Steroidobacteraceae. The taxonomy of this order is structured from the inferences derived from the 16S rRNA gene and genome-based phylogenetic tree analyses. However, previous taxonomic studies of the order failed to incorporate most of the representatives from other established orders within the class Gammaproteobacteria. Other divergent members within the class Gammaproteobacteria were therefore overlooked. In this study, the taxonomy of the order Nevskiales was revisited using genome-based analyses with an expanded scope of outgroups representing the vast majority of the diversity within the class Gammaproteobacteria. Results from the phylogenetic analyses strongly supported the exclusion of the family Steroidobacteraceae from the order Nevskiales and further implied the assignment of the family into a novel order. In addition, the analyses also supported the reclassification of Steroidobacter gossypii, Steroidobacter soli, Steroidobacter agariperforans, and Steroidobacter agaridevorans into a novel genus. The identified conserved signature indels in 33 protein sequences further reinforced the new taxonomic assignments. Furthermore, the results of the average nucleotide identity and average amino acid identity analyses, together with the phenotypic and genomic characteristics among the members of the genus Steroidobacter also provided evidence supporting the reclassification of the four Steroidobacter species. Based on these results, the family Steroidobacteraceae is proposed to be assigned into a novel order Steroidobacterales ord. nov., and the species S. gossypii, S. soli, S. agariperforans, and S. agaridevorans are proposed to be moved into a novel genus Peristeroidobacter gen. nov. within the family Steroidobacteraceae.

Luteolibacter marinus sp. nov., a novel bacterium in the family Verrucomicrobiaceae, isolated from marine sediment

A Gram-negative, rod-shaped, non-motile and strictly aerobic bacterium, designated NBU1238^T, was isolated from marine sediment sampled on Meishan Island located in the East China Sea. Strain NBU1238^T was able to grow optimally at 28-32 °C, at pH 7.5 and with no NaCl. Catalase and oxidase activities, H₂S production and hydrolysis of Tweens 40 and 60 were positive. Methyl red reaction, Voges-Proskauer test and hydrolysis of starch, casein and Tweens 20 and 80 were negative. The major cellular fatty acids were iso-C_14 : 0, C_16 : 0, C_16 : 1  ω9c and C_14 : 0. The only respiratory quinone was menaquinone-9. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylmethylethanolamine. The 16S rRNA gene sequence of strain NBU1238^T showed 95.6, 95.6, 94.8 and 93.8% sequence similarity to Luteolibacter flavescens GKX^T, Luteolibacter luteus G-1-1-1^T, Luteolibacter arcticus MC 3726^T and Luteolibacter pohnpeiensis A4T-83^T, respectively. Phylogenetic analyses indicated that strain NBU1238^T clustered with the genus Luteolibacter and was closely related to strains L. flavescens GKX^T, L. arcticus MC 3726^T and L. luteus G-1-1-1^T. The average nucleotide identity and digital DNA-DNA hybridization values between strain NBU1238^T and related species of genus Luteolibacter were well below the threshold limit for prokaryotic species delineation. The DNA G+C content of the genomic DNA was 65.0 mol%. Based on its phenotypic, chemotaxonomic and genotypic data, strain NBU1238^T is considered to be a representative of a novel species in the genus Luteolibacter, for which the name Luteolibacter marinus sp. nov. is proposed. The type strain is NBU1238^T (=KCTC 82227^T=MCCC 1K04772^T).

Hanstruepera marina sp. nov. and Hanstruepera flava sp. nov., two novel species in the family Flavobacteriaceae isolated by a modified in situ cultivation technique from marine sediment

A modified in situ cultivation technique was developed and applied to resource mining of uncultured microbes from marine sediments of Meishan Island in the East China Sea. Two novel strains NBU2968T and NBU2984T were isolated by this method but not standard Petri dish, which indicated the modified technique was more effective compared to conventional approaches for isolating uncultured microbes and could be popularized and applied to other aquatic environments. The two novel strains were identified by the polyphasic taxonomic approach. Cells of both strains were observed to be Gram-staining-negative, rod-shaped, nonmotile, aerobic, and yellow-pigmented. Catalase and oxidase activities and hydrolysis of Tweens 40, 60, and 80 of two novel strains were positive. Methyl red reaction, H2S production, and hydrolysis of Tween 20 were negative. According to 16S rRNA gene sequence analysis, two novel strains shared the highest similarities (96.4-97.7%) to the species with a validated name in the genus Hanstruepera, while shared lower sequence similarities (<95.6%) to all other genera. Phylogenetic analysis revealed that strains NBU2968T and NBU2984T were affiliated with the genus Hanstruepera. ANI and dDDH values between the two novel strains and Hanstruepera species were 77.4-78.3% and 20.4-20.9%, respectively, which were below the thresholds for species delineation. The 16S rRNA gene sequence similarity, ANI, and dDDH values between the two novel strains were 99.3, 88.9, and 36.3%, respectively, indicating that the two strains represent different species. The genomes of NBU2968T and NBU2984T were 3.28 Mbp with a G+C content of 34.2% and 3.09 Mbp with a G+C content of 34.4%, respectively. The only respiratory quinone was menaquinone-6 (MK-6). The major cellular fatty acids were iso-C15:0, iso-C15:1G, and iso-C17:0 3-OH. The major polar lipids of the two strains were phosphatidylethanolamine, unidentified amino lipids, and unidentified lipids. Based on the above polyphasic characteristics, strains NBU2968T and NBU2984T represent two novel species within the genus Hanstruepera, for which the names Hanstruepera marina sp. nov. and Hanstruepera flava sp. nov. are proposed. The type strains are NBU2968T (= MCCC 1K06392T= KCTC 82913T) and NBU2984T (= MCCC 1K07472T= KCTC 92511T), respectively.

Pelagibius marinus sp. nov., a novel bacterium isolated from marine sediment, and emended description of the genus Pelagibius

A Gram-stain-negative, rod-shaped, motile and aerobic marine bacterium, designated strain NBU2595T, was isolated from marine sediment sampled on Meishan Island, located in the East China Sea. Strain NBU2595T grew at 10–40 °C (optimum, 37 °C), at NaCl concentration of 0–10.0 % (w/v; optimum, 0.5 %) and at pH 6.0–8.0 (optimum, pH 7.0). Catalase and oxidase activities and H2S production were positive. Methyl red reaction and hydrolysis of casein, starch and Tweens 20, 40, 60 and 80 were negative. The major cellular fatty acids were summed feature 8 (C18 : 1  ω7c and/or C18 : 1  ω6c), C18 : 1 2-OH and C18 : 0 3-OH. The sole respiratory quinone was ubiquinone 10. The major polar lipids were phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidylmonomethylethanolamine. Comparative analysis of 16S rRNA gene sequences showed highest similarity to Pelagibius litoralis CL-UU02T (97.9%), and low similarities (<92.9 %) to other species. Phylogenetic analyses indicated that strain NBU2595T clustered with the genus Pelagibius and was closely related to P. litoralis CL-UU02T. The average nucleotide identity and digital DNA–DNA hybridization values between strain NBU2595T and the related species of the genus Pelagibius were well below the thresholds for prokaryotic species delineation. The DNA G+C content was 66.5 mol%. Based on its phenotypic, chemotaxonomic and genotypic data, strain NBU2595T should be placed in the genus Pelagibius as representing a novel species, for which the name Pelagibius marinus sp. nov. is proposed. The type strain is NBU2595T (=MCCC 1K04773T=KCTC 82223T).

Paraneptunicella aestuarii gen. nov., sp. nov., a member of the family Alteromonadaceae isolated from seawater in East China Sea

An aerobic Gram-stain-negative, curved rod-shaped and non-spore-forming bacterial strain (NBU2194^T) was isolated from seawater collected in an intertidal zone in Ningbo, Zhejiang Province, PR China. It was motile though a single polar flagellum and grew at 20-42 °C (optimum, 30 °C), in 0-2.0 % NaCl (0 %, w/v) and at pH 5.0-9.0 (pH 6.0-7.0). The sole respiratory quinone was ubiquinone-8. The major cellular fatty acids were C_16 : 0, C_16 : 1  ω7c and/or C_16 : 1  ω6c. The polar lipids contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified phospholipid and two unidentified aminophosphoglycolipids. A phylogenetic analysis based on 16S rRNA gene sequences and 65 genomic core genes showed that strain NBU2194^T formed a distinct lineage in the family Alteromonadaceae. The genome of strain NBU2194^T was 4 913 533 bp with a DNA G+C content of 43.9 mol% and coded 3895 genes, 12 rRNA genes and 47 tRNA genes. The average nucleotide identity, amino acid identity and digital DNA-DNA hybridization values between strain NBU2194^T and related species of Alteromonadaceae were below the threshold limit for prokaryotic species delineation. NBU2194^T could be distinguished from other genera in the family Alteromonadaceae based on phenotypic, chemotaxonomic and genomic characteristics. On the basis of the polyphasic taxonomic evidence collected in this study, strain NBU2194^T is considered to represent a novel genus and species in the family Alteromonadaceae, for which the name Paraneptunicella aestuarii is proposed. The type strain is NBU2194^T (=KCTC 82442^T=GDMCC 1.2217^T).

Flagellatimonas centrodinii gen. nov., sp. nov., a novel member of the family Nevskiaceae isolated from toxin-producing dinoflagellate Centrodinium punctatum

A Gram-stain-negative, aerobic, rod-shaped strain (R2A-3^T) was isolated from the toxin-producing dinoflagellate Centrodinium punctatum and identified as a novel genus and new species based on a polyphasic taxonomic approach. The optimum conditions for growth of the strain were at 25 °C, pH 8.0 and in the presence of 3 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA genes and 92 core genes sets revealed that strain R2A-3^T belongs to the family Nevskiaceae in the class Gammaproteobacteria and represented an independent taxon separated from other genera. The 16S rRNA gene of strain R2A-3^T showed the highest sequence similarity to Polycyclovorans algicola TG408^T (95.2%), Fontimonas thermophila HA-01^T (94.1%) and Sinimarinibacterium flocculans NH6-24^T (93.2%), and less than 92.8 % similarity to other genera in the family Nevskiaceae. The genome length of strain R2A-3^T was 3608892 bp with 65.2 mol% G+C content. Summed feature 8 (comprising C_18 : 1  ω7c and/or C_18 : 1  ω6c) was the major fatty acid (>10 %). Diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine were detected as the major polar lipids. The major respiratory quinone was ubiquinone-8. According to its phylogenetic, phenotypic, chemotaxonomic and genomic features, strain R2A-3^T represents a new species in the new genus of the family Nevskiaceae. It is recommended to name it Flagellatimonas centrodinii gen. nov., sp. nov. The type strain is R2A-3^T (=KCTC 82469^T=GDMCC 1.2523^T).

Nisaea sediminum sp. nov., a heavy metal resistant bacterium isolated from marine sediment in the East China Sea

A Gram-negative, rod-shaped, motile and strictly aerobic bacterium, designated NBU1469^T, was isolated from marine sediment sampled on Meishan Island located in the East China Sea. Strain NBU1469^T grew optimally at temperature of 40 °C, NaCl concentration of 2.0% (w/v) and pH 7.5. Catalase and oxidase activities, H₂S production, nitrate reduction and hydrolysis of Tween 20 were positive. Indole, methyl red reaction, urease, hydrolysis of gelatin, starch, casein, Tweens 40, 60 and 80 were negative. The major cellular fatty acids were C_16:0, C_19:0 cyclo ω8c and summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). The only respiratory quinone was ubiquinone-10 (Q-10). The major polar lipids were phosphatidylglycerol, two unidentified amino-phospholipids and two unidentified phospholipids. Comparative analysis of the 16S rRNA gene sequence showed highest similarities to the species with validated name Nisaea nitritireducens DR41_18^T (98.1%) and Nisaea denitrificans DR41_21^T (97.6%). Phylogenetic analyses indicated that strain NBU1469^T formed a distinct lineage with strains Nisaea nitritireducens DR41_18^T and Nisaea denitrificans DR41_21^T within the genus Nisaea. The average nucleotide identity and digital DNA-DNA hybridization values between strain NBU1469^T and related species of genus Nisaea were well below the threshold limit for prokaryotic species delineation. The DNA G + C content was 63.6%. Based on its phenotypic, chemotaxonomic and genotypic data, strain NBU1469^T is considered to be a representative of a novel species in the genus Nisaea, for which the name Nisaea sediminum sp. nov. is proposed. The type strain is NBU1469^T (=KCTC 82224 ^T =MCCC 1K04763^T).

Nesterenkonia ebinurensis sp. nov., a Novel Actinobacterium Isolated From Populus euphratica

During our studies focused on the microorganism diversity and community structure of Populus euphratica at Ebinur lake wetland nature reserve in Xinjiang Uyghur Autonomous Region, PR China, a Gram-positive, aerobic, short rod-shaped bacterium without flagellum, designated as MD2^T, was isolated from a piece of resina on Populus euphratica. The isolate grew at temperature of 10-45 °C (optimum 37 °C), pH of 7.0-12.0 (optimum pH 8.0) and NaCl concentration of 1-18% (optimum 3%, w/v). Based on the 16S rRNA gene sequences and the phylogenetic analysis, the strain shared the highest sequence similarities to Nesterenkonia alkaliphila JCM 19766^T (96.3%), Nesterenkonia populi KCTC 29119^T (95.9%), Nesterenkonia alba CCTCC AB 207011^T (95.5%), and was placed within the radiation of Nesterenkonia species in the phylogenetic trees. The draft genome of the isolate was sequenced, which comprised 3,739,891 bp with G + C content of 63 mol%, and was annotated to contain 3614 protein-coding genes, 44 tRNA genes and 5 rRNA genes. Chemotaxonomic analysis indicated that the main respiratory quinones were MK-8 and MK-9, the predominant cellular fatty acids were anteiso-C_17:0, anteiso-C_15:0 and iso-C_16:0, the major polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol andphosphatidylinositol. According to the phenotypic, chemotaxonomic and phylogenetic features, strain MD2^T is considered to represent a novel species, for which the name Nesterenkonia ebinurensis sp. nov. is proposed. The type strain is MD2^T (= KCTC 52999^T = MCCC 1K03343^T).

Shimia sediminis sp. nov., a bacterium isolated from marine sediment in the East China Sea

A Gram-stain-negative, ovoid-shaped, motile and strictly aerobic bacterium, designated ZQ172^T, was isolated from marine sediment sampled on Zhoushan Island located in the East China Sea. Strain ZQ172^T grew optimally at temperatures of 25-30 °C, at NaCl concentration of 2.0 % (w/v) and at pH 7.0-8.5. Catalase and oxidase activities, urease, and nitrate reduction were positive. Indole production, methyl red reaction, H₂S production and hydrolysis of gelatin, starch, casein and Tweens 20, 40, 60 and 80 were negative. The major cellular fatty acid was summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c). The only respiratory quinone was ubiquinone-10. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylcholine. Comparative analysis of the 16S rRNA gene sequence showed highest similarities to Shimia aestuarii JC2049^T (97.5 %), Shimia abyssi JAMH 043^T (97.5 %) and Shimia thalassica CECT 7735^T (97.3 %). Phylogenetic analyses indicated that strain ZQ172^T clustered with the genus Shimia and was closely related to Shimia thalassica CECT 7735^T. The average nucleotide identity and digital DNA-DNA hybridization values between strain ZQ172^T and related species of the genus Shimia were well below the threshold limit for prokaryotic species delineation. The DNA G+C content was 59.6 mol%. Based on its phenotypic, chemotaxonomic and genotypic data, strain ZQ172^T is considered to be a representative of a novel species in the genus Shimia, for which the name Shimia sediminis sp. nov. is proposed. The type strain is ZQ172^T (=KCTC 62578^T=MCCC 1K03531^T).

Microbulbifer hainanensis sp. nov., a moderately halopilic bacterium isolated from mangrove sediment

A new bacterium was successfully isolated from a mangrove sediment sample in Haikou City, Hainan Province, China. The organism is a Gram-negative, rod-shaped, non-motile and strictly aerobic bacterium, named NBU-8HK146^T. Strain NBU-8HK146^T was able to grow at temperatures of 10-40 °C, at salinities of 0-11% (w/v) and at pH 5.5-9.5. Veoges-Proskauer, methyl red reaction and hydrolysis of Tween 20 were negative. Catalase and oxidase activities, H₂S production, hydrolysis of starch, casein, Tweens 40, 60 and 80 were positive. The major cellular fatty acids were C_16:0, iso-C_15:0 and summed feature 9. The major respiratory quinone was ubiquinone-8 (Q-8). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and two unidentified glycolipids. According to 16S rRNA gene sequence similarities, strain NBU-8HK146^T shared 98.0%, 97.9%, 97.7%, 97.6% and 97.3% similarities to the species with validated name Microbulbifer taiwanensis CC-LN1-12^T, Microbulbifer rhizosphaerae Cs16b^T, Microbulbifer marinus Y215^T, Microbulbifer donghaiensis CN85^T and Microbulbifer aggregans CCB-MM1^T, respectively. Phylogenetic analyses indicated that strain NBU-8HK146^T formed a distinct lineage with strains Microbulbifer taiwanensis CC-LN1-12^T and Microbulbifer marinus Y215^T. Both digital DNA-DNA hybridization values (19.5-22.7%) and average nucleotide identity values (73.2-78.9%) between strain NBU-8HK146^T and related species of genus Microbulbifer were below the species delineation cutoffs. The DNA G+C content was 58.9 mol%. Many proteins involving in the adaption of osmotic stress in the salt environment of mangrove were predicted in genome of strain NBU-8HK146^T. From phenotypic, genotypic, phylogenetic and chemotaxonomic characteristics, strain NBU-8HK146^T can be regarded as a new Microbulbifer species for which the name Microbulbifer hainanensis. The type strain is NBU-8HK146^T (= KCTC 82226^T = MCCC 1K04737^T).

Rheinheimera mangrovi sp. nov., a bacterium isolated from mangrove sediment

A Gram-stain-negative, rod-shaped, motile and strictly aerobic bacterium, designated LHK132T, was isolated from a mangrove sediment sample collected in Haikou, Hainan Province, PR China. Strain LHK132T was able to grow at temperatures of 10–45 °C, at salinities of 0–7.0 % (w/v) and at pH 6.0–9.0. Catalase and oxidase activities, H2S production, urease and methyl red reaction were positive. Indole, nitrate reduction, hydrolysis of gelatin, starch, casein and Tweens 20, 40, 60 and 80 were negative. The major cellular fatty acids were C16 : 0 and summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c). The only respiratory quinone was ubiquinone-8. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. According to 16S rRNA gene sequence analysis, strain LHK132T had 98.3, 97.5, 97.4, 97.2 and 97.1% similarities to Rheinheimera soli BD-d46T, Rheinheimera sediminis YQF-1T, Rheinheimera tangshanensis JA3-B52T, Rheinheimera mesophila IITR-13T and Rheinheimera arenilitoris J-MS1T, respectively. Phylogenetic analyses indicated that strain LHK132T formed a distinct lineage with R. soli BD-d46T within the genus Rheinheimera . The average nucleotide identity and digital DNA–DNA hybridization values between strain LHK132T and related species of the genus Rheinheimera were well below the thresholds for species delineation. The DNA G+C content was 46.7 mol%. On the basis of its phenotypic, chemotaxonomic and genotypic data, strain LHK132T is considered a representative of a novel species in the genus Rheinheimera , for which the name Rheinheimera mangrovi sp. nov. is proposed. The type strain is LHK132T (=KCTC 62580T=MCCC 1K03529T).

Azoarcus halotolerans sp. nov., a novel member of Rhodocyclaceae isolated from activated sludge collected in Hong Kong

A floc-forming bacterial strain, designated HKLI-1^T, was isolated from the activated sludge of a municipal sewage treatment plant in Hong Kong SAR, PR China. Cells of this strain were Gram-stain-negative, strictly aerobic, catalase- and oxidase-positive, rod-shaped and motile by means of a single polar flagellum. Growth occurred at 18-37 °C (optimum, 28 °C), pH 5.5-9.0 (optimum, pH 7.5) and with 0-8.0 % (w/v) NaCl (optimum, 1-1.5 %) concentration. The major fatty acids of strain HKLI-1^T were C_16 : 0 and summed feature 3 (C_16 : 1 ω7c and/or C_16 : 1 ω6c). The polar lipid profile contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and three unidentified lipids. The DNA G+C content was 63.5 mol% from whole genomic sequence analysis. Based on the results of 16S rRNA gene sequences analysis, this strain should be assigned to the genus Azoarcus and is closely related to Azoarcus olearius DQS-4^T (94.93 % 16S rRNA gene sequence pairwise similarity), Azoarcus toluclasticus MF63^T (94.91 %) and Azoarcus communis SWub3^T (94.01 %), but separate from them by large distances in different phylogenetic trees. Based on whole genome analysis, the orthologous average nucleotide identity and in silico DNA-DNA hybridization values against four of the closest relatives were 73.03-74.83 and 17.2-23.0 %, respectively. The phylogenetic, genotypic, phenotypic and chemotaxonomic data demonstrated that strain HKLI-1^T could be distinguished from its phylogenetically related species, and that this strain represented a novel species within the genus Azoarcus, for which the name Azoarcus halotolerans sp. nov. is proposed. The type strain is HKLI-1^T (= 72659^T=CCTCC AB 2019312^T).

Polyphasic taxonomic analysis of Sinimarinibacterium arenosum sp. nov., a halophilic bacterium isolated from marine sediment

A Gram stain-negative, aerobic, motile, rod-shaped bacterial strain, designated CAU 1509T, was isolated from marine sediment, and its taxonomic position was determined using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CAU 1509T formed a distinct lineage within the genus Sinimarinibacterium with the highest 16S rRNA gene sequence similarity to Sinimarinibacterium flocculans NH6-24T (97.0%). Similar to another member of Sinimarinibacterium, ubiquinone-8 (Q-8) was the predominant quinone, whereas C16:0, summed feature 3 (C16:1ω7c/ω6c) and summed feature 8 (C18:1ω7c/ω6c) were the major cellular fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, four unidentified glycolipids and three unidentified aminolipids. Strain CAU 1509T has a genome of 4.54 Mb, including 4251 coding sequences, 6 rRNAs and 50 tRNAs, with a genomic DNA G+C content of 63.2 mol%. Based on its phenotypic, chemotaxonomic and phylogenetic properties, strain CAU 1509T should be classified as a novel species of the genus Sinimarinibacterium, for which the name Sinimarinibacterium arenosum sp. nov. is proposed. The type strain is CAU 1509T (= KCTC 72000T = NBRC 113698T).

Alkalilacustris brevis gen. nov., sp. nov., isolated from a soda lake

A Gram-stain-negative, aerobic, non-pigmented and short-rod-shaped bacterium, designated 34079^T, was isolated from a water sample of a soda lake in Jilin, a province of China. Strain 34079^T grew at 10-50 °C (optimum, 35 °C), pH 7-10 (optimum, pH 8.0-8.5). NaCl was required for growth at the concentration range 1-10.0 % (w/v), with an optimum at 2.5-4 % (w/v). Chemotaxonomic analysis indicated that the sole respiratory quinone was Q-10. The predominant cellular fatty acids (>5 %) were summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c) and C16 : 0. The major polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, three unidentified amino lipids, one unidentified amino phosphoglycolipid, one phosphoglycolipid, one unidentified glycolipid, three unidentified phospholipids and two unidentified lipids. The DNA G+C content was 65.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 34079^T formed a distinct lineage in the clade of the family 'Rhodobacteraceae' with the highest sequence similarity of 96.1 % to Pararhodobacter aggregans, followed by Rhodobaca bogoriensis DSM 18756^T (95.7 %) and Roseibaca ekhonensis DSM 11469^T (94.7 %). The distinct biochemical, chemotaxonomic and phylogenetic differences from the previously described taxa supported that strain 34079^T represents a novel species of a new genus, for which the name Alkalilacustris brevis gen. nov., sp. nov. is proposed. The type strain is 34079^T (=KCTC 62428^T=MCCC 1K03493^T).

Stagnimonas aquatica gen. nov., sp. nov., a new member of the family Nevskiaceae isolated from a freshwater mesocosm

A novel bacterial strain, designated THS-13^T, isolated from a freshwater mesocosm in Taiwan, was characterized by taking a polyphasic taxonomic approach. Cells of strain THS-13^T were Gram-stain-negative, aerobic, rod-shaped, motile by means of a single polar flagellum and formed translucent white coloured colonies. Growth occurred at 20-35 °C (optimum, 25 °C), at pH 5-8 (pH 6) and with 0-2 % NaCl (1 %). Phylogenetic analyses based on 16S rRNA gene and coding sequences of 92 protein clusters revealed that the strain belonged to the family Nevskiaceae in the class Gammaproteobacteria and represented an independent taxon separated from other genera. Strain THS-13^T shared low level of 16S rRNA gene sequence similarity (less than 93.0 %) to members of other genera in the family Nevskiaceae and was most closely related to Nevskia aquatilis F2-63^T (92.9 %). Strain THS-13^T showed less than 73.4 % average nucleotide identity and less than 23.8 % digital DNA-DNA hybridization identity compared to the type strains of related genera within the family Nevskiaceae. The predominant fatty acids were C18 : 1ω7c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and iso-C16 : 0. The major isoprenoid quinone was Q-8 and the DNA G+C content was 67.6 mol%. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, an uncharacterized aminophospholipid, an uncharacterized phospholipid and an uncharacterized aminolipid. On the basis of the genotypic and phenotypic data, strain THS-13^T represents a novel species of a new genus in the family Nevskiaceae, for which we propose the name Stagnimonas aquatica gen. nov., sp. nov. The type strain is THS-13^T (=BCRC 81158^T=LMG 30925^T=KCTC 62868^T).

Stenotrophobium rhamnosiphilum gen. nov., sp. nov., isolated from a glacier, proposal of Steroidobacteraceae fam. nov. in Nevskiales and emended description of the family Nevskiaceae

A Gram-stain-negative strain, designated GT1R17^T, was isolated from an ervoconite sample collected from Gawalong glacier in the Tibet Autonomous Region, PR China. Strain GT1R17^T was catalase- and oxidase-positive, and grew optimally at 20-25°C and pH 7.0. The highest level of 16S rRNA gene sequence similarities were found to members of the genera Nevskia(92.27-93.15 %) and Hydrocarboniphaga(91.92-92.96 %). Phylogenetic analyses based on 16S rRNA gene sequences and genomic data revealed that the strain GT1R17^T belonged to the family Nevskiaceae, but could not be assigned to any known genera. The genomic DNA G+C content was 54.4 mol%. The major fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), summed feature 8 (C18 : 1 ω7c and/or C18 : 1ω6c), C16 : 0, iso-C16 : 0 and summed feature 2 (C14 : 0 3OH and/or iso-C16 : 1 I). The polar lipids were phosphatidylglycerol, phosphatidylethanolamine and one unidentified lipid. The ubiquinone was Q-8. On the basis of the phenotypic, chemotaxonomic, genotypic and phylogenetic data, a novel species of a new genus,Stenotrophobiumrhamnosiphilum gen. nov., sp. nov. within the family Nevskiaceae, is proposed, with GT1R17^T (=CGMCC 1.16137^T=NBRC 113346^T) as the type strain. In addition, phylogenetic analyses revealed that Steroidobacter and Povalibacter formed an independent clade in the order Nevskiales and were away from the families Nevskiaceae, Algiphilaceae and Salinisphaeraceae. Therefore, we propose to remove Steroidobacter and Povalibacter from the family Nevskiaceae and propose a new family Steroidobacteraceae in the order Nevskiales.

Meridianimarinicoccus roseus gen. nov., sp. nov., a novel genus of the family Rhodobacteraceae isolated from seawater

A Gram-stain negative, pink-pigmented, strictly aerobic, non-motile and coccoid-shaped bacterial strain, designated TG-679^T, was isolated from a deep-sea water sample collected from the South China Sea. Cells of strain TG-679^T were catalase- and oxidase-positive, lacked bacteriochlorophyll a and carotenoid. Strain TG-679^T was found to grow at 10-40 °C (optimum, 28 °C), pH 5.5-10.0 (optimum, pH 7.5) and with 0.5-2.0 % (w/v) NaCl (optimum, 1.5 %). Chemotaxonomic analysis of strain TG-679^T indicated that the sole respiratory quinone was Q-10, the predominant cellular fatty acid was C18 : 1ω7c, and the major polar lipids consisted of phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified phospholipid and two unidentified glycolipids. The genomic DNA G+C content of strain TG-679^T was 65.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain TG-679^T constituted a separated branch in the family Rhodobacteraceae. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain TG-679^T is clearly distinct from any validly published genus. Based on polyphasic taxonomic characterization, strain TG-679^T is considered to represent a novel species of a novel genus, for which the name Meridianimarinicoccus roseus gen. nov., sp. nov. is proposed. The type strain of the species is TG-679^T (=KCTC 62454^T=MCCC 1K03496^T).

Streptomyces nigra sp. nov. Is a Novel Actinobacterium Isolated From Mangrove Soil and Exerts a Potent Antitumor Activity in Vitro

A new bacterial strain, designated 452^T, was isolated from the rhizosphere soil of the mangrove Avicennia marina in China. As determined, its cell wall peptidoglycan contained LL-diaminopimelic acid; MK-9(H8) and MK-9(H6) were the major isoprenoid quinones; and iso-C_16:0 (31.3%), anteiso-C_15:0 (16.9%), and iso-C_15:0 (12.5%) were the major cellular fatty acids (>10.0%). Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain 452^T formed a distinct lineage in the clade of the genus Streptomyces, and was closely related to S. coerulescens DSM 40146^T (99.6% sequence identity), S. bellus DSM 40185^T (99.5%), and S. coeruleorubidus DSM 41172^T (99.3%). The DNA-DNA relatedness between strain 452^T and these type strains ranged between 29.3 and 42.3%. Based on the phenotypic, chemotaxonomic, and phylogenetic features, the strain 452^T is considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces nigra sp. nov. is proposed. The type strain is 452^T (=KCTC 39960^T = MCCC 1K03346^T). Further, strain 452^T extracts exhibited a pronounced antitumor activity against human cancer cell lines A549, HCT-116, and HepG2, but not against normal human colon cells CCD-18Co. Active substances in the fermentation broth of strain 452^T were isolated by bioassay-guided analysis, and then purified using a macroporous resin, silica gel, sephadex LX-20 column, and semi-preparative high-performance liquid chromatography (HPLC). Eight proline-containing diketopiperazines, namely, cyclo(Pro-Ala), cyclo(Pro-Gly), cyclo(Pro-Phe), cyclo(Pro-Met), cyclo(Pro-Val), cyclo(Pro-Leu), cyclo(Pro-Tyr), and cyclo(L-Leu-trans-4-hydroxy-L-Pro), were identified by electrospray ionization mass spectrometry (MS) and nuclear magnetic resonance (NMR). The compounds displayed different levels of cytotoxicity. The highest cytotoxicity was exhibited by cyclo(Pro-Ala) and cyclo(Pro-Met) against A549 cells, and cyclo(Phe-Pro) and cyclo(Pro-Ala) against HCT-116 cells, with average IC₅₀ values equal to 18.5, 27.3, 32.3, and 47.6 μg/mL, respectively. The diversity of diketopiperazines and other chemicals produced by 452^T was further investigated using gas chromatography (GC)-MS and liquid chromatography (LC)-MS. The analysis revealed 16 types of metabolites with antitumor activity and 16 other types of diketopiperazines. Hence, extracts of the newly identified strain may be used a starting material for the development of antitumor agents.

Polyphasic taxonomic characterisation of a novel strain as Pararhizobium haloflavum sp. nov., isolated from soil samples near a sewage treatment tank

A Gram-stain negative, aerobic, motile and ovoid- to rod-shaped bacteria strain, designated XC0140^T, was isolated from soil samples near the sewage treatment tank of a chemical factory in Zhejiang Province, China, and subjected to polyphasic taxonomic investigation. Strain XC0140^T grew at 10-37 °C and pH 6.0-9.0 (optimum, 35 °C and pH 7.5) and with 0-17% (w/v) NaCl (optimum, 1%). According to phylogenetic analysis based on 16S rRNA gene sequences, strain XC0140^T was assigned to the genus Pararhizobium with high 16S rRNA gene sequence similarity of 95.97% to "Pararhizobium helanshanense CCNWQTX14^T", followed by Pararhizobium sphaerophysae CCNWGS0238^T (95.95%). Chemotaxonomic analysis showed that strain XC0140^T contains ubiquinone-10 as the predominant respiratory quinone and possessed summed feature 8 (comprising C_{18: 1} ω7c and/or ω6c), 11-methyl C_18:1 ω7c, C_{18: 0} and C_{16: 0} as predominant forms of fatty acids. The polar lipids of strain XC0140^T consisted of seven phospholipids (PL), two aminolipids (AL), one glycolipid (GL) and three unidentified lipids (L1, L2 and L3). The DNA G+C content was 62.7 mol%. Based on the polyphasic taxonomic characterization, strain XC0140^T is considered to represent a novel species of the genus Pararhizobium, for which the name Pararhizobium haloflavum sp. nov. is proposed. (type strain XC0140^T = MCCC 1K03228^T = KCTC 52582^T).