Paraflavitalea pollutisoli sp. nov., Pollutibacter soli gen. nov. sp. nov., Polluticoccus soli gen. nov. sp. nov., and Terrimonas pollutisoli sp. nov., four new members of the family Chitinophagaceae from polluted soil

A taxonomic investigation was conducted on four bacterial strains isolated from soil contaminated with polycyclic aromatic hydrocarbons and heavy metals. Phylogenetic analysis revealed that these strains belonged to the family Chitinophagaceae. Examination of the 16S rRNA genes indicated that their sequence identities were below 97.6 % compared to any known and validly nominated bacterial species. The genomes of the four strains ranged from 4.12 to 8.76 Mb, with overall G + C molar contents varying from 41.28 % to 50.39 %. Predominant cellular fatty acids included iso-C15:0, iso-C15:1 G, and iso-C17:0 3-OH. The average nucleotide identity ranged from 66.90 % to 74.63 %, and digital DNA-DNA hybridization was 12.5-12.8 %. Based on the genomic and phenotypic features of the new strains, four novel species and two new genera were proposed within the family Chitinophagaceae. The ecological distributions were investigated by data-mining of NCBI databases, and results showed that additional strains or species of the newly proposed taxa were widely distributed in various environments, including polluted soil and waters. Functional analysis demonstrated that strains H1-2-19XT, JS81T, and JY13-12T exhibited resistance to arsenite (III) and chromate (VI). The proposed names for the four novel species are Paraflavitalea pollutisoli (type strain H1-2-19XT = JCM 36460T = CGMCC 1.61321T), Terrimonas pollutisoli (type strain H1YJ31T = JCM 36215T = CGMCC 1.61343T), Pollutibacter soli (type strain JS81T = JCM 36462T = CGMCC 1.61338T), and Polluticoccus soli (type strain JY13-12T = JCM 36463T = CGMCC 1.61341T).

Longitalea arenae gen. nov., sp. nov. and Longitalea luteola sp. nov., two new members of the family Chitinophagaceae isolated from desert soil

Two strains designated as SYSU D01084^T and SYSU D00799^T, were isolated from a sandy soil sample collected from Gurbantunggut Desert in Xinjiang, north-west China. Cells of both strains were Gram-stain-negative, strictly aerobic, long-rod-shaped, oxidase- and catalase-negative, motile or non-motile. Colonies were circular, translucent, convex, smooth and light-yellow in color on R2A agar. The two isolates were found to grow at 4-50 ºC, at pH 6.0-8.0 and with 0-1.0% (w/v) NaCl. Analysis of their 16S rRNA gene sequences indicated that they belonged to the family Chitinophagaceae, and closely related to the genera Paraflavitalea, Niastella, Pseudoflavitalea and Flavitalea. The two novel strains shared 98.1% 16S rRNA sequence similarity and represent different species on the basis of low average nucleotide identity (ANI, 83.8%) and digital DNA-DNA hybridization (dDDH, 51.4%) values. The genomic DNA G + C contents of strains SYSU D01084^T and SYSU D00799^T were 46.0 and 45.6%, respectively. Phylogenetic trees showed that the two isolates were clustered in an individual lineage and not grouped consistently into any specific genus. The polar lipids contained of phosphatidylethanolamine, four unidentified aminolipids, two unidentified aminoglycolipids, and three or four unidentified lipids. The predominant respiratory quinone was MK-7 and the major fatty acids (> 10%) were identified as iso-C_15:0, iso-C_17:0 3-OH, and iso-C_15:1 G. Based on the combined phenotypic, genomic and phylogenetic analyses, the two strains represent two novel species of a new genus in the family Chitinophagaceae, for which the name Longitalea gen. nov. is proposed, comprising the type species Longitalea arenae sp. nov. (type strain SYSU D01084^T = CGMCC 1.18641^T = MCCC 1K05006^T = KCTC 82283^T) and Longitalea luteola sp. nov. (type strain SYSU D00799^T = MCCC 1K04987^T = KCTC 82282^T = NBRC 114888^T).

Paraflavitalea devenefica sp. nov., isolated from urban soil

A Gram-stain-negative, rod-shaped, mesophilic, milky white-pigmented, aerobic, non-spore-forming and non-flagellated bacterium, designated strain X16^T, was isolated from urban soil of Zibo, Shandong, China. According to 16S rRNA gene sequence analysis, the isolate showed highest similarities with Paraflavitalea soli 5GH32-13^T (97.6 %), Pseudoflavitalea soli KIS20-3^T (96.2 %), Pseudobacter ginsenosidimutans Gsoil 221^T (96.0 %) and Pseudoflavitalea rhizosphaerae T16R-265^T (95.8 %). The neighbour-joining tree based on 16S rRNA gene sequences showed that strain X16^T formed a subcluster with Paraflavitalea soli 5GH32-13^T, and the subcluster was closely related to Pseudoflavitalea soli KIS20-3^T, Pseudobacter ginsenosidimutans Gsoil 221^T and Pseudoflavitalea rhizosphaerae T16R-265^T. Strain X16^T also formed a subcluster with Paraflavitalea soli 5GH32-13^T in phylogenetic tree based on genomic sequences. The polar lipids are phosphatidylethanolamine, two unknown aminolipids, two unknown aminophospholipids, two unknown lipids and two unknown phospholipids. The major quinone of strain X16^T is menaquinone-7 and the main fatty acids (>10 % of total fatty acids) of strain X16^T are iso-C_15 : 0, iso-C_17 : 0 3-OH and iso-C_15 : 1 G. The genome length of strain X16^T is 8.7 Mb with a DNA G+C content of 47.4 %. ANI values among strain X16^T and strain Paraflavitalea soli 5GH32-13^T, Pseudobacter ginsenosidimutans Gsoil 221^T, and Pseudoflavitalea rhizosphaerae T16R-265^T are 78.1, 70.7, 70.6 %, respectively. On the basis of the results of the polyphasic characterization presented in this study, it is concluded that strain X16^T represents a novel species. Besides, strain X16^T can detoxify high toxicity selenite [Se(IV)] to low toxicity elemental selenium [Se(0)], for which the name Paraflavitale devenefica sp. nov. is proposed. The type strain is X16^T (=KACC 21698^T=GDMCC1.1757^T).

Paracnuella aquatica gen. nov., sp. nov., a member of the family Chitinophagaceae isolated from a hot spring

A Gram-stain-negative, rod-shaped bacterium (designated strain N24^T) with gliding motility was isolated from thermal spring water sampled at Xi'an, PR China. Cells were 0.4-0.8 µm wide and 1.8-7.8 µm long. Optimal growth occurred at 33 °C and pH 7.0 on Reasoner's 2A (R2A) agar. Strain N24^T could produce exopolysaccharide on R2A agar at 33 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain N24^T formed a distinct phyletic lineage within the family Chitinophagaceae and was most closely related to members of the genera Flavisolibacter, Cnuella, Niveitalea, Flavitalea, Flaviaesturariibacter and Niastella with 91.7-93.9 % 16S rRNA gene sequence similarities. The major fatty acids of strain N24^T were iso-C15 : 0 (31.8 %), iso-C17 : 0 3-OH (16.1 %) and iso-C15 : 1 G (12.9 %). The polar lipid profile consisted of phosphatidylethanolamine, two aminolipids and six unknown lipids; the quinone system consisted of menaquinone-7 (MK-7). The genomic G+C content was 49.3 mol%. On the basis of the evidence presented in this study, strain N24^T represents a novel species of a new genus in the family Chitinophagaceae, for which the name Paracnuella aquatica gen. nov., sp. nov. is proposed. The type species is N24^T (=KCTC 62083^T=MCCC 1H00301^T).

Flavitalea flava sp. nov., a bacterium isolated from a soil sample, and emended description of the genus Flavitalea

A Gram-stain negative strain, designated AN120636^T, was isolated from a soil sample collected from Goesan-gun, Chungbuk, South Korea. The strain was strictly aerobic, with golden yellow-pigmented colonies on R2A agar. Cells were non-motile, long or short rods and some were observed to be coccal. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain AN120636^T belongs to the genus Flavitalea in the family of Chitinophagacea, with Flavitalea populi (95.4%), Pseudoflavitalea soli (95.0%), Flavitalea gansuensis (94.7%) and Pseudoflavitalea rhizosphaerae (94.7%) as its close relatives. Growth was observed at 15-32 °C, pH 5.0-7.0 and in the absence of NaCl. The strain contained iso-C_17:0 3-OH, iso-C_15:1 G and iso-C_15:0 as its major cellular fatty acids; phosphatidylethanolamine as the major polar lipid; MK-7 as its respiratory quinone; and the polyamine was homospermidine. The genomic DNA G+C content was 44.8 mol%. On the basis of the polyphasic evidence, strain AN120636^T is considered to represent a novel species, for which the name Flavitalea flava sp. nov. is proposed. The type strain is AN120636^T (=KCTC 52346^T=CCTCC AB 2017174^T).

Flavitalea antarctica sp. nov., isolated from Fildes Peninsula, Antarctica

A bright-yellow, Gram-stain-negative, rod-shaped, gliding and aerobic bacterium, designated strain AQ6-291T, was isolated from the Fildes Peninsula, Antarctica, and its taxonomic position was investigated by genotypic, phenotypic and chemotaxonomic analyses. Growth occurred at 4-28 °C (optimum 20 °C) and at pH 5.0-8.0 (optimum pH 7.0). Strain AQ6-291T contained iso-C15 : 1 G, iso-C15 : 0, C16 : 1ω5c, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) as the major cellular fatty acids. The main polar lipids were phosphatidylethanolamine, unknown aminophospholipids, unknown phospholipids, five unknown aminolipids and two unknown polar lipids. MK-7 was the major respiratory quinone. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain AQ6-291T belonged to the genus Flavitalea. The DNA G+C content was 48.1 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain AQ6-291T is considered to represent a novel species of the genus Flavitalea, for which the name Flavitalea antarctica sp. nov. is proposed. The type strain is AQ6-291T (=CCTCC AB 2016109T=KCTC 52491T).

Pseudoflavitalea rhizosphaerae gen. nov., sp. nov., isolated from rhizosphere of tomato, and proposal to reclassify Flavitalea soli as Pseudoflavitalea soli comb. nov

A bacterial strain, designated T16R-265T, was isolated from rhizosphere of tomato in Buyeo-gun, Chungcheongnam-do, South Korea. The strain was Gram-stain-negative, aerobic, non-flagellated and rod- or long-rod-shaped. It grew at the range of 10-40 °C (optimum 28-30 °C), pH 6.0-9.0 (optimum pH 7.0) and with 0-3 % (w/v) NaCl (optimum 0 %). 16S rRNA gene sequence analysis showed that strain T16R-265T had the highest sequence similarity (98.0 %) with Flavitalea soli KIS20-3T and low sequence similarities of below 95 % with all other taxa. The phylogenetic tree revealed that the strain formed a robust monophyletic line with Flavitalea soli KIS20-3T separable from other clades. The predominant quinone of strain T16R-265T was MK-7, the polar lipids consisted of large amounts of phosphatidylethanolamine and an unknown lipid, and the major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 G. DNA-DNA hybridization values with Flavitalea soli KACC 17319T were below 70 %. The DNA G+C content of strain T16R-265T is 46.2 mol%. Based on phylogenetic evidence and the results of phenotypic, genotypic and chemotaxonomic analyses, strain T16R-265T represents a novel species of a new genus, for which the name Pseudoflavitalea rhizosphaerae gen. nov., sp. nov. is proposed. The type strain of the type species is T16R-265T (=KACC 18655T=NBRC 111880T). We also propose the reclassification of Flavitalea soli as Pseudoflavitalea soli comb. nov. (type strain KIS20-3T=KACC 17319T=JCM 19937T).