Rubellimicrobium arenae sp. nov., isolated from desert soil.

Two Gram-stain-negative strains, designated as SYSU D00286T and SYSU D00782, were isolated from a sand sample collected from the Kumtag Desert in Xinjiang, north-west China. Cells were aerobic, non-motile and positive for both oxidase and catalase. Growth occurred at 4-37 °C (optimum, 28-30 °C), pH 6.0-7.0 (optimum, pH 7.0) and NaCl concentration of 0-1.5 % (w/v; optimum, 0%). Growth was observed on Reasoner's 2A agar and nutrient agar, but not on Luria-Bertani agar and trypticase soy agar. The polar lipids were identified as diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, three unidentified aminolipids, one unidentified glycolipid and two unidentified phospholipids. The major respiratory quinone was ubiquinone-10 and the major fatty acids (>10 %) were C16 : 0 and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The 16S rRNA gene sequence similarity between strains SYSU D00286T and SYSU D00782 was 100%, and their average nucleotide identity (ANI), average amino acid identity and (AAI) digital DNA-DNA hybridization (dDDH) values were all 100.0 %. Phylogenetic analysis indicated that these two strains belong to the same species of the genus Rubellimicrobium and show the highest sequence similarity to Rubellimicrobium rubrum KCTC 72461T (98.2 %) and Rubellimicrobium roseum CCTCC AA 208029T (97.5 %). The ANI, AAI and dDDH values between SYSU D00286T (as well as SYSU D00782) and the other five Rubellimicrobium type strains were all less than or equal to 83.2, 80.1 and 23.6 %, respectively. Based on their phylogenetic, phenotypic and chemotaxonomical features, strains SYSU D00286T and SYSU D00782 represent a novel species of the genus Rubellimicrobium, for which the name Rubellimicrobium arenae sp. nov. is proposed. The type strain is SYSU D00286T (=MCCC 1K04981T=CGMCC 1.8626T=KCTC 82271T).

Aridibaculum aurantiacum gen. nov., sp. nov., isolated from the Kumtag Desert soil.

A novel orange-coloured bacterium, designated strain SYSU D00508T, was isolated from a sandy soil sampled from the Kumtag Desert in China. Strain SYSU D00508T was aerobic, Gram-stain-negative, oxidase-positive, catalase-positive and non-motile. Growth occurred at 4-45°C (optimum 28-30°C), pH 6.0-9.0 (optimum pH 7.0-8.0) and with 0-2.5 % NaCl (w/v, optimum 0-1.0 %). The major polar lipids consisted of phosphatidylethanolamine (PE), unidentified aminolipids (AL1-3) and unidentified polar lipids (L1-5) were also detected. The major respiratory quinone was MK-7 and the major fatty acids (>10 %) were iso-C17 : 0 3-OH, iso-C15 : 0 and iso-C15 : 1 G. The genomic DNA G+C content was 42.6 %. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SYSU D00508T belonged to the family Chitinophagaceae and showed 93.9 % (Segetibacter koreensis DSM18137T), 92.9 % (Segetibacter aerophilus NBRC 106135T), 93.0 % (Terrimonas soli JCM 32095T) and 92.8 % (Parasegetibacter terrae JCM 19942T) similarities. Based on the phylogenetic, phenotypic and chemotaxonomic data, strain SYSU D00508T is proposed to represent a novel species of a new genus, named Aridibaculum aurantiacum gen. nov., sp. nov., within the family Chitinophagaceae. The type strain is SYSU D00508T (=KCTC 82286T=CGMCC 1.18648T=MCCC 1K05005T).

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 D01084T and SYSU D00799T, 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 D01084T and SYSU D00799T 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-C15:0, iso-C17:0 3-OH, and iso-C15:1 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 D01084T = CGMCC 1.18641T = MCCC 1K05006T = KCTC 82283T) and Longitalea luteola sp. nov. (type strain SYSU D00799T = MCCC 1K04987T = KCTC 82282T = NBRC 114888T).