Taxonomic descriptions of Aeromicrobium duanguangcaii sp. nov., Aeromicrobium wangtongii sp. nov. and Aeromicrobium senzhongii sp. nov

Six Gram-stain-positive, facultative anaerobic, nonmotile and rod-shaped strains, designated zg-Y50T, zg-Y1362, zg-Y1379T, zg-Y869, zg-629T and zg-Y636, were isolated from the intestinal contents of Marmota himalayana in Qinghai Province, PR China. Strains zg-Y50T, zg-Y1379T and zg-629T exhibited the highest 16S rRNA gene sequence similarities of 99.2, 98.9 and 98.8 % to Aeromicrobium choanae 9 H-4T, Aeromicrobium ginsengisoli JCM 14732T and Aeromicrobium flavum TYLN1T, respectively. Phylogenetic and phylogenomic analyses based on the 16S rRNA gene and genomic sequences, respectively, revealed that the six strains formed three distinct clades within the genus Aeromicrobium. The genome sizes of strains zg-Y50T, zg-Y1379T and zg-629T were 3.1-3.7 Mb, with DNA G+C contents of 69.6-70.4 mol%. Average nucleotide identity and digital DNA-DNA hybridization values between each novel strain and available members of the genus Aeromicrobium were all below species thresholds. All novel strains contained MK-9 (H4) as the major menaquinone and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the polar lipids. The predominant fatty acid of the six isolates was C18 : 1  ω9c. The cell-wall peptidoglycan contained ʟʟ-diaminopimelic acid as the diagnostic diamino acid. Based on the results from this polyphasic taxonomic study, three novel species in the genus Aeromicrobium are proposed, namely, Aeromicrobium duanguangcaii sp. nov. (zg-Y50T=GDMCC 1.2981T=KCTC 49764T), Aeromicrobium wangtongii sp. nov. (zg-Y1379T=GDMCC 1.2982T=KCTC 49765T) and Aeromicrobium senzhongii sp. nov. (zg-629T=CGMCC 1.17414T=JCM 33888T).

Aeromicrobium terrae sp. nov., isolated from a maize field

A polyphasic taxonomic approach was used to characterize a Gram-stain-positive bacterium, designated strain CC-CFT486^T, isolated from soil sampled in a maize field in Taiwan. Cells of strain CC-CFT486^T were short rods, motile with polar flagella, catalase-positive and oxidase-positive. Optimal growth occurred at 30 °С, pH 8 and 1 % NaCl. Phylogenetic analyses based on 16S rRNA genes revealed a distinct taxonomic position attained by strain CC-CFT486^T associated with Aeromicrobium panacisoli (97.0 % sequence identity), Aeromicrobium lacus (97.0 %), Aeromicrobium erythreum (96.8 %) and Aeromicrobium alkaliterrae (96.8 %), and lower sequence similarity values to other species. Average nucleotide identity (ANI) values were 70.6-77.8 % (n=11) compared within the type strains of the genus Aeromicrobium. Strain CC-CFT486^T contained C_16 : 0, C_17 : 0, C_17 : 1  ω8c and C_18 : 1  ω9c as the predominant fatty acids. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, two unidentified aminophospholipids and three unknown phospholipids. The cell wall peptidoglycan of strains CC-CFT486^T contained ll-diaminopimelic acid (ll-DAP) and the major polyamine was spermidine. The DNA G+C content was 70.6 mol% and the predominant quinone was menaquinone 9 (MK-9). Based on its distinct phylogenetic, phenotypic and chemotaxonomic traits together with results of comparative 16S rRNA gene sequence and ANI analyses, strain CC-CFT486^T is proposed to represent a novel Aeromicrobium species, for which the name Aeromicrobium terrae sp. nov. (type strain CC-CFT486^T=BCRC 81217^T=JCM 33499^T).

Draft genome and description of Aeromicrobium phoceense strain Marseille-Q0843T sp. nov., a new bacterium isolated from human healthy skin

In 2019, by culturing a skin swab sample from the back of the hand of a 61-year-old healthy woman and assessing it via the culturomics method, we isolated the new bacterial strain Marseille-Q0843^T (= CSUR-Q0843). Matrix-assisted desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) failed to identify this isolate. Analysis of the 16S ribosomal RNA gene and genome-to-genome comparison suggested that this taxon belongs to a novel bacterial species within the family in Nocardioidaceae in the phylum Actinobacteria. We describe here the main phenotypic characteristics, genome sequence and annotation of Aeromicrobium phoceense strain Marseille-Q0843^T, a new member of the Aeromicrobium genus, which we propose as the type strain.

Aeromicrobium piscarium sp. nov., isolated from the intestine of Collichthys lucidus

A Gram-stain-positive, rod-shaped, whitesmoke-coloured and aerobic bacterium, designated strain Co35T, was isolated from the intestine of Collichthys lucidus collected from the Jiangmen Guangdong Chinese White Dolphin Provincial Nature Reserve. Strain Co35T was able to grow at 15–35 °C (optimal 28 °C), at pH 7.0–8.5 (optimal 8.0) and with 0–9 % (w/v) NaCl (optimal 0.5–1 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Co35T was a member of the genus Aeromicrobium within the family Nocardioidaceae . The genomic DNA G+C content of strain Co35T was 68.4 mol%. Chemotaxonomic analysis showed that the sole respiratory quinone was menaquinone 9 (MK-9), and the major fatty acids included 10-methyl C18 : 0. The polar lipids were found to consist of phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylinositol (PI), two unidentified phospholipids (PL1–2) and two unidentified glycolipids (GL1–2). On the basis of its phylogenetic, phenotypic, chemotaxonomic, genotypic and genomic characteristics presented in this study, strain Co35T represents a novel species in the genus Aeromicrobium , for which the name Aeromicrobium piscarium sp. nov. is proposed. The type strain is Co35T (=KCTC 49280T=MCCC 1K03754T).

Aeromicrobium chenweiae sp. nov. and Aeromicrobium yanjiei sp. nov., isolated from Tibetan antelope (Pantholops hodgsonii) and plateau pika (Ochotona curzoniae), respectively

Four novel strains (592^T, S592, MF47^T and SMF47) were isolated from Tibetan antelopes (Pantholops hodgsonii) and plateau pikas (Ochotona curzoniae), respectively. The cells were aerobic, non-motile, Gram-stain- and catalase-positive, rod-shaped bacteria. The 16S rRNA gene sequences of the four strains showed highest similarities to Aeromicrobium fastidiosum DSM 10552^T (98.1, 98.6, 98.7 and 98.7 %, respectively), and the phylogenetic analyses based on 16S rRNA gene and genomic sequences indicated that strains 592^T and MF47^T represent two novel species. The four isolates produced acid from l-rhamnose, d-xylose and cellobiose, but were unable to reduce nitrate. The DNA G+C contents of strains 592^T and MF47^T were 70.3 and 69.8 mol%, respectively. The digital DNA-DNA hybridization value between strains 592^T and MF47^T was 32.6 %, lower than the threshold of 70 %, indicating they belong to different species. The four strains' genomes displayed less than 24.6 % DNA-DNA relatedness with all available genomes of the genus Aeromicrobium in the NCBI database, including Aeromicrobium fastidiosum NBRC 14897^T and Aeromicrobium ginsengisoli JCM 14732^T. The major fatty acids of the four strains were C_18 : 1  ω9c and C_18 : 0 10-methyl, and the main polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol. The predominant respiratory quinones were MK-9(H₄) and MK-8(H₄). The cell-wall peptidoglycan contained ll-diaminopimelic acid. Based on these genotypic, phenotypic and biochemical analyses, it is proposed that the four unidentified bacteria be classified as two novel species, Aeromicrobium chenweiae sp. nov. and Aeromicrobium yanjiei sp. nov. The type strains are 592^T (=CGMCC1.16526^T=DSM 106289^T) and MF47^T (=CGMCC 1.17444^T=JCM 33790^T), respectively.

Aeromicrobium endophyticum sp. nov., an endophytic actinobacterium isolated from reed (Phragmites australis)

A Gram-staining-positive, motile and short-rod-shaped actinobacterium designated 9W16Y-2^T was isolated from surface-sterilized leaves of reed (Phragmites australis) collected from Taklamakan Desert in Xinjiang Uygur Autonomous Region, China. Colonies were pale greenish yellow, circular, smooth, and convex. The 16S rRNA gene sequence of strain 9W16Y-2^T exhibited highest sequence similarities with Aeromicrobium camelliae CGMCC 1.12942^T (99.0%) and Aeromicrobium erythreum NRRL B-3381^T (97.2%). Phylogenetic analyses based on 16S rRNA gene sequences and single-copy phylogenetic marker genes (pMGs) showed that strain 9W16Y-2^T belonged to the genus Aeromicrobium and formed a monophyletic clade with Aeromicrobium camelliae CGMCC 1.12942^T. Furthermore, average nucleotide identity (ANI) and DNA-DNA hybridization (DDH) clearly separated strain 9W16Y-2^T from the other species of the genus Aeromicrobium with values below the thresholds for species delineation. The G+C content of the genomic DNA is 68.9 mol%. The diagnostic diamino acid of the cell-wall peptidoglycan was LL-diaminopimelic acid. The predominant menaquinone was MK-9(H₄). The major fatty acids (> 10% of the total fatty acids) were C_18:0 10-methyl (TBSA) (28.2%), C_16:0 (21.0%), C_16:0 2-OH (20.8%) and C_18:1ω9c (12.8%). The polar lipid profile comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, an unidentified aminophospholipid and an unidentified lipid. Based on the phylogenic, phenotypic and chemotaxonomic features, strain 9W16Y-2^T represents a novel species of the genus Aeromicrobium, for which the name Aeromicrobium endophyticum sp. nov. is proposed. The type strain is 9W16Y-2^T (= CGMCC 1.13876^T = JCM 33141^T).