Microbacterium aquilitoris sp. nov. and Microbacterium gwkjiense sp. nov., isolated from beach.

Three Gram-reaction-positive bacterial strains, designated KSW-18T, KSW2-22, and KSW4-11T, were isolated from seawater, and two dried seaweed samples collected at Gwakji Beach in Jeju, Republic of Korea, respectively, and their taxonomic positions were examined by a polyphasic approach. The 16S rRNA gene phylogeny showed that strain KSW4-11T was tightly associated with Microbacterium oleivorans NBRC 103075T, while strains KSW-18T and KSW2-22 formed a distinctive subline at the base of a clade including the above two strains. The three isolates showed high sequence similarity with one another (99.7-99.9%; 1-4 nt differences) and Microbacterium oleivorans (99.8-99.9%; 1-3 nt differences). The chemotaxonomic features were typical for the genus Microbacterium; Lysine as the diagnostic diamino acid and N-glycolylated muramic acid of the peptidoglycans, the predominant menaquinones of MK-11, MK-10 and MK-12, the major fatty acids of anteiso-C15:0 and anteiso-C17:0, and the major polar lipids including diphosphatidylglycerol, phosphatidylglycerol, and two or three unidentified glycolipids. In core genome-based phylogenetic tree, strains KSW-18T and KSW2-22 were closely associated with Microbacterium oleivorans NBRC 103075T, while strain KSW4-11T formed a distinctive subline at the base of a clade including the above three strains, in contrast to the 16S rRNA gene tree. Strains KSW-18T and KSW2-22 shared an OrthoANIu of 98.6% and a digital DNA-DNA hybridization of 87.6% with each other, representing that they were strains of a species, while the OrthoANIu and digital DNA-DNA hybridization values between strains KSW-18T and KSW4-11T, and between both of these isolates and all members of the genus Microbacterium were ≤86.5% and ≤30.7%, respectively. The analyses of overall genomic relatedness indices and phenotypic distinctness support that the three isolates represent two new species of the genus Microbacterium. Based on the results obtained here, Microbacterium aquilitoris sp. nov. (type strain KSW-18T = KCTC 49623T = NBRC 115222T) and Microbacterium gwkjiense sp. nov. (type strain KSW4-11T = KACC 23321T = DSM 116380T) are proposed.

Speluncibacter jeojiensis gen. nov. sp. nov., a novel bacterium of the order Mycobacteriales isolated from a cave and a proposal of Speluncibacteraceae fam. nov.

Two Gram-stain-positive, aerobic, non-spore-forming, non-motile, irregular rod-shaped actinobacteria, designated as D2-41T and D3-21, were isolated from soil samples collected in a natural cave in Jeju, Republic of Korea. Both of the isolates were shown to share 100 % 16S rRNA sequence identity. The cell wall contained meso-diaminopimelic acid, arabinose and galactose. The predominant menaquinone was MK-8(H2). The polar lipids contained phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, an unidentified aminolipid, an unidentified aminoglycolipid, an unidentified phospholipid and two unidentified lipids. The predominant fatty acids were C16 : 0 and summed feature 3 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH). Mycolic acids of C30-C38 were present. The 16S rRNA gene trees showed that the organisms occupied a distinct position remotely located from recognized genera within the order Mycobacteriales, albeit with the 16S rRNA gene similarities of 97.0-97.1 % with Rhodococcus olei, Rhodococcus rhodnii and Rhodococcus triatomae. The genome sizes and DNA G+C contents of strains D2-41T and D3-21 were 4.77-4.88 Mbp and 69.8 mol%, respectively. Both of the isolates shared an average nucleotide identity of 99.4 % and digital DNA-DNA hybridization of 95.2 % to each other, revealing that strains D2-41T and D3-21 belonged to the same species. In the core genome-based phylogenomic tree, both of the isolates were found to be closely associated with members of the genus Tomitella. However, strains D2-41T and D3-21 revealed the highest amino acid identity values (mean 66.5 %, range 66.2-67.0 % with the genus Prescottella of the family Nocardiaceae, followed by the genus Tomitella (mean 64.1 %, range 63.6-64.7 %) of the family Tomitellaceae. Based on the combined data obtained here, the novel isolates belong to a new genus of the new family for which the name Speluncibacter jeojiensis gen. nov. sp. nov. is proposed, with Speluncibacteraceae fam. nov. The type strain is strain D2-41T (=KACC 17930T=DSM 101875T).

Larsenimonas rhizosphaerae sp. nov., isolated from a tidal mudflat.

A Gram-reaction-negative, aerobic, motile, rod-shaped bacterium, designated GH3-8T, was isolated from rhizosphere mudflats of halophytes on the seashore of Gangwha Island, Republic of Korea. Growth was observed at pH 4-10 (optimum, pH 7-8), at 4-40 °C (optimum, 37 °C) and in the presence of 0.5-20 % (w/v) NaCl (optimum, 4 %). The predominant respiratory quinone was Q-9. The major fatty acids were C18 : 1 ω7c, C16 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and C12 : 0 3OH. The polar lipids contained phosphatidylethanolamine, phosphatidylglycerol, an unidentified phosphoglycolipid, an unidentified phosphoglycoaminolipid, an unidentified glycoaminolipid, two unidentified phospholipids and two unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences exhibited that the isolate belonged to the family Halomonadaceae, with the most closely related species, Larsenimonas suaedae (98.1 % sequence similarity) and Larsenimonas salina (97.9 %). Sequence similarity values between the isolate and other representatives of the family Halomonadaceae were all below 95.3 %. The values of average nucleotide identity between strain GH3-8T and members of the genus Larsenimonas were 73.42 % with L. salina CCM 8464T and 72.38 % with L. suaedae DSM 22428T. Strain GH3-8T showed digital DNA-DNA hybridization values of 18.5-18.6 % with members of the genus Larsenimonas. Based on phenotypic and chemotaxonomic distinctiveness together with low overall genomic relatedness indices and phylogenetic data, the isolate is considered to represent a new species of the genus Larsenimonas, for which the name Larsenimonas rhizosphaerae sp. nov. is proposed, with the type strain GH3-8T (=KCTC 62127T=NBRC 113214T).

Microbacterium tenebrionis sp. nov. and Microbacterium allomyrinae sp. nov., isolated from larvae of Tenebrio molitor L. and Allomyrina dichotoma, respectively.

Two Gram-positive bacterial strains, designated as YMB-B2T and BWT-G7T, were isolated from larvae of Tenebrio molitor L. and Allomyrina dichotoma, respectively, and their taxonomic positions examined by a polyphasic approach. Both of the isolates contained ornithine as the cell-wall diamino acid. The acyl type of murein was N-glycolyl. The predominant menaquinones were MK-11 and MK-12. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unidentified glycolipid. Both of the isolates contained C15 : 0 anteiso and C17 : 0 anteiso as the major fatty acids. Strain YMB-B2T also had C16 : 0 iso as an additional major fatty acid. The 16S rRNA gene phylogeny showed that the novel strains formed two distinct sublines within the genus Microbacterium. Strain YMB-B2T was most closely related to the type strains of Microbacterium aerolatum (99.1 % sequence similarity) and Microbacterium ginsengiterrae (99.0 %), whereas strain BWT-G7T formed a tight cluster with the type strain of Microbacterium thalassium (98.9 %). The phylogenomic analysis based on 92 core genes supported their relationships in 16S rRNA gene phylogeny. Overall genomic relatedness indices warranted that the isolates represent two new species of the genus Microbacterium. Based on the results obtained here, Microbacterium tenebrionis sp. nov. (type strain YMB-B2T=KCTC 49593T=CCM 9151T) and Microbacterium allomyrinae sp. nov. (type strain BWT-G7T=KACC 22262T=NBRC 115127T) are proposed.

Actinomadura terrae sp. nov. and Actinomadura litoris OS3-89, isolated from rhizosphere soil of cactus.

Two mycelium-forming actinobacterial strains, designated OS3-83 T and OS3-89, were isolated from rhizosphere soil of a cactus (Opuntia ficus-indica) sampled on Mara Island, Jeju, Republic of Korea. Both of the isolates were found to grow at 20-37 °C, pH 6.0-10.0 and with 0-2 % (w/v) NaCl. Their taxonomic positions were investigated by a polyphasic approach. Strains OS3-83T and OS3-89 were most closely related to the type strain of Actinomadura litoris (99.5 % and 98.9 % 16S rRNA gene sequence similarity, respectively). Both of the isolates shared 99.2 % sequence similarity to each other. Morphological and chemotaxonomic characteristics supported the affiliation of the two isolates to the genus Actinomadura. 16S rRNA gene phylogeny exhibited that strain OS3-83T formed a tight cluster with A. litoris, while strain OS3-89 occupied a position located remotely from A. litoris. Nevertheless, phylogenomic analysis based on 92 core gene sequences showed that both of the isolates formed a tight clade with A. litoris. The values of average nucleotide identity and digital DNA-DNA hybridization between strain OS3-83T and the closest relative, A. litoris, were 92.2 and 46.2 %, respectively, whereas strain OS3-89 shared an average nucleotide identity value of 97.5 % and a digital DNA-DNA hybridization value of 76.9 % with A. litoris. These results strongly suggested that strain OS3-83T (=KACC 19752T=NBRC 114688T) represents a novel species and strain OS3-89 (=KACC 19753=NBRC 114400) is a strain of A. litoris. On the basis of the data obtained here, strain OS3-83T is considered to represent a new species of the genus Actinomadura, for which the name Actinomadura terrae sp. nov. is proposed.

Four new Microbacterium species isolated from seaweeds and reclassification of five Microbacterium species with a proposal of Paramicrobacterium gen. nov. under a genome-based framework of the genus Microbacterium.

The taxonomic relationships of 10 strains isolated from seaweeds collected from two beaches in Republic of Korea were studied by sequencing and analyses of 16S rRNA genes and whole genomes. For the construction of a more reliable and robust 16S rRNA gene phylogeny, the authentic and nearly complete 16S rRNA gene sequences of all the Microbacterium type strains were selected through pairwise comparison of the sequences contained in several public databases including the List of Prokaryotic names with Standing in Nomenclature (LPSN). The clustering of the ten study strains into five distinct groups was apparent in this single gene-based phylogenetic tree. In addition, the 16S rRNA gene sequences of a few type strains were shown to be incorrectly listed in LPSN. An overall phylogenomic clustering of the genus Microbacterium was performed with a total of 113 genomes by core genome analysis. As a result, nine major (≥ three type strains) and eight minor (two type strains) clusters were defined mostly at gene support index of 92 and mean intra-cluster OrthoANIu of >80.00%. All of the study strains were assigned to a Microbacterium liquefaciens clade and distributed further into four subclusters in the core genome-based phylogenetic tree. In vitro phenotypic assays for physiological, biochemical, and chemotaxonomic characteristics were also carried out with the ten study strains and seven closely related type strains. Comparison of the overall genomic relatedness indices (OGRI) including OrthoANIu and digital DNA-DNA hybridization supported that the study strains constituted four new species of the genus Microbacterium. In addition, some Microbacterium type strains were reclassified as members of preexisting species. Moreover, some of them were embedded in a new genus of the family Microbacteriaceae based on their distinct separation in the core genome-based phylogenetic tree and amino acid identity matrices. Based on the results here, four new species, namely, Microbacterium aurugineum sp. nov., Microbacterium croceum sp. nov., Microbacterium galbinum sp. nov., and Microbacterium sufflavum sp. nov., are described, along with the proposal of Paramicrobacterium gen. nov. containing five reclassified Microbacterium species from the "Microbacterium agarici clade", with Paramicrobacterium agarici gen. nov., comb. nov. as the type species.

Aeromicrobium stalagmiti sp. nov., isolated from a lava cave.

A Gram-reaction-positive, strictly aerobic, non-sporulating, non-motile, rod-shaped bacterium, designated YC3-14T, was isolated from pieces of stalagmite collected in a lava cave in Jeju, Republic of Korea. Cells showed growth at 15-35 °C, pH 6.0-9.0 and with 0-3 % (w/v) NaCl. Colonies of the cells were circular, smooth, convex and cream in colour. A 16S rRNA gene-based neighbour-joining tree indicated that the organism belonged to the genus Aeromicrobium and formed a sublineage between an Aeromicrobium endophyticum-Aeromicrobium fastidiosum cluster and an Aeromicrobium yanjiei-Aeromicrobium chenweiae cluster. The highest 16S rRNA gene similarity values of strain YC3-14T were with the type strains of A. yanjiei (99.2 %), A. endophyticum (99.1 %), A. fastidiosum (98.8 %), A. ginsengisoli (98.8 %) and A. chenweiae (98.7 %). The cell-wall peptidoglycan contained ll-diaminopimelic acid as the diagnostic diamino acid. The major menaquinone was MK-9(H4). The predominant fatty acids were C18 : 0.10-methyl, C18 : 1 ω9c and C16 : 0. The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, an unidentified phospholipid and two unidentified lipids. The G+C content of the genome DNA was 69.9 mol%. These chemotaxonomic features of the isolate were typical for the genus Aeromicrobium. The genome-based phylogeny showed the same tree topology as the 16S rRNA gene phylogeny. The average nucleotide identity (≤84.5 %) and digital DNA-DNA hybridization (≤27.5 %) values supported that the isolate belongs to a novel species of the genus Aeromicrobium. On the basis of data obtained by a polyphasic approach, strain YC3-14T (=KCTC 49469T=NBRC 114653T) represents a novel species of the genus Aeromicrobium, for which the name Aeromicrobium stalagmiti sp. nov. is proposed.

Vagococcus allomyrinae sp. nov. and Enterococcus larvae sp. nov., isolated from larvae of Allomyrina dichotoma.

The taxonomic positions of two novel strains isolated from larvae of an insect (Allomyrina dichotoma) collected in Jeju, Republic of Korea, were determined by a polyphasic approach. Strain BWB3-3T was closely related to the type strain of Vagococcus salmoninarum, having 97.2 % 16S rRNA gene sequence similarity, whereas strain BWM-S5T formed an independent cluster within the genus Enterococcus in the 16S rRNA gene phylogeny and the closest relative was the type strain of Enterococcus canis (98.1 % sequence similarity). The core gene analysis supported the phylogenetic positions of the isolates revealed by 16S rRNA gene phylogeny. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain BWB3-3T and the type strain of V. salmoninarum were 73.2 and 20.0 %, respectively, whereas strain BWM-S5 T showed an ANI value of 70.9 % with the type strain of Enterococcus canis. The dDDH values between strain BWM-S5T and all the type strains of Enterococcus species were ≤25.1 %. On the basis of the results obtained here, the two isolates are considered to constitute two novel species of the family Enterococcaceae, for which the names Vagococcus allomyrineae sp. nov. and Enterococcus larvae sp. nov. are proposed, with the type strains BWB3-3T (=KCTC 43277T=CCM 9080T) and BWM-S5T (=KACC 22156T=CCM 9075T), respectively.

Tenebrionicola larvae gen. nov., sp. nov., isolated from larvae of mealworm Tenebrio molitor L., and a proposal to transfer Erwinia teleogrylli Liu et al. 2016 to a new genus Entomohabitans as Entomohabitans teleogrylli comb. nov.

Two enterobacterial strains, designated YMB-R21T and YMB-R22, were isolated from larvae of mealworm Tenebrio molitor L. and examined for their taxonomic characteristics. A 16S rRNA gene-based neighbour-joining tree showed that the two isolates formed two distinct sublineages within the family Enterobacteriaceae and were separated from other genera of the family. The isolates showed 16S rRNA gene sequence similarity of 98.9 % to each other and ≤96.5 % to members of the order Enterobacteriales. The phylogenomic analysis based on 92 singly-copy core genes showed that the two isolates belonged to the family Enterobacteriaceae and formed a distinct sublineage at a position located remotely from the genera of the family. The loosely associated members were the type strain of Erwinia teleogrylli and members of the genus Shimwellia. Average nucleotide identity and digital DNA-DNA hybridization values showed that the isolates represented members of a novel species in the family Enterobacteriaceae. The values of amino acid identity between the two isolates and the closest relatives were 74.5-75.0 % with the type strain of E. teleogrylli and 74.5-74.8 % with the type strains of two Shimwellia species, while E. teleogrylli showed the amino acid identity values of 76.3-76.5 % with two Shimwellia species. Based on the results obtained here, we propose a new genus Tenebrionicola with the description of Tenebrionicola larvae sp. nov. (type strain YMB-R21T=KCTC 82597T=CCM 9152T and strain YMB-R22=KCTC 82598=CCM 9153), with the transfer of Erwinia teleogrylli Liu et al. 2016 to a new genus Entomohabitans as Entomohabitans teleogrylli comb. nov. (type strain SCU-B244T=CGMCC 1.12772T=DSM 28222T=KCTC 42022T).

Antrihabitans stalagmiti sp. nov., isolated from a larva cave and a proposal to transfer Rhodococcus cavernicola Lee et al. 2020 to a new genus Spelaeibacter as Spelaeibacter cavernicola gen. nov. comb. nov.

An actinobacterial strain, designated YC3-6T, was isolated from a larva cave in Jeju, Republic of Korea. The novel isolate was found to grow at 10-30 °C, pH 5.0-10.0 and 0-4% (w/v) NaCl. The 16S rRNA gene phylogeny showed that the novel isolate formed a distinct subline within the family Nocardiaceae. Levels of 16S rRNA gene similarity indicated that the close relatives are Rhodococcus cavernicola (98.4% sequence similarity) and "Rhodococcus psychrotolerans" (98.2%) followed by Antrihabitans stalactiti (96.8%). However, the core gene-based phylogeny revealed that the novel isolate formed a tight cluster with A. stalactiti and was separated from R. cavernicola and other members of the family Nocardiaceae. The morphological and chemotaxonomic characteristics of strain YC3-6T are in line with those of the genus Antrihabitans. Strain YC3-6T showed an average nucleotide identity of 75.5% and a digital DDH of 20.3% with A. stalactiti. In addition, the core gene analysis showed that R. cavernicola formed a distinct subline between an Antrihabitans cluster and Aldersonia kunmingensis, and well separated from members of the genus Rhodococcus. The average amino acid identity values of R. cavernicola to closely related neighbours were 69.3-69.4% with members of the genus Antrihabitans and 67.3% with Ald. kunmingensis, while the POCP values ranged from 56.9 to 63.6%. On the basis of results obtained here, strain YC3-6T is concluded to represent a novel species of the genus Antrihabitans, for which the name Antrihabitans stalagmiti sp. nov. (type strain, YC3-6T = KACC 19963T = DSM 107561T) is proposed. Based on overall genome relatedness and chemotaxonomic differences, it is also proposed that R. cavernicola Lee et al. 2020 be transferred to a new genus Spelaeibacter as Spelaeibacter cavernicola gen. nov., comb. nov.

Jinshanibacter allomyrinae sp. nov., isolated from larvae of Allomyrina dichotoma, proposal of Insectihabitans xujianqingii gen. nov., comb. nov. and emended descriptions of the genera Jinshanibacter, Limnobaculum and Pragia.

Taxonomic positions of four Gram-negative bacterial strains, which were isolated from larvae of two insects in Jeju, Republic of Korea, were determined by a polyphasic approach. Strains CWB-B4, CWB-B41 and CWB-B43 were recovered from larvae of Protaetia brevitarsis seulensis, whereas strain BWR-B9T was from larvae of Allomyrina dichotoma. All the isolates grew at 10-37 °C, at pH 5.0-9.0 and in the presence of 4 % (w/v) NaCl. The 16S rRNA gene phylogeny showed that the four isolates formed two distinct sublines within the order Enterobacteriales and closely associated with members of the genus Jinshanibacter. The first group represented by strain CWB-B4 formed a tight cluster with Jinshanibacter xujianqingii CF-1111T (99.3 % sequence similarity), whereas strain BWR-B9T was most closely related to Jinshanibacter zhutongyuii CF-458T (99.5 % sequence similarity). The 92 core gene analysis showed that the isolates belonged to the family Budviciaceae and supported the clustering shown in 16S rRNA gene phylogeny. The genomic DNA G+C content of the isolates was 45.2 mol%. A combination of overall genomic relatedness and phenotypic distinctness supported that three isolates from Protaetia brevitarsis seulensis are different strains of Jinshanibacter xujianqingii, whereas one isolate from Allomyrina dichotoma represents a new species of the genus Jinshanibacter. On the basis of results obtained here, Jinshanibacter allomyrinae sp. nov. (type strain BWR-B9T=KACC 22153T=NBRC 114879T) and Insectihabitans xujianqingii gen. nov., comb. nov. are proposed, with the emended descriptions of the genera Jinshanibacter, Limnobaculum and Pragia.

Rhodococcus spelaei sp. nov., isolated from a cave, and proposals that Rhodococcus biphenylivorans is a later synonym of Rhodococcus pyridinivorans, Rhodococcus qingshengii and Rhodococcus baikonurensis are later synonyms of Rhodococcus erythropolis, and Rhodococcus percolatus and Rhodococcus imtechensis are later synonyms of Rhodococcus opacus.

Two novel actinobacterial strains, designated C9-5T and C3-43, were isolated from soil samples of a cave in Jeju Island, Republic of Korea, and subjected to taxonomic study by a polyphasic approach. The organisms exhibited a typical rod-coccus developmental cycle during growth and grew at 10-30 °C, pH 5-9 and 0-3 % (w/v) NaCl. In 92 single-copy core gene sequence analysis, strain C9-5T was loosely associated with Rhodococcus tukisamuensis, albeit sharing low 16S rRNA gene sequence similarity (97.4 %). A combination of morphological and chemotaxonomic characteristics supported assignment with the genus Rhodococcus. With respect to 16S rRNA gene sequence similarity, the novel isolates showed the highest identity to the type strain of Rhodococcus subtropicus (98.7 % sequence similarity), followed by Rhodococcus olei (98.5 %) and Rhodococcus pedocola (98.4 %).The average nucleotide identity and digital DNA-DNA hybridization values between strain C9-5T and members of the genus Rhodococcus were ≤81.5 and ≤37.1 %, respectively. A set of physiological and chemotaxonomic properties together with overall genomic relatedness differentiated the novel isolates from members of the genus Rhodococcus, for which the name Rhodococcus spelaei sp. nov. is proposed. The type strain is C9-5T (=KACC 19822T=DSM 107558T). Based on genome analysis performed here, it is also proposed that Rhodococcus biphenylivorans Su et al. 2015 is a later heterotypic synonym of Rhodococcus pyridinivorans Yoon et al. 2000, Rhodococcus qingshengii Xu et al. 2007 and Rhodococcus baikonurensis Li et al. 2004 are later heterotypic synonyms of Rhodococcus erythropolis (Gray and Thornton 1928) Goodfellow and Alderson 1979 (Approved Lists 1980), and Rhodococcus percolatus Briglia et al. 1996 and Rhodococcus imtechensis Ghosh et al. 2006 are later heterotypic synonyms of Rhodococcus opacus Klatte et al. 1995.

Rahnella laticis sp. nov. and Rahnella contaminans sp. nov., and emended description of the genus Rahnella.

Taxonomic positions of six isolates, which were recovered from two different environments in Jeju, Republic of Korea, were examined by a polyphasic analysis. Cells of the isolates were Gram-reaction-negative, facultatively anaerobic, motile and rod-shaped and showed growth at 4-30 °C, pH 4.0-9.0 and with 0-6 (w/v) NaCl. In phylogenomic analysis based on 92 single-copy core genes, it was shown that the isolates belonged to the genus Rahnella and formed three distinct sublines within the genus. The isolates shared 16S rRNA gene sequence similarities of 97.9-100 % with one another. The isolates contained ubiquinone-8 was as the major isoprenoid quinone. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and an unidentified aminophospholipid. The predominant fatty acids were C16 : 0 and C17 : 0 cyclo. The G+C content of their genomic DNA was 52.8-53.1 %. Average nucleotide identity and digital DNA-DNA hybridization values supported that strains SAP-17T and Lac-M11T represented two new species of the genus Rahnella, whereas strain SAP-10 was a strain of Rahnella victoriana. Based on the results obtained here, Rahnella laticis sp. nov. (type strain SAP-17T=KCTC 72960T=NBRC 114723T=CCM 9079T) and Rahnella contaminans sp. nov. (type strain Lac-M11T=KACC 21743T=NBRC 114406T) are proposed. Also, an emended description of the genus Rahnella is given on the basis of our physiological and chemotaxonomic results.

Rouxiella aceris sp. nov., isolated from tree sap and the emended description of the genus Rouxiella.

Polyphasic taxonomic studies were performed for the seven strains, which were isolated from sap extracted from Acer pictum in Mt. Halla in Jeju, Republic of Korea. Cells of all the isolates were Gram-reaction-negative, facultatively anaerobic, short rods and contained the major isoprenoid quinone of Q-8, the predominant fatty acids of C16:0 and C17:0 cyclo and the major polar lipids including phosphatidylethanolamine, phosphatidylglycerol and an unidentified aminophospholipid. The G + C contents of the genomic DNAs were 50.6-51.3%.The 16S rRNA gene-based phylogeny exhibited that the seven isolates formed two distinct sublines within the family Yersiniaceae. In the 92 core gene analysis, strain SAP-1T formed a subline at the base of radiation of the genus Rouxiella and its assignment to the genus Rouxiella was supported by high amino acid identity values (82.0-83.4%), albeit with sharing low 16S rRNA gene identities (96.0-96.9%). The average nucleotide identity and digital DNA-DNA hybridisation values together with phenotypic differences showed that strains SAP-1T, SAP-7, SAP-8 and SAP-13 belonged to a new species of the genus Rouxiella, while strains SAP-2, SAP-3 and SAP-27 were strains of Rouxiella silvae. On the basis of data obtained here, Rouxiella aceris sp. nov. (type strain, SAP-1T = KCTC 72599T = CCM 9078T) is proposed, with the emended description of the genus Rouxiella.

Duganella aceris sp. nov., isolated from tree sap and proposal to transfer of Rugamonas aquatica and Rugamonas rivuli to the genus Duganella as Duganella aquatica comb. nov., with the emended description of the genus Rugamonas.

A Gram-reaction-negative, strictly aerobic, betaproteobacterial strain, designated SAP-35T, was isolated from sap extracted from Acer pictum in Mt. Halla in Jeju, Republic of Korea, and its taxonomic status was examined by a polyphasic approach. Cells of the organism were non-sporulating, motile rods and grew at 4-30 °C, pH 6-7 and in the absence of NaCl. 16S rRNA gene- and whole genome-based phylogenetic analyses showed that strain SAP-35T belonged to the family Oxalobacteraceae and was closely related to Rugamonas rivuli (98.9% 16S rRNA gene sequence similarity) and Rugamonas aquatica (98.4%). The phylogenomic clustering and average amino acid identity values supported that strain SAP-35T belonged to the genus Duganella and two Rugamonas species should be transferred to the genus Duganella. The major isoprenoid quinone of the isolate was Q-8. The major polar lipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and an unidentified aminophospholipid. The predominant fatty acids were summed feature 3, C16:0 and C17:0 cyclo. The G + C content of genome was 64.9%. The average nucleotide identity and dDDH values between strain SAP-35T and the members of the genera Rugamonas and Duganella were < 85.1% and < 49%, respectively. Based on the combined data presented here, strain SAP-35T (= KCTC 72227T = NBRC 113903T) represents a novel species of the genus Duganella, for which the name Duganella aceris sp. nov. is proposed. Also, Rugamonas aquatica Lu et al. (Int J Syst Evol Microbiol 70: 3328-3334, 2020) and Rugamonas aquatica Lu et al. 2020 are reclassified as Duganella aquatica comb. nov., with the emended description of the genus Rugamonas.

Hongsoonwoonella zoysiae gen. nov., sp. nov., a new member of the family Stappiaceae isolated from a tidal mudflat.

A Gram stain-negative bacterial strain, designated SY4-7T, was isolated from rhizosphere mudflat of a halophyte (Zoysia sinica) collected around Seonyu Island, Republic of Korea. Cells of the organism were strictly aerobic, non-sporulating, non-motile rods and grew at 20-42 °C, pH 6-8 and 1-6% (w/v) NaCl. The 16S rRNA gene-based phylogenetic analyses revealed that strain SY4-7T formed an independent cluster separated from the recognized genera of the family Stappiaceae, which was also supported by phylogenomic analysis-based 92-core gene sequences. The type stains of the phylogenetically closest relatives were Stappia indica (95.6% sequence similarity), Stappia stellulata (95.1%) and Roseibium hamelinense (95.1%). The isoprenoid quinone was Q-10. The polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, three unidentified aminophospholipids, an unidentified phosphoglycolipid, an unidentified aminolipid, two unidentified phospholipids and an unidentified lipid. The major cellular fatty acids are C18:1ω7c and C19:1 cyclo ω8c. The G + C content of the genomic DNA is 60.7%. Discrimination of the organism from all the recognized genera of the family Stappiaceae was apparent by the chemotaxonomic and phylogenetic features. Based on the results presented here, strain SY4-7T (= KCTC 72226T = NBRC 113902T) represents a novel species of a new genus in the family Stappiaceae, for which the name Hongsoonwoonella zoysiae sp. nov. is proposed.

Aurantiacibacter rhizosphaerae sp. nov., isolated from a rhizosphere mudflat of a halophyte and proposal to reclassify Erythrobacter suaedae Lee et al. 2019. and Erythrobacter flavus Yoon et al. 2003 as Aurantiacibacter suaedae comb. nov. and Qipengyuania flava comb. nov., respectively.

A marine alphaproteobacterium, designated as strain GH3-10T, was isolated from the rhizosphere mud of a halophyte (Suaeda japonica) collected at the seashore of Gangwha Island, Republic of Korea. The isolate was found to be Gram-stain-negative, strictly aerobic, catalase- and oxidase-positive, non-motile, short rods and produced orange-coloured colonies. The 16S rRNA gene- and whole genome-based phylogenetic analyses exhibited that strain GH3-10T belonged to the genus Aurantiacibacter and was most closely related to Aurantiacibacter atlanticus s21-N3T (98.7 % 16S rRNA gene sequence similarity) and Aurantiacibacter marinus KCTC 23554T (98.4 %). The major respiratory quinone was ubiquinone-10. The polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid and an unidentified lipid. The major fatty acids were C18 : 1 ω7c, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and C18 : 1 ω7c 10-methyl. The DNA G+C content was 61.3 mol% (by genome). Average nucleotide identity and DNA-DNA relatedness values between the isolate and its phylogenetically closest relatives, together with phenotypic distinctness warranted the taxonomic description of a new species. On the basis of data obtained by a polyphasic approach, strain GH3-10T (=KCTC 62379T=JCM 32444T) represents a novel species of the genus Aurantiacibacter, for which the name Aurantiacibacter rhizosphaerae sp. nov. is proposed. According to phylogenetic coherence based on 16S rRNA genes and core genomes, it is also proposed that Erythrobacter suaedae Lee et al. 2019. and Erythrobacter flavus Yoon et al. 2003 be transferred to Aurantiacibacter suaedae comb. nov. and Qipengyuania flava comb. nov., respectively.

Kangsaoukella pontilimi gen. nov., sp. nov., a new member of the family Rhodobacteraceae isolated from a tidal mudflat.

A strictly aerobic, Gram-stain-negative, non-motile, ovoid- and rod-shaped bacterium, designated strain GH1-50T, was isolated from a tidal mudflat sample collected from Dongmak seashore on Gangwha Island, Republic of Korea. The organism showed growth at 20-40 °C (optimum, 30 °C), pH 7-8 (optimum, pH 7) and 2-6  % (w/v) NaCl (optimum, 5 %). The pufLM genes were present but bacteriochlorophyll a was not detected. The major isoprenoid quinone was Q-10. The polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, an unidentified aminolipid and five unidentified lipids. The predominant cellular fatty acids were C18 : 1 ω7c, C18 : 1 ω7c 11-methyl and C18 : 0. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that the isolate belonged to the family Rhodobacteraceae and was loosely associated with members of the recognized genera. The closest relative was the type strain of Pseudoruegeria marinistellae (96.8 % similarity) followed by Boseongicola aestuarii (96.4 %). Other members of the family shared 16S rRNA gene similarity values below 96.0 % to the novel isolate. The DNA G+C content calculated from the draft genome sequence was 64.0 %. The average amino acid identity, average nucleotide identity and digital DNA-DNA hybridization values between genome sequences of strain GH1-50T and all the type strains of the recognized taxa compared were <70.0, <84.1 and <20.5 %, respectively. Based on data obtained by a polyphasic approach, strain GH1-50T (=KCTC 72224T=NBRC 113929T) represents a novel species of a new genus in the family Rhodobacteraceae, for which the name Kangsaoukella pontilimi gen. nov., sp. nov. is proposed.