Twelve isolates representing two novel Acinetobacter species were isolated from various fresh meat and meat preparation samples collected from supermarkets in León, Spain. These isolates were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and GTDB-Tk software as members of the genus Acinetobacter. Phylogenomic analysis based on the core genome showed that these isolates formed two separate branches (1 including 11 isolates: ULE_I046[T], ULE_I001, ULE_I024, ULE_I037, ULE_I053, ULE_I057, ULE_I064, ULE_I068, ULE_I075, ULE_I080 and ULE_I092; and the other only one, ULE_I010[T]) separated from all known Acinetobacter species. Average nucleotide identity and digital DNA-DNA hybridization values of all isolates with closely related type strains of species of the genus Acinetobacter supported their status as new species. The names Acinetobacter legionensis sp. nov. (comprising 11 isolates) and Acinetobacter psychrotolerans sp. nov. (comprising one strain) were proposed for the two novel taxa. Additional phylogenomic and phenotypic analyses showed that strain LMG 10606 (=RUH 2236), originally assigned to Acinetobacter guillouiae, belongs to A. legionensis sp. nov. Other two strains from the original description of A. guillouiae (LUH 5606 and LUH 6980) may also represent members of A. legionensis sp. nov., as indicated by a rpoB gene phylogenetic tree analysis. The phenotypic characteristics most useful for the differentiation of the novel species described in the present study from known Acinetobacter species were the assimilation of malonate and the inability to grow on histamine and phenylacetate of A. legionensis sp. nov., and the inability of A. psychrotolerans sp. nov. to grow over 30 °C. The type strain A. legionensis ULE_I046[T] (=CECT 31169[T]=CCP 535[T]) has a genome size of 4.58 Mb and a G+C content of 37.7 mol%. The type strain A. psychrotolerans ULE_I010[T] (=CECT 31168[T]=CCP 534[T]) has a genome size of 3.56 Mb, with a G+C content of 37.2 mol%.

Strain 7D2-24[T], an alkali-tolerant bacterium isolated from coastal sediments of Jiaozhou Bay, China, belongs to the genus Planococcus. The strain was Gram-stain-positive, aerobic, motile and orange-pigmented. It was able to grow at 4-40 °C (optimum, 25-40 °C) and at pH 7.0-12.0 (optimum, pH 8.0-12.0). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 7D2-24[T] formed a lineage within the genus Planococcus with the closest phylogenetic neighbour Planococcus ruber CCTCC AB 207187[T] (98.39%). Digital DNA-DNA hybridization value and the average nt identity value of strain 7D2-24[T] with P. ruber CGMCC 1.19134[T] were 36.1 and 89.3%, respectively, falling below the species delineation thresholds of 70 and 95%. The genomic G+C content was 44.9 mol%. The predominant menaquinones were MK-7 (35.9%) and MK-8 (64.1%), and the major cellular fatty acids (>5% of the total) were anteiso-C15:0 (39.2%), anteiso-C17:0 (10.1%), iso-C16:0 (8.7%) and iso-C15:0 (5.6%). The major cellular polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphoglycolipid and three unknown lipids. Based on phenotypic, phylogenetic and genotypic data, a novel species, Planococcus alkaliphilus sp. nov., is proposed with the type strain 7D2-24[T] (=CGMCC 1.65191[T]=KCTC 43862[T]).

A Gram-staining positive, greenish-yellow, immotile, catalase-positive, oxidase-negative actinobacterium, designated strain G70[T], was isolated from the marine sediment in the Bohai Sea, China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that the strain G70[T] belongs to the genus Isoptericola, revealing 99.1% similarity to Isoptericola halotolerans YIM 70177[T], 98.7% similarity to Isoptericola chiayiensis 06182 M-1[T] and 98.2% similarity to Isoptericola salitolerans TRM F109[T]. Strain G70[T] grew at 4-45 °C (optimum 30 °C), pH 6-13 (optimum 8-9) and 0-25% (wt/v) NaCl (optimum 1%). The genome size of strain G70[T] was 3.59 Mb, with DNA G+C content of 72.6 mol%. Average nucleotide identities between strain G70[T] and I. halotolerans YIM 70177[T] and I. chiayiensis 06182 M-1[T] were 83.6 and 80.7%, respectively. The digital DNA-DNA hybridization values among I. halotolerans YIM 70177[T] and I. chiayiensis 06182 M-1[T] are 26.5 and 23.0%, respectively. The predominant fatty acids (>10%) of strain G70[T] were anteiso-C15 : 0 and C16 : 0, and the respiratory quinones were MK-9 (H4), MK-9 (H2) and MK-9. The polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, an unknown phosphoglycolipid and an unknown phospholipid. Strain G70[T] showed significant broad-spectrum antimicrobial activity against both Gram-staining-negative and Gram-staining-positive bacteria and fungi. Based on all these phenotypic, genotypic and phylogenetic results, strain G70[T] was distinguished from other species with validly published names in the genus Isoptericola and should be classified as representing a novel species, for which the name Isoptericola maris sp. nov. was proposed. The type strain is G70[T] (MCCC 1K08870[T]=KCTC 59000[T]).

Two Gram-stain-negative, rod-shaped, aerobic bacterial strains, designated 200-1SW[T] and C21-150M6[T], were isolated from seawater samples of the western Pacific Ocean. Both strains were able to grow in the presence of 1-10% NaCl, at pH 6-9 and at 10-37 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that both strains belong to the genus Pseudooceanicola, with strain 200-1SW[T] closest to Pseudooceanicola marinus CECT 7751[T] (97.6% sequence similarity) and C21-150M6[T] to Pseudooceanicola flagellatus DY470[T] (97.8%). Genome sizes were 4.77 Mb (G+C content: 67.1 mol%) for 200-1SW[T] and 4.32 Mb (G+C content: 63.4 mol%) for C21-150M6[T], with average nucleotide identity and digital DNA-DNA hybridization values with other Pseudooceanicola species below 86.5 and 32.0%, respectively. In silico genome mining identified several putative secondary metabolite biosynthetic gene clusters, suggesting that the strain possesses unexplored biosynthetic potential. Cellular fatty acid profiles identified summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C19 : 0 cyclo ω8c and C16 : 0 as the predominant fatty acids for 200-1SW[T], as well as C18 : 1 ω7c 11-methyl, C16 : 0, C18 : 0 and summed feature 8 as the major fatty acids for C21-150M6[T]. The only respiratory quinone detected was ubiquinone 10 for both strains. The major polar lipids of both strains were phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol and phosphatidylmonomethylethanolamine. Based on phenotypic, chemotaxonomic and genomic characteristics, strains 200-1SW[T] and C21-150M6[T] represent two novel species within the genus Pseudooceanicola, for which the names Pseudooceanicola aquaeponti sp. nov. and Pseudooceanicola profundi sp. nov. are proposed; the type strains are 200-1SW[T] (=MCCC 1A12849[T]=NBRC 117448[T]) and C21-150M6[T] (=MCCC M22851[T]=NBRC 117449[T]), respectively.

A novel bacterial strain, designated JK66[T], was isolated from the rhizosphere soil of diseased Cistanche plants collected in Turpan, Xinjiang, China. Strain JK66[T] grew at 20-42 °C (optimum, 37 °C), pH 5.0-10.0 (optimum, pH 7.0), and with 0-3.0% (w/v) NaCl (optimum, 2.0% (w/v)). The strain was selected for taxonomic characterization because of its antagonistic activity against Fusarium acuminatum and its potential to produce indole-3-acetic acid. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JK66[T] belongs to the genus Pseudomonas, showing the highest sequence similarity to Pseudomonas borbori R-20821[T] (98.70%), followed by Pseudomonas cuatrocienegasensis 1N[T] (98.46%), Pseudomonas segetis CIP108523[T] (98.35%), Pseudomonas marincola KMM3042[T] (98.32%) and Pseudomonas xionganensis R-22-3w-18[T] (98.15%). The DNA G+C content of strain JK66[T] was 61.63%. The average nucleotide identity and digital DNA-DNA hybridization values between strain JK66[T] and closely related type strains were 76.82-82.06% and 21.10-25.30%, respectively, which are below the threshold values for species delineation. Chemotaxonomic analyses showed that the respiratory quinone was ubiquinone Q-9. The major polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid, unidentified glycolipid, unidentified phosphoglycolipid and two unidentified lipids and the predominant fatty acids (>5%) were C12:0, C12:0 3-OH, summed feature 3, C16:0 and summed feature 8. On the basis of phenotypic, physiological, biochemical, phylogenetic and genomic evidence, strain JK66[T] represents a novel species within the genus Pseudomonas, for which the name Pseudomonas cistanchae sp. nov. is proposed. The type strain is JK66[T] (=CCTCC AB 2025123[T]=LMG 34229[T]). The GenBank accession numbers for the 16S rRNA gene sequence and the whole-genome sequence are PX795502 and JBTLWN000000000, respectively.

An ascomycetous yeast strain, designated CICC 33164, was isolated from the gut of Serrognathus titanus collected in the Baotianman Nature Reserve, Henan Province, central China. Molecular phylogenetic analyses showed that this strain is most closely related to two described species of the genus Debaryomyces, namely, Debaryomyces robertsiae and Debaryomyces udenii. Genetically, strain CICC 33164 differed from the type strains of these two species by only 4-5 (0.7-0.9%) nt substitutions in the D1/D2 domain, but by 15-17 (2.6-2.8%), 78-82 (10.4-11.5%) and 104-111 (15.4%) nt mismatches in the internal transcribed spacer region and the partial ACT1 and RPB2 genes. Physiologically, the novel strain can be distinguished from D. robertsiae and D. udenii by its ability to assimilate inulin and dl-lactate and by its inability to assimilate l-rhamnose or melezitose or to ferment glucose. Based on the combined phylogenetic and phenotypic evidence, strain CICC 33164 represents a novel species of the genus Debaryomyces, for which the name Debaryomyces henanensis sp. nov. is proposed.

A novel psychrophilic member of the phylum Actinomycetota, designated strain CPHL_1[T], was isolated from the shoreline of Cape Hallett, Antarctica. Cells were Gram-positive, aerobic, non-motile, non-spore-forming rods (0.7-1.0 µm in length) with orange to yellow pigmentation. Optimal growth occurred at 15 °C, pH 8.0, with NaCl tolerance up to 3% (w/v). Strain CPHL_1[T] exhibited cytosolic cold-active β-galactosidase activity, with an optimum at 15 °C and pH 7.0 and formed non-adherent biofilms. Phylogenetic analysis based on 16S rRNA gene sequence placed the strain within the genus Rhodoglobus, showing high similarity to Rhodoglobus vestalii LV3[T] (99.4%) and Rhodoglobus aureus CMS 81y[T] (97.6%). Chemotaxonomic characteristics, including the predominance of anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0 fatty acids, the presence of MK-11, MK-10 and MK-12 as the major respiratory quinones, and genomic G+C content of 60%, further supported its assignment to the genus Rhodoglobus. Whole-genome comparisons revealed clear taxonomic distinction, with strain CPHL_1[T] sharing 88.9% average nucleotide identity (ANI) and 38.3% digital DNA-DNA hybridization (dDDH) values with R. aureus, and 81.7% ANI and 25.1% dDDH with R. vestalii, confirming its status as a novel species. Phylogenetic analysis revealed that the β-galactosidases from these Rhodoglobus strains form a well-supported clade with high sequence similarity. Based on these data, a novel species is proposed: Rhodoglobus galactosidasius sp. nov. (type strain CPHL_1[T] =ITEM 19986[T] =KCTC 59592[T]). Genomic analyses also highlighted its biosynthetic potential for specialized metabolites, consistent with the recognized metabolic diversity of the genus.

Recent phylogenomic analyses revealed that the genus Methanobrevibacter, which consists almost exclusively of representatives from the intestinal tract of animals, is severely underclassified. Based on the large relative evolutionary divergence between individual subclades, members of the genus Methanobrevibacter have been reclassified into eight novel genera as new combinations proposed under the rules of the Code of Nomenclature of Prokaryotes Described from Sequence Data. Here, we validly publish the new names for all taxa with type strains also under the rules of the International Code of Nomenclature of Prokaryotes. This includes members of the genera Methanacia, Methanobaculum, Methanobinarius, Methanocatella and Methanoflexus. Moreover, we propose to place Methanobrevibacter acididurans, whose genome was only recently sequenced, in the new genus Methanobotrus and describe a new isolate from the gut of a cockroach as Methanomonile shimae gen. nov. sp. nov. Based on the large evolutionary distance from the remaining members of Methanobacteriaceae, we propose to reclassify all genera within the radiation of Methanobrevibacter sensu lato into their own family, Methanobrevibacteraceae fam. nov. In addition, we reclassify Methanothermobacter tenebrarum as Methanothermobaculum tenebrarum gen. nov. comb. nov. into a new family, Methanothermobaculaceae (Methanobacteriales) and provide emended descriptions for the phylum Methanobacteriota and the classes Methanobacteria and Methanococci.

Four Gram-stain-positive, aerobic, non-motile and rod-shaped bacterial strains, designated A82T, A588, A196T and A204, were isolated from soil samples collected from Marmota sibirica burrows in Hulun Buir, Nei Mongol Autonomous Region, China. All four strains grew at 4-30 °C, pH 6.0-10.0 and 0-6.5% (wt/v) NaCl, and they were positive for oxidase and catalase activities. Phylogenetic analysis of 16S rRNA gene sequences indicated that the four strains belonged to two species within the genus Microbacterium. Strains A82T and A588 exhibited the highest sequence similarity to Microbacterium profundi Shh49T (98.83%) and Microbacterium murale 1 Gi-001T (98.67%). Strains A196T and A204 were most closely related to Microbacterium aerolatum NBRC 103071T (99.10%) and Microbacterium shaanxiense CCNWSP60T (98.63%). Comparing the four isolates with their reference strains showed that average nucleotide identity and digital DNA-DNA hybridization values were below the accepted species-delineation benchmarks of 95-96 and 70%, respectively. For the type strains A82T and A196T, the DNA G+C content was 64.7 and 65.4 mol%, respectively. Chemotaxonomic analysis revealed that both type strains possessed MK-13 as the sole respiratory quinone. Additionally, diphosphatidylglycerol, phosphatidylglycerol and unidentified glycolipids were the major polar lipids. Furthermore, anteiso-C15 : 0 was identified as the major fatty acid, and the diamino acid in the cell-wall peptidoglycan contained alanine, glutamic acid, glycine, aspartic acid and ornithine. Therefore, strains A82T/A588 and A196T/A204 represent two novel species within the genus Microbacterium. Microbacterium wangyouchuni sp. nov. (A82T/A588, type strain A82T=GDMCC 1.5865T=JCM 38342T) and Microbacterium zouquanmingi sp. nov. (A196T/A204, type strain A196T=GDMCC 1.6024T=JCM 38357T) are proposed.

Two novel actinobacteria strains, designated YCB024T and YCB041T, were isolated from rhizosphere soil samples of Camellia oleifera collected from Xingning City, Guangdong Province, PR China. Both strains exhibited mycelial filaments and intertwined hyphal cells. Phylogenetic analysis revealed that strain YCB024T exhibited the highest 98.8% 16S rRNA gene similarity with Streptomyces yogyakartensis NBRC 100779T, Streptomyces javensis NBRC 100777T and Streptomyces violaceusniger NBRC 13459T, and strain YCB041T exhibited the highest 98.9% similarity with Streptomyces albospinus NBRC 13846T. The average nucleotide identities (ANI) and digital DNA-DNA hybridization (dDDH) values among the two strains and their closely related species indicated that they were clearly different from other known Streptomyces species. The draft genome sizes of the two strains were 6.9 Mbp and 9.5 Mbp with DNA G+C contents of 70.4 mol% and 71.7 mol%. The major cellular fatty acids in strain YCB024T included iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C16 : 0, and strain YCB041T included iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C16 : 0. The major polar lipids of the two strains were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside or unidentified aminophospholipid. The respiratory quinones of both strains included MK-9 (H6), MK-9 (H8) and MK-10 (H4). Based on phylogenetic analysis, ANI and dDDH values, physiological and chemical properties, strains YCB024T and YCB041T represent two novel species of the genus Streptomyces, for which the names Streptomyces xingningensis sp. nov. (type strain YCB024T=GDMCC 4.314T=JCM 36249T) and Streptomyces rhizosphaerae sp. nov. (type strain YCB041T=GDMCC 4.469T=JCM 38170T) are proposed, respectively.

Two novel aerobic, rod-shaped, motile bacterial strains, designated as sgz302134[T] and sgz301742[T], were isolated from paddy soil in Fujian Province. Strains sgz302134[T] and sgz301742[T] shared the highest 16S rRNA gene sequence similarities with the type strains Azospirillum isscasi C340-1[T] (98.2%) and Azospirillum thiophilum DSM 21654[T] (97.4%), respectively. The phylogenetic tree based on 16S rRNA gene sequences showed that two strains clustered with members of the genus Azospirillum. Growth of strains sgz302134[T] and sgz301742[T] was observed at 10-45 °C, pH 5.0-9.5 and 0-0.5% (w/v) NaCl and 15-37 °C, pH 6.0-9.0 and 0-1.0% (w/v) NaCl, respectively. Strains sgz302134[T] and sgz301742[T] contained Q-10 as the main quinone. The main fatty acids (>10%) of both strains were summed feature 2 (C12 : 0 aldehyde), summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C16 : 0. The genomic DNA G+C content of strains sgz302134[T] and sgz301742[T] was 68.4 and 68.3%, respectively. The digital DNA-DNA hybridization and average nucleotide identity values between the two strains and their related reference strains were 27.8 and 87.4% and 22.0 and 84.3%, respectively. Both strains possessed nif genes nifBDEHKN. Based on the above results, these two strains represent two novel species of the genus Azospirillum, for which the names Azospirillum mesophilum sp. nov. and Azospirillum terrae sp. nov. are proposed. The type strains are sgz302134[T] (=MCCC 1K09520[T]=KCTC 8840[T]) and sgz301742[T] (=MCCC 1K09804[T]=KCTC 18149[T]), respectively.

Three Gram-stain-negative bacterial strains, KR7-65[T], KR7-225[T] and CN5-332[T] isolated from oil-contaminated soil in Korea and China were identified. Phylogenetic analysis based on 16S rRNA gene sequences placed the strains within the family Xanthobacteraceae, with KR7-65[T] and KR7-225[T] affiliated with the genus Xanthobacter and CN5-332[T] with the genus Aquabacter. Sequence similarities to type strains of validly published species were below 98.5%. Core genome phylogeny showed that the four strains formed distinct clusters occupying different positions in the phylogenetic tree and exhibited different closest relatives. Average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization (dDDH) values between KR7-65[T] and KR7-225[T] and members of Xanthobacter were 78.7-87.0%, 74.8-87.8% and 22.7-32.3%, respectively, whereas those between CN5-332[T] and members of Aquabacter were 80.2-80.7%, 79.6-80.5% and 23.4-23.9%, supporting their assignment as novel species. The DNA G+C contents were 68.0, 69.9 and 66.5 mol% for KR7-65[T], KR7-225[T] and CN5-332[T], respectively. Strains KR7-65[T] and KR7-225[T] contained phosphatidylcholine, phosphatidylglycerol, phosphatidyl monomethyl ethanolamine, diphosphatidylglycerol (DPG) and an unidentified glycolipid as major polar lipids, whereas DPG was absent in strain CN5-332[T]. The primary fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), cyclo C19 : 0ω8c and C16 : 0. On the basis of phylogenetic, genomic and phenotypic evidence, strains KR7-65[T] and KR7-225[T] represent two novel species of the genus Xanthobacter, for which the names Xanthobacter pollutisoli sp. nov. (type strain KR7-65[T]=KACC 23453[T]=NBRC 116939[T]) and Xanthobacter luteus sp. nov. (type strain KR7-225[T]=KACC 23282[T]=NBRC 116940[T]) are proposed. Strain CN5-332[T] represents a novel species of the genus Aquabacter, for which the name Aquabacter albus sp. nov. (type strain CN5-332[T]=KACC 23276[T]=CCTCC AB 2024343[T]) is proposed.

Shouchella hunanensis DSM 23008[T] and Shouchella miscanthi AK13[T] were originally described from forest soil and the rhizosphere of Miscanthus sacchariflorus, respectively. The two strains share closely similar phenotypic properties, and their 16S rRNA gene sequences show 99.5% similarity. Phylogenetic analysis of all 16S rRNA gene copies revealed copy-dependent placements, whereas the phylogenomic analysis placed the two type strains and three additional genomes in a strongly supported, short-branched cluster. Eight 16S rRNA gene copies were identified in each genome, with detectable intragenomic heterogeneity, particularly in AK13ᵀ. Pairwise average nt identity among the two type-strain genomes and three additional publicly available genomes ranged from 99.0% to 99.3%, clearly above the accepted species boundary. The digital DNA-DNA hybridization value between strains S. hunanensis DSM 23008[T] and S. miscanthi AK13[T] was 92.5%. On the basis of the combined phylogenetic, genomic and phenotypic evidence, S. miscanthi (Shin et al. 2020) Joshi et al. 2022 is proposed as a later heterotypic synonym of S. hunanensis (Patel and Gupta 2020) Joshi et al. 2022.

Yeasts recovered from wastewater of a public hospital in Minas Gerais state, Brazil, included a single isolate representing a putative novel species. Sequence analysis of the ITS-5.8S region and the D1/D2 domains of the LSU rRNA gene placed this yeast within the genus Sungouiella, close to Sungouiella thailandica. Phylogenomic inference based on 1,849 single-copy orthologues from Sungouiella species with available genomes confirmed that strain UFMG-CM-Y7468 forms a distinct lineage with S. thailandica as its closest known relative. The name Sungouiella purgamenti sp. nov. (MycoBank MB 863665) is proposed, with CBS 19634 designated as the holotype. The isolate was able to grow at 37 °C, showed susceptibility to most antifungal agents tested, except for itraconazole with an MIC of 0.5 mg l[-1], within the dose-dependent range, and exhibited strong extracellular protease activity. However, S. purgamenti showed a genomic toolkit consistent with a stress-tolerant and environmentally versatile lifestyle, while no specific or unique virulence determinants were identified based on genome content alone.

A novel nitrogen-fixing rhizobial strain, designated Z1P35ᵀ, was isolated from root nodules of Pisum sativum grown in the Zaër region of Morocco. Phylogenetic analysis of the 16S rRNA gene placed strain Z1P35ᵀ within the genus Rhizobium, showing 100% sequence identity with several undescribed genospecies of the Rhizobium leguminosarum species complex (Rlc). Strain Z1P35ᵀ exhibited low average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values with all described Rhizobium species, but high ANI and dDDH values (97.62 and 78.8%, respectively) with Rhizobium sp. SRDI565, representing genospecies M (GsM) of the Rlc, suggesting that Z1P35ᵀ represents a novel species corresponding to GsM within this complex. FastANI screening against all Rhizobium genomes available in GenBank revealed that Z1P35ᵀ shares ANI values above the bacterial species delimitation threshold with 17 unclassified strains, which, together with Z1P35ᵀ and Rhizobium sp. SRDI565 (GsM), form a distinct lineage within the Rlc. These 17 strains originate from root nodules of diverse legume hosts and are distributed across the Mediterranean region and Australia, including representatives of the symbiovars viciae and trifolii. Phylogenomic analysis further confirms the clustering of Z1P35ᵀ with Rhizobium sp. SRDI565 (GsM) and several undescribed Rhizobium strains, forming a unique taxonomic unit clearly distinct from other members of the Rlc. Strain Z1P35ᵀ has a genome of 7.6 Mb with a G+C content of 61 mol% and carries numerous genes associated with chemotaxis, nodulation, nitrogen fixation, phosphate solubilization, iron acquisition and abiotic stress tolerance. Differentiation of Z1P35ᵀ from described Rhizobium species was further supported by phenotypic and chemotaxonomic analyses. Based on these results, we conclude that Z1P35[T] belongs to a novel species, corresponding to genospecies M within the Rlc, for which we propose the name Rhizobium zaerense sp. nov. The type strain is Z1P35ᵀ (DSM 120601ᵀ=CCMM B1365ᵀ).