- Volume 74, Issue 12, 2024

Three strains of actinobacteria, designated as B-S-A6T, B-S-A8T and B-S-A12T, were isolated from soil samples collected in the Phu Pha Phet Cave located in the Satun UNESCO Global Geopark, Satun Province, Thailand. A comprehensive polyphasic approach was used to describe these strains. Strains B-S-A6T, B-S-A8T and B-S-A12T were identified within the genus Streptomyces based on a comparative examination of 16S rRNA gene sequences. Strains B-S-A8T and B-S-A12T showed a high genetic similarity to Streptomyces spectabilis NBRC 13424T (99.0%, for both) and to Streptomyces deserti C63T (98.6 and 98.7 %, respectively). Meanwhile, strain B-S-A6T exhibited 98.6% sequence similarity with S. spectabilis NBRC 13424T and Streptomyces koyangensis VK-A6 T. However, upon further comparison, the 16S rRNA gene sequence of strain B-S-A6T showed a similarity of 99.6% to B-S-A8T and 99.7% to B-S-A12T. Contrastingly, B-S-A8T showed a very high similarity of 99.8% with B-S-A12T. The use of digital DNA–DNA hybridization, along with the analysis of average nt identities and aa identities, comparing the three strains to their closest known type strains, validated that each of these strains represents a new and distinct species. Three newly identified strains exhibited phenotypic characteristics and chemotaxonomic properties consistent with the members of the genus Streptomyces. The primary menaquinones identified in these strains were MK-9(H6) and MK-9(H8). The major fatty acids were iso-C15 : 0 and anteiso-C15 : 0. Their polar lipid profiles included diphosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The comprehensive phenotypic and genomic analyses of the Streptomyces strains strongly suggest that strains B-S-A6T, B-S-A8T and B-S-A12T represent three new species for which the names Streptomyces cavernicola sp. nov. (type strain B-S-A6T =TBRC 17074T =NBRC 116118T), Streptomyces solicavernae sp. nov. (type strain B-S-A8T =TBRC 17072T =NBRC 116117T) and Streptomyces luteolus sp. nov. (type strain B-S-A12T =TBRC 17060T =NBRC 116116T) are proposed.

Two novel actinomycete strains, designated as V23-08T and V4-01T, were isolated from a foliose lichen collected in Doi Inthanon National Park, Chiang Mai Province, Thailand. Strain V23-08T showed the highest similarity (98.40%) to Amycolatopsis tolypomycina DSM 44544T. Similarly, strain V4-01T showed the highest 16S rRNA gene similarity relatedness (98.89%) to Actinacidiphila acidipaludis PLK6-54T. Chemotaxonomic analysis revealed distinct characteristics for each strain. The isomers of diaminopimelic acid were identified as meso-DAP in strain V23-08T and  ll -DAP in strain V4-01T. The predominant menaquinones were MK-9(H2) for strain V23-08T and MK-9(H6) and MK-9(H8) for strain V4-01T. Strain V23-08T contained mannose, glucose, galactose and arabinose as whole-cell sugars, with iso-C16:0 as the major fatty acid. The polar lipid profile included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, unidentified aminophospholipids, unidentified phospholipids and unidentified lipids. In contrast, strain V4-01T exhibited glucose and galactose as whole-cell sugars, with iso-C16:0, anteiso-C16:0 and C16:0 as major fatty acids, and a polar lipid composition of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The taxonomic data, supported by digital DNA–DNA hybridization and average nucleotide identity analyses, confirm that strains V23-08T and V4-01T represent novel species within the genera Amycolatopsis and Actinacidiphila, respectively. Based on these findings, the names Amycolatopsis heterodermiae sp. nov. (strain V23-08T: TBRC 16208T and NBRC 115837T) and Actinacidiphila polyblastidii sp. nov. (strain V4-01T: TBRC 16209T and NBRC 115865T) are proposed.

Two novel bifidobacteria (designated F806-1T and F814-1.1) isolated from the gut of honeybee (Apis mellifera) were characterized in the present study. 16S rRNA gene sequence analysis indicated that strains F806-1T and F814-1.1 belonged to the Bifidobacterium asteroides group and were most closely related to Bifidobacterium apousia W8102T and Bifidobacterium polysaccharolyticum W8117T, having 98.9–99.4% 16S rRNA gene sequence similarities. Strains F806-1T and F814-1.1 had the highest 16S rRNA gene sequence similarities (99.1 and 99.4 %) with B. polysaccharolyticum W8117T. Strains F806-1T and F814-1.1 had 73.2–90.5% average nucleotide identity, 21.5–40.8% digital DNA–DNA hybridization and 67.4–92.5% average amino acid identity values with type strains of all species in the B. asteroides group. Acid production from d-arabinose, l-arabinose, d-xylose, l-xylose, d-galactose, d-fructose, d-mannose and methyl-α-d-glucopyranoside; tolerance to 3% NaCl and activity of cystine arylamidase, N-acetyl-β-glucosaminidase, α-mannosidase and α-fucosidase could differentiate strains F806-1T and F814-1.1 from the type strain of B. polysaccharolyticum. Based on the data obtained in the present study, a novel species, Bifidobacterium apicola sp. nov., is proposed, and the type strain is F806-1T (=CCTCC AB 2024129T=JCM 37002T).

A novel Gram-stain-positive, black-pigmented bacterium, designated as WL48A T, was isolated from the surface of badland sedimentary rock in the Red Desert of Wyoming and characterized using a polyphasic taxonomic approach. Good growth occurred at 28–32 °C, pH 7–9, and NaCl less than 1% (w/v). Colonies, growing well on International Streptomyces Project media (ISP) 3 and ISP 7, were black and adhering to the agar. Phylogenetic analyses based on 16S rRNA gene and draft genome sequences showed that strain WL48AT belongs to the family Geodermatophilaceae, forming a distinct sub-branch with Geodermatophilus bullaregiensis DSM 46841T. The organism showed 16S rRNA gene sequence similarity of 98.8% with G. bullaregiensis DSM 46841T. Digital DNA–DNA hybridization value between the genome sequences of strain WL48A T and G. bullaregiensis DSM 46841T was 51.8%, below the threshold of 70% for prokaryotic species delineation. The chemotaxonomic investigation revealed the presence of galactose, glucose, mannose, xylose and ribose as well as meso-DAP in the peptidoglycan layer. The polar lipid profiles contained phosphatidylcholine (PC), phosphatidylinositol (PI), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE) phosphoglycolipid, phospholipids and an unidentified lipid. The menaquinone profile consisted of MK-9(H4) (98.2%) and MK-9(H2) (10.8%). The major fatty acid profile (>15%) comprised iso-C15 : 0 and iso-C16 : 0. Based on phenotypic, genetic and genomic data, strain WL48AT (=DSM 116197T = NCIMB 15483T=NCCB 100957T =ATCC TSD-376T) merits to be considered as a novel species for which the name Geodermatophilus maliterrae sp. nov. is proposed.

Two mycelium-forming actinobacterial strains, designated as DLS-47 and DLS-62T, were isolated from volcanic ash collected from the surface of a rock on the peak of Darangshi Oreum (a volcanic cone) in Jeju, Republic of Korea, and their taxonomic positions were investigated by a polyphasic approach. Both of the isolates showed growth at 20–42 °C, pH 6.0–9.0 and 0–1% (w/v) NaCl. Furthermore, DLS-47 was found to grow at 45 °C, while strain DLS-62T grew at pH 10.0 and 3% (w/v) NaCl. The 16S rRNA gene-based phylogeny showed that both of the isolates belonged to the genus Actinomadura; strain DLS-47 was most closely related to Actinomadura chokoriensis DSM 45346T (100% sequence identity), while strain DLS-62T formed a tight cluster with Actinomadura bangladeshensis DSM 45347T (99.5% sequence similarity). Morphological and chemotaxonomic characteristics supported the affiliation of the two isolates to the genus Actinomadura. Phylogenomic analysis based on 92 core gene sequences showed that both of the isolates were most closely related to A. chokoriensis DSM 45346T. Strain DLS-47 shared 100% of orthologous average nucleotide identity and digital DNA–DNA hybridization values with A. chokoriensis DSM 45346T, while strain DLS-62T showed orthologous average nucleotide identity ≤89.8% and digital DNA–DNA hybridization values ≤39.4% with strain DLS-47 and members of the genus Actinomadura. The results of phenotypic assays and comparison of overall genomic relatedness indices support the conclusion that strain DLS-47 (= KACC 23347=DSM 116423) is a strain of A. chokoriensis, while strain DLS-62T (= KACC 23345T = DSM 116424T) represents a new species of the genus Actinomadura, for which the name Actinomadura monticuli sp. nov. is proposed. Also, Actinomadura glauciflava Lu et al. 2003 is reclassified as a later heterotypic synonym of Actinomadura luteofluorescens (Shinobu 1962) Preobrazhenskaya et al. 1975 (Approved Lists 1980) based on analysis of overall genomic relatedness indices and phenotypic similarity.

A hydrogenotrophic methanoarchaeon, designated strain FWC-SCC4T, was isolated from cold seep sediment of Four-Way Closure Ridge, offshore southwestern Taiwan. Strain FWC-SCC4Tutilizes H2/CO2 or formate, but not acetate, secondary alcohols, methylamines, methanol or ethanol for growth and methane production. Yeast extract is required for growth. The cell morphology is coccoid, with a diameter of 0.8–1.2 µm, and the cell envelope is composed of S-layer protein with Mr about 137.00 kDa. Cells possess multiple flagella and usually occur singly. Strain FWC-SCC4T grows at a temperature range of 20–40 °C (optimum 37 °C) and a pH range of 5.4–7.2 (optimum 7.0). The NaCl range for growth is 0–0.86 M (optimum 0.09 M). The result of phylogenetic analysis of 16S rRNA gene sequences indicates that the most closely related species are Methanoplanus limicola M3T and Methanoplanus endosymbiosus MC1T, with similarities of 95.95 and 95.63%, respectively. The G+C content of the genomic DNA is 40.3 mol%. The overall genome-relatedness indexes (OGRIs) and concatenated ribosomal protein (RBP) phylogenic analysis indicate that strain FWC-SCC4T is a novel lineage of Methanomicrobiaceae. In addition to strain FWC-SCC4T, the differences between Methanomicrobium antiquum MobHT and Methanomicrobium mobile BPT demonstrated by comparative analysis of genomic G+C content and phylogenetic analysis with non-type strain genomes are enough to support the establishment of a novel genus. In conclusion, strain FWC-SCC4T (BCRC AR10058T= NBRC 114595T) is proposed as the type strain of Methanochimaera problematica gen. nov., sp. nov., and Methanoeremita antiquus gen. nov., comb. nov. is proposed as the new name for Methanomicrobium antiquum MobHT (=DSM 21220T= NBRC 104160T).

Sphingobacterium, as the type genus of the family Sphingobacteriaceae, comprises a diverse array of species found in various environments. In this study, we aim to reassess and elucidate the taxonomic relationships of Sphingobacterium species. Based on 16S rRNA gene sequences, the phylogeny of 70 validly published Sphingobacterium species was reconstructed. Of which, 50 species with available genomes were further subjected to overall genome relatedness indices (OGRI) analysis, resulting in the identification of distinct pairs of closely related species. One such pair, consisting of the type strains of Sphingobacterium soli and Sphingobacterium cellulitidis, exhibited an average nucleotide identity (ANI) of 97.7%, a digital DNA–DNA hybridization (dDDH) of 80.1% and an average amino acid identity (AAI) of 98.3%, alongside a 16S rRNA gene sequence similarity of 99.8%. Based on the phylogenetic, OGRI and phenotypical evidence, we propose S. soli as a later heterotypic synonym of S. cellulitidis. Additionally, another pair of type strains, Sphingobacterium siyangense and Sphingobacterium cladoniae, possessed ANI, dDDH, AAI and 16S rRNA gene sequence similarity values of 96.3, 70.1, 96.0 and 99.0%, respectively. These values, together with differences in phenotypic traits, support the proposal of two subspecies within this taxonomic lineage. Thus, we propose the establishment of two new subspecies, S. siyangense subsp. siyangense subsp. nov. and S. siyangense subsp. cladoniae subsp. nov.

A Gram-stain-negative, non-spore-forming, rod-shaped, obligately anaerobic bacterium, designated strain BP47G, was isolated from the hindgut of a silver drummer (Kyphosus sydneyanus) fish collected from the Hauraki Gulf, New Zealand. Phylogenetic analysis based on the 16S rRNA gene sequence of the isolate indicated that it belonged to the family Oscillospiraceae in the phylum Bacillota. The gene sequence of BP47G was most similar to Oscillibacter valericigenes with 95.23% sequence identity. Isolate BP47G grew on agar medium containing mannitol and fish gut fluid as the sole carbon sources. Clear colonies of ~1 mm diameter grew within a week at 20–28 °C (optimum 28 °C) and pH 7.1–8.5 (optimum 8.5). BP47G tolerated the addition to the medium of up to 1% NaCl. Formate and butyrate were the major fermentation products. The major cellular fatty acids were C12:0, C13:0, iso-C14:0, C16:0 and C16:1 cis 7. Genomic analyses comparing BP47G with its closest relatives indicated low genomic relatedness based on the average nucleotide identity, average amino acid identity, percentage of conserved protein and in silico DNA–DNA hybridization. Supported by the phenotypic and taxonomic characteristics observed in this study, a novel genus and species Bengtsoniella intestinalis gen. nov., sp. nov. is proposed for isolate BP47G (=ICMP 24688=JCM 35770).

Three Gram-stain-positive aerobic bacteria, characterized by branched mycelia with putative sporangia, were isolated from forest soil inside a decayed bamboo stem from a geothermal area in West Java, Indonesia. The strain S3.2.2.5T grew at 15–37 °C (optimum 30 °C), at pH 5.0–7.0 (optimum 7.0) and in the presence of 0–1% NaCl (optimum 0%). Strain S3.2.2.5T was able to hydrolyse cellulose, xylan, starch and skim milk. The cell-wall sugars were composed of xylose and mannose, and the peptidoglycan hydrolysates contained d-glutamic acid, glycine, d-alanine, l-alanine, β-alanine and l-ornithine. The major fatty acids (>10%) were anteiso-C17:0, iso-C17:0, C16:1 2-OH and iso-C16:1. The major polar lipids were phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, unidentified glycolipids and unidentified phospholipids. The major menaquinone was MK-9 (H2). The results of the analysis of the phylogenetic tree based on the 16S rRNA gene indicated that these three isolates belong to the genus Dictyobacter and they were most closely related to the type strain of species Dictyobacter aurantiacus S-27T (97.41–98.00%). The strain S3.2.2.5T exhibited a genome size of 9.41 Mbp, which was significantly larger than the known Dictyobacter species. The G+C content was 54.3 mol%. The average nucleotide identity (90.77%) and the digital DNA–DNA hybridization values (42.6%) between strain S3.2.2.5T and D. aurantiacus S-27T were below the threshold value for species delineation. Based on the phenotypic, chemotaxonomic and molecular characteristics of strain S3.2.2.5T, a novel species of the genus Dictyobacter, for which the name Dictyobacter halimunensis sp. nov., is proposed. The type strain is S3.2.2.5T (= UICC B-128T = CGMCC 1.61913T = KCTC 43728T).

Three Gram-negative, aerobic and non-motile bacterial strains, BT552T, BT553T and KR1UV-12T, were isolated from soil samples in Gwangju-si and Gangneung-si, the Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequence showed that strains BT552T, BT553T and KR1UV-12T clustered to a distinct clade within the family Sphingomonadaceae (order Sphingomonadales, class Alphaproteobacteria). The strains exhibited the highest genetic similarity with representatives of the genus Sphingomonas; moreover, strains BT552T and BT553T tightly clustered with Sphingomonas melonis DAPP-PG 224T (98.2 and 98.1 %) and Sphingomonas aquatilis JSS-7T (98.1 and 98.0 %), while strain KR1UV-12T clustered with S. melonis DAPP-PG 224T (97.9%) and Sphingomonas rubra BH3T (97.8%), respectively. The major cellular fatty acids of all three strains were summed feature 8 (C18:1 ω7c/C18:1 ω6c), comprising 44.7, 46.4 and 48.5%. Additionally, their respiratory quinone is Q-10, and polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phospholipids, sphingolipid and phosphatidylcholine. They all grow well at an optimum temperature of 25 °C, at pH 7. The draft genomes of strains BT552T, BT553T and KR1UV-12T measures 4 035 561 bp, 3 941 714 bp and 3 418 792 bp, respectively, comprising 3 804 3648 and 3236 coding sequences and 50, 48 and 45 RNA genes. The average nucleotide identity analysis and digital DNA–DNA hybridization values between BT552T, BT553T and KR1UV-12T and closely related Sphingomonas species range from 72.7 to 80.2% and 19.4 to 24.3%, respectively. Based on phenotypic, genotypic and chemotaxonomic data, these three strains BT552T, BT553T and KR1UV-12T represent three novel bacterial species within the genus Sphingomonas for which the names Sphingomonas longa sp. nov. (type strain BT552T= KCTC 82094T =NBRC 114993T), Sphingomonas mollis sp. nov. (type strain BT553T =KCTC 82095T =NBRC 114994T) and Sphingomonas aurea sp. nov. (type strain KR1UV-12T = KCTC 92959T = TBRC 18506T) are proposed.

Three fluorescent bacterial strains, K1, K13 and K18, were obtained from watermelon (Citrullus lanatus) foliage symptomatic of bacterial leaf spot of cucurbits in Florida. The strains underwent phenotypic characterization, including LOPAT (levan production, oxidase activity, pectolytic activity on potato, arginine dihydrolase production and hypersensitive response (HR) on both tobacco and tomato) and pathogenicity testing on watermelon and squash seedlings. Whole-genome sequencing of the isolates was performed, and multi-locus sequence analysis (MLSA) utilizing housekeeping genes gltA, rpoD, gapA and gyrB placed the isolates into two distinct clades within the Pseudomonas genus. Average nucleotide identity based on blast (ANIb) was used to compare the isolates to Pseudomonas reference genomes. Using ANIb, the closest relatives to the novel strains were identified as Pseudomonas wayambapalatensis (K1 : 82.58%; K13 : 83.77%) and Pseudomonas kilonensis (K18 : 87.16%), although ANIb values were below the 95% threshold for species delineation. DNA–DNA hybridization (genome–genome distance calculation method), comparison to the online Type Genome Server, Biolog biochemical profiling and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were also unable to identify the isolates as any known species of Pseudomonas. Based on the combination of genetic and phenotypic data, we conclude that these isolates represent two novel Pseudomonas species, for which we propose the names Pseudomonas boreofloridensis sp. nov. (K1, K13T, NCPPB 4759=LMG 33364) and Pseudomonas citrulli sp. nov. (K18T, NCPPB 4761=LMG 33365). The specific epithet boreofloridensis was chosen for the geographic location of isolation (northern Florida), while citrulli designates the host of origin (C. lanatus).

The genus Herbaspirillum comprises 13 species, the majority of which are plant colonizers. However, some species are occasionally isolated from environmental sources, including water and polluted soil, while others are opportunistic human pathogens. Four novel bacterial strains were isolated from diseased foliage of tomato and Boston fern in Florida, USA. Phylogenetic analysis based on the 16S rRNA gene sequence placed all strains into the genus Herbaspirillum. The Gram-negative strains produced opaque, creamy white, mucoid colonies, which is typical of the genus Herbaspirillum. Biolog biochemical profiling also identified those strains as members of Herbaspirillum. The strains were subjected to whole-genome sequencing, and their genomes were compared with those of reference strains of Herbaspirillum spp. using average nucleotide identity (ANI). The two strains isolated from Boston fern shared 99% pairwise ANI, as did the two strains isolated from tomato. Among all reference genomes tested, the novel strains shared the highest ANI to Herbaspirillum huttiense subsp. huttiense (G21-1742 and NC 40101, 96.76%; SE1, 97.23%; F1, 97.16%) and to H. huttiense subsp. putei. These values are above the established 95% threshold for species delineation based on ANI. As the ANI between members of the two currently described subspecies of H. huttiense, i.e. huttiense and putei, is also ~97%, it can be inferred that the two groups of novel strains described in this study should be considered as candidates for classification as two new subspecies of H. huttiense, given that the current H. huttiense subspecies also have ~97% with the fern and tomato strains. In silico DNA–DNA hybridization results were consistent with those of ANI; comparison of G21-1742 and NC 40101 with H. huttiense subsp. putei IAM 15032Tand H. huttiense subsp. huttiense LMG 2199T produced DNA–DNA hybridization (DDH) values of 66.1 and 73.6 %, respectively. Similarly, SE1 and F1 had DDH values of 68.9 and 68.8% with H. huttiense subsp. putei IAM 15032T and 77.1 and 76.7% with H. huttiense subsp. huttiense LMG 2199T, respectively. The genomes of all novel isolates carry genes involved in plant pathogenesis, including those of the type III secretion system, which are not present in other H. huttiense strains. Based on genomic and phenotypic data, we conclude that these strains represent the first phytopathogenic subspecies within H. huttiense and the names proposed are H. huttiense subsp. nephrolepidis for the two strains isolated from Nephrolepis exaltata (designated strain, G21−1742=LMG 33362=NCPPB 4765) and H. huttiense subsp. lycopersici (designated strain, SE1=LMG 3361=NCPPB 4764) for the two strains isolated from Solanum lycopersicum.

A novel Stenotrophomonas species was isolated as a contaminant in viral transport media at the District of Columbia Department of Forensic Sciences Public Health Laboratory. Phylogenomic and biochemical analyses of the isolate determined that it represented a novel species within Stenotrophomonas. Related strains in public genome databases suggested that this novel species is associated with clinically acquired infections, similar to closely related Stenotrophomonas maltophilia. The name Stenotrophomonas forensis sp. nov. is proposed. Comparative genomic and phylogenetic analyses of the S. maltophilia complex reveal that Stenotrophomonas africana is an independent species and is not a later heterotypic synonym of S. maltophilia. We also propose the transfer of two misclassified Pseudomonas species into Stenotrophomonas as Stenotrophomonas beteli comb. nov. and Stenotrophomonas hibiscicola comb. nov. The type strain for S. forensis sp. nov. is DFS-20110405T (=ATCC TSD-272T=NCTC 14893T).

A new species of bacterial predator (PP10T) was isolated from a biocrust sample taken from near Potter Cove, King George Island, Antarctica (62°14′15.62″S 58°43′15.65″W). The Bdellovibrio and like organism was vibrio-shaped and employed a single polar flagellum for motility. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that this isolate clustered within the genus Bacteriovorax in the family Bacteriovoracaceae. The 16S rRNA gene sequence similarities between isolate PP10T and the type strain (Bacteriovorax stolpii DSM 12778T) were only 97.14%. The draft genome of PP10T has a size of 4.243 Mbps, with 4148 genes and a G+C content of 38.49%. While the optimal temperature for its growth was 25 °C, PP10T was active at 4 °C, classifying it as psychrotolerant. The results of genetic and physiological tests indicated phenotypic differentiation of strain PP10T from the type strain Bx. stolpii DSM 12778T. Based on physiological and phylogenetic analyses, as well as the prey spectrum, isolate PP10 represents a novel species within the genus Bacteriovorax, for which the name Bacteriovorax antarcticus sp. nov. is proposed. The type strain is PP10T (= KCTC 8097T = DSM 116241T).

Six Pseudomonas strains isolated from muskmelon and watermelon seedlings affected by stem rot and wilting in Serbia were reported as P. cichorii based on pathogenicity, LOPAT and cell wall fatty acid analyses. Recent bacterial isolates from cucurbit crops displaying P. cichorii-like symptoms in Alabama, USA, were identified as P. capsici, prompting polyphasic re-evaluation of the Serbian strains. All six strains were found to cause severe disease in watermelon and squash seedlings under greenhouse conditions. Strains KFB 138 and KFB 140 underwent whole-genome sequencing and were found to have the highest level of 16S rRNA similarity to P. lijiangensis LJ2T (both 99.87%). Phylogenies based on housekeeping genes and core-genome analysis placed both strains into phylogroup 11 of the Pseudomonas syringae species complex, with KFB 138 forming a lineage basal to all other phylogroup 11 members. In core-genome phylogeny, KFB 140 was placed into a clade alongside P. lijiangensis LJ2T. Average nucleotide identity based on blast (ANIb) identified KFB 140 as a member of P. lijiangensis (95.85%), though KFB 138 did not produce an ANIb value over 95% to any Pseudomonas type strain to which it was compared. Values for in silico DNA–DNA hybridization for both strains were below 70% to all reference strains tested, though KFB 140 was found to be most similar to P. lijiangensis (68.2%). KFB 138 and KFB 140 were further characterized using the online Type Genome Server, biochemical profiling with the Biolog Gen III MicroPlate system, matrix-assisted laser desorption/ionization time of flight mass spectrometry and imaged with transmission electron microscopy. From the results of the above analyses, we conclude that KFB 140 is a member of the species P. lijiangensis and that KFB 138 represents a novel Pseudomonas species, for which we propose the name Pseudomonas serbiensis (KFB 138T, NCPPB 4762=LMG 33366), named for its location of isolation.

Two yeast strains, NYNU 224191 and NYNU 22411, were isolated from plant leaves of Cyclobalanopsis jenseniana and Schisandra sp. harvested from Qingyuan Mountain, Quanzhou City, Fujian Province, southeast China. Molecular phylogenetic analyses demonstrated that these two strains represent a novel species in the genus Meira. They are more closely related to M. marina, M. nashicola, M. plantarum and M. pileae than other Meira species based on phylogenetic analysis of the internal transcribed spacer (ITS) region and the D1/D2 domain of the large subunit (LSU) rRNA gene. The novel species differed from its closest relatives, M. marina, M. nashicola, M. plantarum and M. pileae, by 1.8–2% sequence divergence (11–12 substitutions and 1–2 gaps) in the D1/D2 domain and over 6.7% sequence divergence (40–60 substitutions and 53–77 gaps) in the ITS region, respectively. We propose the name Meira qingyuanensis sp. nov. (Holotype CICC 33567; Mycobank MB 855328) for the new species, which differs phenotypically from M. marina, M. plantarum and M. pileae in its ability to assimilate methyl-α-d-glucoside and the inability to assimilate salicin, and from M. nashicola in its ability to assimilate nitrate and nitrite and grow at 30 °C.

The genus Exophiala, known for its melanized, yeast-like appearance, includes a diverse group of fungi with significant implications across various fields. An isolate representing a novel species was identified within this genus from a ginger tuber from India, based on morphological characteristics and molecular phylogenetic analysis. Phylogenetic analysis of the D1/D2 domain of the 26S LSU rRNA gene, SSU rRNA gene and the internal transcribed spacer (ITS) region confirmed this strain as a new species. It was named Exophiala zingiberis sp. nov. (MycoBank no. MB 855415), with MCC 9960T designated as the holotype and PYCC 9834 as the isotype. Exophiala zingiberis was positioned as a sister species to a clade that includes Exophiala castellanii, Exophiala mali and three additional species. Phylogenetic analysis indicates that while E. zingiberis shares a common ancestor with these species, it is genetically distinct, underscoring its novel status. The type strain of this novel species differs from Exophiala yuxiensis YMF1.07354T, the most closely related species, by 19 nucleotide substitutions (3.6% sequence variation) in the D1/D2 region (549 bp compared) and 104 nucleotide substitutions and 44 gaps (27.1% sequence variation) in the ITS region (546 bp compared).

An obligately anaerobic, Gram-stain-negative, non-spore-forming and non-motile rod (strain LPYR103-PreT) was isolated from a two-phase methane fermentation system. Using 16S rRNA gene sequence-based phylogenetic analysis, strain LPYR103-PreT was classified in the genus Segatella. The 16S rRNA gene sequence similarity, average nucleotide identity and digital DNA–DNA hybridization between strain LPYR103-PreT and its phylogenetically nearest species – Segatella cerevisiae JCM 30867T – were 94.4, 77.9 and 23.4%, respectively. The genome size of strain LPYR103-PreT was 3 326 733 bp, and its genomic DNA G+C content was 44.05%. The most abundant cellular fatty acid was anteiso-C15 : 0. The growth of strain LPYR103-PreT was stimulated by the addition of pectin, d-galacturonate and d-glucuronate; in contrast, the strain exhibited poor growth in the presence of common sugars, such as glucose. Therefore, strain LPYR103-PreT was classified as a pectinophile – a bacterium that shows a preference for pectin and a few related compounds as substrates. Glucose is degraded by type strains of 12 species belonging to the genus Segatella; thus, strain LPYR103-PreT is the first described pectinophile belonging to this genus. Strain LPYR103-PreT produced succinate and acetate as its major metabolic end products. Based on the differences in the phylogenetic, genomic, physiological and chemotaxonomic characteristics of strain LPYR103-PreT and related species, the name Segatella asaccharophila sp. nov. is proposed to accommodate strain LPYR103-PreT (= NRIC 0997T = JCM 37351T=DSM 118531T = KCTC 25923T).