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A novel bacterial strain, designated 24SJ04S-52T, was isolated from bank-side soil in the Osucheon Stream of the Seomjin River, Republic of Korea. This strain is aerobic, Gram-stain-positive, and short-rod-shaped, with optimal growth observed at 30 °C, pH 7, and 0% salinity, and growth occurring across a temperature range of 15–37 °C, pH 5–9, and salinity of 0–4%. Phylogenetic analysis of the 16S rRNA gene showed that strain 24SJ04S-52T shares 98.3% sequence similarity with Oryzobacter terrae PSGM2-16T. However, the average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values were 85.0% and 50.1%, respectively, which are well below the species delineation thresholds of 95–96% for ANI and 70% for dDDH, confirming the novelty of this species. Genomic analysis identified a genome size of 3.98 Mb with a G+C content of 72.9 mol%. Functional annotation revealed various genes involved in amino acid, carbohydrate, and protein metabolism, suggesting metabolic versatility that may support adaptation to nutrient-variable environments. Chemotaxonomic analyses revealed distinctive profiles, including major fatty acids such as C17:1 ω8c, iso-C16:0, and iso-C14:0, with MK-8(H4) as the predominant menaquinone. The polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylinositol, and the peptidoglycan was of type A4γ with meso-diaminopimelic acid as the diagnostic diamino acid. These comprehensive analyses support the classification of strain 24SJ04S-52T as a novel species within the genus Oryzobacter, for which the name Oryzobacter telluris sp. nov. is proposed. The type strain is 24SJ04S-52T (=KACC 23836T = FBCC-B16192T).

A Gram-stain-negative, obligately aerobic, non-motile, rod-shaped bacterial strain designated SJW1-29T was isolated from brackish water samples collected from the Seomjin River, Republic of Korea. The purpose of this study was to characterize strain SJW1-29T and determine its taxonomic position as a potential new genus within the family Spirosomaceae. The strain grew within the range of 10–30 °C (optimum, 25 °C), pH 5.0–10.0 (optimum, 7.0), and 1–4% NaCl (optimum, 3%). Phylogenetic analysis based on the 16S rRNA gene revealed that strain SJW1-29T belongs to the family Spirosomaceae and is closely related to Persicitalea jodogahamensis Shu-9-SY12-35CT (91.3% similarity), Rhabdobacter roseus R491T (90.6%), and Arundinibacter roseus DMA-K-7aT (90.0%), while the similarities to strains within the order Cytophagales were lower than 90.0%. The genome is 7.1 Mbp with a G+C content of 50.7 mol%. The use of genome-relatedness indices confirmed that this strain belongs to a new genus. The major polar lipid profile consisted of phosphatidylethanolamine, and MK-7 was the predominant menaquinone. The predominant fatty acids were summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), iso-C15:0, iso-C17:0 3-OH, and C16:0, representing more than 80% of the total fatty acids. The phenotypic, chemotaxonomic, genetic, and phylogenetic properties suggest that strain SJW1-29T represents a novel species within a new genus in the family Spirosomaceae, for which the name Salmonirosea aquatica gen. nov., sp. nov., is proposed. The type strain of Salmonirosea aquatica is SJW1-29T (=KCTC 72493T = NBRC 114061T = FBCC-B16924T).

Phialemonium inflatum is a useful fungus known for its ability to mineralise lignin during primary metabolism and decompose polycyclic aromatic hydrocarbons (PAHs). However, no functional genetic analysis techniques have been developed yet for this fungus, specifically in terms of transformation. In this study, we applied an Agrobacterium tumefaciens-mediated transformation (ATMT) system to P. inflatum for a functional gene analysis. We generated 3689 transformants using the binary vector pSK1044, which carried either the hygromycin B phosphotransferase (hph) gene or the enhanced green fluorescent protein (eGFP) gene to label the transformants. A Southern blot analysis showed that the probability of a single copy of T-DNA insertion was approximately 50% when the co-cultivation of fungal spores and Agrobacterium tumefaciens cells was performed at 24–36 h, whereas at 48 h, it was approximately 35.5%. Therefore, when performing gene knockout using the ATMT system, the co-cultivation time was reduced to ≤36 h. The resulting transformants were mitotically stable, and a PCR analysis confirmed the genes’ integration into the transformant genome. Additionally, hph and eGFP gene expressions were confirmed via PCR amplification and fluorescence microscopy. This optimised transformation system will enable functional gene analyses to study genes of interest in P. inflatum.

We investigated the diversity of aquatic fungi from freshwater environments in Korea. From the survey of aquatic fungi, three Tetracladium (Leotiomycetes, Helotiales) strains, NNIBRFG814, NNIBRFG1997, and NNIBRFG3891, were isolated from decaying leaves of Fraxinus rhynchophylla located in Taebaek-si, Gangwon-do; freshwater foam in the freshwater of the Gam stream in Gimcheon-si; and from filtered freshwater of the Yangsan stream in Mungyeong-si, Gyeongsangbuk-do, respectively. The isolated fungal strains were identified using ITS sequence analysis and morphological characters. A sequence analysis indicated that the fungal isolates were closely related to Tetracladium breve MK371730 (100%, NNIBRFG814), Tetracladium setigerum KU519120 (98.96%, NNIBRFG1997), and T. marchalianum MK353126 (98.14%, NNIBRFG3891). In terms of growth conditions, it was confirmed that NNIBRFG814 grew best at 20 °C, did not grow above 30 °C, and grew at 5 °C as a psychrophilic fungus. NNIBRFG814 was included in the T. breve clade but its morphology was not similar to that of T. breve. Thus, NNIBRFG814 is a new species, and T. fraxineum sp. nov. NNIBRFG1997 and NNIBRFG3891 are the first records in Korea of T. setigerum and T. marchalianum, respectively.