Parachitinimonas caeni gen. nov., sp. nov., a novel member of family Burkholderiaceae isolated from activated sludge collected in Shenzhen, PR China.

A Gram-stain-negative, strictly aerobic and filamentous bacterial strain, designated as DQS-5T, was isolated from the activated sludge of a municipal sewage treatment plant in Shenzhen, PR China. Optimal growth was observed at 28 °C and pH 7.5. Catalase and oxidase activities were detected. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DQS-5T was most closely related to the genera Chitinimonas and Chitinivorax (91.0-93.4 % and 92.5 % 16S rRNA gene sequence similarity, respectively) and was close to the member of the family Burkholderiaceae. The complete genome sequence of strain DQS-5T contains 5 653 844 bp and 57.3 mol% G+C. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between the genome of strain DQS-5T and those of its close relatives were 75.9-77.2, 19.0-20.3 and 57.2-61.8 %, respectively. Chemotaxonomic analysis of strain DQS-5T indicated that the sole respiratory quinone was ubiquinone-8, the predominant cellular fatty acids were C16 : 0 and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), and the major polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, aminophospholipid and aminolipid. The phylogenetic, genotypic, phenotypic and chemotaxonomic data demonstrate that strain DQS-5T represents a novel species in a novel genus within the family Burkholderiaceae, for which the name Parachitinimonas caeni gen. nov., sp. nov., is proposed. Strain DQS-5T (=KCTC 92788T=CCTCC AB 2022320T) is the type and only strain of P. caeni.

Aquibaculum arenosum gen. nov., sp. nov., a novel member of the family Rhodovibrionaceae, isolated from sea sand.

A Gram-negative, non-motile, and creamy-white coloured bacterium, designated CAU 1616T, was isolated from sea sand collected at Ayajin Beach, Goseong-gun, Republic of Korea. The bacterium was found to grow optimally at 37 °C, pH 8.0-8.5, and with 1-5 % (w/v) NaCl. Phylogenetic analyses based on the 16S rRNA gene sequences placed strain CAU 1616T within the order Rhodospirillales. The highest 16S rRNA gene sequence similarity was to Fodinicurvata fenggangensis YIM D812T (94.1 %), Fodinicurvata sediminis YIM D82T (93.7 %), Fodinicurvata halophila BA45ALT (93.6 %) and Algihabitans albus HHTR 118T (92.3 %). Comparing strain CAU 1616T with closely related species (Fodinicurvata fenggangensis YIM D812T and Fodinicurvata sediminis YIM D82T), the average nucleotide identity based on blast+ values were 69.7-69.8 %, the average amino acid identity values were 61.3-61.4 %, and the digital DNA-DNA hybridization values were 18.4-18.5 %. The assembled draft genome of strain CAU 1616T had 29 contigs with an N50 value of 385.8 kbp, a total length of 3 490 371 bp, and a DNA G+C content of 65.1 mol%. The predominant cellular fatty acids were C18 : 1 2-OH, C19 : 0 cyclo ω8c, and summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c). The major respiratory quinone was Q-10. Based on phenotypic, phylogenetic, and chemotaxonomic evidence, strain CAU 1616T represents a novel genus in the family Rhodovibrionaceae, for which the name Aquibaculum arenosum gen. nov., sp. nov. is proposed. The type strain is CAU 1616T (=KCTC 82428T=MCCC 1K06089T).

Characterization and comparative genomic analysis of a marine Bacillus phage reveal a novel viral genus.

Bacillus pumilus exhibits substantial economic significance, with its metabolism, adaptability, and ecological functions regulated by its bacteriophages. Here, we isolated and characterized a novel temperate phage vB_BpuM-ZY1 from B. pumilus derived from mangrove sediments by mitomycin C induction. Phage vB_BpuM-ZY1 is a typical myophage, which has an icosahedral head with a diameter of 43.34 ± 2.14 nm and a long contractible tail with a length of 238.58 ± 5.18 nm. Genomic analysis indicated that vB_BpuM-ZY1 encodes genes for lysogeny control, and its life cycle may be intricately regulated by multiple mechanisms. vB_BpuM-ZY1 was predicted to employ P2-like 5'-extended-cos packaging strategy. In addition, genome-wide phylogenetic tree and proteome tree analyses indicated that vB_BpuM-ZY1 belongs to the Peduoviridae family but forms a separate branch at a deeper taxonomic level. Particularly, the comparative genomic analysis showed that vB_BpuM-ZY1 has less than 70% intergenomic similarities with its most similar phages. Thus, we propose that vB_BpuM-ZY1 is a novel Bacillus phage belonging to a new genus under the Peduoviridae family. The protein-sharing network analysis identified 44 vB_BpuM-ZY1-related phages. Interestingly, these evolutionarily related myophages infect a broad range of hosts across different phyla, which may be explained by the high structural variations of the host recognition domain in their central spike proteins. Collectively, our study will contribute to our understanding of Bacillus phage diversity and Bacillus-phage interactions, as well as provide essential knowledge for the industrial application of B. pumilus. IMPORTANCE: Although recent metagenomics research has obtained a wealth of phage genetic information, much of it is considered "dark matter" because of the lack of similarity with known sequences in the database. Therefore, the isolation and characterization of novel phages will help to interpret the vast unknown viral metagenome data and improve our understanding of phage diversity and phage-host interactions. Bacillus pumilus shows high economic relevance due to its wide applications in biotechnology, industry, biopharma, and environmental sectors. Since phages influence the abundance, metabolism, evolution, fitness, and ecological functions of bacteria through complex interactions, the significance of isolation and characterization of novel phages infecting B. pumilus is apparent. In this study, we isolated and characterized a B. pumilus phage belonging to a novel viral genus, which provides essential knowledge for phage biology as well as the industrial application of B. pumilus.

Functional Plasticity, Redundancy, and Specificity of Lanosterol 14α-Demethylase in Regulating the Sensitivity to DMIs in Calonectria ilicicola.

Cytochrome P450 sterol 14α-demethylase (CYP51) is a key enzyme involved in the sterol biosynthesis pathway and serves as a target for sterol demethylation inhibitors (DMIs). In this study, the 3D structures of three CPY51 paralogues from Calonectria ilicicola (C. ilicicola) were first modeled by AlphaFold2, and molecular docking results showed that CiCYP51A, CiCYP51B, or CiCYP51C proteins individually possessed two active pockets that interacted with DMIs. Our results showed that the three paralogues play important roles in development, pathogenicity, and sensitivity to DMI fungicides. Specifically, CiCYP51A primarily contributed to cell wall integrity maintenance and tolerance to abiotic stresses, and CiCYP51B was implicated in sexual reproduction and virulence, while CiCYP51C exerted negative regulatory effects on sterol 14α-demethylase activity within the ergosterol biosynthetic pathway, revealing its genus-specific function in C. ilicicola. These findings provide valuable insights into developing rational strategies for controlling soybean red crown rot caused by C. ilicicola.