Chryseobacterium cheonjiense sp. nov., isolated from forest soil

Area of Science:

• Microbiology
• Bacteriology
• Genomics

Background:

• The genus Chryseobacterium is known for its diverse roles in environmental and clinical settings.
• Accurate taxonomic classification of novel bacterial isolates is crucial for understanding microbial diversity and ecological functions.
• Previous studies have identified various Chryseobacterium species, highlighting the need for continued exploration of soil microbial communities.

Purpose of the Study:

• To characterize a novel yellow-pigmented, rod-shaped bacterium isolated from forest soil.
• To determine the phylogenetic position and taxonomic status of the isolate RJ-7-14^T within the genus Chryseobacterium.
• To propose a new species designation based on comprehensive genomic, chemotaxonomic, and phenotypic data.

Main Methods:

• Isolation and cultivation of the bacterium from forest soil samples.
• Phylogenetic analysis using 16S rRNA gene sequences.
• Whole-genome sequencing and analysis, including gene content and G+C content determination.
• Chemotaxonomic analysis of respiratory quinones, cellular fatty acids, and polar lipids.
• Phenotypic characterization, including Gram staining and pigment production.

Main Results:

• Strain RJ-7-14^T is a Gram-negative, non-motile, yellow-pigmented, rod-shaped bacterium producing flexirubin-type pigments.
• Phylogenetic analysis placed strain RJ-7-14^T within the genus Chryseobacterium, with closest relatives showing <98.2% 16S rRNA gene sequence similarity.
• Genomic analysis revealed a genome size of 4,276,416 bp with 3779 protein-coding genes. Average nucleotide identity (ANIu) and in silico DNA-DNA hybridization (dDDH) values were below established thresholds for species delineation (≤88.2% and ≤35.0%, respectively).
• Chemotaxonomic data included MK-6 as the sole respiratory quinone, major fatty acids iso-C_15:0, summed features 9 and 3, and iso-C_17:0 3-OH, with phosphatidylethanolamine (PE) as the major polar lipid.
• The DNA G+C content was determined to be 37.2 mol%.

Conclusions:

• Based on phylogenetic, genomic, chemotaxonomic, and phenotypic data, strain RJ-7-14^T represents a novel species within the genus Chryseobacterium.
• The proposed name for this new species is Chryseobacterium cheonjiense sp. nov.
• The type strain is RJ-7-14^T (KACC 21625^T = NBRC 114362^T).