Roseomonas rosulenta sp. nov., isolated from rice paddy soil

Area of Science:

• Microbiology
• Bacteriology
• Genomics

Background:

• The genus Roseomonas comprises Gram-negative, aerobic bacteria with limited characterized species.
• Soil environments, such as rice paddies, are rich reservoirs of microbial diversity.
• Accurate taxonomic classification of novel bacterial isolates is crucial for understanding microbial ecosystems.

Purpose of the Study:

• To characterize three novel bacterial isolates from rice paddy soil.
• To determine the phylogenetic and genomic relatedness of these isolates to known Roseomonas species.
• To formally propose a new species within the genus Roseomonas.

Main Methods:

• Isolation and cultivation of bacterial strains from rice paddy soil.
• Phylogenetic analysis using 16S rRNA gene sequencing.
• Whole-genome sequencing and analysis (genome size, G+C content, gene prediction).
• Average Nucleotide Identity (ANI) and Digital DNA-DNA Hybridization (dDDH) calculations.
• Fatty acid analysis and quinone profiling for chemotaxonomic characterization.

Main Results:

• Three Gram-negative, non-motile, coccobacilli-shaped bacterial strains (OP-27^T, OP-5, OP-30) were isolated.
• Phylogenetic analysis placed the isolates within the genus Roseomonas, closely related to *Roseomonas sediminicola* and *Roseomonas lacus*.
• Genomic data (5.2 Mb genome, 71.2% G+C content) and low ANI (81.1-83.1%) and dDDH (24.6-26.8%) values distinguished the isolates from related species.
• Distinct phenotypic and chemotaxonomic profiles (major fatty acids, predominant quinone) were observed.
• High DNA-DNA hybridization values (84-100%) among the three isolates confirmed their conspecificity.

Conclusions:

• The three isolated strains represent a novel species within the genus Roseomonas.
• The proposed name for this new species is *Roseomonas rosulenta* sp. nov.
• Strain OP-27^T is designated as the type strain for the new species.