Methylobacterium nigriterrae sp. nov., isolated from black soil

Area of Science:

• Microbiology
• Environmental Science
• Taxonomy

Background:

• The genus Methylobacterium comprises diverse Gram-negative bacteria known for their roles in various environments.
• Accurate taxonomic classification is crucial for understanding microbial diversity and ecological functions.
• Soil microbial communities harbor numerous uncharacterized species with potential biotechnological applications.

Purpose of the Study:

• To characterize a novel bacterial isolate from a black soil sample in China.
• To determine the phylogenetic and taxonomic position of the novel isolate within the genus Methylobacterium.
• To propose a new species designation based on comprehensive polyphasic analyses.

Main Methods:

• Isolation and cultivation of bacteria from black soil.
• 16S rRNA gene sequencing for phylogenetic analysis.
• Phenotypic characterization, including growth conditions and biochemical tests.
• Chemotaxonomic analyses: polar lipids, fatty acids, and respiratory quinones.
• Genomic analysis: G+C content, average nucleotide identity (ANI), and digital DNA-DNA hybridization (dDDH).

Main Results:

• A novel aerobic, Gram-negative, motile rod bacterium, strain SYSU BS000021^T, was isolated.
• Phylogenetic analysis placed the isolate within the genus Methylobacterium, with highest 16S rRNA similarity to M. segetis and M. oxalidis.
• Genomic analyses (ANI and dDDH) revealed values below thresholds for novel species delineation, supporting its distinctiveness.
• Characteristic polar lipids, major fatty acids (C18:0, C18:1 ω7c/ω6c), and Q-10 as the predominant quinone were identified.

Conclusions:

• Strain SYSU BS000021^T represents a novel species within the genus Methylobacterium.
• The proposed name for this new species is Methylobacterium nigriterrae sp. nov.
• The type strain is SYSU BS000021^T (=GDMCC 1.3814^T =KCTC 8051^T).