Arthrobacter rhizosphaerae sp. nov., isolated from wheat rhizosphere

Area of Science:

• Microbiology
• Bacteriology
• Plant-Microbe Interactions

Background:

• The genus Arthrobacter comprises diverse Gram-positive bacteria found in various environments.
• Rhizosphere microorganisms play crucial roles in plant health and nutrient cycling.
• Characterization of novel bacterial species enhances our understanding of microbial diversity and function.

Purpose of the Study:

• To isolate and characterize novel bacteria from the wheat rhizosphere.
• To determine the taxonomic position of newly isolated strains using polyphasic characterization.
• To propose a new species within the genus Arthrobacter.

Main Methods:

• Isolation of bacteria from wheat rhizosphere samples.
• 16S rRNA gene sequence analysis for phylogenetic placement.
• Genomic relatedness studies including average nucleotide identity (ANI) and genome-to-genome distance (GDD).
• Chemotaxonomic analyses: major fatty acid profiles, polar lipid composition, and menaquinone determination.
• Peptidoglycan type analysis.

Main Results:

• Three Gram-positive, aerobic, non-spore-forming strains (CCNWLXL 1-35^T, CCNWLXL 12-2, CCNWLXL 21-a) were isolated.
• Phylogenetic analysis based on 16S rRNA gene sequences indicated close relatedness to Arthrobacter globiformis.
• Genomic analyses confirmed the strains represent a single species.
• Chemotaxonomic data (major fatty acid anteiso-C_15:0, polar lipids, MK-9, peptidoglycan A4α) supported the classification within the genus Arthrobacter.

Conclusions:

• The isolated strains represent a novel species within the genus Arthrobacter.
• The proposed name for the novel species is Arthrobacter rhizosphaerae sp. nov.
• The type strain is CCNWLXL 1-35^T, with additional strains CCNWLXL 12-2 and CCNWLXL 21-a.