Planococcus halotolerans sp. nov., isolated from a saline soil sample in China

Area of Science:

• Microbiology
• Bacterial Taxonomy
• Environmental Microbiology

Background:

• Saline soils are unique environments harboring diverse microbial communities.
• Understanding bacterial diversity in extreme environments is crucial for ecological studies.
• The genus Planococcus comprises Gram-positive bacteria with various environmental adaptations.

Purpose of the Study:

• To isolate and characterize a novel bacterial strain from a saline soil environment in China.
• To determine the taxonomic position of the novel isolate using a polyphasic approach.
• To propose a new species within the genus Planococcus based on genotypic, phenotypic, and chemotaxonomic data.

Main Methods:

• Isolation and cultivation of bacteria from saline soil.
• 16S rRNA gene sequencing and phylogenetic analysis.
• Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) for species delineation.
• Physiological and biochemical characterization, including growth conditions and fatty acid analysis.
• Chemotaxonomic analyses: peptidoglycan type, polar lipids, and DNA G+C content.

Main Results:

• A novel Gram-positive, orange-pigmented, coccoid/short rod bacterium, strain SCU63^T, was isolated.
• Phylogenetic analysis placed strain SCU63^T within the genus Planococcus.
• ANI and dDDH values confirmed its status as a distinct species.
• The bacterium is halotolerant (0-15% NaCl) and psychrotolerant (0-40°C), with optimal growth at 30-35°C and pH 7.0-7.5.
• Key chemotaxonomic features include MK-8/MK-7 quinones, anteiso-C15:0 as a major fatty acid, and A4α peptidoglycan.

Conclusions:

• Strain SCU63^T represents a novel species within the genus Planococcus.
• The proposed name for this new species is Planococcus halotolerans sp. nov.
• This discovery contributes to the understanding of microbial diversity in saline, cold-adapted environments.