Deinococcus ruber sp. nov., a radiation-resistant bacterium isolated from soil

Area of Science:

• Microbiology
• Bacterial Taxonomy
• Radiation Biology

Background:

• Isolation of novel bacterial strains from environmental sources is crucial for understanding microbial diversity.
• Certain bacterial species exhibit remarkable resistance to radiation, offering insights into DNA repair mechanisms and potential biotechnological applications.

Purpose of the Study:

• To taxonomically characterize two gamma- and UVC-resistant bacterial strains, JSH3-1T and 9-2-2, isolated from garden soil.
• To determine if these strains represent a new species within the Deinococcus genus based on polyphasic taxonomic analysis.

Main Methods:

• Polyphasic taxonomic study including 16S rRNA gene sequencing, DNA-DNA reassociation, chemotaxonomic analysis (respiratory quinones, fatty acids, polar lipids), and determination of DNA G+C content.
• Phylogenetic analysis to ascertain evolutionary relationships with known Deinococcus species.

Main Results:

• Strains JSH3-1T and 9-2-2 are Gram-positive, aerobic, non-motile, spherical bacteria.
• Phylogenetic analysis showed highest 16S rRNA gene sequence similarity (94.7-94.9%) to Deinococcus radiomollis.
• High DNA reassociation (81%) between the two strains and low reassociation (<25%) with other Deinococcus species, coupled with typical Deinococcus chemotaxonomic features, supported their distinctiveness.
• DNA G+C content was determined to be 62.0-61.9 mol%.

Conclusions:

• Strains JSH3-1T and 9-2-2 are phenotypically, genotypically, and phylogenetically distinct from previously described species.
• The proposed name Deinococcus ruber sp. nov. is introduced for these two novel strains, expanding the known diversity of the Deinococcus genus.