Comparative Genomics and Phylogenomics of Novel Radiation-Resistant Bacterium Paracoccus qomolangmaensis sp. nov. S3-43T, Showing Pyrethroid Degradation

This study focused on the multifunctional characteristics and bioremediation potential of <i>Paracoccus</i> spp. A novel Gram-stain-negative, aerobic, non-motile, ellipsoidal bacterium, named <i>Paracoccus qomolangmaensis</i> S3-43^T, was isolated from moraine samples collected from the north slope of Mount Everest at an altitude of 6109 m above sea level (a.s.l.). To clarify the phylogenetic relationship of this strain within the <i>Paracoccus</i> genus and systematically characterize its features, analyses were conducted using polyphasic taxonomy and comparative genomics. Results revealed two distinct functional characteristics of strain S3-43^T: First, strain S3-43^T exhibits exceptional radiation resistance, particularly tolerance to ionizing radiation. Genome annotation indicates abundant DNA repair and antioxidant-related genes (e.g., <i>vsr</i>, <i>mutL</i>, <i>mutS</i>, <i>ruvC</i>, <i>radA</i>, <i>addA</i>, <i>recA</i>, <i>recN</i>, <i>recO</i>). Second, strain S3-43^T contained several pyrethroids degradation related genes, including cytochrome P450, monooxygenase, and aminopeptidase. The results of the genomic comparison of strain S3-43^T with related type strains also revealed differences and distribution of key genes related to stress response, environmental variables, and bioactive metabolites. Based on the results of the polyphasic taxonomic analysis, strain S3-43^T (=KCTC 8297^T = GDMCC 1.3460^T) should be classified as a novel species of the genus <i>Paracoccus</i>, designated as <i>Paracoccus qomolangmaensis</i> sp. nov.