## Results and Discussion
### Genome-Centric Evaluation of Strain SRS-W-1-2016  
The genome size of strain SRS-W-1-2016 was predicted to be approximately 4,564,701 bases with a G+C content of 64.1. Moreover, the strain contained a total of 4327 coding sequences, with 58 total RNA genes, 57 tRNA genes, and two copies of the 165 rRNA genes, respectively. A circular genomic map of strain SRS-W-1-2016 using the 93 contigs with an N50 contig length of 92,788 bases is shown in Figure 2.  
Further genome-centric evaluation of strain SRS-W-1-2016 revealed that out of 4318 total protein coding genes, 64.75% genes associated with clusters of orthologous groups of proteins (COGs); 74.34% genes annotated to protein coding function predictions; 24.36% genes annotated as protein coding genes with enzyme production; and 25.59% genes were connected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Note that COGs represent proteins that are an ortholog or direct evolutionary counterpart among bacterial genomes as they evolve over time. When the whole genome sequence of strain SRS-W-1-2016 was taxonomically analyzed using the One Codex RefSeq database, 52.5% of classified reads (readcount 42) clustered with _Arthobacter aurescens_ TC1, followed by 25% (readcount 20) with _Arthobacter globiformis_ NBRC 12,137, respectively (Figure 3). Two-way average nucleotide identity (ANI) between strain SRS-W-1-2016 and the closest relative _Arthobacter aurescens_ TC1 was estimated to be 80.28%, (SD: 5.24%; Supplementary Figure S1), from 3101 fragments that were included in this analysis, indicating that SRS-W-1-2016 may be a new species that is distinctly different than _Arthobacter aurescens_ TC1. Similar to the ANI, when digital DNA-DNA hybridization (dDDH) was estimated using the Genome-to-Genome Distance web service, it was estimated that strain SRS-W-1-2016 was 21.20% similar to _Arthobacter aurescens_ TC1 (data not shown). Note that according to the pipeline used, DDH? 70% (via logistic regression) would mean that the two genomes belong to the same species. Together, this is strong evidence that SRS-W-1-2016 has a unique taxonomic position relative to other members of _Arthobacter_ species for which whole genome sequence data is available. Figure 1: Shown are (**a**) growth experiments to determine the resistance abilities of _Arthobacter_ sp. strain SRS-W-1-2016 to Uranium (U) and Nickel (Ni), respectively. Growth of strain is shown in 4M media without amendments, as well as supplemented with 500 uM U, 1000 uM Ni and, and in the combination of 500 uM U and 1000 uM Ni, respectively; (**b**) shown are the measured concentrations of U and Ni over a three-day period that were spiked in microcosms containing strain SRS-W-1-2016; (**c**) histochemical plate-based growth assay to show phosphatase enzyme-based U-precipitation potential of strain SRS-W-1-2016. Bacteria that display a phosphatase-positive phenotype appear bright green on Trypose Phosphate Methyl GreenTPMG agar plate. _Arthrobacter_ species, which are members of the soil actinobacteria, are ubiquitously distributed in diverse ecological habitats, and are known for their ability to survive in extreme conditions such as UV irradiation and radioactivity [26]. Efficient molecular adaptation mechanisms in  
Figure 3: Whole genome sequence-based phyllotree of _Arthrobacter_ sp. strain SRS-W-2-2016 relative to a cohort of 24 _Arthrobacter_ spp., for which genome sequences are available. The highest taxonomic affiliation of strain was found with _Arthrobacter aurescens_ TC1 based on the highest number of whole genome sequence reads (42; shown in parenthesis) that clustered with this group. The tree was generated based on the presence of the Pfam function category amongst _Arthrobacter_ spp. available in the integrated microbial genome expert review (IMG/er) database. Displayed nodes are those with at least one read (<1% of classified reads). Figure 2: Circular genome map of _Arthrobacter_ sp.