## Results and Discussion
### Genomic Comparison of Arthrobacter sp. Strain SRS-W-1-2016  
To further infer the evolutionary relatedness of strain SRS-W-1-2016 with close phylogenetic relatives, we ran the EDGAR analysis shown in Figure 7. This revealed that strain SRS-W-1-2016 harbors 1159 distinct genes that are not shared between the other four _Arthrobacter_ species. Moreover, several distinctive genes, shown in parentheses, were also identified for each of the analyzed species: _Penaarthrobacter aurescens_ TC1 (766); _A. cupressi_ strain CGMCC1 (528); _A. globiformis_ strain NBRC 1237 (841); and _Pseudoarthrobacter phenanthrenivorans_ strain SWC37 (535), respectively. Notably, the SRS-W-1-2016--encoded distinct genes constituted approximately 26.7% of its total genome size, with much of this genome found to encode metal resistance proteins (e.g., for cadmium, cobalt, and zinc), transporter proteins, stress proteins, cytochromes, and drug resistance, respectively (Table 2). This comparative genomics analysis confirms the strong catabolic and bioremediation potential possessed by strain SRS-W-1-2016. Figure 6: Shown are the putative genomic islands (GEIs) of _Arthrobacter_ sp. strain SRS-W-1-2016. The outer green circle represents the scale line in Mbps and GEIs obtained from each of the following methods are shown in color: SIGI-HMM (orange), IslandPath-DIMOB (blue), and integrated detection (red), respectively. Further comparative genomic analysis to identify the presence of large-scale evolutionary events, such as rearrangements and inversions, was performed by the multiple alignment of strain \begin{table}
\begin{tabular}{c c} \hline \hline
**Category** & **Gene Homologue** \\ \hline \multirow{4}{*}{Transporter proteins} & Low-affinity inorganic phosphate transporter \\  & H(+)/Cl(-) exchange transporter _ClCA_ \\  & Putative inner membrane transporter _YhbE_ \\  & Divalent metal cation transporter _MntH_ \\ \hline \multirow{2}{*}{Stress proteins} & General stress protein 14 \\  & Universal stress protein/MT2085 \\ \hline \multirow{2}{*}{Cytochromes} & Cytochrome P450 107B \\  & Cytochrome bc complex cytochrome b subunit \\ \hline \multirow{4}{*}{Metal resistance proteins} & Cadmium, cobalt and zinc/H(+)-K(+) antiporter \\  & Arsenical resistance operon repressor \\  & Copper resistance protein A precursor \\  & Copper chaperone _CopZ_ \\ \hline \multirow{2}{*}{Drug resistance} & Multidrug resistance operon repressor \\  & Multidrug resistance protein \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Shown are PROKKA-annotated gene homologues that likely perform a biodegradable or metal resistance function in _Arlrbucater_ sp. strain SRS-W-1-2016. The analysis was conducted by manually querying the set of 1159 genes that were identified only in _Arthrobucater_ sp. strain SRS-W-1-2016, for desired bioremediation functions. Figure 7: Shown are the whole genome-based Venn diagrams generated between _Arthrobacter_ sp. SRS-W-1-2016 with its closest functional relatives. Venn diagram sectors belong to 1, _Phenarthrobacter aurescens_ TC1; 2, _Arthrobacter cupressi_ strain CGMCC; 3, _Arthrobacter globiformis_ strain NBRC12137; 4, _Arthrobacter_ sp. SRS-W-1-2016; and 5, _Pseudoarthrobacter phenanthrevivorans_ strain Sphe3. The number of singleton genes appear in red, green, yellow, blue, and white areas for strains 1–5 listed above, respectively -along with their core genomes (centered gray area). SRS-W-1-2016 with _Penaarthrobacter aurescens_ TC1, _A. cupressi_ strain CGMCC1, _A. globiformis_ strain NBRC 1237, and _Pseudoarthrobacter phenanthtrenivorans_ strain SWC37, which revealed the presence of several crisscrossing locally collinear blocks (LCBs), suggesting the complicated rearrangement history of strain SRS-W-1-2016 relative to related _Arthrobacter_ genomes. Regions that are inverted relative to strain SRS-W-1-2016 appear shifted below a genome's center axis (Figure 8).