Salmonella enterica subsp. enterica bacteria are important foodborne pathogens with major economic impact. Some isolates exhibit increased heat tolerance, a concern for food safety. Analysis of a finished-quality genome sequence of an isolate commonly used in heat resistance studies, S. enterica subsp. enterica serovar Senftenberg 775W (ATCC 43845), demonstrated an interesting observation that this strain contains not just one, but two horizontally acquired thermotolerance locus homologs. These two loci reside on a large 341.3-kbp plasmid that is similar to the well-studied IncHI2 R478 plasmid but lacks any antibiotic resistance genes found on R478 or other IncHI2 plasmids. As this historical Salmonella isolate has been in use since 1941, comparative analysis of the plasmid and of the thermotolerance loci contained on the plasmid will provide insight into the evolution of heat resistance loci as well as acquisition of resistance determinants in IncHI2 plasmids. Resources in this dataset:Resource Title: Supplementary Material. File Name: "inline-supplementary-material-1.pdf", url: https://msystems.asm.org/content/msys/2/1/e00190-16/DC1/embed/inline-supplementary-material-1.pdf The map of plasmid pSSE ATCC-43845 is shown, with the thermotolerance locus islands indicated as orange regions. Base modification signals generated by BaseModFunctions.v.2.1.R and Circos are overlaid on the plasmid map. Qmod values are height proportional to the interpulse distance ratio for each of the modified bases on the positive strand (red outmost track) and negative strand (red innermost track). Green hash marks correspond to the CAGAG motifs present on the plasmid. The map of plasmid pSSE ATCC-43845 is shown, with the thermotolerance locus islands indicated as orange regions. Base modification signals generated by BaseModFunctions v2.1.R and Circos are overlaid on the plasmid map. Qmod values are height proportional to the interpulse distance ratio for each of the modified bases on the positive strand (red outmost track) and negative strand (red innermost track). Blue hash marks correspond to the GATC motifs present on the plasmid.