Genome resequencing analysis of Salmonella typhimurium LT-2 strains TA98 and TA100 for the establishment of a next-generation sequencing-based mutagenicity assay.

Next-generation sequencing (NGS) is a potentially useful technology to achieve a more precise evaluation of chemical mutagenicity. To establish NGS-based mutagenicity assays, which enable the direct detection of chemically induced mutations in a whole genome manner, the selection of appropriate biological resources and their precise genome sequences are essential. Here, we performed genome re-sequencing analyses of Salmonella typhimurium LT-2 strains TA98 and TA100, which have been frequently used in mutagenicity assays. We identified several strain-specific mutations including those that were relevant to their known phenotypes (his, ΔuvrB and rfa). The details of rfa mutations were first clarified in this study, which was a frameshift variant in rfaF and a missense variant in rfaC in TA98 and TA100, respectively. The uvrB deletion in TA98 was larger than that in TA100, which suggested differences in defects of lipopolysaccharide synthesis between these strains. The re-sequenced genome data of TA98 and TA100 will help us establish NGS-based bacterial mutagenicity assays and understand the biological events seen in them. Copyright © 2017 John Wiley & Sons, Ltd.