Objective   Target genes of Salmonella Typhimurium sRNA SdsR were investigated to further understand the interactions between the sRNA and the target genes as well as the pathogenic mechanism of S. typhimurium.

  Method   The TargetRNA2 software was used to predict the target of sRNA SdsR in the pathogen. According to the results obtained in a previous sRNA SdsR knock-out transcriptome sequencing study, the predicted genes were annotated into GO, KEGG, and eggNOG databases for analysis. Those with high hybridization energy were further verified by RT-qPCR.

  Result   There were 29 targets predicted by TargetRNA2. Among them, hemA, STM0951, mreC, STM1252, and dcoC showed high hybridization energy with a possibility of having a continuous base to match the sRNA SdsR. They might be associated with the heme synthesis, redox process, oxaloacetate decarboxylase synthesis, and membrane components and cytoplasmic protein synthesis in S. typhimurium. The RT-qPCR showed, after sRNA SdsR knockout, hemA to be downregulated by 0.70 times and mreC 0.39 times, while STM0951, STM1252, and dcoC upregulated by 0.51, 0.35 and 1.86 times, respectively, over the wild strain 3409.

  Conclusion   It appeared that the genes identified in this study, including hemA, STM0951, mreC, STM1252 and dcoC, could directly be regulated by the sRNA SdsR and might affect the expressions of some target genes.