COMPARATIVE TRANSCRIPTOME ANALYSIS BETWEEN Listeria monocytogenes WaX12 AND DELTA sigB MUTANT REVEALED BY RNA-SEQ
Listeriosis in humans and animals is caused by Listeria monocytogenes, which exist in various environments. The general environmental stress response, controlled by the alternative sigma factor, has an important role for bacterial survival. σB, encoded by sigB, contributes as a key role in adapting at different environmental stresses.
To elucidate the σB-regulated genes and their expression level directly, we compared the transcriptome of L. monocytogenes WaX12 and its delta sigB mutant by RNA-Seq technology. First, we constructed the delta sigB gene mutant of L. monocytogenes WaX12. The results of transcriptome showed the assembly formed into 3,048 unigenes referring to EGD-e genome in WaX12. We used quantitative real-time PCR verifying the expression profiles of 7 different genes, and confirmed the reliability of all the 140 regulated genes. Based on gene set enrichment analysis (GSEA) of the transcriptome data against the KEGG database, four significantly affected metabolic pathways with enrichment test p value below 0.05 were identified between WaX12-△sigB and WaX12. They included the fructose and mannose metabolism, phosphotransferase system (PTS), amino sugar and nucleotide sugar, butanoate metabolism. The fructose and mannose metabolism was the most significant difference (p<0.05) changed in metabolic pathways from KEGG. Comparative transcript analysis displayed 123 positive and 17 negative genes under control of σB.
Our findings provided the basis for future research on novel development at a molecular level in L. monocytogenes under different environments.