Effect of Temperature on Gene Expression of Escherichia marmotae

Increased temperature is one of the first environmental cues encountered by bacteria upon entering a mammalian host. Here, we investigated the effects of temperature on the transcriptome and proteome of Escherichia marmotae and E. coli. Previous studies demonstrated that temperature affects motility in E. marmotae; therefore, we examined how temperature alters gene expression at 37 {degrees}C versus 28 {degrees}C and whether this response is conserved in E. coli. Strains were grown under static conditions at both temperatures, and gene expression and protein abundance were assessed by RNA transcriptome analysis and global proteomics. Temperature altered the expression of 111 genes (2.7%) in E. marmotae and 99 genes (2.5%) in E. coli (adjusted p < 0.05, [&ge;]2-fold change), with changes concentrated within specific functional pathways. In E. marmotae, flagellar and chemotaxis genes and operons involved in cellulose-dependent biofilm formation and nitrate respiration were markedly downregulated at 37 {degrees}C. In contrast, genes associated with fimbrial adhesion and immune evasion, including fimA/fimB, ompT, and prophage-associated loci, were upregulated. Proteomic analysis corroborated these trends, showing reduced flagellar and chemotaxis proteins and increased stress-adaptation and host-interaction proteins. E. coli showed a distinct response, with stronger enrichment of metabolic and amino-acid biosynthesis pathways and minimal changes in motility regulation. Together, these findings demonstrate that E. marmotae motility is temperature-dependent and may represent a mechanism for immune evasion within the host.