RpoS-regulated SEN1538 gene promotes resistance to stress and influences Salmonella enterica serovar enteritidis virulence.
Aryashree ArunimaSunil Kumar SwainShilpa RayBirendra Kumar PrustyMrutyunjay SuarPublished in: Virulence (2021)
Salmonella enterica serovar Enteritidis (S. Enteritidis; wild type (WT)) is a major cause of foodborne illness globally. The ability of this pathogen to survive stress inside and outside the host, such as encountering antimicrobial peptides and heat stress, determines the efficiency of enteric infection. These stressors concertedly trigger virulence factors encoded on Salmonella pathogenicity islands (SPIs). Although RpoS is a well-known central transcriptional stress and virulence regulator, functional information regarding the genes of the regulon is currently limited. Here, we identified SEN1538 as a conserved RpoS-regulated gene belonging to the KGG protein superfamily. We further assessed its role in pathogenic stress responses and virulence. When SEN1538 was deleted (Δ1538), the pathogen showed reduced survival during antimicrobial peptide introduction and heat stress at 55°C compared to WT. The mutant displayed 70% reduced invasion in the HCT116 colon epithelial cell line, 5-fold attenuated phagocytic survival in RAW264.7 cells, and downregulation of several SPI-1 and SPI-2 genes encoding the three secretion system apparatus and effector proteins. Δ1538 also showed decreased virulence compared to WT, demonstrated by its reduced bacterial counts in the feces, mLN, spleen, and cecum of C57BL/6 mice. Comparative transcriptomic analysis of Δ1538 against WT revealed 111 differentially regulated genes, 103 of which were downregulated (fold change ≤ -1.5, P < 0.05). The majority of these genes were in clusters for metabolism, transporters, and pathogenesis, driving pathogenic stress responses and virulence. SEN1538 is, therefore, an important virulence determinant contributing to the resilience of S. Enteritidis to stress factors during infection.
Keyphrases
- heat stress
- escherichia coli
- pseudomonas aeruginosa
- biofilm formation
- staphylococcus aureus
- antimicrobial resistance
- genome wide identification
- transcription factor
- genome wide
- wild type
- candida albicans
- heat shock
- dna methylation
- single cell
- type diabetes
- metabolic syndrome
- stress induced
- gene expression
- genome wide analysis
- depressive symptoms
- dendritic cells
- skeletal muscle
- social support
- listeria monocytogenes
- cell proliferation
- regulatory t cells
- social media
- peripheral blood
- climate change
- endoplasmic reticulum stress
- health information