Peptide transporter YjiY influences the expression of the virulence gene mgtC to regulate biofilm formation in Salmonella

Abstract

Formation of a biofilm is one of the coping strategies of Salmonella against antimicrobial environmental stresses including nutrient starvation. However, the channeling of the starvation cue towards biofilm formation is not well understood. Our study shows that a carbon starvation gene, yjiY, coding for a peptide transporter, influences the expression of a virulence-associated gene mgtC in Salmonella to regulate biofilm formation. We demonstrate here that the mutant strain ΔyjiY is unable to form a biofilm due to the increased expression of mgtC. The upregulation of mgtC in the ΔyjiY strain correlates with the downregulation of the biofilm master regulator gene, csgD, and reduced levels of ATP. Our work further indicates that a yjiY-encoded peptide transporter may regulate the expression of mgtC by transporting proline peptides.

Global transcriptional regulation by cell-free sup of S. Typhimurium peptide transporter mutant leads to inhibition of intraspecies biofilm initiation

“…sodA downregulation suggests that these cells are prone to ROS assault. Previous study has shown that YjiY depletion upregulates mgtC leading to bio lm defect 14 . Interestingly, we observed downregulation of mgtC, implying that the bio lm inhibition by ΔyjiY sup and the inherent bio lm defect of ΔyjiY strain follow different mechanisms.…”

Global transcriptional regulation by cell-free supernatant ofSalmonellaTyphimurium peptide transporter mutant leads to inhibition of intra-species biofilm initiation

“…1A ), which was absent in the supernatant of the strain where yjiY was trans-complemented in a plasmid (STM Δ yjiY:pQE60-yjiY) . Previous study showed that Δ yjiY is a biofilm deficient strain (14). To check whether the biofilm inhibitory property is specific to Δ yjiY supernatant, we inoculated WT strain with biofilm deficient strain Δ csgD ( Fig.…”

“…sodA downregulation suggests that these cells are prone to ROS assault. A previous study from our group showed that YjiY depletion upregulates mgtC leading to biofilm defect (14). Interestingly, we observed downregulation of mgtC , implying that biofilm inhibition by Δ yjiY supernatant and the inherent biofilm defect of the Δ yjiY strain follow different mechanisms.…”

“…In S . Typhimurium, YjiY is known to regulate virulence by affecting flagellar class III genes, and the deletion of yjiY leads to reduced colonization in mice (9, 13), and upregulation of the virulence factor mgtC , leading to biofilm deficiency (14). This could indicate the possible role of YjiY in survival and defense against host induced stress in bacteria.…”

Distribution and expression of virulence genes in potentially pathogenic bacteria isolated from seafood in Thailand

“…Virulence genes are consequently important for bacterial infection and pathogenesis. The expression of virulence genes has been found to be affected by several factors such as nutrient starvation (Chandra et al, 2017;Paytubi et al, 2017); concentrations of NaCl (Larsen & Jespersen, 2015), oxygen (Melson & Kendall, 2019), and glucose (Valdes et al, 2018); temperature (Guijarro et al, 2015); growth phase (Koohsari et al, 2017); kind of carbon source (Ferrando et al, 2014;Kentache et al, 2016); pH (Do et al, 2019); sodium glycocholate (Joffre et al, 2019); and L-glutamine (Haber et al, 2017).…”