A Novel LysR Family Factor STM0859 is Associated with The Responses of Salmonella Typhimurium to Environmental Stress and Biofilm Formation

Abstract

Salmonella enterica subsp. enterica serovar Typhimurium (ST) is an intracellularly parasitic bacterium. This zoonotic pathogen causes food poisoning and thus imposes a severe threat to food safety. Here, to understand the regulatory roles of the novel transcription factor STM0859 on the response of ST to environmental stress and biofilm formation, the STM0859 gene-deficient strain and the complementation strain ΔSTM0859/STM0859 were generated, respectively. Then, its capacity of responding to environmental stresses and biofilm (BF) formation ability under different stresses, including acid, alkali, high salt, cholate, and oxidative stresses was tested. We further analyzed the interaction between the STM0859 protein and the promoter of the acid stress response-related gene rcsB by performing an electrophoresis mobility shift assay (EMSA). The results showed that acid resistance and BF formation capacities of ST-ΔSTM0859 strain were significantly weaker, as compared with those of Salmonella Typhimurium SL1344 (ST-SL1344) wild strain (p < 0.01). Quantitative qRT-PCR analysis showed that the expression levels of acid stress and BF formation-related genes, rcsB and rpoS, of ST-ΔSTM0859 strain were significantly reduced at the transcription levels, while the transcription levels of these genes were fully restored in complementation strain ST-ΔSTM0859/STM0859. The results of EMSA showed that STM0859 was capable of binding the promoter DNA fragments of the rcsB gene, suggesting that STM0859 can promote the transcription of the rcsB gene through interaction with its promoter, thereby exerting an indirectly regulatory role on the adaptive responses to acid stress and BF formation of ST. This study provided new insights into the regulatory mechanisms of the LysR family factors on the tolerances of ST under adverse environmental stresses.

The DUF1127 containing protein and ProQ had opposite effects on biofilm formation in Vibrio alginolyticus

“…Extracellular polysaccharides act as a scaffold to which other carbohydrates, proteins, nucleic acids, and lipids adhere [44]. Extracellular proteins can attach to the cell surface or polysaccharides, aiding in the formation and stability of bio lms [45]. Additionally, the DNA secreted by bacteria plays a crucial role in the attachment of bio lms [46,47].…”

“…In bacteria, LysR family regulator plays a crucial role in in uencing the bio lm formation. In Klebsiella pneumoniae, the LysR family regulator Bcal3178 can positively regulate expressions of genes, including hD, phbB, and astB, thus promoting the synthesis of bacterial bio lms [45]. The STM0859 protein with a DNA-binding domain is a transcriptional regulator of the LysR family and can promote bio lm formation of Salmonella typhimurium by binding to the promoter fragment of the rcsb [45].…”

“…In Klebsiella pneumoniae, the LysR family regulator Bcal3178 can positively regulate expressions of genes, including hD, phbB, and astB, thus promoting the synthesis of bacterial bio lms [45]. The STM0859 protein with a DNA-binding domain is a transcriptional regulator of the LysR family and can promote bio lm formation of Salmonella typhimurium by binding to the promoter fragment of the rcsb [45]. Moreover, alsS is involved in cell lysis and eDNA release which expression was downregulated may led the more bio lm formation in DUF1127 deletion strain [42].…”

Transcriptional control of carbohydrate catabolism by the CcpA protein in the ruminal bacterium Streptococcus bovis

“…The yellowgreeen module contains a transcription factor, gene1011 (encodes a LysR family of proteins called YbhD). Its specific function is not yet clear; however, the LysR protein family has been implicated in the regulation of bacterial quorum sensing, bioactivity control, biofilm formation, and cell division, leading to speculation that it may be involved in the regulation of strain growth ( 44 ). CcpA protein can regulate carbon metabolism indirectly by regulating the above transcription factors.…”