MogR is a ubiquitous transcriptional repressor affecting motility, biofilm formation and virulence in<i>Bacillus thuringiensis</i>

Smith, Veronika; Josefsen, Malin; Lindbäck, Toril; Hegna, Ida K.; Finke, Sarah; Tourasse, Nicolas J.; Nielsen-LeRoux, Christina; Økstad, Ole Andreas; Fagerlund, Annette

doi:10.1101/2020.09.26.311894

Cited by 4 publications

(3 citation statements)

References 104 publications

(119 reference statements)

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“…The copyright holder for this this version posted February 15, 2022. ; https://doi.org/10.1101/2022.02.15.480532 doi: bioRxiv preprint may provide competitive benefits in nature. Importantly, how chemicals typically encountered by bacterial cells in their environment influences the multicellular systems is less understood (45). Various chemicals have distinct effects on the ability of bacterial species to form biofilms.…”

Section: Discussionmentioning

confidence: 99%

NaCl Triggers the Sessile-to-Motile Transition of Bacillus subtilis

Murugan

Gupta

Sankar

et al. 2022

Preprint

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Various chemical cues are known to alter the motile and sessile states of bacteria differentially and, in turn, the formation of biofilms. However, the underlying mechanisms at the cellular and molecular level remain less understood, which severely limits our ability to control biofilms. Here, we systematically studied the effects of NaCl on the dynamics of biofilm formation across various length scales and the associated changes in the regulation of gene expression in an undomesticated natural isolate of Bacillus subtilis. Interestingly, NaCl induced significant changes in the architecture of pellicles and yielded systematic increase in lateral expansion rates of biofilms when grown on an agar surface. At the microscopic level, we observed an intriguing NaCl-induced transition from slow and isotropic super diffusion behavior of individual bacterial cells to rapid anisotropic diffusion behavior. The average orientation of the cells (at the edge) along the expanding direction and the increased flagellation in a subpopulation of cells in the presence of NaCl corroborates well with the observed rapid anisotropic diffusion of cells. Further, the cellular uptake of NaCl resulted in the downregulation of several genes underlying the formation of biofilms, revealing the role of chemical cues like NaCl in controlling the gene regulatory circuit underlying the sessile to motile transition. Our study opens a new avenue to decipher the competitive advantage provided to the subcellular populations by NaCl due to lifestyle switch in Bacillus subtilis.

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Section: Discussionmentioning

confidence: 99%

NaCl Triggers the Sessile-to-Motile Transition of Bacillus subtilis

Murugan

Gupta

Sankar

et al. 2022

Preprint

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“…The RNA-Seq analysis showed that the motility genes were down-regulated in 7 dpi bacteria compared to in-vitro -grown cells, and that the motility repressor-encoding gene mogR [32] was up-regulated in 7 dpi bacteria compared to exponentially growing cells. Similarly, the biofilm-associated genes calY , tasA and the eps2 locus [33, 34], were up-regulated compared to exponentially growing cells.…”

Section: Discussionmentioning

confidence: 99%

A sporulation-independent way of life for Bacillus thuringiensis in the late stages of an infection

Toukabri

Lereclus

Slamti

2022

Preprint

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The formation of endospores has been considered as the unique mode of survival and transmission of sporulating Firmicutes due to the exceptional resistance and persistence of this bacterial form. However, the persistence of non-sporulated bacteria (Spo-) was reported during infection in Bacillus thuringiensis, an entomopathogenic sporulating Gram-positive bacterium. In this study, we investigated the behavior of a bacterial population in the late stages of an infection as well as the characteristics of the Spo- bacteria in the B. thuringiensis/Galleria mellonella infection model. Using fluorescent reporters coupled to flow cytometry as well as molecular markers, we demonstrated that the Spo- cells constitute about half of the population two weeks post-infection (pi) and that these bacteria present vitality signs. However, a protein synthesis and a growth recovery assay indicated that they are in a metabolically slowed-down state. Interestingly, they were extremely resistant to the cadaver environment which proved deadly for in vitro-grown vegetative cells and, strikingly, did not support spore germination. A transcriptomic analysis of this subpopulation at 7 days pi revealed a signature profile of this state. The expression analysis of individual genes at the cell level suggests that iron homeostasis is important at all stages of the infection, whereas the oxidative stress response seems of particular importance as the survival time increases. Altogether, these data show that non-sporulated bacteria are able to survive for a prolonged period of time and indicate that they engage in a profound adaptation process that leads to their persistence in the host cadaver.

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“…We thank Christophe Buisson, INRA, France, for performing force-feeding of insect larvae, and Marthe P. Parmer and Leon Reubsaet, School of Pharmacy, University of Oslo, Norway, for quantitation of cellular c-di-GMP levels. This manuscript has been released as a pre-print at bioRxiv (Smith et al, 2020).…”

Section: Acknowledgmentsmentioning

confidence: 99%

MogR Is a Ubiquitous Transcriptional Repressor Affecting Motility, Biofilm Formation and Virulence in Bacillus thuringiensis

et al. 2020

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Flagellar motility is considered an important virulence factor in different pathogenic bacteria. In Listeria monocytogenes the transcriptional repressor MogR regulates motility in a temperature-dependent manner, directly repressing flagellar- and chemotaxis genes. The only other bacteria known to carry a mogR homolog are members of the Bacillus cereus group, which includes motile species such as B. cereus and Bacillus thuringiensis as well as the non-motile species Bacillus anthracis, Bacillus mycoides and Bacillus pseudomycoides. Furthermore, the main motility locus in B. cereus group bacteria, carrying the genes for flagellar synthesis, appears to be more closely related to L. monocytogenes than to Bacillus subtilis, which belongs to a separate phylogenetic group of Bacilli and does not carry a mogR ortholog. Here, we show that in B. thuringiensis, MogR overexpression results in non-motile cells devoid of flagella. Global gene expression profiling showed that 110 genes were differentially regulated by MogR overexpression, including flagellar motility genes, but also genes associated with virulence, stress response and biofilm lifestyle. Accordingly, phenotypic assays showed that MogR also affects cytotoxicity and biofilm formation in B. thuringiensis. Overexpression of a MogR variant mutated in two amino acids within the putative DNA binding domain restored phenotypes to those of an empty vector control. In accordance, introduction of these mutations resulted in complete loss in MogR binding to its candidate flagellar locus target site in vitro. In contrast to L. monocytogenes, MogR appears to be regulated in a growth-phase dependent and temperature-independent manner in B. thuringiensis 407. Interestingly, mogR was found to be conserved also in non-motile B. cereus group species such as B. mycoides and B. pseudomycoides, which both carry major gene deletions in the flagellar motility locus and where in B. pseudomycoides mogR is the only gene retained. Furthermore, mogR is expressed in non-motile B. anthracis. Altogether this provides indications of an expanded set of functions for MogR in B. cereus group species, beyond motility regulation. In conclusion, MogR constitutes a novel B. thuringiensis pleiotropic transcriptional regulator, acting as a repressor of motility genes, and affecting the expression of a variety of additional genes involved in biofilm formation and virulence.

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MogR is a ubiquitous transcriptional repressor affecting motility, biofilm formation and virulence inBacillus thuringiensis

Cited by 4 publications

References 104 publications

NaCl Triggers the Sessile-to-Motile Transition of Bacillus subtilis

NaCl Triggers the Sessile-to-Motile Transition of Bacillus subtilis

A sporulation-independent way of life for Bacillus thuringiensis in the late stages of an infection

MogR Is a Ubiquitous Transcriptional Repressor Affecting Motility, Biofilm Formation and Virulence in Bacillus thuringiensis

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