title: A regulatory feedback loop between RpoS and SpoT supports the survival of Legionella pneumophila in water.
abstract: Legionella pneumophila is a waterborne pathogen, and survival in the aquatic environment is central to its transmission to humans. Therefore, identifying genes required for its survival in water could help prevent Legionnaires' disease outbreaks. In the present study, we investigate the role of the sigma factor RpoS in promoting survival in water, where L. pneumophila experiences severe nutrient deprivation. The rpoS mutant showed a strong survival defect compared to the wild-type strain in defined water medium. The transcriptome of the rpoS mutant during exposure to water revealed that RpoS represses genes associated with replication, translation, and transcription, suggesting that the mutant fails to shut down major metabolic programs. In addition, the rpoS mutant is transcriptionally more active than the wild-type strain after water exposure. This could be explained by a misregulation of the stringent response in the rpoS mutant. Indeed, the rpoS mutant shows an increased expression of spoT and a corresponding decrease in the level of (p)ppGpp, which is due to the presence of a negative feedback loop between RpoS and SpoT. Therefore, the lack of RpoS causes an aberrant regulation of the stringent response, which prevents the induction of a successful response to starvation.
authors.affiliation: Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada.
authors.forename: Hana
authors.initials: H
authors.lastname: Trigui
authors.affiliation: Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada.
authors.forename: Paulina
authors.initials: P
authors.lastname: Dudyk
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, South Korea.
authors.forename: Jinrok
authors.initials: J
authors.lastname: Oh
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, South Korea.
authors.forename: Jong-In
authors.initials: JI
authors.lastname: Hong
authors.affiliation: Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada sebastien.faucher2@mcgill.ca.
authors.forename: Sebastien P
authors.initials: SP
authors.lastname: Faucher
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005246:Feedback; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D016952:Legionella pneumophila / Q000235:genetics* / Q000502:physiology*; D050296:Microbial Viability; D011755:Pyrophosphatases / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D014871:Water Microbiology
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; C027627:guanosine-3',5'-bis(diphosphate) 3'-pyrophosphatase; D011755:Pyrophosphatases