The Effect of pstS and phoB on Quorum Sensing and Swarming Motility in Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen that can cause a wide range of infections and inflammations in a variety of hosts, such as chronic biofilm associated lung infections in Cystic Fibrosis patients. Phosphate, an essential nutrient, has been recognized as an important signal that affects virulence in P. aeruginosa. In the current study we examined the connection between phosphate regulation and surface motility in P. aeruginosa. We focused on two important genes, pstS, which is involved in phosphate uptake, and phoB, a central regulator that responds to phosphate starvation. We found that a mutant lacking pstS is constantly starved for phosphate and has a hyper swarming phenotype. Phosphate starvation also induced swarming in the wild type. The phoB mutant, on the other hand, did not express phosphate starvation even when phosphate was limited and showed no swarming. A double mutant lacking both genes (pstS and phoB) showed a similar phenotype to the phoB mutant (i.e. no swarming). This highlights the role of phoB in controlling swarming motility under phosphate-depleted conditions. Finally, we were able to demonstrate that PhoB controls swarming by up-regulating the Rhl quorum sensing system in P. aeruginosa, which resulted in hyper production of rhamonlipids: biosurfactants that are known to induce swarming motility.

Induction of the pho regulon and polyphosphate synthesis against spermine stress in Pseudomonas aeruginosa

“…These swarming‐associated genes, including flagella genes ( flgBCDEFGHIJKL ) and rhamnolipid biosynthesis genes ( rhIRBA ), showed no sign of repression in H300. It has been reported that phosphorylated PhoB is able to increase swarming mobility by up‐regulating the Rhl quorum sensing system, which resulted in hyper production of rhamonlipids (Blus‐Kadosh et al ., ). On the contrary, in our study the swarming mobility (Fig.…”

Unsupervised Extraction of Stable Expression Signatures from Public Compendia with an Ensemble of Neural Networks

“…One Node164pos gene encodes PhoB, a transcription factor in the PhoR-PhoB two-component system that responds to low environmental phosphate in P. aeruginosa (Bielecki et al, 2015; Blus-Kadosh et al, 2013; Santos-Beneit, 2015). Further, Node164pos is the signature most enriched for a previously defined PhoB regulon (FDR q-value of 8.1e-29 in hypergeometric test).…”

Interplay between genetic regulation of phosphate homeostasis and bacterial virulence

“…In P. aeruginosa, Pi limitation promoted bacterial hyper-swarming through PhoB upregulation of rhlR expression resulting in increased rhamnolipid production. 51 The rhamnolipid biosurfactants facilitate swarming motility. This may explain the hyper-motile phenotype exhibited by the Δpst mutant and the motility defect observed in the ΔphoB mutant.…”