Pho regulon

[2] This is an essential process since phosphate plays an important role in cellular membranes, genetic expression, and metabolism within the cell.

Under low nutrient availability, the Pho regulon helps the cell survive and thrive despite a depletion of phosphate within the environment.

This occurs when the cell senses low concentrations of phosphate within its internal environment causing the response regulator to be phosphorylated inducing an overall decrease in gene transcription.

In the most commonly studied bacterium, E. coli, seven total proteins are used to detect intracellular levels of inorganic phosphate along with transfusing that signal appropriately.

[3] Although the Pho regulon system is most widely studied in Escherichia coli it is found in other bacterial species such as Pseudomonas fluorescens and Bacillus subtilis.

Under phosphate-starved conditions B. subtilis binds its transcription regulator, PhoP and the histidine kinase, PhoR to the Pho-regulon gene which induces a production of teichuronic acid.

[2] This implies that P. aeruginosa uses the low Pi as a signal that the host has been damaged and to start producing toxin to improve chances of its survival.

[8] Synthesis of the Asr protein imparts acid shock resistance to E. coli enabling it to survive in environments like the stomach which has a low pH.

[2] Many acid tolerance genes are induced by more than just the low pH environment and require other environmental signals to be present in order to be activated.