A two-component regulatory system integrates redox state and population density sensing in Pseudomonas putida.
A two-component system formed by a sensor histidine kinase and a response regulator has been identified as an element participating in cell density signal transduction in Pseudomonas putida KT2440. It is a homolog of the Pseudomonas aeruginosa RoxS/RoxR system, which in turn belongs to the RegA/RegB family, described in photosynthetic bacteria as a key regulatory element. In KT2440, the two components are encoded by PP_0887 (roxS) and PP_0888 (roxR), which are transcribed in a single unit. Characterization of this two-component system has revealed its implication in redox signaling and cytochrome oxidase activity, as well as in expression of the cell density-dependent gene ddcA, involved in bacterial colonization of plant surfaces. Whole-genome transcriptional analysis has been performed to define the P. putida RoxS/RoxR regulon. It includes genes involved in sugar and amino acid metabolism and the sulfur starvation response and elements of the respiratory chain (a cbb3 cytochrome oxidase, Fe-S clusters, and cytochrome c-related proteins) or genes participating in the maintenance of the redox balance. A putative RoxR recognition element containing a conserved hexamer (TGCCAG) has also been identified in promoters of genes regulated by this two-component system.
Fernández-Piñar
Regina
R
Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada 18008, Spain.
Ramos
Juan Luis
JL
Rodríguez-Herva
José Juan
JJ
Espinosa-Urgel
Manuel
M
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D009876:Operon / Q000235:genetics / Q000502:physiology; D010084:Oxidation-Reduction; D016958:Pseudomonas putida / Q000502:physiology*; D053038:Quorum Sensing / Q000502:physiology*; D015398:Signal Transduction
D001426:Bacterial Proteins