An Engineered Escherichia coli Consortium for Studying Quorum Sensing

In bacterial communities, quorum sensing (QS) is a generalised cell-to-cell communication strategy individuals use to coordinate their collective behaviour via chemical signalling. Typically, QS involves the production and accumulation of QS signalling molecules to sufficient concentrations to regulate gene expression. A number of bacterial behaviours, such as biofilm formation and virulence factor production, were found to be regulated by QS. In natural environments, bacteria live in niches and form intricate consortia where QS plays an important role in controlling their collective behaviour. Studies using model bacterial communities could be a promising approach to provide insight into how bacteria interact with each other and with the environment, which may aid in the development of new antivirulence strategies based on QS. From design and construction to performance assessment, an E. coli consortium consisting of three fluorescent strains was established. The consortium was designed based on the LuxI/LuxR system of Vibrio fischeri. Three strains possess OHHL (a QS autoinducer) sensing, production, and degradation abilities, respectively, and were constructed as reporters to study the activation and attenuation of QS responses. Meanwhile, these abilities could be regulated by supplementing three inducers and assessed by detecting three fluorescent signals, respectively. The performance of the strains was assessed in the planktonic and encapsulated states. The plasmids of the engineered strains can be modified to study other genes via subcloning. This work can serve as a basis for future studies of QS using an engineered bacterial consortium.