Development of Quorum Sensing Tool Kit for Lactococcus lactis

Gram-positive bacteria comprise various kinds of microbes, among which, Staphylococcus aureus, Streptococcus pneumonia and Mycobacterium tuberculosis can cause a lot of human infections, while Bacillus subtilis and Lactococcus lactis can be used as probiotics, and both of them are also widely used in synthetic biology. Quorum sensing (QS) system can play diverse roles in response to bacteria population density, which makes it an intriguing tool for synthetic biologists. The QS systems have been applied in improving the function of self-organizing networks and synchronizing genetic clocks, etc. These work mostly relied on the N-acyl homoserine lactones (AHLs) based QS tool kit of Gram-negative bacteria, however, QS tool kit for Gram-positive bacteria has rarely reported. In this project, we want to develope a QS tool kit for Gram-positive bacteria. We will build this tool kit based on the Agr system from S.aureus, the PlcR-PapR system from Bacillus cereus, and the AimR-AimP system from the Bacillus subtilis bacteriophage Phi3T. We are going to test the utility of this tool kit in Bacillus subtilis and Lactococcus lactis. The orthogonality of these systems will also be examined through using the Sender-Receiver pair. This QS tool kit will facilitate synthetic biologists to construct more sophisticated systems, both in Gram-positive bacteria and mixed microbial consortia.