Two Completely Orthogonal Quorum Sensing Systems with Self-Produced Autoinducers Enable Automatic Delayed Cascade Control

Abstract

The existence of crosstalk between quorum sensing systems limits their application in a complex environment. In this study, two completely orthogonal quorum sensing systems with self-produced autoinducers were built in one cell to enable the systems to be signal orthogonal and promoter orthogonal to each other. The systems were designed on the basis of the las system from Pseudomonas aeruginosa and the tra system from Agrobacterium tumefaciens. Both were optimized with respect to the orthogonality of signals and promoters by using a series of synthetic biology strategies and high-throughput screening. The systems were applied intracellularly, and an automatic delayed cascade circuit was successfully demonstrated, which can realize sequential gene expression without exogenous inducer. This circuit provides a new tool for biotechnological applications, such as metabolic regulation, that require sequential gene control. This cascade model expands the toolkit of synthetic biology research and indicates a high application potential of quorum sensing systems that are orthogonal to each other.

Development of a N-Acetylneuraminic Acid-Based Sensing and Responding Switch for Orthogonal Gene Regulation in Cyanobacterial Synechococcus Strains

“…48 Besides, two completely orthogonal quorum sensing (QS) systems on the basis of the las system and the tra system were established in E. coli. 49 The QS system demonstrated an automatic delayed cascade circuit, which can realize sequential gene expression without exogenous inducer. Moreover, a "sigma factor toolbox" was generated in E. coli, 50 which was composed of a selected set of orthogonal sigma factors with cognate promoter libraries exhibiting a wide variety of transcription initiation frequencies and functioning orthogonally between each other and toward the host.…”

Development of Optogenetic Dual-Switch System for Rewiring Metabolic Flux for Polyhydroxybutyrate Production

“…The backbone of pGX was amplified from pSR43.6 HN (pSR43.6). CcaS#10, CcaR, cpcG2 promoter, sfgfp , ho1 , and pcyA were assembled into a pSR43.6 HN (pSR43.6) backbone to create pGX through the Gibson assembly method [ 31 ]. To construct a blue light-activated plasmid pYF1, phlF , YF1, and FixJ were amplified from the plasmids JFR1 and JFR2, as described by Fernandez-Rodriguez et al [ 32 ].…”

Control of synthetic microbial consortia in time, space, and composition

“…Additionally, many of the control mechanisms outlined in this work require relatively large genetic parts. Without increases in the number of orthogonal communication methods and more efficient control methods, the advantages of microbial consortia may be weighed down by the very tools that make them possible [73,74]. This is especially true when these control mechanisms are integrated.…”