Quorum Sensing Communication Modules for Microbial Consortia

The power of a single
engineered organism is limited by its capacity
for genetic modification. To circumvent the constraints of any singular
microbe, a new frontier in synthetic biology is emerging: synthetic
ecology, or the engineering of microbial consortia. Here we develop
communication systems for such consortia in an effort to allow for
complex social behavior across different members of a community. We
posit that such communities will outpace monocultures in their ability
to perform complicated tasks if communication among and between members
of the community is well regulated. Quorum sensing was identified
as the most promising candidate for precise control of engineered
microbial ecosystems, due to its large diversity and established utility
in synthetic biology. Through promoter and protein modification, we
engineered two quorum sensing systems (rpa and tra) to add to the
extensively used lux and las systems. By testing the cross-talk between
all systems, we thoroughly characterized many new inducible systems
for versatile control of engineered communities. Furthermore, we’ve
identified several system pairs that exhibit useful types of orthogonality.
Most notably, the tra and rpa systems were shown to have neither signal
crosstalk nor promoter crosstalk for each other, making them completely
orthogonal in operation. Overall, by characterizing the interactions
between all four systems and their components, these circuits should
lend themselves to higher-level genetic circuitry for use in microbial
consortia.