Abstract

Chemical signaling, or quorum sensing (QS), promotes a variety of collective behaviours in bacteria, from biofilm formation to swarming. In principle, QS systems can be coupled with genes controlling motility to enable bacteria to self-organise into tunable spatio-temporal patterns. However, it is not well-understood in general how gene-regulatory networks in individual cells affect population-level patterning.

In this talk, we will investigate the role of the gene-regulatory network on emergent patterning in a population of motile bacteria that interact via QS. I will present a multiscale continuum model that explicitly accounts for genetic regulation of motility and signal production through chemical structuring. Using a WKBJ -like framework in the limit of small noise in the gene-regulatory network, we derive criteria for the onset of two types of emergent patterning. Crucially, we also uncover a new route to the well-known phenomenon of motility-induced phase separation (MIPS) through the genetic regulation of tumbling frequency. Lastly, I will briefly discuss recent progress that extends this work to growing populations and more complicated gene-regulatory kinetics that possess multiple steady-states or limit cycles.