Alnahhas, Razan N.Sadeghpour, MehdiChen, YeFrey, Alexis A.Ott, WilliamJosić, KrešimirBennett, Matthew R.2020-08-142020-08-142020Alnahhas, Razan N., Sadeghpour, Mehdi, Chen, Ye, et al.. "Majority sensing in synthetic microbial consortia." <i>Nature Communications,</i> 11, no. 1 (2020) Springer Nature: https://doi.org/10.1038/s41467-020-17475-z.https://hdl.handle.net/1911/109225As synthetic biocircuits become more complex, distributing computations within multi-strain microbial consortia becomes increasingly beneficial. However, designing distributed circuits that respond predictably to variation in consortium composition remains a challenge. Here we develop a two-strain gene circuit that senses and responds to which strain is in the majority. This involves a co-repressive system in which each strain produces a signaling molecule that signals the other strain to down-regulate production of its own, orthogonal signaling molecule. This co-repressive consortium links gene expression to ratio of the strains rather than population size. Further, we control the cross-over point for majority via external induction. We elucidate the mechanisms driving these dynamics by developing a mathematical model that captures consortia response as strain fractions and external induction are varied. These results show that simple gene circuits can be used within multicellular synthetic systems to sense and respond to the state of the population.engThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.Journal articlehttps://doi.org/10.1038/s41467-020-17475-z