A broad-host-range event detector: expanding and quantifying performance between Escherichia coli and Pseudomonas species

Enoch Yeung,Hans C Bernstein,Nymul Khan,Sarah J Fansler,Yuliya Farris

doi:10.1093/synbio/ysaa002

Abstract

AbstractModern microbial biodesign relies on the principle that well-characterized genetic parts can be reused and reconfigured for different functions. However, this paradigm has only been successful in a limited set of hosts, mostly comprised from common lab strains of Escherichia coli. It is clear that new applications such as chemical sensing and event logging in complex environments will benefit from new host chassis. This study quantitatively compared how the same chemical event logger performed across four strains and three different microbial species. An integrase-based sensor and memory device was operated by two representative soil Pseudomonads—Pseudomonas fluorescens SBW25 and Pseudomonas putida DSM 291. Quantitative comparisons were made between these two non-traditional hosts and two benchmark E. coli chassis including the probiotic Nissle 1917 and common cloning strain DH5α. The performance of sensor and memory components changed according to each host, such that a clear chassis effect was observed and quantified. These results were obtained via fluorescence from reporter proteins that were transcriptionally fused to the integrase and downstream recombinant region and via data-driven kinetic models. The Pseudomonads proved to be acceptable chassis for the operation of this event logger, which outperformed the common E. coli DH5α in many ways. This study advances an emerging frontier in synthetic biology that aims to build broad-host-range devices and understand the context by which different species can execute programmable genetic operations.

Highlights

Synthetic biology is built on the concept that complex biological behaviors can be programmed using relatively simple modules of biological parts
An integrase-based sensor and memory device was operated by two representative soil Pseudomonads—Pseudomonas fluorescens SBW25 and Pseudomonas putida DSM 291
The Bxb1 gene was transcriptionally fused to a green fluorescent protein (GFP) to monitor the sensor’s output

Summary

Introduction

Synthetic biology is built on the concept that complex biological behaviors can be programmed using relatively simple modules of biological parts. While the field of microbial biodesign has seen major advances, the overwhelming majority of parts have only been tested in model organisms. We know little about how even our most standard genetic devices will perform in microbial hosts beyond common laboratory strains of Escherichia coli or Saccharomyces cerevisiae. This represents a major knowledge gap and limitation in the field.

Methods

Results

Discussion

Conclusion