Quantitative Gene Circuits and Computationally Designed Transcriptional Sensors in Plants

Plants are an attractive system for application of synthetic biology. Due to the long life cycle of plants, rigorous quantitative characterization of genetic components, assembly and testing of complex gene circuits, can take several months to years.  For this reason, there is currently a very limited number of characterized genetic parts available for plants. We have developed methodology that allows rapid testing and quantitative characterization of a large number of synthetic genetic parts in isolated plant cells. We used this methodology to select genetic components for assembly of complex gene circuits and predict their function in transgenic plants. We have developed quantitatively tuned genetic circuits, such as positive feedback loops and toggle switches, which can be used to precisely control traits in plants with external inputs.  In addition, we have developed a computationally redesigned transcriptional sensor in plants. Computationally redesigned proteins are engineered to be destabilized in the absence of the ligand and stabilized by ligand binding, leading to transcriptional activation in plants. These advances are allowing synthetic biology to take root in plants.