iGEM UZurich 2020


PRRs as a new tool for synthetic biology

As a team, each of us is deeply passionate about the world of synthetic biology and its community. It was an invaluable opportunity for us to learn new skills — scientific and personal ones — and to hopefully improve the experience of future iGEM teams and researchers in our field. The development of a new application for plant immunity receptors through the study and re-engineering of plant pattern recognition receptors (PRRs) has been an exciting and enriching journey. Establishing an endogenous plant system in yeast (especially a transmembrane-based one) was definitely demanding. It posed many challenges in the lab and introduced us to a whole new conceptual and technical framework. Part of this framework includes the particular plasmid design, so that our constructs may be expressed and properly located. At the end of this project, we were very happy to have obtained initial results that pointed towards the establishment of PRR systems in yeast for biosensing applications.

Since we are introducing components that have never been used in iGEM before, we wanted to go beyond the design/characterization of new BioBricks and give this system the spotlight it deserves. We compiled a comprehensive guide about PRRs, comprising the general aspects of this system, its natural diversity, molecular mechanisms, and potential usage in Biotechnology. For beginners, this guide offers a solid basis on plant immunity as well as more in-depth studies which are even beneficial to senior researchers. We hope our efforts on expressing plant immunity proteins in yeast, and discussing their potential implications for water sensing and testing, inspire future research teams to work on this topic.

You can find the PRR Guide here.

Particularly, we hope that our collection of basic parts enables future teams to start new, similar projects and to take advantage of our collection. We explored different versions of each receptor to get a better understanding of what works and what does not. For most of our receptors, we designed two different versions: one with its native signal peptide and one without, to be replaced by a signal peptide native to the chassis organism. We also explored the use of PRRs with the intracellular signaling domain removed and found that these versions worked much better for our use case. Check out the results page to see the difference between different receptor versions. Future teams may profit from these results.

During our project, we also designed multiple composite parts. Most are for the expression of our plant PRRs in different versions, in S. cerevisiae or C. reinhardtii. These include the receptors fused to YFP, designed to visualize expression and localization in the cells, and the receptor fused to a split luciferase protein to assess the ligand-dependent dimerization. These parts can also be found on our parts page.