21EBTA Engineering specialised metabolism and new cellular architectures in plants

Lead Research Organisation: John Innes Centre
Department Name: Biochemistry and Metabolism

Abstract

Plants have a rich endogenous metabolism that can be reprogrammed by genetic transformation. Transient expression techniques have allowed their development as photosynthetic chassis for low-cost high-yield production of vaccines, therapeutic proteins and metabolites. In recent years, several commercial large-scale facilities for transient plant-based bioproduction have been constructed, with products now reaching the market. However, it has proved difficult to engineer high yields of engineered products in true-breeding plant lines, which would pave the way for low-cost bioproduction and new generations of crop varieties.

In this project, we will use fast transient expression systems to design and assemble an artificial synthetic pathway for the production of beta-amyrin, a precursor for many different types of triterpene. The triterpenoids are a large, chemically diverse group of natural products (over 20,000 reported to date), with a wide range of applications in the agricultural, food, cosmetic and pharmaceutical sectors. We will transfer this DNA-encoded pathway into the genome of a new model plant system, the liverwort Marchantia polymorpha. Marchantia is arguably the simplest and easiest land plant to work with at this time. We have constructed many new tools for work with Marchantia, and will use these to trigger beta-amyrin production to specialised oil body containing cells. Oil bodies are natural safe containers for accumulation of high concentrations of compounds in cells. We will then use known developmental regulators to engineer oil cell proliferation in Marchantia tissues to create high-yield harvestable plant organs. We believe the project will provide a prototype for whole organism engineering, and crop improvement.

Technical Summary

This proposal will harness our expertise in large scale assembly of co-regulated gene systems and rapid testing by transient assay in tobacco, and direct these at the challenges of safely transplanting a foreign, high-yield biosynthetic pathway into the chemical and cellular anatomy of a new plant variety.

This project requires (i) the design and assembly of a core synthetic pathway for the production of beta-amyrin, a triterpene scaffold, (ii) optimising the architecture of novel regulatory elements for co-expression of multiple genes, (iii) the modification of endogenous metabolic pathways to maximise availability of substrates, (iv) tissue engineering and targeting of the pathway to specialised cells in order to minimise negative effects on plant growth and maximise yields of beta-amyrin, (v) characterisation of modifying enzymes to decorate and diversify the core triterpene scaffold, and (vi) sharing the emerging toolkits and technologies with research communities in the UK and internationally to underpin future development.

Publications

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