Engineering a synthetic algal pyrenoid to enhance photosynthesis in higher plants

Improving the efficiency of photosynthesis is one of the key remaining targets for increasing the yield potential of globally important crops. Several studies have demonstrated that plant biomass can be increased by enhancing photosynthesis, however further improvements are essential for future food security1. Productivity in globally important C3 crops, such as rice and wheat, is restricted by slow passive diffusion of CO2 from the atmosphere into the leaf and the poor catalytic properties of the CO2-fixing enzyme Rubisco. Some photosynthetic organisms, such as the green alga Chlamydomonas reinhardtii, have evolved highly efficient CCMs that actively concentrate CO2 in the chloroplast where Rubisco is located, thus saturating Rubisco and increasing CO2 assimilation efficiency. The introduction of a CCM to enhance CO2 uptake and improve Rubisco performance has the potential to give yield increases of >50% in C3 crops, as well as reduce water and nitrogen fertilizer requirements1. A better understanding of how the algal CCM can be adapted to work in higher plants opens up the prospect of enhancing crop yields in the future. Work in the McCormick lab is focused on introducing algal CCM components into higher plants, including construction of the critical CCM organelle, the pyrenoid2.

The key focus of this project will be to improve our understanding of pyrenoid biogenesis by attempting to reconstitute a minimal synthetic version of the pyrenoid in a higher plant. This work leverages recent advances in our lab and collaborating labs in understanding the structure and function of the algal CCM2 and expressing algal components in plants3. Recent collaborative results from a high-throughput screen have now identified new components important or essential for formation of the pyrenoid. In this project you will examine their functionality in heterologous systems and explore the phenotypic effects of expressing algal CCM components in model higher plants. The project will use synthetic biology-based approaches to contribute to our basic understanding of an algal mechanism that is of ecological and biogeochemical importance and will improve our ability to enhance plant growth using advanced engineering strategies.

Training: Synthetic biology-based approaches provide opportunities to explore the fundamental principles underlying biological mechanisms. This project is an outstanding multidisciplinary training opportunity to develop a wide range of molecular and whole plant analysis skills, including DNA, RNA and protein analyses (e.g. qRT-PCR, Western blot, mass spectrometry and enzyme activity assays), and photosynthetic physiology using leaf gas exchange and fluorescence techniques. You will gain expertise in synthetic biology-based approaches including high throughput multi-gene cloning (e.g. Golden Gate) and screening. You will generate and characterise the growth phenotypes of plants engineered to express multiple CCM genes to test their compatibility with higher plant systems. This work will provide important new information for both fundamental and applied research. Interacting with plant and algal scientists you will help to develop strategies to take important findings through to application in crops and present your research at regular meetings, including national and international conferences.

Please contact Alistair McCormick ([Email Address Removed]) directly if you are interested in this project (lab website: http://mccormick.bio.ed.ac.uk/