PS Seminar Series - The algal chloroplast as a testbed for synthetic biology and whole genome engineering

Abstract: The tiny, self-contained genetic system of the chloroplast (or plastid) in the green alga Chlamydomonas reinhardtii is well suited for genetic engineering and has recently seen a surge in the deployment of synthetic biology approaches. We seek to take advantage of this system to simplify the complexities of whole genome engineering. One of the main challenges is the full transplantation of the plastid with a synthetic genome in one engineering step. If successful, our priority project is to re-writie the genetic code through first introducing a drastically codon compressed synthetic genome (using just 51 codons) and subsequently transplanting a second synthetic genome, in which one or more endogenous tRNAs are reassigned to alternative codons, to create a so-called ‘genetically recoded organism’. Furthermore, the unused codons in the compressed genome could be assigned to the expression of non-canonical amino acids, facilitating the light-driven expression of new-to-nature proteins. We are also interested in the extent to which the chloroplast genome can be further minimised and simplified by serial deletion of dispensable regions and refactoring of genes into functionally-defined modules. In this talk, I will cover our progress in all of these areas and the research carried out to establish the necessary ground rules. As well as the underlying fundamental questions associated with these aims, we believe the resultant strains and technologies would serve as powerful tools for synthetic biology.

Biolgraphy: Harry’s research journey began with a BSc in Biochemistry, undertaken at Queen Mary, University of London. His final year research project was on the mechanisms of the ATP synthase c-ring and was supervised by Prof John F Allen. This sparked an interest in photosynthesis, molecular and cellular biology and microalgae as model systems for the study of fundamental processes. After graduating, he undertook a PhD at the University of Southampton, under the supervision of Prof Thomas Bibby. Here, he focused on the application of microalgae for biotechnology, establishing genetic engineering tools and high-throughput mutant screening platforms for the oleaginous alga Nannochloropsis gaditana. He then joined Prof Saul Purton’s algal biotechnology lab at University College London as a PDRA, where he is still based. The core theme of Harry’s research is the use of microalgae for basic research and the development of light-driven biomanufacturing platforms for a sustainable future. He currently works on the model alga Chlamydomonas reinhardtii with the main aim of establishing the algal chloroplast as a testbed for synthetic biology and whole genome engineering.