Introducing an Algal Pyrenoid into Higher Plants to Enhance CO2 Assimilation

Meeting the food demands of the rising global population is one of the most pressing challenges for Plant Science. Much research is now focused on overcoming the limitations of photosynthesis to improve plant productivity. One promising strategy lies in introducing a chloroplastic CO₂-concentrating mechanism (CCM) to improve the delivery of CO₂ to Rubisco, and thus increase CO₂ uptake efficiency. Eukaryotic microalgae, such as Chlamydomonas reinhardtii, possess highly efficient CCMs where Rubisco is aggregated in a liquid-liquid phase separated compartment called the pyrenoid. Recently we have shown that aggregation is triggered by binding of the small subunit of Rubisco to an intrinsically disordered protein called EPYC1. In vitro studies showed that EPYC1 can phase separate with Rubisco from a higher plant if Rubisco carries the Chlamydomonas small subunit. Here I will discuss recent work to phase-separate EPYC1 and Rubisco in a plant chloroplast and our ongoing efforts to engineer a functional algal CCM.