We seek to understand and engineer the algal CO2 turbocharger.
The pyrenoid is a fascinating algal structure that mediates approximately one-third of global CO2 fixation. Nearly all eukaryotic algae in the oceans use a pyrenoid to assimilate CO2. If we understood how a pyrenoid works, we could engineer one into crop plants to increase yields by enhancing CO2 uptake [1]. Despite its importance to the global carbon cycle, until recently, the pyrenoid has remained almost completely uncharacterized at a molecular level.
We aim to transform the understanding of pyrenoid protein composition, structure and function. We discovered ~90 protein components of the pyrenoid, and determined their sub-pyrenoid localization and physical interactions [2]. Among them, we identified the key protein that holds the carbon-fixing enzyme Rubisco together in the pyrenoid [3][4]. We discovered that the pyrenoid behaves as a phase-separated, liquid-like organelle [5], not as a crystalline solid as it has long been thought to be. We determined the mechanism for protein targeting to the pyrenoid, and proposed a model for how the pyrenoid's three sub-compartments - the matrix, the membrane tubules, and the starch sheath - are held together [6].
With our collaborators, we are starting to engineer the components we are discovering into model land plants [7][8], with the ultimate aim of increasing global yields of wheat and rice.
The below presentation provides an overview of some of our research:
Image courtesy of Ursula Goodenough and Robyn Roth.