Abstract

Approximately one-third of global carbon-fixation occurs in an overlooked algal organelle called the pyrenoid. The pyrenoid is a biomolecular condensate of the CO2 -fixing enzyme Rubisco that enhances carbon-fixation by supplying Rubisco with a high concentration of CO2 . Recently we have characterized pyrenoids across the eukaryotic tree of life enabling: 1) the timing of convergent evolution of pyrenoids in the green lineage to ~260 Mya during the late Permian O2:CO2 maxima; 2) the demonstration of functional cross compatibility of pyrenoid assembly spanning 800 My of evolution; 3) discovery of a protein shell that encapsulates diatom pyrenoids; and 4) identification of a promiscuous pyrenoid assembly protein that can condense plant Rubisco into proto-pyrenoids in vitro and in vivo. Our data provides insights into the evolution of biomolecular condensation and is guiding the engineering of a pyrenoid into higher plants to enhance crop carbon fixation efficiency.