The secret of high carbon fixation efficiency in Chlamydomonas and its potential to boost yields in land plants

Microalgae are renowned for their exceptional carbon fixation efficiency as photosynthetic organisms. Although they constitute only a small fraction of the total biomass of primary producers, microalgae are responsible for approximately half of the Earth’s daily CO 2 fixation. This extraordinary capacity is primarily attributed to the enhanced carboxylation activity of RuBisCO, an enzyme that fixes CO 2 through biophysical CO 2 -concentrating mechanisms (CCMs). Additionally, microalgae exhibit efficient light capture, robust photoprotective capabilities, and remarkable adaptability and distribution, further contributing to their high carbon fixation efficiency. Understanding the molecular components underlying this efficiency and transferring these traits to higher plants offer a promising approach for boosting crop yields and improving resilience to climate change. This review used Chlamydomonas reinhardtii as a model to explore the principles and molecular mechanisms of CCMs in microalgae. It also discussed the potential applications and challenges of incorporating these mechanisms into land plants to enhance their photosynthetic performance.