The Chlamydomonas CO2 -concentrating mechanism and its potential for engineering photosynthesis in plants

Abstract

Contents Summary I. Introduction 54 II. Recent advances in our understanding of the Chlamydomonas CCM 55 III. Current gaps in our understanding of the Chlamydomonas CCM 58 IV. Approaches to rapidly advance our understanding of the Chlamydomonas CCM 58 V. Engineering a CCM into higher plants 58 VI. Conclusion and outlook 59 Acknowledgements 60 References 60 SUMMARY: To meet the food demands of a rising global population, innovative strategies are required to increase crop yields. Improvements in plant photosynthesis by genetic engineering show considerable potential towards this goal. One prospective approach is to introduce a CO₂ -concentrating mechanism into crop plants to increase carbon fixation by supplying the central carbon-fixing enzyme, Rubisco, with a higher concentration of its substrate, CO₂ . A promising donor organism for the molecular machinery of this mechanism is the eukaryotic alga Chlamydomonas reinhardtii. This review summarizes the recent advances in our understanding of carbon concentration in Chlamydomonas, outlines the most pressing gaps in our knowledge and discusses strategies to transfer a CO₂ -concentrating mechanism into higher plants to increase photosynthetic performance.

Keywords: Chlamydomonas reinhardtii; CO2-concentrating mechanism (CCM); Rubisco; carbon-concentrating mechanism; crop improvement; photosynthesis; plant engineering.