PerspectivePlant Science

Photosynthesis, Reorganized

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Science  15 Apr 2011:
Vol. 332, Issue 6027, pp. 311-312
DOI: 10.1126/science.1205336

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Summary

Photosynthesis—the conversion of carbon dioxide (CO2) into organic compounds using energy from sunlight—occurs via three pathways in terrestrial plants. The most common and ancient of these is C3 photosynthesis, whereas C4 photosynthesis and crassulacean acid metabolism (CAM) are derived from C3. Despite great taxonomic diversity across plants that use C4 and CAM photosynthesis, the core biochemical characteristics of each are similar in many independent plant lineages. How does such convergent biochemistry arise? Shared biochemical properties suggest that C4 and CAM photosynthesis may have arisen through the reorganization of metabolic processes already present in C3 plants. Modified expression of these processes would have been subject to selection and genetic accommodation in producing the distinctive derived phenotypes.