Molecular engineering of C-4 photosynthesis

The majority of terrestrial plants, including many important crops such as rice, wheat, soybean, and potato, are classified as C-3 plants that assimil ate atmospheric CO2 directly through the C-3 photosynthetic pathway. C-4 pl ants such as maize and sugarcane evolved from C-3 plants, acquiring the C-4 photosynthetic pathway to achieve high photosynthetic performance and high water- and nitrogen-use efficiencies. The recent application of recombinan t DNA technology has made considerable progress in the molecular engineerin g of C-4 photosynthesis over the past several years. It has deepened our un derstanding of the mechanism of C-4 photosynthesis and provided valuable in formation as to the evolution of the C-4 photosynthetic genes. It also has enabled us to express enzymes involved in the C-4 pathway at high levels an d in desired locations in the leaves of C-3 plants for engineering of prima ry carbon metabolism.