Fig. 3 |. Targets for improving the efficiency of photosynthesis and primary carbon metabolism that have experimental support for success.

Transgenic manipulations of photosynthetic metabolism that lead to improved photosynthetic efficiency include (1) improving photosynthesis in a dynamic light environment by accelerating recovery from a photoprotected state, by overexpressing enzymes (such as photosystem II subunit S (PSBS) and VDE) that are involved in non-photochemical quenching (NPQ) (the dissipation of excess excitation energy as heat)¹¹⁶; (2) altering the CO₂ response of stomata or the density of stomata on the leaf surface to increase the efficiency of water use^120,122,123; (3) increasing the capacity for mesophyll conductance of CO₂¹⁰⁵; (4) improving the energy efficiency of carbon metabolism by altering mitochondrial enzymes¹⁵⁵; (5) optimizing investment in light collection¹⁰⁵; (6) increasing electron flow through the photosynthetic electron transport chain¹¹⁰; (7) altering Rubisco properties and activation to increase CO₂ assimilation^113,156; (8) bypassing photorespiration¹¹⁷; and (9) increasing the efficiency of ribulose 1,5-bisphosphate (RuBP) regeneration¹¹⁵.