C 2 photosynthesis: a promising route towards crop improvement?

Summary C 2 photosynthesis is a carbon concentrating mechanism that can increase net CO 2 assimilation by capturing, concentrating and re‐assimilating CO 2 released by photorespiration. Empirical and modelling studies indicate that C 2 plants assimilate more carbon than C 3 plants under high temperature, bright light, and low CO 2 conditions. I argue that engineering C 2 photosynthesis into C 3 crops is a promising approach to improve photosynthetic performance under these – and temporally heterogeneous – environments, and review the modifications that may re‐create a C 2 phenotype in C 3 plants. Although a C 2 engineering program would encounter many of the same challenges faced by C 4 engineering programmes, the simpler leaf anatomical requirements make C 2 engineering a feasible approach to improve crops in the medium term.