Cross sections of C3 rice (left) and C4 sorghum (right) shoots. Both grain crops evolved from a common ancestor, but sorghum evolved to photosynthesize more efficiently.

C4 photosynthesis is a specialized mechanism that allows certain plants to efficiently capture carbon dioxide (CO2) and convert it into energy, particularly in hot and dry environments.

For the first time, researchers have identified a key step in the transformation between old-fashioned C3 photosynthesis and new and improved C4 photosynthesis — which could lead to the ...