Increasing the Efficiency of Photosynthesis

 

There are two types of photosynthesis that occur within plants- C3 and C4 photosynthesis. C3 photosynthesis is believed to have evolved first, and this photosynthesis occurs in mesophyll cells. C4 photosynthesis is believed to have evolved after C3 and fixed some of the inefficiencies of C3 photosynthesis by using bundle sheath cells along with mesophyll cells. This allows plants with C4 photosynthesis to conserve more energy and water. C4 photosynthesis is 50% more efficient than C3 photosynthesis, but 95% of plants use C3 photosynthesis. New research has discovered that C3 and C4 plants have the genes and transcription factors required to perform C4 photosynthesis. Gene expression in rice (a C3 plant) and sorghum (a C4 plant) was measured and it was found that the genes to make bundle sheath cells in both species are controlled by a transcription factor family called DOFs. The DOFs were binding to the same regulatory element in both species, and this regulatory element in C4 plants was associated with both bundle sheath identity genes and was turning on the photosynthesis genes. This suggests that C4 plants at some point added the regulatory elements for bundle sheath genes onto photosynthesis genes, allowing both to be turned on at the same time by the DOFs and explaining how bundle sheath cells in C4 plants gained the ability to photosynthesize.

In my opinion, this is an extremely important discovery. Since we now know that C3 plants have both the genes and the transcription factors required to perform C4 photosynthesis, it may be possible to genetically engineer C3 plants to express C4 photosynthesis. Plants could be engineered to better survive increasing temperatures and climate change. The ability to do this would be an extreme benefit to many people, as this could increase the production of so many major sources of food, including rice. This could potentially help reduce hunger worldwide. I think that this is something that needs more attention and focus upon because this is something that could have major benefits for so many people in the future if successful.