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.

Sorghum: Drought Superstar

With the recent drought in California, there is one plant that has been consistent in surviving the drought conditions: Sorghum. It is among some of the most drought-tolerant groups of plants in the world, and 12.3 million dollars of grant money went into researching why.

Currently, it is known that Sorghum can sense when it faces drought conditions and respond by using less water. For example, the wax of the cuticle will become thicker or their cells start to release less water. A genetic component to drought resistance has been connected.

Sorghums are related to other grasses.
Photo credit to Peggy Lemaux of UC Berkeley

Finding the genes that control drought tolerance would be a boon. Primarily because Sorghum seems to know when to switch the genes on and off, and the mechanism that controls it is still hypothesized with no evidence backing it. Researchers will grow two groups of sorghum, one under drought conditions, and the other in normal conditions to see if they can quantify and differences in the plants.

Learning how sorghums can conserve water can lead to new crop variants that will be more drought-tolerant. And if the world continues to warm, with harsher and less wet summers, the production of crops may be in peril. Anything that would aid farmers in keeping their yield up as the water table drops would be a boon.

Original Article: KVPR

Interested in Sorghum? It's genetic sequence was compared to other plants in 2009. You can read the findings here.