Boosting food crops’ capacity for photosynthesis leads to higher yields

26 Agustus 2022

Photo: Pixabay/12019

Last year nearly one out of 10 people worldwide went without enough food and by the end of the decade as many as 660 million people will be facing food scarcity, according to the United Nations.

One reason for this is climate change, which is causing lower crop yields in places like Africa. However, thanks to a breakthrough by scientists in the United States food crops could soon be made to increase their yields through a simple tweak: by boosting plants’ ability of photosynthesis.

The researchers altered several genes in soybean plants to increase their efficiency at converting sunlight into energy, which led to greater yields without any loss of seed quality in field trials, they report.

“The number of people affected by food insufficiency continues to grow, and projections clearly show that there needs to be a change at the food supply level to change the trajectory,” explains Amanda De Souza, a scientist at the international research project called Realizing Increased Photosynthetic Efficiency (RIPE) who was a key author of a paper on the findings.

“Our research shows an effective way to contribute to food security for the people who need it most while avoiding more land being put into production. Improving photosynthesis is a major opportunity to gain the needed jump in yield potential,” De Souza notes.

The scientists improved the the expressions of three genes that code for proteins of the xanthophyll pigment cycle that helps protect plants from damage caused by direct sunlight. Once the plants are exposed fully to sunlight, the cycle is activated in the leaves, which then dissipate the excess energy.

When the leaves are not exposed to direct sunlight, however, this photoprotection mechanism switches off while the leaves continue photosynthesizing with a reserve of sunlight stored in their cells.

“It takes several minutes for the plant to switch off the protective mechanism, costing plants valuable time that could have been used for photosynthesis,” the scientists note.

The overexpression of the three targeted genes speeds up this process so that whenever leaves transition from light to shade their photoprotection mechanism switches off faster, gaining leaves extra minutes of photosynthesis.

When added up throughout the entire growing season, these extra periods of minutes can result in a more than 20% increase in yield, the scientists found. Similar results were achieved with genetically modifed tobacco plants as well, which indicates that the process will work in various food crops.

“Having now shown very substantial yield increases in both tobacco and soybean, two very different crops, suggests this has universal applicability,” says Stephen Long, a professor crop sciences and plant biology at the Carl R. Woese Institute for Genomic Biology in Illinois.

“Our study shows that realizing yield improvements is strongly affected by the environment. It is critical to determine the repeatability of this result across environments and further improvements to ensure the environmental stability of the gain,” Long stresses.

What with the encouraging results, the technique could soon increase yields worldwide.

“The major impact of this work is to open the roads for showing that we can bioengineer photosynthesis and improve yields to increase food production in major crops,” says De Souza. “It is the beginning of the confirmation that the ideas ingrained by the RIPE project are a successful means to improve yield in major food crops.”

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