Scientists create technique that increases soybean productivity

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For decades, scientists have been looking for a tantalizing possibility to increase the food supply and alleviate hunger for the world’s poorest by improving photosynthesis, the biological process in plants that sustains nearly all life on Earth.

Now, researchers say they have used genetic modifications to improve the efficiency of photosynthesis and have significantly increased the productivity of a food crop, soybeans. This gives an idea of ​​the potential of these methods to one day put more food on the tables, as climate change and other threats make it more difficult to feed the world’s vulnerable populations.

The scientists tested their genetic modifications on soybean plants grown in a single location for just two seasons. They recognize that more testing is needed to see if the results are repeated in different environments and weather conditions. Their methods will also have to be approved by government regulators before crops transformed in this way will reach agricultural fields.

And soy — much of which is grown to feed livestock, not humans — is just the beginning. In the long term, the researchers hope to increase the production of staple foods such as rice, beans and cassava.

But as the world will need to greatly scale up food production to meet demand over the next few decades, the findings suggest this genetic fit holds promise for meeting those needs, said Amanda P. de Souza, an agricultural scientist at the University of Illinois Urbana- Champaign and lead author of a new study describing the results, published Thursday in the journal Science.

“There’s a long way to go before we get there,” Souza said. But “this is the time” to work towards as many new solutions as possible, he said.

Humanity’s ability to feed itself is under pressure as societies use land and water resources in unsustainable ways. Human-caused climate change threatens to exacerbate the problem, with increasing droughts and storms causing further disruptions to food supplies. Food production is one of the main drivers of global warming, including through the deforestation of forest lands for crops and pastures.

Without major changes in agriculture, governments’ goals to mitigate climate change are in jeopardy, scientists warn. However, dealing with malnutrition and hunger in the short term may require using more land and other resources, which could accentuate warming.

This is why scientific advances that can help us produce more food without using more land, whether by improving photosynthesis or otherwise, are so promising.

“Human civilization is at a point where we have to get a lot more out of less,” said Daniel Nepstad, executive director of the Earth Innovation Institute research group.

The new research in Illinois focuses on a mechanism in plants that protects them from sun damage. When plants are in bright sunlight, they often receive more light energy than they can use for photosynthesis. This non-photochemical mechanism helps them harmlessly release excess energy as heat. But once the plant is shaded again it doesn’t stop very quickly, which means the plant wastes precious time and energy that could be used to produce carbohydrates.

The researchers’ genetic transformations help plants adjust more quickly to shade. In multilayered plants like rice, wheat, corn and soybeans, this extra agility could theoretically increase photosynthesis in the middle layers of leaves, which are constantly flickering between sunlight and shade during the day.

The work was funded by the Bill and Melinda Gates Foundation; the Foundation for Food and Agriculture Research, a non-profit organization in Washington, DC, that receives money from government, industry and academic sources; and the Commonwealth Development Office.

In 2016, another study author, Stephen P. Long, who is also at the University of Illinois Urbana-Champaign, showed that these modifications increased the growth of tobacco plants by up to 20%. But such findings have met with skepticism. Some scientists have suggested that the modifications may have boosted crop performance not by improving photosynthesis, but by affecting hormone levels. Other researchers have argued that if a process as fundamental as photosynthesis could be perfected, then surely natural selection would have already done so.

Long said he considers this a misunderstanding of evolution. Plants evolved to reproduce, he said, not to be maximally efficient at producing larger seeds or other parts of interest to hungry humans.

“Evolution is about genes passing on to the next generation,” he said. “And productivity is just a small part of that.”

The next step for him and his colleagues was to experiment with genetic transformations in a food culture. When they grew genetically modified soybeans on a University of Illinois at Urbana farm in 2020, the yield per hectare on five of their eight modified plant varieties was 24.5% higher, on average, than on the normal soybean plants they grew. To compare.

(The other three varieties also had higher yields, although the differences were not statistically significant.) Seeds from the modified plants were equally rich in protein compared to the unmodified plants.

The results of a second crop in 2021 were less conclusive. A storm caused the plants’ leaves to fall over each other, leaving the lower leaves permanently shaded, in effect.

Thomas R. Sinclair, an agricultural scientist at North Carolina State University who was not involved in the new study, said he would need to see test data from more years and more locations to be convinced that these methods are effective. Sinclair has written skeptically about this line of research, arguing that the only proven way to increase crop yields is to help plants absorb more nutrients, such as nitrogen, the main ingredient in many fertilizers.

Long said his team hoped to run five years of testing. He also plans to try the same modifications on tropical soybeans and test them in Puerto Rico. One of the team’s goals is to ensure that the highest yielding seeds are available to farmers in the developing world.

Translated by Luiz Roberto M. Gonçalves

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