Genetically Modified Rice Uses Less Fertilizer, Produces More Food

Researchers in China have developed a strain of genetically modified rice that thrives while using less nitrogen. It actually produces 40% to 70% more food. Rice is the primary staple crop in many parts of the world. Modern agriculture relies on fertilizer and much of that fertilizer relies on so-called natural gas, which is more than 90% methane.

According to LNG2019, natural gas is responsible for up to 90% of the cost of fertilizer. Today, as Russia pursues its criminal assault on Ukraine, the cost of natural gas is rising rapidly and causing a similar rise in the price of fertilizer. That, in turn, is leading to the need for new research into ways of growing food with less nitrogen based fertilizer. The scientists published their findings recently in the journal Science. Here’s the introduction.

“Rapid population growth, rising meat consumption, and the expanding use of crops for nonfood and nonfeed purposes increase the pressure on global food production. At the same time, the excessive use of nitrogen fertilizer to enhance agricultural production poses serious threats to both human health and the environment. To achieve the required yield increases and make agriculture more sustainable, intensified breeding and genetic engineering efforts are needed to obtain new crop varieties with higher photosynthetic capacity and improved nitrogen use efficiency (NUE). However, progress has been slow, largely due to the limited knowledge about regulator genes that potentially can coordinately optimize carbon assimilation and nitrogen utilization.”

ArsTechnica reports the scientists began by looking at proteins called transcription factors, which often control the expression of a set of genes that are often involved in varying aspects of a single physiological function. In this case, the focus was on transcription factors that were already known to regulate photosynthesis.

To find the perfect target, they screened a set of 118 transcription factors previously identified to regulate photosynthesis in rice and maize to find any that were also upregulated in response to light and low levels of nitrogen. When they found one, they generated transgenic rice lines that made lots of it. “Overexpressing a transcription factor like this instead of the individual genes it controls is like demanding to speak to the manager instead of getting bounced around between assorted customer service reps in different departments,” Ars says. That’s a pretty good analogy.

The genetically modified rice plants were put in fields with different environmental conditions — temperate fields near Beijing, tropical fields in Hainan province, and subtropical fields in Zhejiang province. Over the course of three years, all of the rice plants exhibited enhanced photosynthetic capacity and improved nitrogen use efficiency.

They had more chlorophyll and more and larger chloroplasts than wild-type rice. They also had more efficient nitrogen uptake in their roots than wild-type rice, and they had more efficient transport of that nitrogen from their roots to their shoots than wild-type rice. This elevated their grain yield, even when the plants were grown with less nitrogen fertilizer.

Other experiments were done with transgenic plants grown hydroponically and in rice paddies, which did equally well. Overexpressing the same transcription factor in a fancier strain of rice — japonica instead of the oryza sativa used in most of the other experiments — had similar effects. The researchers also tried their new technology on wheat and Arabidopsis, the most commonly used model organism in plant biology. Both exhibited the same increases in productivity using less nitrogen as the experimental rice plants.

The scientists suggest genome editing could be used rather than the transgenic techniques they relied on in other crops to also achieve a higher yield. As growing seasons become shorter due to drought and excessive heat, and the availability of arable land is reduced, plants that produce more food with less nitrogen-based fertilizer may become essential to avoiding widespread famine in many parts of the world.

The Takeaway

Genetically modified food conjures up scary thoughts in the minds of many, although much of the food we eat has been modified in one way or another since Gregor Mendel began experiments with peas out behind the parsonage almost 2 centuries ago.

Some refer to genetically modified plants as Frankenfood while others worry about the wisdom of allowing giant corporations to own the seeds civilization needs to survive, since corporations seldom have the best interests of people in mind. The use of fertilizers has exploded in this century. Using fossil fuels to feed ourselves at a time when fossil fuel pollution is threatening the ability of humans to survive on this planet is ultimately a recipe for disaster.


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