Genetically engineered cereals may hold the key to sustainable agriculture
Genetic engineering may be anathema to many card-carrying environmentalists, who typically favor organic farming over other forms of agriculture. But to overcome the threat posed by climate change — while continuing to feed 7.7 billion mouths (and counting) — many scientists say it’s time to fully embrace the three most controversial letters in the food industry: GMO.
Their goal is to radically shrink the carbon footprint of global crop cultivation by doing away with the need for synthetic fertilizers, which account for about 5% of humanity’s total greenhouse gas emissions. Through extensive DNA manipulations, scientists are optimistic they can engineer a self-fertilizing relationship between crop species and root-dwelling microbes, obviating the need for artificial fertilizer.
Plants need nitrogen to make two important building blocks of life: amino acids, which are stitched together to form proteins, and chlorophyll, which traps the sun’s energy to power photosynthesis. For millennia, farmers met their crops’ nitrogen demands either by spreading nutrient-rich manure on their fields or by rotating their crops, alternatively planting legume crops that were plowed under the soil to help fertilize the cereal crops that followed.
The arrival of synthetic fertilizers, pesticides, and high-yield crop varieties during the Green Revolution of the mid-20th century largely replaced these practices, ushering in a new era of bountiful food production — but at a high environmental cost.
The Organic Path
To wean agriculture off its dependence on synthetic fertilizers, many environmentalists advocate a return to organic farming practices. “We already have the solutions that we need,” says Dana Perls, senior food and technology policy campaigner with Friends of the Earth, an environmental advocacy organization based in Berkeley, California. “The most sustainable, least risky, and healthiest way to provide food for people across the world are using organic, regenerative, and ecological agricultural systems.”
A Scientific Fixation
For some scientists, the ultimate goal is to create self-fertilizing crops that can fix nitrogen themselves — but that’s a tall order. The DNA for the task can be extracted from microbes, but it doesn’t function the same way when spliced into plants. It’s such an extreme cross-species conversion, in fact, that it’s only worked in Baker’s yeast, a single-celled fungus that, while not a bacterium, is also not a plant.
It may be easier to keep nitrogen fixation under the purview of microbes and instead genetically recreate the interaction found in legumes within the roots of cereal crops. No scientist has yet succeeded in making this dream a reality, but researchers around the world are pushing forward on several of the required steps.
This kind of “synthetic symbiosis” would obviate the need for synthetic fertilizers, notes Philip Poole, a plant microbiologist at the University of Oxford. It would also have the added bonus of mitigating the concerns around genetically modified plants escaping fields and contaminating other crops, he adds. Since any pollen that blew into a neighboring field would not carry with it the bacteria from its roots, any resulting corn plants would be at a major competitive disadvantage, since they’d be making food for their new root bugs and getting nothing in return. As such, non-modified crops should quickly overtake any intruders.
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