Plant breeding to meet global demand for protein is on the rise.
Global demand for protein, particularly plant protein, is on the rise. However, even animal protein ultimately begins with plants.
“Whether folks eat plant or animal protein, all of the protein that we eat started with plant protein,” says Seth Naeve, University of Minnesota extension soybean agronomist and professor of agronomy and plant genetics, adding that some fish protein could be considered the only exception.
However, protein content in the world’s major field crops is actually declining.
Rouf Mian, USDA-ARS Soybean and Nitrogen Fixation Unit research leader and research geneticist , says soy protein in particular has been on a slow decline for at least 40 years.
“It is generally the same story for almost all crops. Yields are going up and proteins are going down,” Mian says.
Naeve publishes an annual soybean quality report, and his samples show a drop in average protein percentages from 35.8% in 1986 to 33.7% in 2023. Now, seed breeders are working to reverse this decline.
Pricey Protein
“Protein is very expensive for plants to produce in terms of the amount of energy a plant has to allocate to its production,” University of Guelph associate professor of soybean breeding and genetics Milad Eskandari says.
Nitrogen-fixing bacteria found on the plant’s roots convert nitrogen from the atmosphere into usable nitrogen for the plant which allows for greater protein production. In exchange, the plant provides the bacteria with the carbohydrates they need for energy.
“Synthesis of a unit of protein requires more than three times more energy than that is required for synthesis of a unit of carbohydrate,” Mian says.
Naeve says it’s possible for breeders to select for both yield and protein but it’s actually easier to increase harvested protein simply by increasing yields.
“We’ve been able to increase yields so much that, in fact, we are getting more protein per acre, and there are also more acres being harvested. It’s just that the protein is more diluted,” Naeve explains.
However, oil content is also negatively correlated with protein.
“When we started seeing renewable energy mandates, public support for breeding projects that focused on protein tended to decline in favor of those focused on oil,” Naeve says.
However, researchers are seeing significant successes using both traditional breeding and modern biotechnology to counteract this problem and meet the growing demand for high quality protein-rich legumes.
Breeding for Balance
Godfree Chigeza, soybean breeder for the International Institute of Tropical Agriculture (IITA) says that their efforts for African farmers are focused on finding a balance between protein and yield.
“Our farmers are getting very low yields compared to other parts of the world. Average yields in Africa nine years ago were around 900 kgs per hectare but with time and improvement in genetics and also agricultural practices, the average yield now is between 1.2 and 1.5 tons per hectare,” Chigeza says.
Chigeza says they follow a minimum threshold of around 38% protein for a variety to qualify to be registered and released. However, breeders must strike a balance between the two goals.
“Our farmers need the yield,” Chigeza says. “They need to have more product to sell.”
He believes the industry has a role to play in supporting these efforts as well.
“For us to be able to continue to increase the protein content, processors need to offer incentives for farmers who are selling a higher protein content,” he says. “Then the farmers may be more willing to plant those varieties.”
Naeve agrees that incentivizing growers to focus on protein would help in the United States as well.
“There has been some interest in component-based pricing so rates at the elevator would be based on what quality of soybeans farmers deliver, but there is enough resistance to that idea it is unlikely to happen anytime soon,” Naeve says.
“Smaller niche markets, such as the soy food market, often will pay for higher protein contents but that represents less than 5% of U.S. soy,” Mian states.
Quality Over Quantity
Soy is generally considered a high-quality plant protein because it contains all nine essential amino acids, however, the exact combination of amino acids determines the quality of the protein.
“We determined a long time ago that there is an inverse relationship on the quantity and quality of protein, so lower protein soybeans tend to be enriched with some of the most critical essential amino acids for animals,” Naeve says.
Eskandari’s team is specifically working to increase levels of sulfur-containing amino acids such as cysteine and methionine in soybean seeds. Methionine, in particular, cannot be produced by animals and is necessary to initiate protein synthesis in eukaryotic cells.
“When they use soybean meal for feed, they still use protein from fish sources that have essential amino acids to enrich the feed,” Eskandari says. “So, one goal is to increase the sulfur containing amino acids which would be good for food grade soybeans and commodity soybeans as it would enrich the meal after soybeans are processed and oil extracted.”
Specialty Soy
More than just a global demand for livestock feed, consumers continue to show interest for plant-based proteins, particularly organic and non-GMO options.
“People want more protein in everything they eat, and plant proteins have a great opportunity to be a hero in those goals,” says Nicole Atchison, CEO of Puris Holdings, a U.S.-based company specializing in producing and developing plant-based proteins, particularly for the food industry.
In the food industry with specialty soy, customers are concerned not only with protein levels but also traits such as seed size, taste, texture or hilum color.
“We are the processor and the breeder so we have direct access to what the customers want and can bring them in earlier in the selection cycle and have them be a part of which varieties are commercialized,” Atchison says.
But even with an emphasis on consumer-focused traits, yield still drives breeding efforts.
“If it doesn’t yield, it doesn’t matter. We’re not looking for protein at the expense of yield because we recognize that a grower is not going to want to grow that,” Atchison says. “We’re looking to be competitive from a yield perspective with dark hilum, non-GMO soybeans which have typically outperformed clear hilum. It’s also typically a lower seed cost because it doesn’t have the tech stack in it, so the ROI on the acre can be very favorable.”
Puris focuses on traditional breeding techniques to satisfy clean-label consumer-needs and has been breeding non-GMO soybeans, corn, and yellow field peas for decades.
“One of our biggest advantages is time because we’ve been selecting for yield and protein for so long. A focus area of us is getting more organic pea production in the Midwest,” Atchison says. “For growers that are looking for organic farming, peas are a great cash crop to add as part of that rotation to build soil health while participating in that premium market.”
