A Key Meat Protein Has Been Grown in Lettuce For The First Time - ScienceAlert

Add ScienceAlert on Google (nito100/iStock/Getty Images) Eating meat is consistently shown to be one of the worst things we can do for the environment as consumers, due to the outsized negative impacts animal agriculture has on land, water and energy use, and greenhouse gas emissions. Despite this, people all over the world continue to eat meat, due to taste preferences, cultural habits, or for the nutritional benefits it can provide. But what if there were a way to get some of the flavor or protein of meat in plants grown in soil? In research published in Frontiers in Plant Science, scientists achieved that very thing, genetically engineering lettuce and tobacco plants to grow the animal protein myoglobin. "Our study demonstrates, for the first time, that higher plants can stably produce myoglobin, one of the key proteins responsible for many of meat's desirable properties," first author Alexia Groff, a plant biotechnology researcher at Imperial College London, told ScienceAlert. "This is very relevant at a time when the demand for sustainable food production platforms is greater than ever." In their study, Groff and fellow researchers used a technique called biolistic transformation, using a 'gene gun' to bombard the chloroplasts of lettuce (Lactuca sativa) and tobacco (Nicotiana tabacum) seedlings with optimized versions of pig myoglobin genes. After confirming the DNA had been correctly inserted, the plants were grown to adulthood and produced seed, and tests showed the transgene was passed on to their offspring. "One of the biggest surprises was how well the plants tolerated myoglobin production," Groff said. "Although myoglobin binds heme, an important molecule involved in many aspects of plant metabolism, the transformed plants remained healthy, fertile, and showed no significant impairment of photosynthesis." Results showed the technique yielded approximately 810 mg per kilogram of dry weight in lettuce, and 800 mg of myoglobin per kilogram of dry weight in tobacco plants. That's considerably less than the amount of myoglobin produced in meat, but when we consider the environmental advantages of plant agriculture, it's a bit of a different story. "The difference in dry weight myoglobin accumulation is around 10-fold higher in animal muscle compared with the plant yields described in this report," the researchers write in their paper. "Despite this, plant cultivation is far more resource-efficient than livestock production; consequently, plant-derived myoglobin could achieve protein yields per hectare that rival – or even potentially exceed – those of animal agriculture, whilst also benefiting from substantially lower water use and greenhouse gas emissions." The researchers acknowledge further studies are needed to provide a more accurate assessment of how well myoglobin production in plants would compare to existing livestock farming. If the technique becomes adopted, the researchers say the protein could be extracted from plant leaves and used as a component in plant-based meat products, or people could simply eat or prepare the engineered lettuce as a fresh ingredient. But another consideration that could tip the scales in favor of the plant-based pipeline is further refinements to the process. After all, the method described here is only a proof of principle, and the team says there's lots to work on to increase protein yields, and not just for myoglobin. Related: Scientists Invent New Hybrid Food by Growing Beef Inside Grains of Rice "We found that the protein folds correctly but heme incorporation is incomplete, giving us a clear direction for improving future generations of these plants," Groff told ScienceAlert. "Since our results suggest that heme availability is a bottleneck, future work could focus on engineering the heme pathway or other aspects of heme metabolism to increase the proportion of fully assembled myoglobin. "Beyond myoglobin, we are excited to explore other high-value food and functional proteins, as our results suggest that chloroplasts provide a promising platform for sustainable molecular farming." The findings are reported in Frontiers in Plant Science. This article was fact-checked by Rebecca Dyer and edited by Rebecca Dyer. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.