UK scientists engineered lettuce and tobacco plants to produce myoglobin, the protein responsible for meat’s color and flavor, using a gene gun to insert pig DNA into chloroplasts. The study, published in Frontiers in Plant Science, shows plants can stably generate myoglobin, though only 35% of the protein in lettuce contained heme, the iron-rich molecule that gives meat its distinctive properties.
Researchers at Imperial College London and collaborators demonstrated that chloroplasts—organelles responsible for photosynthesis—are superior to plant nuclei for producing large quantities of myoglobin. By firing gold particles coated with myoglobin genes into tobacco and lettuce cells, the team integrated the DNA into chloroplast genomes, enabling the plants to generate the protein. While the process worked, only 35% of the plant-produced myoglobin in tobacco contained heme, compared to 80% in bacterial sources, highlighting a key challenge for future refinement.
Why Chloroplasts? A Bioengineering Breakthrough
Chloroplasts, descendants of ancient bacteria, have a unique advantage: they contain multiple copies of their own DNA and are already equipped to produce heme, the iron-containing molecule critical for myoglobin’s function. Due to their bacterial ancestry and their high number of copies per cell, chloroplasts are generally much better at making large amounts of protein than the cell nucleus,
explained Dr. Alexia Groff, lead author of the study. This setup allowed researchers to bypass traditional genetic engineering hurdles, as chloroplasts naturally handle protein synthesis more efficiently.
The team’s method involved a “gene gun,” a biolistic delivery system that shoots DNA-coated gold particles into plant cells. Despite these levels being lower than beef, the researchers argue plants could eventually rival animal agriculture in protein yield per hectare, with significantly lower water and greenhouse gas footprints.
Heme Challenges and Future Goals
Despite this, the study’s success in producing stable myoglobin in an edible crop like lettuce opens new pathways. This is an important advance on earlier plant and algal research,
said Rodrigo Ledesma-Amaro of Imperial College London’s Bezos Center for Sustainable Protein. He emphasized that plants could complement microbial fermentation in creating sustainable food systems, reducing reliance on livestock.
Implications for Sustainable Food Systems
The research aligns with growing demand for eco-friendly protein sources. Livestock production consumes vast resources and emits significant greenhouse gases, while plant-based alternatives often struggle to replicate meat’s sensory qualities. By engineering crops to produce myoglobin, scientists aim to bridge this gap. 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,
the study authors wrote.
Experts like Dr. Groff stress the work is a proof of concept. 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,
she said. The next steps involve scaling the technology, improving heme integration, and testing whether the protein enhances the flavor and texture of plant-based meats. Regulatory approval and consumer acceptance will also play critical roles in its adoption.
Broader Applications Beyond Meat
Beyond meat alternatives, the technology could revolutionize nutrient delivery. The study’s authors suggest engineered plants might one day serve as direct sources of heme iron, addressing global deficiencies. We could have a future where large quantities of leafy crops could be grown in fields and the myoglobin extracted and purified before being added as an ingredient to plant-based meat products,
the researchers noted. This could also benefit fortified foods, offering a sustainable way to boost dietary iron without synthetic additives.
Such innovations highlight a shift toward bioengineered solutions for food security and environmental sustainability.
What’s Next for Plant-Based Protein?
The study’s authors acknowledge significant work remains. While the technology is proven, practical applications depend on improving heme incorporation, ensuring food safety, and reducing costs. The next phase will likely involve refining the process and exploring partnerships with food manufacturers.
For now, the breakthrough marks a pivotal step in redefining how protein is produced. With continued innovation, plant-based foods may soon offer not just ethical and environmental benefits, but also the taste and texture of traditional meat.
