Scientists engineer lettuce and tobacco to produce meat-coloring myoglobin

Researchers at Imperial College London have used a gene-gun to insert cattle and pig myoglobin genes into lettuce and tobacco, creating plants that synthesize the protein responsible for meat’s red colour and umami taste.

Imperial College London scientists have demonstrated that lettuce and tobacco can be turned into bioreactors for myoglobin, the iron-rich protein that gives meat its characteristic red hue and savory flavor. By cloning the myoglobin genes from pigs and cattle and firing them into plant chloroplasts with a gene-gun, the researchers achieved stable integration that passed to subsequent generations. Yield measurements using liquid chromatography-mass spectrometry indicated roughly 800 mg of myoglobin per kilogram of dry tobacco and 810 mg per kilogram of dry lettuce, outperforming nuclear-based approaches by a factor of three.

Although these amounts are still lower than the 8.1-11.2 mg per gram typical of animal tissue, the authors suggest that large-scale cultivation could deliver protein with far less land, water and greenhouse-gas emissions than conventional livestock. The protein can be extracted with standard industrial purification methods and added to plant-based meat products to improve color, flavor and nutritional value. The work, reported in Frontiers in Plant Science, remains a laboratory-scale proof of principle rather than a commercial technology, but it opens a new pathway for more sustainable meat alternatives.