Scientists have engineered tobacco and lettuce plants to produce myoglobin—the iron-rich protein responsible for much of meat’s red color and savory flavor—inside their chloroplasts. The proof-of-principle study suggests that crops could one day become biological factories for producing key ingredients used in plant-based meat, potentially reducing the land, water and greenhouse-gas emissions associated with livestock farming.
The research, published in Frontiers in Plant Science, focuses on a major challenge facing meat alternatives: reproducing the sensory and nutritional properties of animal meat without raising animals. Plant-based products can imitate texture and appearance, but many still rely on added ingredients to recreate the distinctive color, aroma, flavor and iron content associated with beef or pork. Myoglobin is one of the proteins that could help close that gap.
Myoglobin is found primarily in the heart and skeletal muscles of vertebrates, where it stores and transports oxygen. The protein contains a heme group, an iron-containing molecular structure that binds oxygen. In meat, this iron-rich molecule contributes to the reddish color of muscle and helps generate the metallic, umami-rich flavor that develops during cooking. Although hemoglobin is more widely known for transporting oxygen through the blood, myoglobin performs a similar storage role inside muscle cells.
The researchers first cloned genes encoding myoglobin from pigs and cattle. They then used a technique known as biolistic transformation, or “gene-gun” delivery, to fire microscopic particles coated with DNA into tobacco and lettuce seedlings. The goal was to insert the myoglobin genes into chloroplast genomes rather than into the plants’ nuclear DNA. Chloroplasts are the photosynthetic organelles that convert light energy into chemical energy, and they retain many features inherited from their ancient bacterial ancestors.
Tests confirmed that some of the transformed plants had incorporated the animal genes into the small, circular DNA molecules found inside their chloroplasts. The modified tobacco and lettuce plants were grown to maturity, flowered and produced seeds. Their offspring inherited the inserted genes, demonstrating that the engineered trait could be passed through successive generations rather than appearing only temporarily in laboratory-grown tissue.
For comparison, the team also introduced myoglobin genes into the nuclear genomes of tobacco and lettuce. In addition, the researchers engineered the chloroplasts of the single-celled green alga Chlamydomonas reinhardtii. These comparisons allowed them to examine how the location of the inserted gene affected protein production. The results supported the researchers’ expectation that chloroplasts could outperform the plant nucleus as a production platform.
Chloroplasts contain numerous copies of their genome within each cell, while a plant’s nucleus generally carries only a small number of gene copies. Their bacterial-like molecular machinery can also be highly effective at producing certain proteins. Using liquid chromatography–mass spectrometry, the scientists measured approximately 800 milligrams of myoglobin per kilogram of dry tobacco tissue and 810 milligrams per kilogram of dry lettuce tissue. These levels were at least three times higher than those obtained when the gene was inserted into the nuclear genome of tobacco.
The measured concentration remains modest compared with the amount of myoglobin naturally found in meat, which contains roughly 8.1 to 11.2 milligrams per gram of dry weight. However, the authors argue that the comparison should not be based solely on concentration. Plants can be cultivated over large areas with substantially lower land, water and emissions costs than livestock, and the researchers suggest that total protein production per hectare could eventually become competitive with animal agriculture. That conclusion still requires detailed agricultural, economic and environmental assessments.
The immediate commercial pathway would involve harvesting engineered leaves, extracting the myoglobin and purifying it with industrial protein-processing methods. The purified protein could then be added to plant-based meat formulations to improve their color, flavor and nutritional profile. Lettuce expressing myoglobin could also potentially be developed as a heme-iron-enriched food, although that possibility would depend on further safety testing, regulatory review and public acceptance. Tobacco was used in the study because it is a well-established laboratory model, while lettuce was selected because it is an edible crop with a possible future role in food production.
The work remains an early demonstration rather than a ready-made replacement for microbial fermentation or livestock-derived ingredients. Researchers must still determine how efficiently the protein can be recovered at agricultural scale, whether it retains the desired properties during processing and cooking, and how much energy purification would require. Regulatory questions surrounding genetically modified food crops will also be central. Even so, the study presents a new route for producing animal proteins in plants and shows how chloroplast engineering could turn familiar crops into factories for the next generation of meat alternatives.
Subject of Research: Experimental study on engineering plant chloroplasts to produce animal myoglobin.
Article Title: Sustainable production of myoglobin meat protein in plant chloroplasts
News Publication Date: 6-Aug-2026
Web References: https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2026.1876707/full
References: Frontiers in Plant Science, “Sustainable production of myoglobin meat protein in plant chloroplasts,” DOI: 10.3389/fpls.2026.1876707
Keywords: plant-based meat, myoglobin, chloroplast engineering, genetic engineering, lettuce, tobacco, meat alternatives, sustainable food, plant biotechnology, heme iron
