Ultra-Low Gossypol Cotton: Transforming Cottonseed into a Global Protein Source

Cotton plants produce significantly more seed than lint, with about 1.6 pounds of seed for every pound of lint. While the oil from these seeds can be used for human food, the protein is typically not because it contains a natural toxin called gossypol. Gossypol is a naturally occurring compound in the cotton plant and is present in the plant's stems, leaves, flower buds, and especially the seeds. Gossypol is the main toxic component in cottonseed meal.

Gossypol acts as a natural defense mechanism for the cotton plant, protecting it from insects, pests, and pathogens. It is toxic to monogastric animals such as pigs and poultry, and pre-ruminant/immature ruminants like young calves and lambs. In humans, high levels of gossypol can be detrimental, limiting the use of cottonseed protein in food products. The United States Food and Drug Administration (USFDA) approves cottonseed with no more than 450 ppm free gossypol for human consumption.

Ultra-low gossypol cotton

Scientists tried to breed cotton varieties with less gossypol, but these plants became vulnerable to insect damage. However, researchers at Texas A&M AgriLife Research used genetic engineering to create a dual-purpose cotton variety with an ultra-low gossypol trait that can be used for fiber and human and animal consumption. 

In 2018, the U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) announced the deregulation of genetically engineered cotton with ultra-low levels of gossypol in its seed, developed by experts led by plant biotechnologist Keerti Rathore at Texas A&M AgriLife Research. 

In 2019, the USFDA approved the ultra-low gossypol cottonseed (ULGCS) to be used as human food and animal feed. ULGCS is derived from a transgenic cotton variety TAM66274. It is a unique cotton plant with ultra-low gossypol levels in the seed, which makes the protein from the seeds safe for food use, but also maintains normal plant-protecting gossypol levels in the rest of the plant, making it ideal for the traditional cotton farmer.

According to Rathore, "the amount of protein locked up in the annual output of cottonseed worldwide is about 10.8 trillion grams. That is more than what is present in all the chicken eggs produced globally, and enough to meet the basic protein requirements of over 500 million people." 

The human food ingredients from TAM66274 cottonseed can be roasted cottonseed kernels, raw cottonseed kernels, cottonseed kernels, partially defatted cottonseed flour, defatted cottonseed flour, and cottonseed oil. For animal feed, the low-gossypol cottonseed can be used in the aquaculture and poultry industries. Ultimately, Rathore’s goal is for global adoption of TAM66274 to help address protein malnutrition in impoverished parts of the world that cultivate cotton.

Gossypol-free cottonseed 

In 2022, Rathore's team successfully developed gossypol-free cottonseed. Using RNA interference, they were able to silence the gene d-cadinene synthase to reduce gossypol concentration in the seed by 97%, without lowering the gossypol in other parts of the cotton plant where it is needed as defense against insects and diseases. 

According to the open-access article in Critical Reviews in Plant Sciences, the field trials held in multiple states for several years validated the stability and heritability of the trait without any effect on agronomic performance. 

ULGCS takes next step toward humanitarian use

In 2025, after decades of research, Uzbekistan will become the first country to formally partner with the Texas A&M University System to integrate the ULGCS trait into its cotton crops. The agreement, facilitated by Uzbekistan’s Center of Genomics and Bioinformatics of the Academy of Sciences, will support the incorporation of the trait into cotton varieties adapted for Uzbekistan. This collaboration will also support Uzbekistan's national food security goals. 

Ibrokhim Abdurakhmonov, Ph.D., a former student at Texas A&M Department of Soil and Crop Sciences and current Uzbekistan Minister of Agriculture, facilitated this humanitarian relationship. “The transfer of cutting-edge cotton innovation offers a significant opportunity for Uzbekistan’s cotton industry,” Abdurakhmonov said. “It is of interest to the research community, government, and farmers, aligning fully with Uzbekistan’s food security agenda.”

The partnership is a significant step toward Rathore's goal of making cotton a dual-purpose crop—valued for both its fiber and its seed as a protein source. This development is expected to improve the sustainability of cotton farming worldwide and holds potential for U.S. cotton growers to benefit from shared genetic material in the future.

Conclusion

Gossypol has long been a significant barrier to using cottonseed as a protein source for human food and animal feed. While this natural toxin protects the cotton plant from pests, its presence in the seeds makes them unsafe for human and animal consumption.

The groundbreaking research by Texas A&M AgriLife has changed the future of the cotton industry. With the recent partnership between Texas A&M and Uzbekistan, the global adoption of ULGCS is now a reality. This development represents a major step toward addressing global protein malnutrition, improving food security, and transforming cotton into a dual-purpose crop—valuable for both its fiber and its high-protein seed. 

For Further Reading:

• USDA Approves GE Low-Gossypol Cotton
• Selective Gene Silencing Leads to Ultra-low Gossypol Cottonseed
• GE Cotton Could Help Improve Food Security
• Texas A&M University and Uzbekistan Partner for Next Step Toward Humanitarian Use of Ultra-low Gossypol Cotton
• ULGCS TAM66274

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