The U.S. Department of Agriculture’s Animal & Plant Health Inspection Service (APHIS) announced Oct. 16 the deregulation of Texas A&M University’s cotton variety that has been genetically engineered (GE) to have ultra-low levels of gossypol in its seed.
Gossypol is a naturally occurring compound in the pigment of cotton plants that protects them from pests and diseases. This GE variety maintains protective levels of gossypol in the plants, but the compound is significantly reduced in the seed, APHIS said, noting that this benefits agriculture by lowering cottonseed oil refining costs and potentially expands the use of cottonseed in the livestock and aquaculture feed industries as well as for human food uses.
APHIS said it concluded in its final plant pest risk assessment that this variety of GE cotton is unlikely to pose a plant pest risk to agricultural crops or other plants in the U.S. and is deregulating this variety of GE cotton.
Texas A&M AgriLife Research plant biotechnologist Dr. Keerti Rathore has been working on the project since 1995, the university said in an announcement.
Through a project funded by Cotton Inc., Rathore and the Texas A&M team have developed a transgenic cotton plant — TAM66274 — with ultra-low gossypol levels in the seed that still maintains normal plant-protecting gossypol levels in the rest of the plant.
Dr. Kater Hake, vice president of agricultural and environmental research at Cotton Inc., said it has been a decades-long journey.
“Gossypol suppression in cottonseed has been part of our funded research portfolio for over 30 years,” Hake said. “It took time to tap the innate protein potential in the seed, time for the right technologies to develop and time for the right research team to come along.”
Tom Wedegaertner, director of cottonseed research and marketing at Cotton Inc., underscored the potential of the breakthrough and the journey through the regulatory process.
“Gossypol in the leaves and stalks of the cotton plant serve as a pest deterrent, but its presence in the seed serves no purpose,” Wedegaertner said. “The more widespread use of cottonseed as a livestock feed and even for human consumption has been stymied by the natural levels of gossypol in the seed. As we progress through the regulatory review, the ability to utilize the protein potential in the seed gets that much closer.”
The recent USDA action confirms that TAM66274 and any cotton lines derived from crosses between TAM66274 and conventional cotton or biotechnology-derived cotton granted non-regulated status by APHIS are no longer considered federally regulated articles, he said.
For the past 23 years, Rathore has been determined to create cotton plants that produce seeds containing gossypol well below what the U.S. Food & Drug Administration considers safe levels while maintaining normal levels of gossypol and related chemicals in the foliage, floral parts, boll rind and roots, Texas A&M said.
Gossypol, while toxic to humans and monogastric animals such as pigs, birds, fish and rodents, is useful to cotton plants for defense against insects and pathogens. Therefore, cottonseed containing gossypol is currently used mainly in ruminant animal feed, either as whole seed or cottonseed meal after oil extraction.
“Biotechnology tools that made the ULGCS [ultra-low gossypol cottonseed] technology successful had just become available when I started looking at the potential to make this new source of protein available to hundreds of millions of people,” Rathore said. “I also realized the value to cotton farmers everywhere of removing gossypol from the cottonseed because such a product is likely to improve their income without any extra effort on their part or additional input. Such a product can also be important from the standpoint of sustainability because farmers will produce fiber, feed and food from the same crop.”
Cotton-producing countries with a limited supply of feed protein can realize great benefits by utilizing this seed-derived protein as a feed for poultry, swine or aquaculture species, Rathore said.
“It feels good to have come this far, as Texas A&M AgriLife is only the fourth public institution to have accomplished such a feat as deregulation of an engineered crop,” Rathore said.
Rathore’s research has been reported on in numerous peer-reviewed science journals, and he has been granted several U.S. patents. In 2006, his announcement that cotton plants had been successfully altered in the lab to “silence” gossypol in the seed was published in Proceedings of the National Academy of Sciences. In 2009, field trials verified the lab and greenhouse study results indicating that the crop could become a source of protein.
The cottonseed from these plants met World Health Organization and FDA standards for food consumption, he said, thus opening the potential to make the new source of high-protein food available to hundreds of millions of people a year.
Rathore said cottonseed — with about 23% protein content — can play an important role in human nutrition with the gossypol eliminated, especially in countries where cereal/tuber-based diets provide most of the calories but are low in protein content.
Rathore said for every pound of cotton fiber, the plant produces about 1.6 lb. of seed. Annual global cottonseed production equals about 48.5 million tons.
“The kernels from the safe seed could be ground into a flour-like powder after oil extraction and used as a protein additive in food preparations or perhaps roasted and seasoned as a nutritious snack,” he said.
Rathore said cotton will continue to be grown as a source of natural fiber, but the adoption of the ultra-low gossypol varieties by farmers has the potential to make the seed just as valuable as the lint.
“Our approach, based on the removal of a naturally occurring, toxic compound from the cottonseed, not only improves its safety but also provides a novel means to meet the nutritional requirements of the burgeoning world population,” he said.
Aside from the human aspect, Rathore said the potential of ULGCS as a fish meal replacement in the diets of shrimp and southern flounder has been demonstrated. Additional aquaculture and poultry feeding studies are planned to fully evaluate the nutritional value of the unique cottonseed.
“The next major effort will be aimed at activities to demonstrate the value-added potential of this technology,” Wedegaertner said. “The first step will be to produce enough ULGCS seed for a commercial-scale production run at a cottonseed oil mill. This will take a couple of years.”
Rathore said development of ULGCS involved several patented technologies, so additional steps must be taken to secure agreements with the patent holders, then find a seed company willing to market the ULGCS trait and make it available to cotton farmers worldwide.
As a scientist who has conceived and developed this technology, Rathore said, “My personal preference as we move forward would be to follow the ‘golden rice’ example in terms of its use for humanitarian purposes.”