The US Food and Drug Administration announced this month that a genetically modified cottonseed has been green-lighted for human consumption. Researchers engineered the cotton plants to block the activity of the gene for an enzyme called δ-cadinene synthase in their seeds, which in turn prevents the seeds from making a toxin called gossypol. The plant had already been deregulated by the US Department of Agriculture last year.
Last week, we spoke with Keerti Rathore, a plant scientist at Texas A&M, about why he saw a need for edible cottonseed, and how his team developed it.
The Scientist: How did this project begin?
Keerti Rathore: I came to Texas A&M about 24 years ago. And cotton was something that I was not very familiar with. . . . [But] I started to read literature on cotton. And one thing that really jumped out was this problem of gossypol, which is a toxic terpenoid present in the cotton plant. And that’s where I read some of the reviews that suggested that there’s so much protein locked up in the global output of cottonseed that you could [use it to] meet the basic protein requirements of almost 500 million people.
And so that . . . triggered my interest in this particular project. We’ve been working on it ever since. We proved the science in 2006; we published a paper and showed that the science works. But after that, since it’s genetically engineered, we had to go through USDA approval as well as FDA approval.
TS: What were some of the hurdles that you encountered on the way to figuring out the science?
KR: One was finding the right gene silencing technology. Gossypol is important for the cotton plant, in the sense that it protects the plant from insect attack and some diseases. But . . . because of [the gossypol] we cannot utilize the seed. So one thing was to find a gene that we can silence, that will then eliminate this gossypol only from the seed.
Now with our ultralow gossypol cottonseed, we should be able to feed all these other animals, as well as it can be used as a source of food [for people].—Keerti Rathore, Texas A&M
Initially, we tried a gene silencing technology called antisense . . . and that worked in the first generation, but the trait was unstable. When we went to the next generation, the value of gossypol went back to the normal levels. Finally, we started to use this newer technology called RNA interference, or RNAi for short. And that’s the technology that finally gave us the desired result. We had the result in 2005 showing that this RNAi works, but we wanted to make sure that the trait is stable. So we did several generations in the greenhouse and checked seeds from each generation to make sure that the trait was stable, before we even published the paper.
The other one was to make this trait seed-specific, because you do not want to eliminate gossypol from other parts of the plant, where it has a useful function. . . . It took us a while to isolate a promoter . . . and [we] checked it very carefully to make sure that the promoter is active only in the seed, and in no other part of the plant. Then we used that to control the gene silencing in the cottonseed.
TS: Have you heard from farmers that they are interested in implementing the technology? (Editor’s note: Cotton Incorporated, a nonprofit supported by US cotton growers, was a major funder of the edible cottonseed’s development.)
KR: Oh yes, of course, our cotton farmers in the US want this technology yesterday. Our hope is that, with this expanded use, in time the value of their crop will go up, because right now, cotton farmers don’t really get much money for their seed—they just grow cotton mainly for the fiber. Right now, the biggest use for cottonseed is . . . we do extract oil and gossypol is removed through refining, but the rest of the meal, which has a lot of protein in it, is just simply fed to cows, and cows being ruminant animals [with] multiple stomach chambers, they can tolerate gossypol. . . . They do not suffer as much as the other animals such as chicken, pigs, fish, and all monogastric animals—you cannot feed these animals with the regular cottonseed. But now with our ultralow gossypol cottonseed, we should be able to feed all these other animals, as well as it can be used as a source of food [for people].
TS: Do you think edible cotton could also have an impact on food insecurity?
KR: There are enough calories [being produced] to satisfy all the people in the world right now. But what we do not have are the nutrients, and protein being one of the biggest nutrients that is lacking in the diets of a lot of poor people. So it’s more [about] nutrition security rather than food security. Now that we have approval in the US, we will start looking at other countries.
I also understand that there may be some cultural resistance to eating something that has been traditionally fed to the cows for thousands of years [in India]. But we can easily take this cottonseed and, say, feed it to chicken or fish. Take the case of India: from 1961 to 2017, the chicken meat production has gone up . . . by 51-fold. And similarly, China, I think it went up by 29-fold during that period. And egg production also has gone up significantly in both these countries. One of the best uses of converting feed protein into edible animal protein is to produce eggs. So if you want to produce eggs that’s almost, I would say, seven times more efficient then feeding it to the cows to make beef. So one way or the other, it will be used.
TS: In addition to cultural resistance, do you foresee anti-GMO sentiment as being a potential barrier to adoption, even for animal feed?
KR: One [issue we hear about] is obviously people say ‘you’re tinkering with nature,’ and [for people who feel that way] obviously if it’s a direct source of food, then there is much more hesitation. Whereas cottonseed, as I said, traditionally has been cattle feed, and so extended to chicken or pigs or fish, I think there shouldn’t be as much of a resistance. Also, in my opinion, a lot of this anti-GMO kind of sentiment is really a sentiment against big corporations, whereas [the cottonseed] is developed by public university scientists who really don’t have any profit motive. And so, again, we feel that there won’t be such a big resistance against that.
TS: Have you been experimenting with cottonseed recipes?
KR: We don’t—I wish we had enough cottonseed. We’ve tasted it, people in my lab have tasted it. Last year, [our administrators] wanted to just try it out. And I said, well, we do not have FDA approval on our line yet. But we do have this, the Hopi cottonseed, and if you want to taste it, you’re more than welcome. (Editor’s note: Hopi cottonseed is a variety that naturally lacks gossypol, making it edible but vulnerable to pests.) There is a little unit in our administration that promotes this sort of thing, so they had prepared sweet clusters . . . like peanut brittle. And they also roasted and salted cottonseed. So there are many ways to do this.
Editor’s note: This interview was edited for brevity.
Correction (October 11): FDA did not approve the modified cotton strain, as stated in the original version of this article, but instead completed a consultation process with Texas A&M on the cottonseed's safety that resulted in the agency giving the modified plant the green light. The Scientist regrets the error.