Toxin-Free Cottonseed Engineered; Could Feed Millions, Study Says

Kelly Hearn
for National Geographic News
November 20, 2006

A toxic chemical has been mostly removed from cottonseeds, potentially turning an underused agricultural product into a food source for hundreds of millions of people, according to a new study.

"The world grows cotton for fiber not for seed," said Keerti Rathore, a researcher at Texas A&M University in College Station who helped spearhead the work.

"Few realize, however, that for every pound [0.45 kilogram] of cotton fiber, the cotton plant produces 1.65 pounds [0.75 kilogram] of seeds that contain 21 percent oil and 23 percent of a relatively good quality protein."

Some 48.5 million tons (44 million metric tons) of cottonseed are produced annually, much of it by 20 million farmers in Asian and African countries with high rates of malnutrition and starvation, the study authors write (see a cotton-picking photo).

But nutrient-rich cottonseeds are unfit for human consumption because of a noxious chemical called gossypol, a toxin with properties that keep bugs at bay and cause health problems in humans and many animals.

Currently cottonseeds are used to make feed for cows, which can handle gossypol, thanks to special microbes in their stomachs.

But now the research team has found a way to genetically engineer cottonseeds that barely produce gossypol, possibly making the seeds fit for human menus.

"Global cottonseed production can potentially provide the protein requirements for half a billion people per year," the team reported in tomorrow's issue of the Proceedings of the National Academy of Sciences.

It's a Knockout

Researchers have long wrestled with the problem of cottonseed toxicity, says Danny Llewellyn, an Australian expert in cotton genetics who was not involved in the study.

Initial efforts were aimed at creating toxin-free seeds by crossing cultivated cotton with wild cotton plants that produce more gossypol in their leaves and less in their seeds.

But those tactics failed, because the genomes of wild and domestic cottons are too different.

Continued on Next Page >>




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