Edible cotton breakthrough may help feed the world

Cotton that has been genetically engineered so its seed is no longer toxic could provide protein-rich food for poor countries. The researchers say the technology used could make other toxic plants safe to eat.

Cottonseed contains about 22% protein, and the cotton already produced worldwide has enough protein to meet the requirements of 500 million people. But it also contains the toxin gossypol, making it poisonous to animals, including humans.

In people, gossypol lowers blood potassium to dangerous levels, resulting in fatigue and even paralysis. A surprising side effect is that gossypol is an effective male contraceptive, but research on this aspect was abandoned in the late 1990s. Attempts to eliminate gossypol from cotton plants in the 1960s and 1970s failed: insects that had previously been kept at bay by the toxin happily ate the modified plant.

Keerti Rathore of Texas A & M University in the US has managed to remove gossypol from cotton seed without affecting the toxin load in the rest of the plant, meaning the plant will contain edible seed but not be destroyed by crop pests. - more