US scientists managed to remove the toxic gossypol only from the cottonseeds.
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Could cottonseed soon become human food?

Cottonseed is unsuitable for consumption by humans because it contains the toxin gossypol. A US scientist has now succeeded in specifically removing the toxin from the plant’s seed without negatively influencing any of its other characteristics.

For every pound of fibres, the cotton plant also yields 1.6 kilogrammes of seed. World-wide, 48.5 million tons of seed is created. Cottonseed has a 22 per cent protein content and is highly nourishing. However, the cotton plant also contains the toxin gossypol, which deters harmful insects.

While attempts in the 1970s to grow cotton without gossypol were successful, the plants in the field did not survive insect attacks. Scientist Keerti S. Rathore of the University of Texas, in the USA, has now managed to remove gossypol only from the cottonseed, so that the latter is palatable for humans. The toxin remains in the rest of the plant and thus continues to act as an insect deterrent. The seed could make an important contribution to improving protein supply in the countries that grow cotton.

Rathore opted for the so-called RNAi method. It is modelled on nature’s ribonucleic acid interference. RNA translates hereditary information into proteins. This is accomplished via messenger RNA. RNAi can be used to suspend the translation of gene sequences into proteins. The plant breeder was able to demonstrate that the method could be applied specifically to switch off the formation of gossypol in the seed, while its content remained at the same level in other parts of the plant. The offspring of cotton with seed containing only little gossypol remained stable. The US Ministry of Agriculture authorised the cultivation of the new cotton variety in October 2018, and Rathore is now looking for sales partners.

Roland Krieg, journalist, Berlin/Germany

More information:

Emily Waltz 2018, First edible cottonseed go-ahead, Nature Biotechnology 36:1126

Edible cottonseed now exists — and it could have big implications for world hunger, VOX.com, 19.10.2018

Edible Cottonseed Research At Texas A&M Receives Key USDA Approval, Texas A&M Today, 16.10.2018

USDA Announces Deregulation of GE Low-Gossypol Cotton, United States Department of Agriculture APHIS, 16.10.2018

Ganesan Sunilkumar et al. 2006, Engineering cottonseed for use in human nutrition by tissue-specific reduction of toxic gossypol, PNAS 103:18054-18059