From above: Keerti Rathore (centre) with his team, a cotton plant and the seeds

If this piece of scientific work comes out as good as it looks on paper, mankind might just have discovered a potent tool to fight global hunger. An India-born scientist at the Texas Agricultural Experiment Station has genetically modified cottonseeds so that they no longer release the usual toxins, thus becoming highly edible. If these seeds can actually be made fit for human consumption, and many others genetically modified by the same method, the protein needs of billions across the world can be met.

Dr Keerti Rathore, a plant technologist at the Texas laboratory, whose seminal work recently published in the online version of the Proceedings of the National Academy of Sciences, says he has found a way to bring down the level of a strong toxin called gossypol that is present in cottonseeds. By tinkering with the genes, he has reduced the toxin to such a level that it can be safely consumed by humans.

“The seeds are either thrown away or fed to cows… Modifying their nature to make them palate-worthy means they won’t go waste,” says the Rajasthan-born scientist, happy with the work that took his team over a decade to complete.

Apart from being toxic, gossypol is also a powerful male contraceptive — it deactivates sperms. Getting rid of it would also make it side effect-free for men, Rathore says.

However, gossypol is not entirely unnecessary for the plants themselves. It is there for a purpose, like most things in Nature. The toxins are actually the plant’s very own pest control mechanism. Gossypol is secreted in the stems, leaves and seeds of the plant to protect it against pests. It inhibits breeding and multiplication of pests on the plant body. So wouldn’t reducing gossypol levels mean exposing the plants to pest infestation?

“We tackled this problem too. We used a technique called RNA interference, or RNAi, to suppress one of the key genes involved in producing gossypol only in the seeds. So while the rest of the plant gets its share of gossypol, the seeds remain without the toxin. This serves a dual purpose — pest protection and seed edibility,” he explains.

Groups of scientists across the world have tried time and again through conventional breeding techniques to create cotton plants without gossypol. In the 1950s, attempts were made to develop “glandless cotton”. But such genetically modified plants could not withstand pest attacks. Rathore’s group has shown in experimental greenhouse farms that the no-gossypol variety stood its ground. “My lab has been working to solve this problem for the last 10 years. Our early attempts to use a technology called antisense did not significantly reduce seed gossypol. We then started using the RNAi technology about three years ago,” he says.

So how did they achieve this? The toxins present in cottonseed are almost exclusively gossypol. In the rest of the plant, it occurs with similar toxins like heliocides, H1, H2, H3 and H4. By using modern molecular tools, the team overcame the shortcoming of the glandless cotton previously developed by conventional breeding. The variety they created was seed-specific low-gossypol.

“The results demonstrated that targeted gene silencing can be used to modulate biosynthetic pathways in a specific tissue to obtain a desired variety that is not possible by traditional breeding,” says Rathore. Gossypol values in the seeds from some of the cottonseed lines produced by the group are well below the limit deemed safe for human consumption by the World Health Organization and the United Nations Food and Agriculture Organization.

Though further field and safety trials are to be conducted over the next five years, scientists are already hailing it as one of the most successful applications of GM technology. “This research could open up a new frontier in the use of genetic manipulation to enhance global food supply. It raises the possibility of using a similar approach to eliminating harmful compounds from other potential food sources like Lathyrus sativus, a common legume consumed across Asia and Africa,” says Ganesan Sunilkumar, who worked with Rathore on the cottonseeds project.

Lathyrus could serve as an important source of nutrition-rich food it were not for the presence of the neurotoxin, beta-N-oxalylamino-L-alanine. Beans from this “famine crop” are eaten by the poor, who then suffer from a neural disorder — spastic paraparesis or lathyrism. Also, traditional foods like cassava and fava beans could be made safer for consumption by eliminating toxins like cyanogenic and fava glycosides.

The global production of cottonseeds, containing 22 per cent high-quality protein, is over 44 million tonnes. Grown in over 80 countries, cotton is a cash crop for over 20 million farmers in developing countries in Asia and Africa, where malnutrition and starvation are rampant. “An attribute of cotton not widely recognised is that for every one kg of fibre, the plant produces over 1.65 kg of seed,” Rathore writes in the PNAS paper. GM cottonseeds could thus see a potential surge in the value of the crop with utilities in two major industries — textiles and food.

GM technologists have been awaiting a “killer application” that could silence critics. “The global anti-GM lobby is still treading with caution on the new find. It is not just a matter of finding a new wonder plant… World hunger is a complex problem caused by bad government, poor economies and war,” says Sue Mayer, director of GeneWatch, UK.

However, the introduction of transgenic cottonseed may be delayed in India as the country’s top GM regulator, Genetic Engineering Approval Committee, is yet to approve any GM crop for human consumption.