Genetic Breakthrough

Potrykus sent some of Ye's plants to Beyer in late 1998, and one night in February 1999, Beyer put grains from the plants in a polishing machine to remove their outer husks. When he removed the rice from the machine, he saw with excitement that the grains were not the usual white, but rather a pale yellow. Chemical analysis confirmed that the endosperm of the rice contained beta-carotene, and Beyer e-mailed Potrykus to tell him that the experiment was a success.

Ye formally presented his results on March 31, 1999, at a symposium honoring Potrykus on the occasion of Potrykus's mandatory retirement from the Swiss institute at age 65. Potrykus wrote in AgBioView that Ye's work was "a scientific breakthrough" because multiple genes, coding for a whole metabolic pathway, had never been engineered into a plant before.

To create golden rice, Ingo Potrykus and Peter Beyer's research teams isolated two genes from daffodils and one from a bacterium that, together, made possible the production of beta-carotene. They then added promoters (segments of DNA that turn genes on) to these genes (step 1). The scientists inserted the genepromoter combinations into plasmids, circular combinations of genes in bacteria (step 2). They put the plasmids into Agrobacterium tumefaciens, a type of bacterium that infects plants (step 3). When the bacteria infected embryos (seeds) of rice plants, the bacteria inserted the beta-carotene genes into the plant cells (step 4). The seeds grew into rice plants. Because the grains from these plants carried the added genes, the grains could make beta-carotene (step 5).

Following the suggestion of a Thai business acquaintance, Potrykus and Beyer named their new plant "golden rice." They sent an article about it to Nature, the best-known scientific journal in Europe. In the cover letter that Potrykus sent with the manuscript, he pointed out that the plant's development was important for more than scientific reasons. A fierce debate was taking place worldwide about the value and possible dangers of genetically modified organisms (GMO) in foods, and golden rice, Potrykus said, offered a "timely and important demonstration of positive achievements of the GMO technology." Nature, however, rejected the manuscript. "We got the impression that Nature was more interested in cases which . . . question instead of support the value of genetic engineering technology," Potrykus complained in AgBioView.

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