Plain white rice is pretty nutritionally empty, so if you want something a little healthier, it's probably worth sticking to other varieties like black or red rice. But there may soon be another option after Chinese scientists genetically engineered purple rice that is rich in antioxidants and may reduce the risk of cancer and heart disease.
The added health benefits of the new rice are thanks to the increased levels of anthocyanins. Not only do these compounds boost antioxidant activity, which is linked to reduced risks of cancer, heart disease and diabetes, they also give foods like blueberries and red grapes their eye-catching coloration. As a result, the new rice breed has a rich purple pigment.
This isn't the first time scientists have tried to engineer rice with higher anthocyanin levels, but efforts hadn't borne fruit due to the complicated biosynthesis pathways involved. To get around that road block, researchers from the South China Agricultural University first examined which genes are linked to anthocyanin production in different species of rice.
Japonica and indica rices don't produce anthocyanin, and the team was able to isolate the defective genes and replace them with more useful alternatives. They created a transgene stacking system that can express eight different anthocyanin genes in the grain, giving the rice higher levels of the compound and staining it a pleasant purple in the process.
"We have developed a highly efficient, easy-to-use transgene stacking system called TransGene Stacking II that enables the assembly of a large number of genes in single vectors for plant transformation," says Yao-Guang Liu, senior author of the study. "This is the first demonstration of engineering such a complex metabolic pathway in plants."
The next steps for the team involve studying how safe the new purple rice is to eat, and whether the technique can be applied to other cereals. Eventually, the researchers say the technique could be used to increase the levels of other nutrients and chemicals in plants.
The research was published in the journal Molecular Plant.
Source: South China Agricultural University via Science Daily
