Source: CORDIS News

Researchers in the UK have developed a new genetically modified 'golden rice' strain, which contains up to 23 times more beta-carotene than the original variety unveiled in 2000.

Beta-carotene, or 'pro-vitamin A', is converted into vitamin A by the body. This vitamin is crucial for preventing childhood blindness, which according to the World Health Organisation affects up to 500,000 children each year.

When the original golden rice was developed five years ago, critics argued that the levels of beta-carotene it contained (roughly 1.6 micrograms per gram of rice) were insufficient to positively affect human health. The new variety, by contrast, contains up to 37 micrograms of beta-carotene per gram of rice, which some experts argue may be enough to supply a child's entire recommended daily intake of pro-vitamin A through a normal rice-based diet.

The breakthrough was made when researchers at Syngenta Seeds in Cambridge, UK, scrutinised the original golden rice variety and identified one of the two added genes (phytoene synthase taken from daffodils) as the bottleneck in the production of beta-carotene. By replacing this gene with another taken from maize, the level of pro-vitamin A was significantly increased.

'We found it made a dramatic difference - a 20-fold increase,' said Syngenta's Rachel Drake, who headed the research. 'I'm absolutely delighted, and I think it's a very compelling story.'

Syngenta is donating the new strain to the Golden Rice Humanitarian Board, which runs the golden rice project. In a statement, the Board welcomed the breakthrough and called for further research to determine how the new variety could help to fight vitamin A deficiency in developing countries.

The Board also sounded a note of caution, saying: 'While the large beta-carotene increase in golden rice is an exciting advance, it is important to keep in mind that even with elevated levels of vitamin A, golden rice is not by itself a solution to malnutrition in developing countries. Malnutrition is rooted in political, economic and cultural issues that cannot be magically resolved by a single agricultural technology.'

Rather, the Board feels that the new variety could be another weapon in the fight against vitamin A deficiency, alongside other efforts such as fortifying basic foodstuffs with vitamin A, distributing vitamin supplements, and increasing the consumption of other foods rich in vitamin A.

The statement adds: 'No new or previous varieties of golden rice should be introduced for large-scale planting until independent scientific evaluations and government regulatory reviews have been conducted in countries where it might be cultivated.'

Some observers were less welcoming of the new findings. Christoph Then, a spokesperson for Greenpeace, said: 'There are still lots of unanswered questions. Even after five years of study, the researchers don't even know how much pro-vitamin A is left when the rice is cooked. And no risk assessment for the environment or human health have been performed.'

RELATED RELEASE: Statement from the Golden Rice Humanitarian Board on development of new Golden Rice variety with higher levels of beta-carotene