Scientists discover rare variations of maize gene

Hohoe, March 30, GNA - A team of scientists has discovered rare variations of a maize gene (crtRB1) that could lead to an 18-fold increase in beta-carotene content of maize in an academic research setting. The research is funded by HavestPlus, a global leader in developing micronutrients-rich staple food crops, and was under the auspices of USAID and other multinational organizations.

Plant breeders are beginning to use these naturally occurring genetic variations to breed maize that could provide more beta-carotene to malnourished people.

The body converts beta-carotene into vitamin A. Millions of people in developing countries are too poor to buy foods rich in beta-carotene such as roots and vegetables. This results in vitamin A deficiency, which blinds up to 500,000 children annually. The poor eat cheaper staple foods such as maize daily. Increasing the amount of naturally produced beta-carotene in maize can upgrade its status to a "Supper Food" that provides a valuable nutrient in addition to calories.

Most of beta-carotene produced in maize is converted into other carotenoids, which make less or no vitamin A. The favourable variations of the crtRB1 gene slow down this conversion process resulting in more beta-carotene and hence more vitamin A. The team also identified a molecular marker, essentially a genetic signpost, which makes favourable form of the gene easier to find. "We can now, not only search for this form of the gene in maize using cheap molecular markers but also breed it into any maize variety in the world," says Dr Torbert Rocheford, a member of the team. He said "this could translate into improving the health of children through better nutrition, especially in Africa where maize is a popular staple food."

"We are on track to release conventionally-bred vitamin A maize in Zambia by 2012. Beyond that, this research can accelerate breeding of maize with even more vitamin A," says Dr Howarth Bouis, Director of HarvestPlus. He said under the best scenario, the crtRB1 gene variations can increase concentration of beta-carotene from a little above zero to about 57 percent of the micronutrient target (15 microgrammes/gramme beta-carotene) that HarvestPlus has determined would improve poor people's nutrition and health.