Using Science to Save a Population

Sorghum is one of the main food sources for people in Sub-Saharan Africa, where this drought- and heat-resistant crop feeds an estimated 300 million and serves as a key source of energy in the diet. The problem with this staple crop is that it is deficient in several micronutrients, most notably, beta-carotene, the precursor to vitamin A and an important nutrient in eyesight development. It also contains a compound that binds up iron and zinc so that they are not digested, which can ultimately lead to anemia, stunted growth, and other cognitive and developmental problems. Sadly, many Africans who rely on sorghum as the main source of food are often afflicted with poor eyesight or blindness, or other health conditions. The most vulnerable groups are infants, young children, and pregnant women. Grim as this may seem, a group of scientists is using science- and technology-based approaches to address these nutritional deficiencies in sorghum to improve the health and livelihood of these malnourished people.

The Africa Biofortified Sorghum Project is a public-private group with goals to develop sorghum seed varieties with enhanced levels of beta-carotene and reduced levels of the compound that binds iron and zinc and make the seeds available for distribution to local farmers. (Currently the project is working with farmers in Nigeria and Kenya with plans to expand in the future). One of the key contributors to the project is DuPont Pioneer, and Marc Albertsen, research director with the company, says that his group has leveraged the company’s intellectual property from other projects to develop sorghum seed lines with enhanced traits. Like many scientific advancements, the contributions that DuPont Pioneer is making to the project were born out of unrelated research. Albertsen and other researchers at DuPont Pioneer were working on ways to develop a maize seed variety with high levels of beta-carotene (maize is another staple crop for various populations in Africa and it too lacks sufficient amounts of beta-carotene). Around that time, he says, the Bill & Melinda Gates Foundation announced a program where they would provide funding for the development of biofortified sorghum, rice, banana, and cassava crops to Sub-Saharan Africa. Realizing that their work on maize could be applied to sorghum, the DuPont Pioneer researchers partnered with other organizations, including several in Africa, “to use genetic engineering to develop a solution for all of these nutritional problems that sorghum had,” says Albertsen.

To develop seeds that expressed desired traits—enhanced and stabilized levels of vitamin A, for instance—scientists used a process called transformation, which is simply inserting genes for the desired traits into the cells of the sorghum seed. Albertsen says that although conventional breeding approaches can be used to address nutritional deficiencies in certain plants like maize, genetic transformation actually works best for sorghum. “Sorghum does not have the natural variation that would allow you to put the required traits together” to result in seeds/plants that deliver the enhanced nutrition that remains stable during storage.

The group has made significant progress in reaching its ultimate goals. The researchers have developed two separate trait-enhanced seed lines. One seed line contains increased levels of stabilized beta-carotene. The stability of beta-carotene is important. Without being stabilized, beta-carotene lasted for three weeks and then 50% of it was gone, says Albertsen. The next step was to find a way to stabilize the nutrient. Today, they have a sorghum seed that can deliver 100% of the estimated average requirement for vitamin A for children aged 5 years and younger and remain stable for three months of storage, he adds. For the second seed line, the researchers were able to reduce the compound responsible for binding the iron and zinc, thereby making these two important nutrients bioavailable. “Today we can deliver just over 80% of the estimated average requirement fºr iron and zinc, virtually eliminating iron and zinc deficiency in those fed sorghum from a very early age,” says Albertsen.

Having met these objectives, the group still has more to do. One of the final goals is to manipulate the genetic material to create a third seed line that not only delivers vitamin A but also bioavailable iron and zinc. The work is contingent upon additional funding, but Albertsen feels confident that the seed variety will be ready within 12–18 months. He says that the collaborative Africa Biofortified Sorghum Project, which allows DuPont Pioneer to donate its intellectual property for a humanitarian purpose, will have a profound effect on the lives of millions of people.

Karen Nachay,
Senior Associate Editor
[email protected]