The ARS said vitamin A deficiencies contributed to afflictions such as the eye disease xerophthalmia, which affects about 40m children and can cause blindness. A further 250m people suffer other health problems due to a lack of vitamin A.
ARS has been researching corn with scientists from Purdue University and the International Maize and Wheat Improvement Center (CIMMYT) with a focus on crop carotenoid levels such as beta-carotene which the body converts to vitamin A.
By isolating the two genes the researchers have developed tools to triple carotenoid levels in corn, and have hinted that the levels could be even higher in other crops, said Edward Buckler, a geneticist in ARS’s Robert W Holley Center for Agriculture and Health in Ithaca, New York.
Many corn varieties naturally contains beta-carotene, but typically at very low levels.
“After identification of high-carotenoid corn lines, markers enable efficient transfer of the trait to many new varieties via marker-assisted selection; this is important because farmers in developing nations need high-carotenoid varieties that will grow over a wide range of climates and conditions,” the ARS said.
The researchers identified specific genes and areas of the corn chromosomes that influence carotenoid production using a technique called “association mapping”, which employs statistical analysis and DNA sequencing.
Using this method they isolated two naturally mutated genes that produced lower levels of certain enzymes that then led to higher beta-carotene levels.
ARS said the new varieties may be able to be crossed with local varieties to get the best of both local resilience and boosted beta-carotene levels.
For instance, some African corn has only 0.1mcg of beta-carotene per gram of corn, but the researchers think they could up these levels to 15mcg or more.
The project is partly funded by the National Science Foundation and includes work from geneticist Marilyn Warburton of the ARS Corn Host Plant Resistance Research Unit in Mississippi; Torbert Rocheford, a crop geneticist at Purdue University in West Lafayette, Indiana; and Jianbing Yan, from CIMMYT in Mexico.