Natural Genetic Variation in Lycopene Epsilon Cyclase Tapped for Maize Biofortification

Abstract

Dietary vitamin A deficiency causes eye disease in 40 million children each year and places 140 to 250 million at risk for health disorders. Many children in sub-Saharan Africa subsist on maize-based diets. Maize displays considerable natural variation for carotenoid composition, including vitamin A precursors α-carotene, β-carotene, and β-cryptoxanthin. Through association analysis, linkage mapping, expression analysis, and mutagenesis, we show that variation at the lycopene epsilon cyclase ( lcyE ) locus alters flux down α-carotene versus β-carotene branches of the carotenoid pathway. Four natural lcyE polymorphisms explained 58% of the variation in these two branches and a threefold difference in provitamin A compounds. Selection of favorable lcyE alleles with inexpensive molecular markers will now enable developing-country breeders to more effectively produce maize grain with higher provitamin A levels.