Natural Genetic Variation in Lycopene Epsilon Cyclase Tapped for Maize Biofortification
Carlos E. Harjes,1*
Torbert R. Rocheford,2
Ling Bai,3
Thomas P. Brutnell,3
Catherine Bermudez Kandianis,2
Stephen G. Sowinski,4
Ann E. Stapleton,5
Ratnakar Vallabhaneni,6,7
Mark Williams,4
Eleanore T. Wurtzel,6,7
Jianbing Yan,8
Edward S. Buckler1,9,10
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 
-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 -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.
1 Institute for Genomic Diversity, Cornell University, Ithaca, NY 14853, USA.
2 Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA.
3 Boyce Thompson Institute, Ithaca, NY 14853, USA.
4 DuPont Crop Genetics Research, Wilmington, DE 19880, USA.
5 Department of Biology and Marine Biology, University of North Carolina, Wilmington, NC 28403, USA.
6 Department of Biological Sciences, Lehman College, City University of New York (CUNY), Bronx, NY 10468, USA.
7 The Graduate School and University Center, City University of New York (CUNY), New York, NY 10016, USA.
8 International Maize and Wheat Improvement Center (CIMMYT), Apartado Postal 6-64, 06600 Mexico, DF, Mexico.
9 U.S. Department of Agriculture, Agricultural Research Service, Plant, Soil and Nutrition Research Unit, Ithaca, NY 14853, USA.
10 Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA.
* Present address: Monsanto Company, Leesburg, GA 30903, USA.
To whom correspondence should be addressed. E-mail: esb33{at}cornell.edu (E.S.B); trochefo{at}uiuc.edu (T.R.R.)
