Breeding to increase β-carotene levels in cereal grains, termed provitamin A biofortification, is an economical approach to address dietary vitamin A deficiency in the developing world. Experimental evidence from association and linkage populations in maize (Zea mays L.) demonstrate that the gene encoding β-carotene hydroxylase 1 (crtRB1) underlies a principal quantitative trait locus associated with β-carotene concentration and conversion in maize kernels. crtRB1 alleles associated with reduced transcript expression correlate with higher β-carotene concentrations. Genetic variation at crtRB1 also affects hydroxylation efficiency among encoded allozymes, as observed by resultant carotenoid profiles in recombinant expression assays. The most favorable crtRB1 alleles, rare in frequency and unique to temperate germplasm, are being introgressed via inexpensive PCR marker-assisted selection into tropical maize germplasm adapted to developing countries, where it is most needed for human health.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.




  1. 1.

    , , , & Biofortification of staple crops: an emerging strategy to combat hidden hunger. Compr. Rev. Food Sci. Food Safety 7, 329–334 (2008).

  2. 2.

    & HarvestPlus: breeding crops for better nutrition. Crop Sci. 47, S88–S105 (2007).

  3. 3.

    et al. In vitro and in vivo characterization of retinoid synthesis from β-carotene. Arch. Biochem. Biophys. 472, 126–138 (2008).

  4. 4.

    et al. Natural genetic variation in lycopene epsilon cyclase tapped for maize biofortification. Science 319, 330–333 (2008).

  5. 5.

    , & Cloning and functional analysis of the β-carotene hydroxylase of Arabidopsis thaliana. J. Biol. Chem. 271, 24349–24352 (1996).

  6. 6.

    & Characterization of a second carotenoid β-hydroxylase gene from Arabidopsis and its relationship to the LUT1 locus. Plant Mol. Biol. 47, 379–388 (2001).

  7. 7.

    , , & Novel lycopene epsilon cyclase activities in maize revealed through perturbation of carotenoid biosynthesis. Plant J. 59, 588–599 (2009).

  8. 8.

    et al. Generation of transgenic maize with enhanced provitamin A content. J. Exp. Bot. 59, 3551–3562 (2008).

  9. 9.

    et al. Metabolite sorting of a germplasm collection reveals the hydroxylase3 locus as a new target for maize provitamin A biofortification. Plant Physiol. 151, 1635–1645 (2009).

  10. 10.

    , & Carotenoid biosynthesis in the primitive red alga Cyanidioschyzon merolae. Eukaryot. Cell 6, 533–545 (2007).

  11. 11.

    & Timing and biosynthetic potential for carotenoid accumulation in genetically diverse germplasm of maize. Plant Physiol. 150, 562–572 (2009).

  12. 12.

    , & Maize Y9 encodes a product essential for 15-cis-zeta-carotene isomerization. Plant Physiol. 144, 1181–1189 (2007).

  13. 13.

    & in Food Colorants: Chemical and Functional Properties (ed. Sociaciu, C.) 361–368 (CRC Press, Boca Raton, Florida, USA, 2007).

  14. 14.

    & Quantification of carotenoid and tocopherol antioxidants in Zea mays. J. Agric. Food Chem. 47, 1948–1955 (1999).

  15. 15.

    et al. Using molecular markers to identify two major loci controlling carotenoid contents in maize grain. Theor. Appl. Genet. 116, 223–233 (2008).

  16. 16.

    et al. A unified mixed-model method for association mapping that accounts for multiple levels of relatedness. Nat. Genet. 38, 203–208 (2006).

  17. 17.

    , & Inference of population structure using multilocus genotype data. Genetics 155, 945–959 (2000).

  18. 18.

    & SPAGEDi: a versatile computer program to analyse spatial genetic structure at the individual or population levels. Mol. Ecol. Notes 2, 618–620 (2002).

  19. 19.

    et al. Quality assessment of maize assembled genomic islands (MAGIs) and large-scale experimental verification of predicted genes. Proc. Natl. Acad. Sci. USA 102, 12282–12287 (2005).

  20. 20.

    , & Windows QTL Cartographer 2.5 (North Carolina State University, Raleigh, North Carolina, USA, 2005).

  21. 21.

    & JOINMAP version 3.0, Software for the Calculation of Genetic Linkage Maps (Plant Research International, Wageningen, The Netherlands, 2001).

  22. 22.

    Genetic Dissection of Carotenoid Concentration and Compositional Traits in Maize Grain Doctoral dissertation, University of Illinois, Urbana-Champaign. 〈〉 (December 2009).

  23. 23.

    & PLABQTL: A Computer Program to Map QTL, Version 1.2 (1993).<>

  24. 24.

    SAS Institute. SAS/STAT User's Guide Version 9.2 (SAS Institute, Cary, North Carolina, USA, 2008).

  25. 25.

    et al. TASSEL: software for association mapping of complex traits in diverse samples. Bioinformatics 23, 2633–2635 (2007).

Download references


We thank K. Pixley and J. Chandler for seed and field experiment coordination and W. White, P. Bermudez, S. Islam, C. Paul, W. Liu, S. Xu and Y. Zhou for carotenoid HPLC profiling. Helpful comments on the manuscript from J. Wilkinson and J. Yu are appreciated. This research was supported by the US Agency for International Development (T.R.), HarvestPlus (T.R., D.D.P., J.Y., J.L., M.L.W.), National Science Foundation (NSF) DBI-0321467, DBI-0820619 (E.S.B.), NSF DBI-0604923 (T.R.), USDA-ARS (E.S.B.), NSF DBI-0501713 (T.B.), TRIAD Foundation (T.B.), China NSF-30821140352 (J.L., J.Y.), China Scholarship Fund (Y.F.) and JBT Fellowship-UIUC (C.B.K.).

Author information

Author notes

    • Jianbing Yan
    •  & Catherine Bermudez Kandianis

    These authors contributed equally to this work.


  1. International Maize and Wheat Improvement Center (CIMMYT), Texcoco, Mexico.

    • Jianbing Yan
    • , Maria Zaharieva
    • , Raman Babu
    • , Natalia Palacios
    •  & Marilyn L Warburton
  2. National Maize Improvement Center of China, China Agricultural University, Beijing, China.

    • Jianbing Yan
    • , Xiaohong Yang
    • , Zhiyuan Fu
    • , Qing Li
    • , Yang Fu
    •  & Jiansheng Li
  3. Institute for Genomic Diversity, Cornell University, Ithaca, New York, USA.

    • Jianbing Yan
    • , Carlos E Harjes
    • , Sharon Mitchell
    • , Maria G Salas Fernandez
    •  & Edward S Buckler
  4. Department of Crop Sciences, University of Illinois, Urbana, Illinois, USA.

    • Catherine Bermudez Kandianis
    • , Debra J Skinner
    • , Yang Fu
    •  & Torbert Rocheford
  5. Department of Agronomy, Purdue University, West Lafayette, Indiana, USA.

    • Catherine Bermudez Kandianis
    • , Debra J Skinner
    • , Yang Fu
    •  & Torbert Rocheford
  6. Boyce Thompson Institute, Ithaca, New York, USA.

    • Ling Bai
    •  & Thomas Brutnell
  7. Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA.

    • Eun-Ha Kim
    •  & Dean DellaPenna
  8. Agronomy Department, Iowa State University, Ames, Iowa, USA.

    • Maria G Salas Fernandez
  9. United States Department of Agriculture–Agricultural Research Service: Plant, Soil and Nutrition Research Unit, Ithaca, New York, USA.

    • Edward S Buckler
  10. Department of Plant Breeding and Genetics, Cornell University, Ithaca, New York, USA.

    • Edward S Buckler
  11. United States Department of Agriculture–Agricultural Research Service: Corn Host Plant Resistance Research Unit, Starkville, Mississippi, USA.

    • Marilyn L Warburton
  12. Monsanto, Leesburg, Georgia, USA.

    • Carlos E Harjes


  1. Search for Jianbing Yan in:

  2. Search for Catherine Bermudez Kandianis in:

  3. Search for Carlos E Harjes in:

  4. Search for Ling Bai in:

  5. Search for Eun-Ha Kim in:

  6. Search for Xiaohong Yang in:

  7. Search for Debra J Skinner in:

  8. Search for Zhiyuan Fu in:

  9. Search for Sharon Mitchell in:

  10. Search for Qing Li in:

  11. Search for Maria G Salas Fernandez in:

  12. Search for Maria Zaharieva in:

  13. Search for Raman Babu in:

  14. Search for Yang Fu in:

  15. Search for Natalia Palacios in:

  16. Search for Jiansheng Li in:

  17. Search for Dean DellaPenna in:

  18. Search for Thomas Brutnell in:

  19. Search for Edward S Buckler in:

  20. Search for Marilyn L Warburton in:

  21. Search for Torbert Rocheford in:


C.E.H. and J.Y. identified the gene. X.Y., Z.F., Y.F., R.B., C.B.K., J.Y., M.G.S.F., M.Z. and S.M. carried out the sequencing and genotyping. L.B., E.-H.K. and X.Y. carried out the transcript expression and biochemical assays. J.Y. and D.J.S. developed the crtRB1 molecular markers. R.B. and J.Y. supervised the field testing. C.B.K., Z.F., Q.L. and N.P. carried out the carotenoid profiling. C.B.K. and X.Y. completed the genetic mapping and QTL analyses. J.Y. and C.B.K. carried out the association and genetic analyses. The study was designed and supervised by J.Y., J.L., D.D.P., T.B., E.S.B., M.L.W. and T.R. The manuscript was prepared by J.Y., C.B.K., D.J.S., M.L.W. and T.R. and was edited by D.D.P., T.B. and E.S.B.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Marilyn L Warburton or Torbert Rocheford.

Supplementary information

PDF files

  1. 1.

    Supplementary Text and Figures

    Supplementary Figures 1–5 and Supplementary Tables 1–20

About this article

Publication history






Further reading