Genetic and Physiological Analysis of Iron Biofortification in Maize Kernels

• Published in: PloS one Vol. 6; no. 6; p. e20429
• Main Authors: Lung'aho, Mercy G, Mwaniki, Angela M, Szalma, Stephen J, Hart, Jonathan J, Rutzke, Michael A, Kochian, Leon V, Glahn, Raymond P, Hoekenga, Owen A, Newbigin, Edward
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 08-06-2011; Public Library of Science (PLoS)
• Subjects: Analysis; Anemia; Arabidopsis thaliana; Argon plasma; Bioassays; Bioavailability; biofortification; Biological Availability; Biology; Breeding - methods; Cereal crops; Cloning; Corn; Developing countries; Emission spectroscopy; Food fortification; Food science; Gene loci; genes; Genetic analysis; Genetic research; Genetics; Genomics; Grain; Heritability; Inbreeding; Inductively coupled plasma; Iron; Iron - metabolism; Iron deficiency; Kernels; LDCs; Loci; nutrient deficiencies; Nutrient deficiency; Nutrition; Oryza; phenotype; Phenotyping; Phosphates; Physiological aspects; Physiology; Phytic acid; Phytic Acid - metabolism; Plant breeding; Poverty; Quantitative genetics; Quantitative trait loci; Quantitative Trait Loci - genetics; Regulators; Reproducibility of Results; Rice; Seeds; Seeds - genetics; Seeds - metabolism; Seeds - physiology; Spectroscopy; Trends; variance; Zea mays; Zea mays - genetics; Zea mays - metabolism; Zea mays - physiology; North Carolina; New York; Minnesota; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0020429

Maize is a major cereal crop widely consumed in developing countries, which have a high prevalence of iron (Fe) deficiency anemia. The major cause of Fe deficiency in these countries is inadequate intake of bioavailable Fe, where poverty is a major factor. Therefore, biofortification of maize by increasing Fe concentration and or bioavailability has great potential to alleviate this deficiency. Maize is also a model system for genomic research and thus allows the opportunity for gene discovery. Here we describe an integrated genetic and physiological analysis of Fe nutrition in maize kernels, to identify loci that influence grain Fe concentration and bioavailability. Quantitative trait locus (QTL) analysis was used to dissect grain Fe concentration (FeGC) and Fe bioavailability (FeGB) from the I ntermated B 73 × M o17 (IBM) recombinant inbred (RI) population. FeGC was determined by ion coupled argon plasma emission spectroscopy (ICP). FeGB was determined by an in vitro digestion/Caco-2 cell line bioassay. Three modest QTL for FeGC were detected, in spite of high heritability. This suggests that FeGC is controlled by many small QTL, which may make it a challenging trait to improve by marker assisted breeding. Ten QTL for FeGB were identified and explained 54% of the variance observed in samples from a single year/location. Three of the largest FeGB QTL were isolated in sister derived lines and their effect was observed in three subsequent seasons in New York. Single season evaluations were also made at six other sites around North America, suggesting the enhancement of FeGB was not specific to our farm site. FeGB was not correlated with FeGC or phytic acid, suggesting that novel regulators of Fe nutrition are responsible for the differences observed. Our results indicate that iron biofortification of maize grain is achievable using specialized phenotyping tools and conventional plant breeding techniques.