Provitamin A carotenoids in grain reduce aflatoxin contamination of maize while combating vitamin A deficiency

Authors: SUWARNO, WILLY - International Maize & Wheat Improvement Center (CIMMYT); HANNOK, PATTAMA - International Maize & Wheat Improvement Center (CIMMYT); PALACIOS-ROJAS, NATALIA - University Of Wisconsin; Windham, Gary; CROSSA, JOSE - International Maize & Wheat Improvement Center (CIMMYT); PIXLEY, KEVIN - University Of Wisconsin

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2019
Publication Date: 1/29/2019
Citation: Suwarno, W.B., Hannok, P., Palacios-Rojas, N., Windham, G.L., Crossa, J., Pixley, K.V. 2019. Provitamin A carotenoids in grain reduce aflatoxin contamination of maize while combating vitamin A deficiency. Frontiers in Plant Science. 10:12. https://doi.org/10.3389/fpls.2019.00030.
DOI: https://doi.org/10.3389/fpls.2019.00030

Interpretive Summary: Carotenoids are compounds responsible for the yellow, orange, and red pigments that are found in plant cells. In an effort to reduce vitamin A deficiency in developing countries, maize varieties have been produced that contain high levels of carotenoids that can be converted to vitamin A once consumed by humans. These plant compounds may also benefit humans by protecting them from toxins produced by fungi. Previous laboratory research has shown that carotenoid compounds commonly found in plants can significantly reduce the production of aflatoxin by the fungus Aspergillus flavus. Our study was conducted in field plots to determine if maize varieties with grain containing high levels of carotenoids would suppress aflatoxin production in the developing grain. Twenty maize lines containing varying levels of carotenoids were grown at two locations in Mexico and one location in Mississippi. Developing maize ears were inoculated with A. flavus spores, and aflatoxin concentrations in the maize grain were determined at harvest. Grain of maize hybrids with larger concentrations of carotenoid compounds (beta-carotene, beta-cryptoxanthin, and total provitamin A) had significantly less aflatoxin contamination compared to maize hybrids with lower concentrations of carotenoid compounds. Our findings suggest that maize hybrids that produce grain enriched with carotenoid compounds may be beneficial to people living in developing countries that are plagued by aflatoxin-contaminated maize and vitamin A deficiency.

Technical Abstract: Aflatoxin contamination of maize grain and products causes serious health problems for consumers worldwide, and especially in low- and middle-income countries where monitoring and safety standards are inconsistently implemented. Vitamin A deficiency (VAD) also compromises the health of millions of maize consumers in several regions of the world including large parts of sub-Saharan Africa. We investigated whether provitamin A (proVA) enriched maize can simultaneously contribute to alleviate both of these health concerns. We studied aflatoxin accumulation in grain of 120 maize hybrids formed by crossing 3 Aspergillus flavus resistant and 3 susceptible lines with 20 orange maize lines with low to high carotenoids concentrations. The hybrids were grown in replicated, artificially-inoculated field trials at five environments. Grain of hybrids with larger concentrations of beta-carotene (BC), beta-cryptoxanthin (BCX) and total proVA had significantly less aflatoxin contamination than hybrids with lower carotenoids concentrations. Aflatoxin contamination had negative genetic correlation with BCX (-0.28, p <0.01), BC (-0.18, p <0.05), and ProVA (-0.23, p <0.05). These findings suggest that proVA enriched maize can be particularly beneficial where the health burdens of exposure to aflatoxin and prevalence of VAD converge with high rates of maize consumption.