The effect of enhanced carotenoid content of transgenic maize grain on fungal colonization and mycotoxin content

Abstract

Novel strategies that address vitamin A deficiency have been developed, such as high-carotenoid maize, a biofortified transgenic maize line rich in carotenoids generated by genetic transformation. The South African white maize inbred (M37W), which is devoid of carotenoids, was engineered to accumulate high levels of β-carotene (provitamin A), lutein, and zeaxanthin. Maize seeds contaminated with fumonisins and other mycotoxins pose a serious threat to both humans and livestock. During three consecutive harvests, the fungal incidence and the fumonisin and aflatoxin content of maize seeds grown in an experimental field in Catalonia (Northeastern Spain) were evaluated. Fungal infection was similar in high-carotenoid maize and its isogenic line, with Fusarium verticillioides being the most prevalent fungus in all the harvests. Neither Aspergillus spp. nor aflatoxin contamination was found. Fumonisin levels were lower in high carotenoid than in its isogenic line, but this reduction was statistically significant in only 2 of the 3 years of study. Our results suggest that high carotenoid content reduces fumonisin levels in maize grains.

The study was supported by La Caixa (Recercaixa project PC084082 VitaMaize: high-quality and safe food through antioxidant fortified maize), the Agrotecnio Center, the Catalonian Government (2014 SGR 1296 Agricultural Biotechnology Research Group and XaRTA Reference Network on Food Technology) and the Spanish Ministry of Economy and Competitiveness (BIO2014-54441-P). J. Díaz-Gómez thanks the University of Lleida for a pre-doctoral grant. The authors would like to thank the Agricultural Biotechnology group of the University of Lleida, Antonio Michelena, and Jaume Lloveras for their work in the experimental field.