Association between FUM expression and fumonisin contamination in maize from silking to harvest

Fusarium verticillioides is the main fumonisin-producing species of fungi within the Fusarium fujikuroi species complex (FFSC), leading to notorious economic losses. The current study evaluated the relative expression of FUM1, FUM3, FUM6, FUM7, FUM8, FUM13, FUM14, FUM15 and FUM19 in comparison to the frequency of F. verticillioides and fumonisin contamination in maize samples from silking to harvest. Positive correlation was not observed between FUM relative expression and the isolation of F. verticillioides and between FUM relative expression and FB1/FB2 contamination. However, the probability of amplifying FUM genes varies according to the kernel maturity stage, with the highest probability in milk stage. It was also observed a positive correlation between the mean levels of FB1 and the kernel maturity stage. The results may indicate that the relative expression of FUM could be a complementary tool to aid in the detection of fumonisin contamination in early stages of maize growth. This is the first report involving FUM expression during the maturation of maize grains, and its correlation with F. verticillioides contamination and fumonisin accumulation.