Maize lipids play a pivotal role in the fumonisin accumulation

This study investigates the role of lipids in maize - Fusarium verticillioides interaction in the accumulation of free and masked fumonisins in field conditions. In this context, 10 maize hybrids were sampled at 4 growing stages from different fields located in North Italy. The chemical composition, the fungal incidence and the free and masked fumonisin contamination were determined. In spite of the very different behavior of maize towards fumonisin contamination, the data suggested a significant implication of fatty acids content in maize kernels in both fungal infection and toxin accumulation. Fatty acid composition, involved in plant responses to pathogen, may be influenced by different environmental clues. Thus, we decide to perform an untargeted lipidomic analysis of the maize kernels along the growing season and at harvest. Combining mass spectrometry with the chemometric analysis we individuated 7 compounds able to differentiate high-contaminated from low-contaminated samples (cut-off: 2000 µg/Kg of fumonisin B1). Amongst them, the oxylipin 9-HODE and 3 sphingoid bases were identified. These results suggested that F. verticillioides and fumonisins could severely interfere with sphingolipid and oxylipin metabolism even in plants growing in field; if this alteration is causal or a mere effect due to fumonisins remains to be ascertained.