Fusarium verticillioides and maize interaction in vitro: Relationship between oxylipin cross-talk and fumonisin synthesis

Fusarium verticillioides is one of the most important fungal pathogens to cause ear and stalk rot in maize, even if frequently asymptomatic, producing the harmful series of compounds named fumonisins. Plant and fungal oxylipins play a crucial role in determining the outcome of the interaction between the pathogen and its host. Moreover, oxylipins result as factors able to modulate the secondary metabolism in fungi. To uncover the existence of the relation between the oxylipin production and fumonisin synthesis in F. verticillioides, we analysed some molecular and physiological parameters such as the expression of genes whose products are related to oxylipin synthesis (i.e. lipoxygenase, diol synthases and fatty acid oxidase), the oxylipin profile of both cracked maize and the pathogen by using a lipidomic approach, (i.e. combining LC-TOF and LC-MS/MS approaches with a robust statistical analysis) and the synthesis of fumonisin B1. The results suggested a close relation between the modification of the pathogen oxylipin profile with the fumonisin synthesis. Notably, a modification of the oxylipin profile of the pathogen during its growth on cracked maize can be demonstrated. The switch in oxylipin synthesis could indicate that the “presence” of maize determinants (e.g. plant cell wall fragments and/or lipids) was able to promote the modification of the pathogen lifestyle also by tuning the secondary metabolism, notably fumonisin synthesis.