Oxylipin involvement in the cross-talk Fusarium verticillioides and maize

Fusarium verticillioides became an interesting fungus for maize crop in 1989 when fumonisins were discovered. The detection of hidden fumonisins (2009) and their occurrence in raw maize (2010) increased health concerns. The involvement of fatty acids, both in hybrid susceptibility to contamination and in fumonisin esterification were recently also described. Therefore, oxylipins and their role in host plat-fungus cross-talk were considered in this project. A multifaceted approach was followed to describe the cross-talk that included: 1) artificial inoculation to study in detail the role of biological and ecological parameters; 2) field sampling to clarify the role of maize hybrids and the growth stage where their behaviour can be highlighted. All samples were managed with biological (fungal isolation, identification, mutant generation), chemical (fumonisin determination, lipidomic analysis)and molecular (fungal and plant gene expression, focus on LOX and LDS) approaches. The expected involvement of lipid composition of maize kernels in fungal infection and toxin accumulation was confirmed. Four lipid entities differentiated high-contaminated from low-contaminated samples (cut-off of 2000 micrograms/Kg of fumonisins), confirming that sphingolipid and oxylipin metabolism in maize kernels interfere with F. verticillioides growth and fumonisin production. FvLDS1 and ZmLOX12 in FB1 seem the genes most involved.