Involvement of volatiles constituents from maize kernels on Fusarium Verticillioides infection.

FAUGUEL CM; CAMPOS BERMUDEZ VA; FERNANDEZ M; IGLESIAS J; SAMPIETRO D; ANDREO CS; PRESELLO DA

Simposio; 32nd New Phytologist Symposium; 2013

Many plants respond to fungal infection by releasing a specific blend of volatiles called oxylipins. The majority of oxylipins are produced through the lipoxygenase (LOX) pathway. The purpose of the current research was to examine LOX gene expression and oxylipin responses in kernels of six maize genotypes with contrasting response to Fusarium verticillioides infection. In inverted potato glucoseagar Petri plate bioassays, we found that volatiles emitted from mill grains of different maize genotypes had an intense effect on F. verticillioides growth. To determine the volatiles that could be responsible for the observed bioactivity, emitted volatiles were analyzed by SPME (Solid Phase Microextraction) and GC-MS. Field-susceptible maize genotypes exhibited a larger concentration of total volatiles when compared to field-resistant genotypes. C9-volatiles were the most prominent released oxylipins. A real time LOX study revealed that resistant genotypes had higher basal LOXs expression compared with the susceptible ones. This result indicates that it is likely that the products of the 9-LOX pathway can be used by F. verticillioides to promote infection in the susceptible genotype and that resistance may be mainly due to constitutive defense mechanisms preventing fungal infection.