Field trial on the interaction between mycotoxin producers Fusarium graminearum and F.poae

Fusarium head blight (FHB) is a very important cereal fungal disease. In Italy, it has been permanently present in wheat since 1995. The most frequent species of Fusarium causing the disease are F. graminearum, F. culmorum and recently F. poae. These species are responsible for yield losses and decreasing grain quality characteristics, including the accumulation of mycotoxins responsible of serious health effects to humans and animals. The most dominant F. graminearum mycotoxins are the trichothecenes, with deoxynivalenol and nivalenol being the most prevalent derivatives. F. poae is able to produce an extensive range of mycotoxins and, in some cases T-2 toxin and its derivative HT-2. T-2 toxin is the most dangerous among all trichothecenes of classes A and B, with an LD50 value 20-times lower than deoxynivalenol. F. graminearum and F. poae strains, producing different mycotoxins, were tested for their interaction in vitro and in vivo trials. The strains were inoculated singularly or mixed in a durum wheat cultivar sensible to FHB. The incidence and the severity of the disease were also evaluated. In the flour obtained from the grains, real-time PCR and HPLC-MS were used to estimate the biomass of F. graminearum/F. poae and determine the amounts of mycotoxins, respectively. The aim of this work was to investigate the direct interaction between F. graminearum and F. poae, which might substantially contribute to the population dynamic of these species in the field. The interest of the scientific community in F. poae has been steadily growing due to its potential to produce dangerous mycotoxins. In order to control Fusarium head blight and limit the contamination of grain with mycotoxins, we need to better understand the role of F. poae in the disease and its ecology including interaction with other pathogens colonizing wheat ears.