Mycotoxin contamination in oats, - characterization of the infection process by the major T-2 and HT-2 toxin producer Fusarium langsethiae

The trichothecene deoxynivalenol (DON) is frequently found in wheat. However, in Norway also the more toxic trichothecenes T-2 and HT-2 are often found, particularly in barley and oats. In 1999 Langseth and Rundberget concluded that 'Norwegian oats were f ound to contain HT-2 and T-2 toxin in concentrations that might be a threat to human health for high consumers of oats.' The newly identified Fusarium species, F. langsethiae has been observed in countries all over the world but seem to pose a serious pro blem only in the northern regions where it is recognised as the major contributor to the contamination by T-2 and HT-2 toxins in cereal grains. Grain lots infected by F. langsethiae do not show any visible symptoms, and grain samples highly contaminated w ith T-2 and HT-2 can thus not be distinguished from uncontaminated cereal grains. The situation with F. langsethiae in oats resulting in very high toxin levels represents a serious problem, and in the proposed research project our aim is to address this p roblem. While the infection process of F. graminearum in wheat and barley is well described, nothing is known about the infection process of oats. We will apply a general approach (SSH) to identify candidate genes that might be involved in the infection. A more specific approach will be used to characterize the function of specific candidate genes in pathogenicity. Further on, a directed approach will be used to study the infection of F. langsethiae using a GFP reporter strain, and to disrupt the mycotoxi n-producing pathway to investigate the role of the T-2 and HT-2 toxins in pathogenicity. This project will broaden our knowledge of the infection process by identifying genes, mechanisms, and/or signalling pathways critical for the infectious ability of F usarium on cereals. Such knowledge will form a crucial basis for future development of novel, stable, and environmentally sensible disease management practices that will ensure food safety and quality.