Fusarium head blight of wheat: pathogenic species and their mycotoxins

Fusarium head blight is a wheat disease of global importance and devastating impact in some years, especially in regions with high cereal production. Wheat grain contamination with mycotoxins is the result of head infection with several Fusarium pathogens. Among all metabolites accumulated in grain of wheat and other cereals infected with Fusarium culmorum and Fusarium graminearum, deoxynivalenol (DON) and other trichothecenes as well as zearalenone (ZEA) are accumulated with the highest levels and frequencies. Furthermore, moniliformin and enniatins were identified in several countries, where Fusarium avenaceum frequency was high. Several other species occurring with lower frequency have been reported. The chemotypes of individual isolates were established with the use of specific PCR markers. This review summarises the information on toxigenic Fusarium species infecting wheat heads, the morphological and molecular identification methods, toxic metabolites accumulated in the infected grain and on recent Fusarium genomic research. The interaction between the aggressive Fusarium pathogens and wheat host plant is discussed, particularly concerning the level of accumulation of DON and ZEA in grain samples. Various types of plant resistance against Fusarium head blight are described, together with wheat quantitative trait loci and DNA markers for their identification, that are useful for resistance breeding. Taking into account the risk of increased occurrence of several Fusarium mycotoxins, regulatory limits of DON, ZEA and fumonisins were established in EU, USA, Canada and other countries.