Fusarium Infection in Wheat, Aggressiveness and Changes in Grain Quality: A Review

Fusarium Head Blight, one of the most devasting diseases on small-grain cereals, has caused severe epidemics worldwide, altering yield and quality parameters of grains and contaminating them with fungal toxins. The aggressiveness of Fusarium spp. could be ascribed to different mechanisms, such as the production and release of extracellular plant-cell-wall-degrading enzymes and proteases which are crucial in the processes of fungal colonization and disease establishment. Once infection is established, mycotoxins are released, and they interfere with the metabolism of the host. Wheat grains damaged by Fusarium graminearum present changes in their cell structure and in the composition of carbohydrate, protein and starch granules of the endosperm, which modify their physical and chemical properties, altering the desired quality characteristics for baked goods. The protein content of wheat is one of the main determinants of its commercial value since the industrial quality of the grain depends on the concentration and type of its proteins. To evaluate the quality and end use of flour, laboratories and industries use different techniques to analyze its protein content. Since yield and quality of wheat grains depend on the genetic of cultivars, environment and level of infection in the harvested grains, this review focuses on the main events related to the infection by Fusarium and the evaluation of the disease from grains and flour. Special attention to changes in the protein fraction are discusses, due to its direct relationship with the commercial value.