The Influence Of Fusarium And Its Mycotoxins On Wheat Kernels

Fusarium head blight(FHB), one of the major fungal diseases of cereals worldwide, affect the wheat development and the wheat kernels. FHB has a bad influence on the quliaty of wheat kernels, and mycotoxins which the Fusarium produced is limited in our national standards. The quantity of research on FHB is small and there have been few studies have unanimous conclusions. To explore how FHB effect grain quality of wheat, we inoculated the wheat after flowering two days. We paid attention to the changes of the structure and qulity of the wheat kernesls, and analysis the changes of protein and starch granules in wheat kernels. We had a few conclusions as follows:(1) Compared to the sound one, There many changes in the pericarp, crease, embryos and aleurone regions in FDK. FDK had a lot of cavities that appeared primarily in the pericarp, crease, and aleurone regions. Pin-holes and craters were frequent found on FDK kernel surfaces, both close to and far from the presence of fungal hyphae.(2) There were big change in embryos and aleurone layers. Some characteristic structures of embryos and aleurone layers were replaced with honeycomb-like substances in the FDK.(3) In heavily infected kernels, the protein matrix in starchy endosperm were partly or completely disappeared. The cell walls disappeared. Big holes could be seen in the equatorial plane or on the lateral surfaces of starch granules, and the outline of some starch granules was hard to be seen.(4) we found little change in total protein content, but the quality of the protein had been changed a lot. From the result of HPLC about whole protein, we can see that high molecular weight proteins is close to disappearing. Small molecular weight proteins, emerged relative increase in FDK. UPP% was smaller in FDK. The gliadin content of FDK decreased, especially the α-/β-and γ-gliadin.(5) we found that grain hardness index and kernel weight of FDK have declined, and grain viability decreased.(6) There were an decrease in amylose content, a change in the starch pasting properties; what’s more, there was little change in fat content, which was similar to the fatty acid composition in FDK.(7) DON content in bread made of wheat flour were without reduction, and DON content in the center portion of bread is higher than bread epidermis by 30%. DON content did not increase in steamed bread, and DON content in the center portion is higher than steamed bread epidermis by 18%. DON content in cooked noodles decreased by 42%. DON content in cookies decreased by 57%.In summary, the infection of Fusarium will not only damage to the structure of the wheat, but also affect the forming of grain quality, resulting in bad quality of wheat grain, especially on protein and starch. What we found will also provide further explanation of how Fusarium and its toxins change wheat quality.