Suppression of Fusarium graminearium growth by differently structured starch types

摘要

We investigated the growth behavior and amylolytic enzymes of Fusarium graminearum cultivated on different types of native starch granules including barley (A-type crystalline polymorph), potato and Curcuma zedoaria (B-type crystalline polymorph), cassava (C-type crystalline polymorph), and high AM maize (A + Vh-type crystalline polymorphs). F. graminearum grew poorly on B-type starches and the accumulation of biomass was similar to that obtained for fungi cultivated under carbohydrate starvation conditions. In comparison, three- to fivefold higher accumulation of fungal biomass was observed for growth on the A-, C- and A + Vh-type starches. Fungal glucoamylase and a-amylase activity increased over time in the presence of native starch granules. Interestingly, resistant B-type starches induced the highest amylolytic activity indicating that F. graminearum interacts with B-type granules although only limited degradation occur. Starch degradation products maltose and malto-oligosacharides was found to increase glucoamylase and a-amylase activity, whereas glucose acted as a catabolite repressor.