Siderophore in Ustilago maydis: Synthese, Transport, Funktion und Regulation

The phytopathogenic basidiomycete U. maydis acquires iron via two high-affinity iron upatke systems. The permease-based system is essentiell for virulence of U. maydis. In addition U. maydis produces the two siderophores ferrichrome and ferrichrome A. I identified 6 new enzymes that are involved in siderophore biosynthesis. Furthermore, it was posssible to identify siderophore im- and exporters. While the siderophores are dispensable for vireulence, they are crucial for iron storage in the vacuoles, the cytoplasm and the spores. The two high-affinity iron uptake systems are differentially regulated during biotrophic development within the host plant maize. This regulation is achived in response to H2O2 produced by the palnt as defense signal.