The Siderophore Ferricrocin Mediates Iron Acquisition in Aspergillus fumigatus
Isidor Happacher, Mario Aguiar, Mostafa Alilou, Beate Abt, Tim Baltussen, Clemens Decristoforo, Willem J. G. Melchers, Hubertus Haas
Abstract
Aspergillus fumigatus is one of the most common airborne fungal pathogens for humans. Low-molecular-mass iron chelators, termed siderophores, have been shown to play a central role in iron homeostasis and, consequently, virulence of this mold. Previous studies demonstrated the crucial role of secreted fusarinine-type siderophores, such as triacetylfusarinine C, in iron acquisition, as well as of the ferrichrome-type siderophore ferricrocin in intracellular iron storage and transport. Here, we demonstrate that ferricrocin is also secreted to mediate iron acquisition during germination together with reductive iron assimilation. During early germination, ferricrocin secretion and uptake were not repressed by iron availability, indicating developmental regulation of this iron acquisition system in this growth phase.