Karlsruhe Institute of Technology (KIT) - South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Fritz-Haber-Weg 4, D-76131, Karlsruhe, Germany.
Karlsruhe Institute of Technology (KIT) - North Campus, Institute of Functional Interfaces, Bioengineering and Biosystems, Hermann-von-Helmholtz-Platz 1, D-76344, Eggenstein Leopoldshafen, Germany.
Sci Rep. 2020 Feb 27;10(1):3587. doi: 10.1038/s41598-020-60468-7.
Iron is one of the most abundant elements on earth and essential for life. However, Fe ions are rather insoluble and microorganisms such as fungi may use siderophores as strong chelators for uptake. In addition, free cytoplasmic iron is rather toxic and intracellular siderophores are used to control the toxicity. Siderophores are also important for iron storage. We studied two siderophore systems in the plant necrotrophic fungus Alternaria alternata and show that the non-ribosomal peptide synthase, Nps2, is required for the biosynthesis of intracellular ferricrocin, whereas Nps6 is needed for the formation of extracellular coprogen and coprogen B. Whereas nps2 was dispensable for growth on iron-depleted medium, nps6 was essential under those conditions. nps2 deletion caused an increase in spore formation and reduced pathogenicity on tomato. Our results suggest that A. alternata employs an external and an internal siderophore system to adapt to low iron conditions.
铁是地球上最丰富的元素之一，也是生命所必需的。然而，Fe 离子的溶解度较低，真菌等微生物可能会使用铁载体作为摄取的强螯合剂。此外，游离细胞质中的铁具有相当的毒性，细胞内的铁载体被用来控制毒性。铁载体对于铁的储存也很重要。我们研究了植物坏死真菌交链孢菌中的两种铁载体系统，结果表明，非核糖体肽合酶 Nps2 是细胞内三价铁血卟啉合成所必需的，而 Nps6 则是细胞外 coprogen 和 coprogen B 形成所必需的。虽然 nps2 缺失对缺铁培养基上的生长是可有可无的，但在这些条件下，nps6 是必不可少的。nps2 缺失导致孢子形成增加，对番茄的致病性降低。我们的研究结果表明，交链孢菌采用外部和内部铁载体系统来适应低铁条件。
