title: Differentially regulated high-affinity iron assimilation systems support growth of the various cell types in the dimorphic pathogen Talaromyces marneffei.
abstract: Iron is a key trace element important for many biochemical processes and its availability varies with the environment. For human pathogenic fungi iron acquisition can be particularly problematical because host cells sequester free iron as part of the acute-phase response to infection. Fungi rely on high-affinity iron uptake systems, such as reductive iron assimilation (RIA) and siderophore-mediated iron uptake (non-RIA). These have been extensively studied in pathogenic fungi that exist outside of host cells, but much less is known for intracellular fungal pathogens. Talaromyces marneffei is a dimorphic fungal pathogen endemic to Southeast Asia. In the host T. marneffei resides within macrophages where it grows as a fission yeast. T. marneffei has genes of both iron assimilation systems as well as a paralogue of the siderophore biosynthetic gene sidA, designated sidX. Unlike other fungi, deletion of sidA or sidX resulted in cell type-specific effects. Mutant analysis showed that T. marneffei yeast cells also employ RIA for iron acquisition, providing an additional system in this cell type that differs substantially from hyphal cells. These data illustrate the specialized iron acquisition systems used by the different cell types of a dimorphic fungal pathogen and highlight the complexity in siderophore-biosynthetic pathways amongst fungi.
authors: Department of Genetics, University of Melbourne, Victoria, 3010, Australia.
authors: Shivani
authors: S
authors: Pasricha
authors: Division of Molecular Biology and Division of Clinical Biochemistry and the Protein Micro-Analysis Facility, Innsbruck Medical University, Innsbruck, Innrain 80-82, Innsbruck, A-6020, Austria.
authors: Lukas
authors: L
authors: Schafferer
authors: Division of Molecular Biology and Division of Clinical Biochemistry and the Protein Micro-Analysis Facility, Innsbruck Medical University, Innsbruck, Innrain 80-82, Innsbruck, A-6020, Austria.
authors: Herbert
authors: H
authors: Lindner
authors: Department of Genetics, University of Melbourne, Victoria, 3010, Australia.
authors: Kylie
authors: K
authors: Joanne Boyce
authors: Division of Molecular Biology and Division of Clinical Biochemistry and the Protein Micro-Analysis Facility, Innsbruck Medical University, Innsbruck, Innrain 80-82, Innsbruck, A-6020, Austria.
authors: Hubertus
authors: H
authors: Haas
authors: Department of Genetics, University of Melbourne, Victoria, 3010, Australia.
authors: Alex
authors: A
authors: Andrianopoulos
mesh_terms: D053898:Biosynthetic Pathways; D005502:Food; D006706:Homeostasis; D025301:Hyphae / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008264:Macrophages / Q000382:microbiology; D017262:Siderophores / Q000378:metabolism*; D032901:Talaromyces / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D017262:Siderophores; D007501:Iron