title: HapX-mediated iron homeostasis is essential for rhizosphere competence and virulence of the soilborne pathogen Fusarium oxysporum.
abstract: Soilborne fungal pathogens cause devastating yield losses and are highly persistent and difficult to control. During the infection process, these organisms must cope with limited availability of iron. Here we show that the bZIP protein HapX functions as a key regulator of iron homeostasis and virulence in the vascular wilt fungus Fusarium oxysporum. Deletion of hapX does not affect iron uptake but causes derepression of genes involved in iron-consuming pathways, leading to impaired growth under iron-depleted conditions. F. oxysporum strains lacking HapX are reduced in their capacity to invade and kill tomato (Solanum lycopersicum) plants and immunodepressed mice. The virulence defect of ΔhapX on tomato plants is exacerbated by coinoculation of roots with a biocontrol strain of Pseudomonas putida, but not with a siderophore-deficient mutant, indicating that HapX contributes to iron competition of F. oxysporum in the tomato rhizosphere. These results establish a conserved role for HapX-mediated iron homeostasis in fungal infection of plants and mammals.
authors.affiliation: Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain.
authors.forename: Manuel S
authors.initials: MS
authors.lastname: López-Berges
authors.forename: Javier
authors.initials: J
authors.lastname: Capilla
authors.forename: David
authors.initials: D
authors.lastname: Turrà
authors.forename: Lukas
authors.initials: L
authors.lastname: Schafferer
authors.forename: Sandra
authors.initials: S
authors.lastname: Matthijs
authors.forename: Christoph
authors.initials: C
authors.lastname: Jöchl
authors.forename: Pierre
authors.initials: P
authors.lastname: Cornelis
authors.forename: Josep
authors.initials: J
authors.lastname: Guarro
authors.forename: Hubertus
authors.initials: H
authors.lastname: Haas
authors.forename: Antonio
authors.initials: A
authors.lastname: Di Pietro
mesh_terms: D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005670:Fusarium / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D006706:Homeostasis; D007501:Iron / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000276:immunology* / Q000382:microbiology; D008297:Male; D051379:Mice; D010802:Phylogeny; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018517:Plant Roots / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D058441:Rhizosphere; D016415:Sequence Alignment; D017384:Sequence Deletion; D017262:Siderophores / Q000235:genetics / Q000378:metabolism; D014774:Virulence
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D005656:Fungal Proteins; D017262:Siderophores; D007501:Iron