Format

Send to

Choose Destination
Plant Signal Behav. 2013 Feb;8(2):e23012. doi: 10.4161/psb.23012. Epub 2013 Jan 8.

Iron competition in fungus-plant interactions: the battle takes place in the rhizosphere.

Author information

1
Departamento de Genética; Universidad de Córdoba; Córdoba, Spain; Campus de Excelencia Internacional Agroalimentario (ceiA3); Córdoba, Spain.
2
Unitat de Microbiologia; Facultat de Medicina i Ciències de la Salut; Institut d'Investigació Sanitària Pere Virgili; Universitat Rovira i Virgili; Reus, Spain.
3
Division of Molecular Biology/Biocenter; Innsbruck Medical University; Innsbruck, Austria.
4
Institut de Recherches Microbiologiques Jean-Marie Wiame; Brussels, Belgium.
5
Department of Bioengineering Sciences; Research Group Microbiology and Flanders Institute for Biotechnology; Department of Structural Biology; Vrije Universiteit Brussel; Brussels, Belgium.
6
Departamento de Genética; Universidad de Córdoba; Córdoba, Spain; Unitat de Microbiologia; Facultat de Medicina i Ciències de la Salut; Institut d'Investigació Sanitària Pere Virgili; Universitat Rovira i Virgili; Reus, Spain.

Abstract

Soilborne fungal pathogens are highly persistent and provoke important crop losses. During saprophytic and infectious stages in the soil, these organisms face situations of nutrient limitation and lack of essential elements, such as iron. We investigated the role of the bZIP transcription factor HapX as a central regulator of iron homeostasis and virulence in the vascular wilt fungus Fusarium oxysporum. This root-infecting plant pathogen attacks more than hundred different crops and is an emerging human opportunistic invader. Although iron uptake remains unaffected in a strain lacking HapX, de-repression of genes implicated in iron-consuming processes such as respiration, amino acid metabolism, TCA cycle and heme biosynthesis lead to severely impaired growth under iron-limiting conditions. HapX is required for full virulence of F. oxysporum in tomato plants and essential for infection in immunodepressed mice. Virulence attenuation of the ΔhapX strain on tomato plants is more pronounced by co-inoculation of roots with the biocontrol strain Pseudomonas putida KT2440, but not with a mutant deficient in siderophores production. These results demonstrate that HapX is required for iron competition of F. oxysporum in the tomato rhizosphere and establish a conserved role for HapX-mediated iron homeostasis in fungal infection of plants and mammals.

KEYWORDS:

Fusarium; HapX; Pseudomonas; iron; rhizosphere; siderophores; virulence

PMID:
23299422
PMCID:
PMC3656999
DOI:
10.4161/psb.23012
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Taylor & Francis Icon for PubMed Central
Loading ...
Support Center