Differential toxicity of antifungal protein AFP against mutants of Fusarium oxysporum Authors Magdalena Martín-Urdiroz Department of Genetics, University of Córdoba, Córdoba, Spain School of Biosciences, University of Exeter, Exeter, United Kingdom Ana L. Martínez-Rocha Department of Genetics, University of Córdoba, Córdoba, Spain School of Biosciences, University of Exeter, Exeter, United Kingdom Antonio Di Pietro Department of Genetics, University of Córdoba, Córdoba, Spain Álvaro Martínez-del-Pozo Departament of Biochemistry and Molecular Biology I, Faculty of Chemical Sciences, Complutense University of Madrid, Madrid, Spain M. Isabel G. Roncero Department of Genetics, University of Córdoba, Córdoba, Spain Keywords: Fusarium oxysporum, antifungal protein, chitin synthase, cell wall Abstract Antifungal protein (AFP) from Aspergillus giganteus was assayed for toxicity against the Fusarium oxysporum wild-type strain and mutants in genes involved in cell signaling (ΔpacC, pacCc Δfmk1) or cell-wall biogenesis (ΔchsV, Δchs7, Δgas1). The mutants were classified into two groups according to their sensitivity to AFP: ΔpacC, Δgas1 and Δchs7, which were significantly more resistant to AFP than the wild-type, and pacCC, Δfmk1 and ΔchsV, which were more sensitive. Western blot analysis revealed increased binding of AFP to the three resistant mutants, ΔpacC, Δgas1 and Δchs7, but also to ΔchsV, indicating that differential binding may not be a key determinant for sensitivity. Addition of Ca2+ or K+ dramatically reduced antifungal activity and binding of AFP, suggesting that these cations compete for the same targets as AFP at the surface of the fungal cell. [Int Microbiol 2009; 12(2):115-121] Author Biographies Magdalena Martín-Urdiroz, Department of Genetics, University of Córdoba, Córdoba, Spain School of Biosciences, University of Exeter, Exeter, United Kingdom Department of Genetics, University of Córdoba, Córdoba, Spain School of Biosciences, University of Exeter, Exeter, United Kingdom Ana L. Martínez-Rocha, Department of Genetics, University of Córdoba, Córdoba, Spain School of Biosciences, University of Exeter, Exeter, United Kingdom Department of Genetics, University of Córdoba, Córdoba, Spain School of Biosciences, University of Exeter, Exeter, United Kingdom Antonio Di Pietro, Department of Genetics, University of Córdoba, Córdoba, Spain Department of Genetics, University of Córdoba, Córdoba, Spain Álvaro Martínez-del-Pozo, Departament of Biochemistry and Molecular Biology I, Faculty of Chemical Sciences, Complutense University of Madrid, Madrid, Spain Departament of Biochemistry and Molecular Biology I, Faculty of Chemical Sciences, Complutense University of Madrid, Madrid, Spain M. Isabel G. Roncero, Department of Genetics, University of Córdoba, Córdoba, Spain Department of Genetics, University of Córdoba, Córdoba, Spain Downloads PDF Published 2010-01-13 Issue Vol. 12 No. 2 (2009) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.