Biotechnologically relevant enzymes and proteins

Antifungal mechanism of the Aspergillus giganteus AFP against the rice blast fungus Magnaporthe grisea
  • Ana Beatriz Moreno
  • Álvaro Martínez del Pozo
  • Blanca San Segundo
Biotechnologically Relevant Enzymes and Proteins

DOI: 10.1007/s00253-006-0362-1

Cite this article as:
Moreno, A.B., Martínez del Pozo, Á. & San Segundo, B. Appl Microbiol Biotechnol (2006) 72: 883. doi:10.1007/s00253-006-0362-1

Abstract

The mold Aspergillus giganteus produces a basic, low molecular weight protein showing antifungal properties against economically important plant pathogens, the AFP (Antifungal Protein). In this study, we investigated the mechanisms by which AFP exerts its antifungal activity against Magnaporthe grisea. M. grisea is the causal agent of rice blast, one of the most devastating diseases of cultivated rice worldwide. AFP was purified from the extracellular medium of A. giganteus cultures. The AFP protein was found to induce membrane permeabilization in M. grisea cells. Electron microscopy studies revealed severe cellular degradation and damage of plasma membranes in AFP-treated fungal cells. AFP however failed to induce membrane permeabilization on rice or human HeLa cells. Furthermore, AFP enters the fungal cell and targets to the nucleus, as revealed by co-localization experiments of Alexa-labeled AFP with the SYTOX Green dye. Finally, AFP binds to nucleic acids, including M. grisea DNA. Our results suggest that the combination of fungal cell permeabilization, cell-penetrating ability and nucleic acid-binding activity of AFP determines its potent antifungal activity against M. grisea. These results are discussed in relation to the potential of the AFP protein to enhance crop protection against fungal diseases.

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Ana Beatriz Moreno
    • 1
  • Álvaro Martínez del Pozo
    • 2
  • Blanca San Segundo
    • 1
  1. 1.Laboratorio de Genética Molecular Vegetal, Consorcio CSIC-IRTA, Departamento de Genética Molecular,Instituto de Biología Molecular de BarcelonaBarcelonaSpain
  2. 2.Departamento de Bioquímica y Biología Molecular I, Facultad de QuímicaUniversidad Complutense, Ciudad UniversitariaMadridSpain