Advertisement

Molecular and General Genetics MGG

, Volume 260, Issue 2–3, pp 218–225 | Cite as

The expression of genes involved in parasitism by Trichoderma harzianum is triggered by a diffusible factor

  • C. Cortés
  • A. Gutiérrez
  • V. Olmedo
  • J. Inbar
  • I. Chet
  • A. Herrera-Estrella
ORIGINAL PAPER

Abstract

The mycoparasite Trichoderma harzianum has been extensively used in the biocontrol of a wide range of phytopathogenic fungi. Hydrolytic enzymes secreted by the parasite have been directly implicated in the lysis of the host. Dual cultures of Trichoderma and a host, with and without contact, were used as means to study the mycoparasitic response in Trichoderma. Northern analysis showed high-level expression of genes encoding a proteinase (prb1) and an endochitinase (ech42) in dual cultures even if contact with the host was prevented by using cellophane membranes. Neither gene was induced during the interaction of Trichoderma with lectin-coated nylon fibres, which are known to induce hyphal coiling and appressorium formation. Thus, the signal involved in triggering the production of these hydrolytic enzymes by T. harzianum during the parasitic response is independent of the recognition mediated by this lectin-carbohydrate interaction. The results showed that induction of prb1 and ech42 is contact-independent, and a diffusible molecule produced by the host is the signal that triggers expression of both genes in vivo. Furthermore, a molecule that is resistant to heat and protease treatment, obtained from Rhizoctonia solani cell walls induces expression of both genes. Thus, this molecule is involved in the regulation of the expression of hydrolytic enzymes during mycoparasitism by T. harzianum.

Key words Biocontrol   Mycoparasitism   Chitinase    Protease   Cell wall 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • C. Cortés
    • 1
  • A. Gutiérrez
    • 1
  • V. Olmedo
    • 1
  • J. Inbar
    • 2
  • I. Chet
    • 2
  • A. Herrera-Estrella
    • 1
  1. 1.Centro de Investigación y Estudios Avanzados Plant Biotechnology and Genetic Engineering Unit Apartado Postal 629, 36500 Irapuato Gto., México e-mail: aherrera@irapuato.ira.cinvestav.mx Fax: +52-462-45849
  2. 2.The Hebrew University of Jerusalem Otto Warburg Center for Agricultural Biotechnology Faculty of Agriculture, P.O. Box 12 Rehovot 76100, IsraelIL

Personalised recommendations