Ultrastructural and cytochemical aspects of the interaction between the ectomycorrhizal fungus Laccaria laccata and the saprotrophic fungi, Trichodermaharzianum and T. virens

Abstract

Different interactions between soil fungi competing in the rhizosphere with each other are necessary to understand their influence on plant growth and health. The interactions between the ectomycorrhizal (ECM) fungus Laccaria laccata and soil saprotrophic fungi (T. harzianum, T. virens) were studied by transmission electron microscopy, and by gold cytochemistry to assess the potential role of cell wall lytic enzymes in mycoparasitism. Anti-β-1,3-glucan antibody, WGA/ovomucoid–gold complex and PATAg test were used to localize β-1,3-glucan, chitin and polysaccharides. Cytoplasm disorganisation of the saprotrophic fungi occurred concurrently with dissolution of β-1,3-glucan in walls of hyphae and conidia of the saprotrophic fungi. Then digestion of polysaccharides and chitin of colonised fungal structures occurred. The studies suggest sequential contribution of cell wall lytic enzymes and importance of disturbing the host's cell integrity during mycoparasitism. We conclude that the ECM fungus can parasitise on the saprotrophic fungi not only in dual culture on artificial medium but also in the rhizosphere of Scots pine.

Keywords:

• Ectomycorrhizal fungi
• saprotrophic fungi
• antagonism
• mycoparasitism
• cytochemistry

Acknowledgements

This study was supported financially by the Polish Committee for Scientific Research, grants: No. 3 P04C 064 22. We would like to thank Jori N. Sharda for correcting the text and valuable discussions. Special credit is due to Professor Paweł Pukacki for valuable help during gold preparation.