Dynamic Cell Wall Architecture in Trichoderma Mycoparasitism

Plant pests represent an enormous burden for agriculture. Filamentous soil fungi of the genus Trichoderma spp. are particularly known for their parasitic behavior towards phytopathogenic fungi. These mycoparasites attack pathogens by special infectious structures, by the production of metabolites and the secretion of enzymes. Thus, the use of mycoparasites as biological control agents, represents a promising alternative to conventional chemical pesticides in agrobiotechnology. Despite the rigid shape, the cell wall of fungi is dynamically restructured during growth and in particular during mycoparasitism. The ability to invade host organisms requires adaptive structuring of the cell wall outer layer to prevent recognition by the host and its defensive responses. This flexibility ensures an enormous adaptability to changing environmental conditions, but also increases the resistance against hosts. The most important components of the fungal cell wall are chitin, chitosan and glucan. Chitosan, the deacetylated form of chitin, in particular plays a prominent role in the resistance of filamentous fungi during interaction with a host. Strategies, by which the cell wall evades the host`s immune system are common to all plant and human pathogens, but have not yet been elucidated in mycoparasites. The project deals with the characterization of the dynamic interplay of chitin, chitosan and glucan in the cell wall of Trichoderma atroviride, and selected modulating enzymes. Using fluorescence microscopic methods, the synergistic behavior of the most important enzymes during the mycoparasitic interaction and in hyphal development will be analyzed. In addition, chitosan will be microscopically analyzed in real time in cooperation with national project partners. Thus, the development of a chitosan-specific probe enables detection in vivo and could be used as a rapid test for the detection of microbes in general. The present study aims to obtain a holistic picture of the dynamic Trichoderma cell wall during mycoparasitism compared to vegetative growth. In addition, studying Trichoderma atroviride helps expand knowledge about organic farming. The climate crisis requires a reassessment of biological crop control with regard to the changed EU laws. Ultimately, the knowledge gained could also be transferred to pathogenic fungi for humans, animals, plants, and thus advance the development of new, more effective antimycotics for the future.