G-Protein coupled receptores in the host recognision

01.10.2005 - 30.04.2010
Research funding project
Trichoderma atroviride is a mycoparasitic fungus commercially applied as biological control agent against several fungal pathogens. The mycoparasitic interaction is host specific and includes recognition, attack and killing of the host through production of specialised infection structures, cell wall lysing enzymes, and antifungal metabolites. Investigations on the underlying signal transduction pathways of T. atroviride and T. virens revealed that alpha subunits of heterotrimeric G proteins, which are responsible for transducing signals from transmembrane G protein-coupled receptors (GPCRs) to a variety of intracellular targets, are involved in host recognition and activation of the mycoparasitic response. Besides their role in the regulation of general growth properties and conidiation, Tga1 and Tga3, the subgroup I and III G alpha subunits of T. atroviride, were shown to directly affect mycoparasitism-related processes like chitinase gene transcription, antifungal metabolite production, and formation of infection structures. Extracellular signals such as diffusible host-derived molecules or lectins present on the host surface were previously shown to induce enzyme production and infection structure formation (coiling, appresoria) in Trichoderma, but until now the involved receptors transducing these host-derived signals to intracellular signalling pathways have not been identified. Based on the fundamental role of G protein signalling in mycoparasitism, the aim of the proposed project is the isolation of GPCRs from T. atroviride and the elucidation of their functions by generating respective knockout mutants. Furthermore, by applying the yeast Two-Hybrid system direct interactions of the isolated GPCRs with the Trichoderma G protein alpha and beta ¿nsubunits Tga1, Tga2, Tga3, and Tgb1 shall be identified and for those receptors which are mycoparasitism-related additional interaction partners shall be screen for. As the knowledge on Trichoderma signalling pathways involved in transducing host-derived signals is very limited, the isolation and characterisation of the responsible receptors being on the top of the respective signalling cascade and the identification of their interaction partners would be a milestone for a better understanding of the processes underlying mycoparasitism in this important biocontrol fungus. As Trichoderma also interacts with the plant, the expected results could lead to establishment of Trichoderma as a model for reciprocal interactions between the three participants Trichoderma-host-plant.

People

Project leader

Project personnel

Institute

Grant funds

  • FWF - Österr. Wissenschaftsfonds (National) Austrian Science Fund (FWF)

Research focus

  • Biological and Bioactive Materials: 50%
  • Structure-Property Relationsship: 50%

Keywords

GermanEnglish
TrichodermaTrichoderma
Biokontrollebioconrol
G-ProteineG-Proteins
RezeptorenReceptors

External partner

  • IFA Tulln

Publications