Trichoderma spp.

 

Trichoderma species are important biological control agents used in plant disease management. They are imperfect fungi, with their teleomorph perfect stage belonging to Hypocreales of Ascomycetes. They are capable of secreting hydrolytic enzymes and cause mycoparasitism on fungal pathogens of plants.  Besides, they produce antibiotics and toxins that inhibit the fungal plant pathogens. They are better rhizosphere colonizers than the plant pathogens, hence competing with other organisms for food and space in rhizosphere there by reducing the chances of colonization by pathogenic fungi.

The study of the influence of environmental parameters on Trichoderma strains is of great importance when planning the application of strains for biocontrol. Strains used in applied biological control should have better stress tolerance levels than the targeted plant pathogens causing plant diseases. The important stress factors include high temperature, fungicides, salinity, low moisture and soil pH.  Though there are few reports on the susceptibility of Trichoderma species to these stresses in vitro, there is lack of comprehensive information on the mechanism(s) of stress tolerance in Trichoderma to these stresses, especially at biochemical and molecular level.

In India, there is great diversity in soil characteristics especially with respect to soil pH.  Trichoderma strains are able to grow in a wide range of pH from 2.0 to 6.0 with maximal growth rates at 4.0, the optimum range being 4.6 to 6.8. However there is a need to have strains specifically for saline soils and sodic soils.  Similarly, in major parts of country, high soil temperature is an important factor for the survival of Trichoderma species. The residual toxicity due to fungicides used for the control of soil borne pathogens is an important environmental concern. Therefore the improvement of stress tolerance in Trichoderma strains could result in increasing their efficacy against plant pathogenic fungi even under unfavourable  environmental conditions. For this purpose the understanding of molecular mechanisms with respect to stress tolerance is essential.  

In this NAIP project, it is proposed to study stress tolerance in Trichoderma with respect to these stresses at biochemical and molecular levels.  The outcome of this project may help us understand and predict the potential applicability of location-specific strains in agricultural soils with certain stresses like salinity, residual toxicity due to fungicides, low moisture and high temperature.

 

 

Trichoderma spores