From Biological Control to Bioactive Metabolites: Prospects with Trichoderma for Safe Human Food

Trichoderma, a commonly known mycoparasite inhabiting nearly all agricultural soils, has shown outstanding biological properties in controlling growth of other less desirable or more harmful (pathogenic) types of fungi. What makes Trichoderma very interesting is that it uses local materials (decaying products) for proliferation, is non-toxic and biodegradable, produces numerous useful metabolites with complex chemistry and performs diverse biological activities. What is more intriguing, however, is its ability to target a specific mechanism rather than killing or repelling organisms indiscriminately. Although the biological control ability of Trichoderma has been studied and proven for many years, the ability of these fungi to increase the rate of plant growth and development, particularly to enhance the production of more robust roots, is now being documented. While working on more than 260 strains of Trichoderma collected from different habitats, the researchers have documented the bio-control ability of these organisms, not only at laboratory level but also at the field level, as well as up to the extent of commercialization. Based on the study, the researchers also discovered that several strains increased the size and numbers of deep roots which were quite below the soil surface. These deep roots cause crops, such as corn, fruit crops and ornamental plants, to become more resistant to drought. Besides such potentialities, certain Trichoderma species are highly efficient producers of many extracellular enzymes and are used commercially for the production of cellulases and other enzymes which degrade complex polysaccharides. They are frequently used in the food and textile industries. In particular, Trichoderma protease appears to exhibit excellent mechanisms of action in controlling grey mold on the surface of bean leaf by preventing germination of mold spore and deactivating harmful mold enzymes. The researchers’ recent interests warrant the use of secondary metabolites as potential biopesticidal and biofungicidal agents. From the local free-living Trichoderma isolates, different chemical fractions are extracted and separated in search of novel bioactive metabolites for their in vitro testing against phytopathogenic fungi, bacteria and pests. In addition to this, the researches are now planning to extend such studies to the marine-derived Trichoderma species, such as Trichoderma reesie, with an aim to evaluate their biological activity and ability to be successfully used in field trials to control many crop pathogens.