Antimicrobial secondary metabolites from Trichoderma spp. as next generation fungicides

Abstract

Abstract The exploitation of antagonistic potential and plant-growth-promoting factors in microorganism is a well-investigated area in modern agriculture for plant protection. Trichoderma spp. is one of the highly potential biocontrol agents exploited for plant disease management and can be easily cultured by producing a rapid growth in the medium with natural conditions. Trichoderma is mostly associated with the plant root system thereby triggering systemic resistance and improving plant nutrient uptake. Several mechanisms have been proposed to explain the biocontrol potential of Trichoderma on the plant host. One factor that provides the beneficial biological activities of Trichoderma spp. is the wide range of metabolites that they produce. These metabolites have been found not only to directly inhibit the growth of the pathogen but also to trigger the defense system in the host plant to increase the disease resistance. Trichoderma spp. produces secondary metabolites in the form of antibiotic compounds, enzymes, toxins, and hormones. This review describes the important secondary metabolites produced by Trichoderma spp. and their ecological functions in the host plant. Many secondary metabolites of Trichoderma may also have antibiotic properties, which enable them to inhibit and/or kill other microorganisms. In addition to direct toxic activity against plant pathogens, biocontrol-related metabolites may increase disease resistance by triggering systemic plant defense activity and/or enhance root and shoot growth. The large-scale application of selected secondary metabolites to induce host resistance and/or to promote crop yield may be an effective alternative to chemicals. We discuss the bioactivity of selected Trichoderma-derived secondary metabolites with a focus on their roles in the interactions of Trichoderma between plants and fungal prey.