Trichoderma: Advent of Versatile Biocontrol Agent, Its Secrets and Insights into Mechanism of Biocontrol Potential

Trichoderma is an important biocontrol agent for managing plant diseases. Trichoderma species are members of the fungal genus hyphomycetes, which is widely distributed in soil. It can function as a biocontrol agent as well as a growth promoter. Trichoderma species are now frequently used as biological control agents (BCAs) to combat a wide range of plant diseases. Major plant diseases have been successfully managed due to their application. Trichoderma spp. is being extensively researched in order to enhance its effectiveness as a top biocontrol agent. The activation of numerous regulatory mechanisms is the major factor in Trichoderma ability to manage plant diseases. Trichoderma-based biocontrol methods include nutrient competition, mycoparasitism, the synthesis of antibiotic and hydrolytic enzymes, and induced plant resistance. Trichoderma species may synthesize a variety of secondary metabolites that can successfully inhibit the activity of numerous plant diseases. GPCRs (G protein-coupled receptors) are membrane-bound receptors that sense and transmit environmental inputs that affect fungal secondary metabolism. Related intracellular signalling pathways also play a role in this process. Secondary metabolites produced by Trichoderma can activate disease-fighting mechanisms within plants and protect against pathogens. β- Glucuronidase (GUS), green fluorescent protein (gfp), hygromycin B phosphotransferase (hygB), and producing genes are examples of exogenous markers that could be used to identify and track specific Trichoderma isolates in agro-ecosystems. More than sixty percent of the biofungicides now on the market are derived from Trichoderma species. These fungi protect plants from harmful plant diseases by developing resistance. Additionally, they can solubilize plant nutrients to boost plant growth and bioremediate environmental contaminants through mechanisms, including mycoparasitism and antibiosis. Enzymes produced by the genus Trichoderma are frequently used in industry. This review article intends to provide an overview update (from 1975 to 2022) of the Trichoderma biocontrol fungi, as well as information on key secondary metabolites, genes, and interactions with plant diseases.