Secondary Metabolism in Trichoderma: Chemo- and Geno-Diversity

Trichoderma species are filamentous ascomycetous fungi that have wide biotechnological applications in industry as well as agriculture. Having nearly 300 species, this genus represents one of the most diverse groups of fungi. Secondary metabolites are useful natural products having widespread applications in agriculture and medicine. Trichoderma species are prolific producers of secondary metabolites (natural products) with proven role in disease suppression. Genes for biosynthesis of these metabolites are often present as gene clusters, and one such cluster may be responsible for synthesis of a range of metabolites and intermediates. Depending on the chemical nature, these metabolites could be grouped as non-ribosomal peptides, polyketides, terpenes, steroids, etc. Three species of Trichoderma (T. virens, T. atroviride, and T. reesei) are well studied from genomics point of view, and this article focuses mainly on these three species. We discuss here the level of diversity with respect to secondary metabolite biosynthesis machinery at the genus, species, and strain level with genetic evidence where available. The article highlights the untapped potential of Trichoderma spp. as a source of a variety of secondary metabolites with potential applications in agriculture and medicine.