Trichoderma: the genomics of opportunistic success

Key Points Trichoderma is a genus of filamentous fungi that display a range of lifestyles and interactions with other fungi, animals and plants.Because of their ability to antagonize plant-pathogenic fungi and to stimulate plant growth and defence, some Trichoderma strains are used for biological control of plant diseases. A recent comparative analysis of the genomes from Trichoderma reesei , Trichoderma virens and Trichoderma atroviride (known as Hypocrea jecorina , Hypocrea virens and Hypocrea atroviridis in their respective teleomorphic (sexual) forms) has revealed that mycotrophy seems to be an ancient trait of the genus, as illustrated by an amplification of several gene families that encode proteins and enzymes involved in antagonism and killing of other fungi. Mycotrophy and various forms of parasitism on other fungi (mycoparasitism), combined with broad environmental opportunism, seem to have driven the evolution of the present interactions of Trichoderma spp. with plants and animals. The presence of potential fungal prey and plant root-derived nutrients in the plant rhizosphere may have been major attractors for the colonization of the rhizosphere by Trichoderma spp. ancestors. The phylogeny of Trichoderma strains suggests that endophytic strains and strains that are facultative pathogens of humans have recently evolved towards these new niches (that is, plant and animal tissues). This evolution may have been facilitated by the presence of genes that enable effective competition and opportunism. Trichoderma spp. are common filamentous fungi that interact with other fungi, animals and plants and are used for biological control of plant diseases. In this Review, Kubicek and colleagues highlight how saprotrophy and parasitism on other fungi may have driven the evolution of the interactions of Trichoderma spp. with plants and animals. Trichoderma is a genus of common filamentous fungi that display a remarkable range of lifestyles and interactions with other fungi, animals and plants. Because of their ability to antagonize plant-pathogenic fungi and to stimulate plant growth and defence responses, some Trichoderma strains are used for biological control of plant diseases. In this Review, we discuss recent advances in molecular ecology and genomics which indicate that the interactions of Trichoderma spp. with animals and plants may have evolved as a result of saprotrophy on fungal biomass (mycotrophy) and various forms of parasitism on other fungi (myco