Home • Trichoderma harzianum CBS 226.95 v1.0
Trichoderma harzianum image

Trichoderma harzianum Rifai, Mycol. Pap. 116: 38 (1969) A - pustules, B, D - conidiophores; C - shape of conidia (not scaled)

Image credits: Samuels, G.J., Chaverri, P., Farr, D.F., & McCray, E.B. Trichoderma Online Systematic Mycology and Microbiology Laboratory, ARS, USDA.

The filamentous fungus Trichoderma harzianum sensu stricto is the genetically distinct temperate agamospecies belonging to the group of closely related (cryptic), albeit diverse, species of the Harzianum clade of Trichoderma (teleomorph Hypocrea, Ascomycota, Dikarya). In the broad taxonomic sense these fungi (T. harzianum sensu lato) are the most frequent Trichoderma species cultivated from soil worldwide. They display a remarkable diversity of lifestyles ranging from saprotrophy in free soil and dead wood, in rhizosphere and on dead fungal biomass to biotrophy in necrotrophic mycoparasisitic attacks of other fungi and endophytic associations with plants. Because of its mycotrophyc ability T. harzianum has often been set equal to Trichoderma-based biocontrol agents in general, as it is the principal component in several commercial biofungicide formulations. It is used for foliar application, seed and soil treatments for suppression of various diseases causing by such pathogens as Botrytis, Fusarium and Penicillium sp. Although T. harzianum is not a causative agent of the green mold disease on mushroom farms it is frequently isolated from infected cultures of Agaricus and Pleurotus and respective substrata. Interestingly, the causative agents of the mushroom green mold diseases (T. aggressivum, T. pleurotum and T. pleuroticola, respectively) also belong to the Harzianum clade, i.e. are closely related to T. harzianum. Similar to T. virens (teleomorph Hypocrea virens), a rhizosphere-competent T. harzianum may not only grow on plant roots, but its hyphae penetrate root epidermis (endophytism), which enhances plant growth and immune system. Some molecular mechanisms of Trichoderma mycotrophy and interactions with plants - such as the role and regulation of formation of cell wall hydrolytic enzymes and antagonistic secondary metabolites - have been intensively investigated in T. harzianum. As a mycoparasitic and antagonistic fungus T. harzianum is suggested to be a powerful environmental opportunist, which is able to interplay in communities of invasive Trichoderma spp. in various disturbed ecosystems and thus replace or suppress the local mycofauna. Hence the genome sequence of such an outstanding opportunistic fungus as T. harzianum is expected to provide a platform to identify genetic resource to be used in pest control, development of biofungicides, improvement of plant health and in environmental monitoring.

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