Inventory of the Genus Hypocrea in Europe

Within the ascomycetes the order Hypocreales contains many species which have economic and ecological importance, as pathogens of economically important crops, as pathogens of cultivated mushrooms, as sources of pharmaceuticals and mycotoxins, as biological control agents of plant pathogenic fungi, and as sources of industrial enzymes. Particularly important is the genus Trichoderma, which is one of the principal components of fungi in soil. Studies of this genus are therefore mainly carried out with material isolated from soil. Teleomorphs of this genus belong to the genus Hypocrea and occur commonly on wood, other plant material and various fungi. Due to limited morphological variation among the species of Hypocrea, identification based on gene sequences from genomic DNA extracted from mycelial isolates prepared from Hypocrea teleomorphs is essential in addition to morphological characterization. Project P16564 was mainly designed to assess the biodiversity of the genus Hypocrea in (Central) Europe, based on freshly collected teleomorphs, and to detect new species of Hypocrea and unknown connections between Hypocrea teleomorphs and Trichoderma anamorphs. The results of project P16564 exceed by far initial expectations regarding the number of species occurring in Europe. Based on collected specimens 53 species were identified, ca. 20 of them being new to science. Until January 2006, 14 species have been fully characterized, and 2 of them published as new species. Due to the highly advanced and laborious standard in the characterization of species of Hypocrea / Trichoderma, it is impossible to describe all species in a single project. For this reason a follow-up project is proposed in order to (1) characterize and describe the residual species using morphology of their teleomorphs, anamorphs, and synanamorphs, and their phylogenetic features, (2) to clarify the taxonomy of other species not collected within the project, (3) to reassess and redefine the concept of some poorly known species, (4) to clarify phylogenetic relationships of all species characterized by molecular data, (5) to analyze and document the ecology of the species collected, (6) to establish a complete inventory of the European species in a monograph providing a clear taxonomic basis for further studies which may involve enzymology and antibiotic and/or growth promoting traits of the isolates prepared in the project.

This work is an integral part of a larger project that has the objective to investigate the biodiversity of Hypocrea, i.e. how many and which species of this fungal genus exist in Europe, and to find as many new species as possible. Altogether 620 specimens were collected in Europe and nearly 500 cultures were prepared from them. Seventy five Hypocrea species were identified using gene sequences in combination with morphological and ecological data. This number exceeds all earlier estimations by far. Twenty seven species are new, of which 6 have been published. All residual species are described in a European monograph, published in 2 parts (first part: http://www.studiesinmycology.org/content/vol63/issue1/). Cultures of new species have been deposited in an official strain collection (CBS, Utrecht), where they are freely accessible after their publication. The cultures represent a substantial potential for future research on various aspects of Trichoderma. What makes Hypocrea / Trichoderma important ? Species of the moulds belonging to this genus produce a large number of substances, such as antibiotics (e.g. peptaibols) and enzymes like cellulases (to degrade plant material) or chitinases (to degrade fungi). Thus, they are applied in several spheres of life such as detergents, textile and paper industry, but also in the biological control of pathogenic fungi, and in the production of biofuels. The sexual stage of Trichoderma, Hypocrea, forms brightly coloured pillows, pustules or crusts on wood and bark, other fungi, and more rarely on grasses. Several hundred names have been established but it is unknown how many true species exist. To find out the number of known or new species in a certain area, they have to be collected intensively and analysed. Several methods were applied to identify and to characterise the collected species: morphology of the sexual state (Hypocrea), preparation of pure cultures and anamorphs (Trichoderma) from ascospores, morphology of the anamorphs, growth experiments, and determination of gene sequences to elucidate species limits and phylogenetic relationships.