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Title: RDNA AND TEF1-ALPHA SEQUENCES RESOLVE FUNGAL SPECIES WITHIN TRICHODERMA SECT. TRICHODERMA

Author
item DODD, SARAH - PENN STATE UNIVERSITY
item Samuels, Gary

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Trichoderma sect. Trichoderma is one of five sections within the fungal asexual genus Trichoderma. The section currently includes three species viz. T. viride, T. atroviride and T. koningii. These species are ubiquitous and frequently cited in biocontrol and ecology literature. Recent comparison of DNA sequences of the ITS regions of the ribosomal gene complex (rDNA) indicated that these species hardly differ from each other and might even be considered one species. This is supported by the fact that the species T. viride was split between two ITS sequence types. Moreover, the Hypocrea teleomorphs (sexual equivalents) of these Trichoderma species all fit the H. rufa species description and are, therefore, morphologically similar and possibly indistinguishable. For this taxonomic study we sequenced the ITS rDNA and the translation elongation factor (tef 1-_à) genes of 180 Trichoderma/Hypocrea putative members of T. sect. Trichoderma and of the closely related section T. sect. Pachybasium. Comparison of sequence data from the ITS-1 region revealed a strongly supported, but unresolved, group consisting of the species T. asperellum (T. sect Pachybasium) and T. hamatum (T. sect Pachybasium), plus the three T. sect Trichoderma species T. viride, T. atroviride, and T. koningii. Preliminary results from the examination of tef1-à sequences revealed the resolution of more species than was achieved using ITS sequence data. In particular, the resolution of species T. atrovirirde was well supported. However, the T. koningii, and to a lesser extent the T. viride species, remained dispersed among diverse genotypes. To conclude, results to date indicate that there are more than the three currently recognized species within T. sect Trichoderma.