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ARS Home » Research » Publications at this Location » Publication #87669


item Samuels, Gary

Submitted to: Canadian Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: The development of management strategies to control fungal diseases through the use of biological control agents as well as the search for more effective industrial enzymes are hindered by lack of knowledge about species in the genus Trichoderma and its sexual state, Hypocrea. Some species have never been adequately characterized and their concepts are confused in the literature. Such is the case with Trichoderma koningii, a species for which a type specimen no longer exists. A strain of this fungus has been selected as the neotype that will serve as the standard reference for this species. Using strains from throughout the world, Trichoderma koningii and its Hypocrea sexual state are described using both morphological and molecular characteristics. These results will be useful to agricultural scientists who need to identify these fungi as well as to scientists working on the development of novel agents for the biological control of disease-causing fungi.

Technical Abstract: A neotype is selected for Trichoderma koningii. The species is redescribed by morphological and molecular characters, the latter including PCR fingerprinting and RFLP analysis and direct sequencing of the variable regions of the ribosomal DNA (internal transcribed spacers 1 and 2, ITS-1 and ITS-2). The neotype was selected from among four cultures obtained from msoil at the type locality. These cultures were compared to a broader collection of Trichoderma strains and anamorphs of Hypocrea that morphologically conform to T. koningii. Comparison was also made to the Hyppocrea rufa complex (Trichoderma sect. Trichoderma) and to the Hypocrea schweinitzii complex (Trichoderma sect. Longibrachiatum). According to its ITS sequences, T. koningii is a member of the H. rufa complex, showing very low variability in comparison to T. viride or T. atroviride. We found 5 additional strains from various geographical regions that are identical to the neotype in morphology and in their sequences. One of them is Hypocrea koningii sp. nov, which we consider to be the teleomorph of T. koningii. PCR fingerprint patterns demonstrate the high genetic similarity of these nine strains. There was only low similarity in molecular characters between T. koningii and the H. schweinitzii complex despite morphological similarities.