Submitted to: Mycological Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/1996
Publication Date: N/A
Interpretive Summary: Diseases caused by fungi result in millions of dollars damage to agricultural crops and crop products each year. Many of these fungal diseases can be controlled using environmentally friendly means. Members of the fungal genus Trichoderma are useful as agents of biological control for many of these disease. An accurate classification of these fungi is needed in order to locate and identify strains that will be useful in biological control. Using RAPD analyses strains of fungi Trichoderma section Longibrachiatum were studied to determine their genetic relatedness. It was determined that several species should be recognized as distinct. In general, these species correlate with their geographic distribution. Based on the results of this paper, those seeking improved methods of biological control may be able to locate fungi in nature that serves as effective agents for the biological control of diseases.
Technical Abstract: Randomly polymorphic DNA amplification (RAPD), has been used to analyze 145 isolates characteristic of Trichoderma sect. Longibrachiatum and Hypocrea species with anamorphs referable to that section, and to identify strains with named species of sect. Longibrachiatum. To this end, ex-type strains of T. longibrachiatum, T. pseudokoningii, T. citrinoviride, T. parceramosum, and T. reesei were analyzed, and the similarity coefficients of RAPD characters used as a criterion for the alignment of strains to individual species. The ex-type strains of T. saturnisporum and T. ghanense exhibited the same interspecific similarity index as the other ex-tape strains of Trichoderma sect. Longibrachiatum, and clustered well within it Most of the anamorphic isolates could be aligned with T. citrinovride or T. longibrachiatum, whereas only a few strains of T. saturnisporum and T. parceramosum were found. No naturally occurring anamorphs with homology to the ex-type strains of T. reesei and T. pseudokoningii were found. While T longibrachiatum and T. citrinoviride overlapped through much of their geographic ranges the former was present in Africa and India but not in South East Asia, while the reverse was true of the latter. The African strains of T. longibrachaitum were equally distant from the ex-type strains of T. longibrachiatum, T. paraceramosum and T. saturnisporum. The type strain of T. ghanense was identifed as belonging to this group. T. pseudokoningii, the anamorhp of H. cf. schweinitzii was found exclusively in eastern Australia and New Zealand. No Hypocrea strains could be identified as teleomorphs of T.longibrachiartum,T. paraceramosum or T. saturnisporum.