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Title: REVISION OF TRICHODERMA SECT. LONGIBRACHIATUM INCLUDING RELATED TELEOMORPHSBASED ON ANALYSIS OF RIBOSOMAL DNA INTERNAL TRANSCRIBED SPACER SEQUENCES.

Author
item KUHLS, K - HUMBOLDT UNIV. GERMANY
item LIECHFELDT, E - HUMBOLDT UNIV GERMANY
item Samuels, Gary
item MEYER, WIELAND - DUKE UNIVERSITY
item KUBICEK, CHRISTIAN - TECHNISCHE UNIV AUSTRIA

Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/1997
Publication Date: N/A
Citation: 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 diseases. An accurate classification of these fungi is needed in order to locate and identify strains that will be useful in biological control. Using ITS, sequencing strains of fungi in 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. These data correlated with data obtained by RAPD analysis. Based on the results of this paper, those seeking improved methods of biological control may be able to locate fungi in nature that serve as effective agents for the biological control of diseases.

Technical Abstract: Variation within the internal transcribed spacer (ITS-1 and ITS-2) regions of ribosomal DNA of 99 strains was studied to examine the relationships within Trichoderma sect. Longibrachiatum and the related telemorphs Hypocrea schweinitzii and H. jecorina. The four species T. longibrachiatum, T. pseudokoningii, T. parceramosum and T. citrinoviride, that were originally assigned by morphological criteria to this section could be recognized by sequence analysis. Two additional species ere found to belong to this section: T. reesei, which was previously considered to be synonymous with T. longibrachiatum, and T. saturnisporum which was place originally in a different section (sect. Saturnisporum) because of its unusual morphological features. Trichoderma "todica", is T. parceramosum. rDNA sequences of T. ghanense, a species originally assigned to sect. Saturnisporum, could not be distinguished from sequences of T. parceramosum, indicating that the two may be synonymous. Interspecific variability within sect. Longibrachiatum was low when compared with species of other sections. Phylogenetic analysis showed that sect. Longibrachiatum is strongly monophylryic. The Hypocrea teleomorphs with anamorphs that can be assigned to section Longibrachiatum fall into at least 5 distinct, and in part geographically defined, groups on the basis of ITS sequences. The anamorphs of three of these groups can be assigned to T. longibrachiatum, T. citrinoviride, and T. pseudokoningii, respectively. Hypocrea jecorina and T. reesei showed 100% sequence homology. Variability among these groups is in the same order of magnitude as among the six species of sect Longibrachiatum.Classification derived from ITS sequences is discussed in comparison with results from other molecular methods.