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Title: PHYLOGENY OF THE GENUS TRICHODERMA BASED ON SEQUENCE ANALYSIS OF THE INTERNAL TRANSCRIBED SPACER REGION 1 OF THE RDNA CLUSTER

Author
item KINDERMANN, JOHANNA - INST.BIOCHEMISCHE AUSTRIA
item EL-AYOUTI, YASSIN - UNIV. OF AZGAZIP EGYPT
item Samuels, Gary
item KUBICEK, CHRISTIAN - INST.BIOCHEMISTRY AUSTRIA

Submitted to: Fungal Genetics and Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: The development of management strategies to control crop diseases and use of biological control agents as well as the search for more effective industrial enzymes are hindered by lack of knowledge about the relationships among fungi in the genus Trichoderma. Members of the fungal genus Trichoderma are useful as agents of biological control for many fungal diseases. Species are also known as aggressive contaminants of cultivated mushrooms. Phylogenetic relationships among species of Trichoderma were evaluated based on sequence analysis of the internal transcribed spacer region of the DNA. This papers presents an overview of this genus of asexually reproducing fungi with connections made to the sexual stages where known. Data on the mushroom house contaminate suggest that these strains of Trichoderma are strikingly different from those used in biological control of plant pathogenic fungi. These results will be useful to extension agents, plant breeders, and other agricultural scientists who need to identify these fungi as well as to scientists working on the development of these strains as agents of biological control.

Technical Abstract: Sequences of the internal transcribed spacer region 1 (ITS1) of the ribosomal DNA were used to determine the phylogenetic relationships of species of Trichoderma sect. Pachybasium. To this end, 85 strains- including all the available ex-type strains-were analyzed. Fitch-Margoliash genetic distance trees and consensus trees from parsimony analysis consistently grouped the strains into two main clades, well supported by bootstrap coefficients: one paraphyletic (clades A1 and A2)and one monophyletic (clade B). Clade A1 comprised T. polysporum, T.piluliferum and T. minutisporum; clade A2 included T. hamatum, T. pubescens and T. strigosum in addition to species previously included in sect. Trichoderma (i.e. T. viride, T. atroviride, and T. koningii). Clade B contained the sect. Pachybasium members T. harzianum, T. fertile, T. croceum, T. longipile, T. strictipile, T. tomentosum, T. oblongisporum, T. flavofuscum, T. spirale, and the anamorphs of Hypocrea semiorbis and H. cf gelatinosa. The ex-type strain of T. fasciculatum was unique as parsimony analysis placed it in its own clade that was a basal branch of clade B upon analysis of genetic distance. Sequence differences among clades A1, A2 and B were in the same order of magnitude as between each of them and T. longibrachiatum, which was used as an outgroup in these analyses. The sequence of a previously described aggressive mushroom competitor group of T. harzianum strains (Th2) was strikingly different from that of the ex-type strain of T. harzianum and closely related species, and is likely to be a separate species.