Trichoderma spp. are considered as potential antagonists of other fungi. These fungi produce varoius secondary metabolites. An important group of bioactive Trichoderma metabolites is consisting of non-ribosomal peptides (NRPs), especially the peptaibols which are small linear peptides (5-20 residues) contain nonproteogenic aminoacides and are distinguished by an acetylated N-terminal and amino alcohol at the C-terminal end. T. asperellum isolate examined in this study derived from Fungal Herbarium of Bu Ali Sina University of Hamedan. The crude methanolic extract of this isolate showed remarkable antibacterial activities against Micrococcus luteus. Amino acid sequences of peptaibols was determined by HPLC-ESI-IT MS and MS/MS at the Department of Microbiology of University of Szeged. Analysis of the MS chromatograms of crude extracts was performed by MS data review. The detected peptaibol compounds contain 18 amino acid residues belonging to the neutral trichotoxin groups of peptaibols known as A50. From 27 identified peptaibols, 6 sequences were found in the on line comprehensive peptaibol database as trichotoxins A-50 E (T5E), A-50 F (T5F), A-50 I (T5I), A-50 J (T5J), trichotoxin T5D2 and trichotoxin sequence 05 while 21 sequences proved to be new, yet undescribed trichotoxin sequences. Biocontrol Index (BCI) values of T. asperellum were evaluated based on in vitro confrontation against different plant pathogenic fungi. The profiles of peptaibols were examined during these interactions in order to gain information about the role of peptaibols durinf mycoparasitism. Analysis of the MS chromatograms of crude extracts from control and confronted cultures revealed that changes in the peptaibol profiles were depending from the confronted fungal pathogens. Certain compounds were overproduced, while some of them completely disappeared or were repressed in the extracts deriving from T. asperellum . Further studies are in progress in order to clear the role of each compound
