Identification of antibiotic peptaibols from fermentation broth of Trichoderma harzianum

Four microheterogenous peptaibol antibiotics containing 20 amino acids were isolated from fermentation broth of Trichoderma harzianum and purified by polystyrene resin, sephadex, preparative thin-layer chromatography (TLC) and preparative high-performance liquid chromatography (HPLC). They were identified as Alamethicin F-50, Atroviridin B, Alamethicin II and Atroviridin C with ESI-IT-MS ^2. Mycelial growth and spore germination experiments showed that the 4 compounds have strong inhibiting effects against Thanatephorus cucumeris, Rhizoctonia solani, Fusarium oxysporum f. Sp. Cucumerinum , F. oxysporum f. sp. niveum, Magnaporthe oryzae, and Alamethicin F-50 exerted synergistic antibiotic effect when applied with trichodermin on the tested plant pathogens.