Screening the natural habitat: New peptaibiotics from specimens and pure cultures of the fungicolous fungus Hypocrea pulvinata

In order to further investigate the significance of antibiotics for the producing organism(s) in the natural habitat, we screened specimens of the fungicolous fungus Hypocrea pulvinata growing on its natural hosts Piptoporus betulinus and Fomitopsis pinicola1. Using a peptaibiomics approach2, we detected 17-, 18-, 19- (major sequences), and 20-residue peptide sequences in the five specimens
analyzed by (U)HPLC/HR-ESI-QqTOF-MS. Structures of peptaibiotics found were independently confirmed by analyzing the peptaibiome of pure agar cultures obtained by single-ascospore isolation from the specimens1. Major, 19-residue peptaibols were assigned as deletion sequences of the trichosporins B3 lacking the Ala/Aib residue in position3. Our results corroborate that: i) peptaibiotics are, indeed, biosynthesized in the natural habitat, thus, ii) their membrane-perturbing formation of ion channels may support the parasitic life style of a fungicolous fungus.