UNIVERSIDAD MILITAR NUEVA GRANADA Screening for antifungal activity of endophytes isolated from Burseraceae

Control of fungal pathogens is mainly addressed by chemically synthesized fungicides which, after a prolonged use, produce environment pollution and develop resistance. In this context, endophytes have been recognized as potential biocontrolers and also potential source of antifungal metabolites. Therefore, as part of our research on phytopathogen controllers, 355 fungal endophytes were isolated from Protium heptaphyllum and Trattinnickia rhoifolia (Burseraceae), both important etnobotanical tree species that produce secondary metabolites of agronomic and industrial interest. Endophytes were tested by in vitro dual culture against Fusarium oxysporum, an important phytopathogen of agronomic importance. Five endophytes exerted at least 40 % of inhibition on F. oxysporum growth. Ethyl acetate (EtOAc) extracts were obtained from the most-antagonistic fungi growth in three different liquid media. The extracts were tested against a conidial suspension of F. oxysporum by direct bioautography. Two extracts derived from fungi identified as Chaetomium globosum, F211_UMNG and Meyerozima sp. F281_UMNG exhibited inhibition of the pathogen growth. The isolate Chaetomium globosum, F211_UMNG was selected for a chemical profiling by RPHPLC-DAD-ESI-MS and antifungal molecules such as cladosporin, chaetoatrosin A and chaetoviridin A were tentatively identified by their MS data.