Diversity and antimicrobial activity of fungal endophyte communities associated with plants of Brazilian savanna ecosystems

Fungal endophyte communities associated with leaves of Myrciaria floribunda, Alchornea castaneifolia, and Eugenia aff. bimarginata were examined, collected from Brazilian Cerrado ecosystems, and studied for their ability to produce antimicrobial activity. A total of 93 isolates of endophytic fungi were obtained and identified by sequencing of internal transcribed spacer (ITS) regions of the rRNA gene, which revealed the presence of 20 Ascomycota and three Basidiomycota taxa. The genus Colletotrichum is the most frequent endophyte associated with M. floribunda and A. castaneifolia. Mycosphaerella is the most frequent genus associated with E. aff. bimarginata. All fungal endophytic isolates were cultured and the crude extracts were screened to examine the antimicrobial activities against pathogenic microorganisms. Thirty-eight fungal extracts presented antimicrobial activity against at least one of the different target microorganisms tested. Emericellopsis donezkii and Colletotrichum gloesporioides showed the best minimum inhibitory concentration (MIC) values, which were lower or similar to MICs of known antibacterial and antifungal drugs. Our results suggest that the plants of Brazilian Cerrado shelter a diverse endophytic fungal community, which includes bioactive taxa capable of producing promising antimicrobial metabolites.