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Aims: Microbial endophytes produce specialized metabolites, including antibiotics and other compounds of pharmaceutical and agricultural value. This study aimed to investigate the diversity and bioactivity of endophytes from medicinal plants used by the Dharawal People of Gamay (Botany Bay), Australia. Methods and Results: Of the 48 endophytes isolated, 19 tested positive for polyketide synthase or non‐ribosomal peptide synthetase genes via a PCR incorporating degenerate primers. The biosynthetically talented endophytes were identified by 16S rRNA gene sequencing and included 4 bacteria species belonging to the orders Bacillales, Rhizobiales and Burkholderiales and 15 Ascomycota fungi species belonging to the orders Botryosphaeriales, Cladosporiales, Glomerellales, Microascales and Eurotiales. Antimicrobial testing using the disc diffusion assay demonstrated that 15 of the 19 isolates had broad‐spectrum activity against a range of Gram‐positive and Gram‐negative bacteria. Conclusions: Taken together, these results suggest that Australian bush medicines harbour diverse biosynthetically talented microbial endophytes capable of producing broad‐spectrum antibacterial compounds. Significance and Impact of the Study: This study suggests that compounds produced by microbial endophytes likely contribute to the collective medicinal properties of Australian bush medicines. Significantly, it highlights that Indigenous botanical knowledge and modern molecular approaches can be used in tandem to prioritize microorganisms that produce pharmaceutically relevant compounds. [ABSTRACT FROM AUTHOR]

Aim To initiate a genetic and bioactivity-based screening programme of culturable endophytes to identify micro-organisms capable of producing bioactive polyketides and peptides. Methods and Results Fungal endophytes were isolated from flowers, leaves and roots of Rhoeo spathacea, revealing a community consisting of Colletotrichum sp., Fusarium sp., Guignardia sp., Phomopsis sp., Phoma sp. and Microdochium sp. Genetic screening showed that all isolates had polyketide synthase ( PKS) genes and most had nonribosomal peptide synthetase ( NRPS) genes. Ethyl acetate extracts of the fungal isolates exhibited antiproliferative activity against at least one of the seven bacterial and mycobacterial test strains. Nuclear Magnetic Resonance -guided fractionation of the crude extract from a Fusarium sp. strain which exhibited strong antiproliferative activity against Mycobacterium tuberculosis resulted in the isolation of the polyketide javanicin. This compound was active against Myco. tuberculosis ( MIC = 25 μg ml−1) and Mycobacterium phlei ( MIC = 50 μg ml−1). Conclusions The medicinal plant R. spathacea hosts a variety of fungal endophytes capable of producing antibacterial and antimycobacterial compounds. There is a positive correlation between the presence of PKS and/or NRPS encoding genes in endophytes and the bioactivity of their respective organic extracts. Significance and Impact of the Study This is the first report on the fungal endophytic diversity of R. spathacea, and the isolation of an antimycobacterial compound from the plant which has been traditionally used for the treatment of tuberculosis symptoms. [ABSTRACT FROM AUTHOR]