Australian bush medicines harbour diverse microbial endophytes with broad-spectrum antibacterial activity

S. D. Ingrey, L. A. Pearson, J. A. Kalaitzis, B. A. Neilan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
Number of pages13
JournalJournal of Applied Microbiology
Early online date27 Apr 2021
DOIs
Publication statusE-pub ahead of print - 27 Apr 2021
Externally publishedYes

Bibliographical note

Funding Information:
The authors would like to acknowledge the senior women of the Dharawal Elders Group, many of whom have passed away since the commencement of this study. In particular, we wish to acknowledge the lead author's grandmother and her sister, who diligently continued their cultural practices and preserved and generously shared their knowledge of Dharawal bush medicines. This project was financially supported by a Discovery Indigenous Research Development Grant from the Australian Research Council (DI0668388).

Publisher Copyright:
© 2021 The Society for Applied Microbiology

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

Keywords

  • antibacterial activity
  • bush medicine
  • Dharawal
  • endophyte
  • ethnobotany
  • medicinal plants
  • NRPS
  • PKS

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