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DOI: 10.1055/s-0036-1596690
Fungi as a source for antibacterial compounds
Publication History
Publication Date:
14 December 2016 (online)
Phytopathogenic bacteria constantly develop resistance against existing antibiotic drugs. Today, this is a real threat to human health, but it also leads to secondary effects in agriculture such as great losses of crops and vegetable yield. Development of new drugs, especially in area of infectious diseases, represents today one of the most important area of research. Natural products exhibit biological properties including antibacterial, antifungal, herbicidal, anticancer and insecticidal which are used for pharmaceutical drug discovery and agro-chemical applications [1]. Fungi are known to produce a vast array of secondary metabolites that are often bioactive; species like Aspergillus, Penicillium, Fusarium and Acrimonies have the potential to produce numerous secondary metabolites [2]. In the current work, twelve different fungal strains of both habitats (soil borne and endophytes) were screened against two phytopathogenic bacterial strains, i-e Clavibacter michiganensis and Xanthomonas campestris, using dual culture technique [3]. Based on the antagonistic effect of fungi against the two bacterial strains, three fungi named Aspergillus flavus, Penicillium EU003 and Trichoderma harzianum were selected. The cultivation of the three fungi was optimized on different growth media with the aim to identify the medium which secondary metabolites possessing comparatively more inhibition against phytopathogens [4]. The following culture media were used: Glucose Peptone Yeast Broth (GPYB), Yeast Extract Broth (YEB), Growth Nutrient Broth (GNB) and Potato Dextrose Broth (PDB), and the fungi were then extracted with ethyl acetate. All organic extracts obtained from culture media were tested for the bench top antibacterial activity using a disc diffusion method [5]. The results revealed that the crude extract of Aspergillus flavus grown on PDB show highest inhibition against the two plant pathogenic bacterial strains as compared to other medias. Similarly, crude extracts of Penicillium EU003 and Trichoderma harzianum showed good results on GNB culture media.
Acknowledgements: Higher Education Commission Pakistan.
Keywords: Dual culture technique, culture media optimization, in-vitro antibacterial bioassay.
References:
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[5] Xiulan XU, Miller SA, Gurel B, Gartemann KH, Eichenlaub R, Rajasheara G. Bioluminescence imaging of Clavibacter michiganensis subsp. michiganensis infection of tomato seeds and plants. Appl Environ Biotech 2010; 76: 3978 – 3988
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No conflict of interest has been declared by the author(s).