Induction of cryptic metabolite production through epigenetic tailoring in Colletotrichum gloeosporioides isolated from Syzygium cumini

Abstract

Recent advancement in the fungal molecular genetics has established that fungi have numerous genes or gene clusters that remain silent or unexpressed under the normal conditions. These genes can be activated through epigenetic modifiers to produce a wide range of potential bioactive metabolites of agricultural and pharmaceutical values. In this study one DNA methyltransferase inhibitor (5-azacytidine) and one histone deacetylase inhibitor (sodium butyrate) were used for the epigenetic treatment to the Colletotrichum gloeosporioides isolated from the surface-sterilized leaves of S. cumini. The crude compounds isolated from the epigenetically treated C. Gloeosporioides were observed to exhibit increased antibacterial activity against human bacterial pathogens (Aeromonas hydrophila, Enterococcus faecalis, Escherichia coli, Salmonella typhi, Shigella boydii, and Staphylococcus aureus). In terms of antibacterial efficacy, the secondary metabolites extracted from the culture treated with 5-azacytidine were found to be the most effective against all the tested bacterial pathogens followed by cultures treated with sodium butyrate and the combined treatment of both 5-azacytidine and sodium butyrate compared to control except against the S. Typhi. The HPLC profiling showed that fungal crude metabolite compounds from different treatments of epigenetic modulators activated the production of additional metabolites compared to the untreated control. Further, the total amount of secondary metabolites extracted with ethyl acetate from treated cultures showed severalfold increase. This indicates toward the change in the expression of some cryptic genes or gene cluster through epigenetic modification by 5-azacytidine and/or sodium butyrate treatment(s).