Epigenetic modifier induced enhancement of fumiquinazoline C production in Aspergillus fumigatus (GA-L7): an endophytic fungus from Grewia asiatica L.

Present study relates to the effect of valproic acid, an epigenetic modifier on the metabolic profile of Aspergillus fumigatus (GA-L7), an endophytic fungus isolated from Grewia asiatica L. Seven secondary metabolites were isolated from A. fumigatus (GA-L7) which were identified as: pseurotin A, pseurotin D, pseurotin F2, fumagillin, tryprostatin C, gliotoxin and bis(methylthio)gliotoxin. Addition of valproic acid in the growth medium resulted in the alteration of secondary metabolic profile with an enhanced production of a metabolite, fumiquinazoline C by tenfolds. In order to assess the effect of valproic acid on the biosynthetic pathway of fumiquinazoline C, we studied the expression of the genes involved in its biosynthesis, both in the valproic acid treated and untreated control culture. The results revealed that all the genes i.e. Afua_6g 12040, Afua_6g 12050, Afua_6g 12060, Afua_6g 12070 and Afua_6g 12080, involved in the biosynthesis of fumiquinazoline C were overexpressed significantly by 7.5, 8.8, 3.4, 5.6 and 2.1 folds respectively, resulting in overall enhancement of fumiquinazoline C production by about tenfolds.