In vitro production of antifungal phenolic acids by Hypomyces perniciosus, the causal agent of wet bubble disease of Agaricus bisporus

Wet bubble disease caused by Hypomyces perniciosus (syn: Mycogone perniciosa) is one of the major constraints in the production of button mushroom (Agaricus bisporus) worldwide. Deformation of basidiome and exudation of brown coloured liquid are the characteristic symptoms of wet bubble disease. The objective of this research was to assess the in vitro production of antimicrobial compounds by H. perniciosus. The culture filtrate of H. perniciosus induced leakage of cellular electrolytes from the mycelium of A. bisporus. Thin-layer chromatography analysis of the ethyl acetate extract of the culture filtrate of H. perniciosus revealed the presence of a predominant band at R_f 0.8 reacting to Folin–Ciocalteu reagent. The compounds at R_f 0.8 were capable of inducing electrolyte leakage from A. bisporus mycelium. Ultra-performance liquid chromatography analysis of the purified fraction revealed the presence of syringic, vanillic, cinnamic, 2-hydroxycinnamic, ferulic and p-coumaric acids suggesting that phenolic acids in the culture filtrate might be involved in the mycoparasitic activity of H. perniciosus.