Profiling of volatile secondary metabolites of Chaetomium globosum for potential antifungal activity against soil borne fungi

Abstract

The present research has been undertaken to identify various bioactive secondary metabolites for their potential activity against soil borne phytopathogens. Three isolates of C. globosum has been screened against Sclerotinia sclerotiorum, Sclerotium rolfsii, Macrophomina phaseolina, and Fusarium oxysporumby dual culture technique. Production of selected isolate (CG-5157) has been carried out in Potato Dextrose Broth. Culture filtrate was sequentially extracted by cold extraction process with petroleum ether followed by ethyl acetate and methanol. Extracted solvents were evaporated under reduced pressure below 40 °C in rotary evaporator to obtain various concentrates. Fungicidal activity was carried out in-vitro against the same fungi using poisoned food technique to determine the percent inhibition (%). Petroleum ether concentrate was found to be most effective against S. sclerotiorum with inhibition of 74.1%. Hexane concentrate was found to be significantly inhibit growth of all the soil borne fungi causing severe damage to plant health. Petroleum ether concentrate was subjected to GC-MS analysis to identify major bioactive metabolites. Various hydrocarbons, phenols, terpenoids and sulphar compounds were identified in the concentrate, representing 73.6% of the total concentrate. Among these, 4-methyl-(1,5-dimethyl-4-hexenyl-benzene (9.3%), tetradecane (6.8%), dodecane (6.3%), hexadecane (6.1%), β-bisabolene (3.5%), dimethyl-propyl-disulphide (1.34%) were identified as major components.