PRODUCTION OF AN ANTIBACTERIAL COMPOUND AGAINST THE PLANT PATHOGEN Erwinia carotovora subs. Carotovora BY THE BIOCONTROL STRAIN Gliocladium sp. T.N.C73

Abstract

Gliocladium sp. T.N.C73 was originally isolated as a biocontrol agent from suppressive soil against the phytopathogen Phytophtora capsici. Apart from producing chitinase, this biocontrol fungal strain also produces secondary metabolites having antibacterial properties against the Gram positive bacteria Bacillus subtilis and Staphylococcus aeureus. In order to further explore the ability of Gliocladium sp. T.N.C73 in managing plant diseases caused by bacteria, ethyl acetate extracts of the fermentation medium of this strain was analyzed for its ability to inhibit the Gram negative Erwinia carotovora subsp. carotovora that causes soft rot disease in food crops. Disc diffusion bioassays showed that the extracts could inhibit E. carotovora subsp. carotovora growth. Depending on the initial spore concentration of the fermentation medium inoculum, several compounds were detected by thin layer chromatography (TLC) of the ethyl acetate extracts that fluorescence under UV light, and one compound that gave a bright red spot when sprayed with a p-anisaldehyde solution.