Extraction and identification of bioactive compounds (eicosane and dibutyl phthalate) produced by Streptomyces strain KX852460 for the biological control of Rhizoctonia solani AG-3 strain KX852461 to control target spot disease in tobacco leaf

摘要

Streptomyces strain having antifungal activity against Rhizoctonia solani AG-3 that is the causal agent of target spot disease in tobacco leaf. The aim of the study was to determine the antifungal activity of Streptomyces strain extract against R. solani AG-3 and to identify bioactive antifungal compounds produced by strain . Crude substance was produced by submerged fermentation process from Streptomyces strain . Various solvent was used to extract the culture filtrate. Among all, ethyl acetate extracted supernatant showed great potency against R. solani AG-3 . The active fractions were purified by silica gel column chromatography having 52 mm zone of inhibition against R. solani AG-3 . The purified fractions were identified by gas chromatography–mass spectrometry technique. Twenty-seven compounds were identified and most of the compounds were the derivatives of aromatic compounds. Eicosane (C20H42) and dibutyl phthalate (C16H22O4) were found antifungal compounds in this study. While morphinan, 7,8-didehydro-4,5-epoxy-17-methyl-3,6-bis[(trimethylsilyl)oxy]-, (5.Alpha. 6.Alpha)—(C23H35NO3Si2), cyclononasiloxane, octadecamethyl—(C18H54O9Si9) and benzoic acid, 2,5-bis(trimethylsiloxy) (C16H30O4Si₃) were the major compounds with highest peak number. These results suggested that Streptomyces strain had good general antifungal activity and might have potential biocontrol antagonist against R. solani AG-3 to cure the target spot in tobacco leaf.