Biological control of plant fungal diseases using volatile substances of Streptomyces griseus

Streptomyces griseus is a useful bacterium that produces many secondary metabolites and volatile compounds. In this project, antifungal activity of volatile substances derived from Streptomyces griseus against Aspergillus niger, A. flavus, Fusarium oxysporum and Botrytis cinerea was studied in vitro. The compositions of volatiles were also determined by gas chromatography comb with mass spectrometry analysis. Fungal spore germination and mycelium growth of tested fungi cultures were significantly suppressed in the presence of the volatiles. Gas chromatography comb with mass spectrometry analysis results showed that twenty volatile compound s were identified in one week old diphasic cultures (Tryptic Soy Agar and Tryptic Soy Broth) of S. griseus. The volatile compounds were chemically grouped into organic acids, alcohol, alkanes, alkenes, alkens and ketones. The most abundant compounds in volatile of S. griseus were Phenol,2-methyl-5-1methylethyl (Carvacrol). Chemicals of less abundant were Isocyclocitral, Benzene, 1,2-dimethoxy -4-1-methylethenyl. The antifungal activity of three abundant compounds was analyzed. The volatile substances of S. griseus have a potential for using as a biofumigant to control plant fungal diseases.