[Identification of endophytic Actinomycete Lj20 from plant and its antifungal substances].

ABSTRACT

OBJECTIVE: Endophytic actinomycete Lj20 with antifungal activity was isolated from the roots of capsicum plants. We identified Lj20 and synthesized its antifungal substances. METHODS: Morphological, biological and biochemical characteristics, chemotaxonomy analysis and 16S rDNA sequences were used to identify Lj20. According to GC-MS extrapolation result, one of antifungal substances in the metabolites of Lj20 was chemically synthesized. The bioactivities were determined by mycelium growth inhibition method. RESULTS: Lj20 belonged to Streptomyces sp. and was similar to Streptomyces rochei. The metabolites contained butylated hydroxytoluene and 3, 5-di-tert-butyl-4-hydroxybenzyl methyl ether. The median effective concentration (EC50) of these two compounds to Botrytis cinerea Pers. were 237.04 mg/L of the water and 186.48 mg/L of the water, respectively. CONCLUSION: Lj20 was classified as Streptomyces rochei. Butylated hydroxytoluene and 3, 5-di-tert-butyl-4-hydroxybenzyl methyl ether had significant inhibition to the pathogen.