| The plant endophyte can metabolize many intereting secondary metabolites with novel structure and distinctive activities, which is an important source of new bioactive moleculars. The aims of this study are to isolate endophytic fungus from Euonymus japonicus and screen the strains that produce agricultural antibiotics, then work about the isolation and identification of active components have been carried out。The main results are as follows:1. Taking different separating culture medium, 49 strains of endophytic fungus were separated from Euonymus japonicu. The screening tests indicated that M-1 strain possessed potant fungicidal activities.2.The fungicidal activites of M-1 strain has been studied. The inhibition rate of fermentation broth of M-1 strain against Alternaria solani, Fusarium oxysporium sp niveum, Colletotrichum gloesporioides were 80.3%,78.5% and 87.8%respectively. The result of antibacterial bioassay indicated that the inhabitation zone of M-1 strain against Bacillus cereus Bcillus subtills Staphyococcus aureus and Escherichia coli were 23.0mm 20.0mm 16.0mm and 20.0mm, respectively.The ethyl acetate extract of M-1 fermentation broth had higher antifungal activity against C. gloesporioides, and the IC50 was 63.6μg/mL. By the Doskochilova solvent system, fermentation broth of M-1 may include sulfurluteolin.3. The optimum composition of culture medium and fermentation conditions of the strain M-1were demonstrated respectively. The optimum culture medium is about pH 7.5. Inoculum volume was 18 entries per 100mL medium. A 250mL flask containing 110mL medium was cultivated at 26℃for 240h. Under this culture conditions, the product and activity against Bacillus cereus were high than any conditions.4. By means of observation on aerial mycelium, macroconidia, microconidia and colony morphology characteristics and comprised with related classify system, strain M-1 was preliminarily identified as Alternaria spp.. |
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