Studies On Pesticidal Ingredients Of Strain As Of The Endophytic Fungi In Celastrus Angulatus

In the course of screening new pesticidal compounds, Strain As, an Endophytic fungus has been isolated from Celastrus angulatus.In this paper, the taxonomy of strain As together with the fungicdal activity of it's metabolites, purification of active compounds and optimization of fermentation conditions will be described. The main results are as follows:1.The fungicidal activities of the metabolites of the strain As have been tested. The results showed that the active ingredients in the mycelium could be extracted by ethylacetate or methanol, but methanol was the more appropriate solvent. For Valsa malt and Botrytis cinerea, mycelium growth inhibition was observed at the concentration of 4000μg/mL, the inhibitory ratio was above 80 percent; For Curvulavia lunata, Fusarium coeruleum, Alternaria longipes, spore germination inhibition was observed at the concentration of 5000μg·mL-1, the inhibitory ratio was also above 80 percent. The results of pot test indicated that the methanol extracts of mycelium could effectively control of wheat powdery mildew, the protective and therapeutic efficacy were all above 65% at the concentration of 4000μg·mL-1.2.By morphological taxonomy means, the aerial mycelium, macroconidia, microconidia and colony morphology characteristics of strain As was observed. By comparised with related classify system, strain As was identified as Fusarium oxysporum..3.By means of open silica gel, macroporous resin column chromatography, and preparative HPLC, three compounds, Z01, Z02 and Z03, were isolated from the methanol extracts of fermentation products of strain As. The sturcture characteristic of compound Z02 were carried by UV, MS, 1H NMR, and 13C NMR technology, but the structure elucidation was difficult and unfinished by now. The structure of compound Z01 and Z03 could not be tested for no appropriate solvent. At the concentration of 200μg·mL-1, Z01 had no evident fungicidal activity, Z02 and Z03 had an evident fungicidal activity against Fusarium coeruleum, Curvulavia lunata, Exserohilum turcicum and Botrytis cinerea by means of spore germination. For Z02, the value of EC50 anainst Curvulavia lunata was 86.63μg·mL-1.4.The optimum composition of culture medium and fermentation conditions of the strain As were demonstrated by the test of uni-factor and orthogonal design, respectively. The optimum culture medium consisted of glucose 2%, potato 20%, peptone 0.5% , K2HPO4 0.1%, MgSO4 0.1%,and original pH6.0-7.0. The seeding age was 96h. Inoculum volume was 5 entries per 100mL medium. A 250mL flask containing 100mL medium was cultivated at 26℃for 168h and the rotatory velocity was 180 rpm.