Studies On Fungicidal Ingredient Of Endophytic Fungus A10 In Celastrus Angulatus

Endophytic fungus of strain A10, which was isolated from the root of Celastrus angulatus, has been studied on the taxonomy, agricultural bioactivities, isolation and identification of active components. The main results were as follows:1 The results of mycelial growth and spore germination test indicated that metabolites of ethyl acetate and methanol extracts of mycelium had evident fungicidal activity at the concentration of 1000μg·mL^-1. The fungicidal activity of ethyl acetate extract was higher than that of methanol, and the inhibition rates were more than 90% against Alternaria longipes, Bipolaris sorokiniana, Exserohilum turcicum, Botrytis cintrea, Macorphoma kawatsukai under the concentration of 1000μg·mL^-1. In the pot test, ethyl acetate extract showed more than 70% of protective efficacy and therapeutic efficacy against wheat powdery mildew under the concentration of 2000μg·mL^-1.2 By observing aerial mycelium, microconidia and colony morphology characteristics of strain A10 using optics microscope, compared with related classify system, strain A10 was identified as Oospora wallr.3 By means of open silica gel, macroporous resin column chromatography, and preparative HPLC, five compounds, QY01,QY02,QY03,QY04,QY05, were isolated from extracts of fermentation products of strain A10. On the basis of spectral technology (MS, FT-IR, 1H NMR, 13C NMR, 2D MNR), and compared with related literatures, QY01,QY04,QY05 were identified as cytochalasin D, ergosterin and Dulcitol, respectively. Cytochalasin D had an evident fungicidal activity against Alternaria longipes under the concentration of 100μg·mL^-1 by means of spore germination. The EC50 is 35.01μg·mL^-1.4 Effect of different addition with the fermentation of A10 had been studied. The results indicated that the addition of ethidium bromide had a positive influence on the fermentation of A10. Compared with initial culture fluid, the contention of biomass and cytochalasin D had a obviously increase at the concentration of 0.4×10-6mg·mL^-1. Contrast, the production of biomass and cytochalasin D was negative correlation the additive of 2-amino pyridine.