Preliminary Study On The Islation And Ungicidial Activity Of Chestnut Endophyte

In this paper, 69species of strain isolated from leaves, leafstalks, stems of chestnut. From the distribution,the number of endophytic fungi were varied in differert parts, but the distribution of trends were consistent: stem phloem>leave>leafstalk>stem xylem. 69 strains in 14 genuses were classified,identified, and belonged to fourteen genera,six families,and three orders according to their morphological and micro structure characters . Alternaria sp.and Fusrium sp.are dominant endophytic fungi population in chestnut which occupy 50%in 69 strains.It showed that the quantity,species,and distribution of the endophytic fungus varied in different parts of chestnut.Antimicrobial activity of 35 strains endophytic fungus and their secondary metabolites was screened with three kinds of germs(Staphylococcus aureus, Bacillus subtilis, Escherichia coli)and eight kinds of pathogenic fungi(Alternaria brassicae, Fusarium graminearum, Thanatephoruscucumeris,Fusarium,oxysporum,ValsaMaliMiyabeetYamada,Alternariaalternata, Botrytiscirerea, Cryphonectria parasiticac) as tested bateria.we chose CL8 CL9 and CL20 as our target strains according to results of activity screening results. CL8 strain which was isolated from the leaves of chestnut was shown to be inhibitory to three kinds of germs and eight kinds of pathogenic fungi.Analyzed the physical-chemical character of fermentation broth of antigonistic strain CL8:Fermentation broth CL8 strain displays a higher stability to heat and acid. It could keep a good antifungal activity under the conditions of temperature below 70℃, pH5~8; The storage stability of CL8 fermentation broth is good under 4℃, but under the hot conditions activeness loses was big ; The CL8 fermentation broth is stable under the daylight lamp and the natural light, but it is sensitive to the ultraviolet ray.Studied the extraction and purification method of active component of CL8 antibiotic product, The methods of separation and purification is as follows:①pretreatment of fermentation broth;②Using theconcentrated solution to full with Silica gel column, and selecting the solvent system of chloroform-ethanol-water-n-butyl alcohol(2:3:1:0.5,v/v) to elution, collecting active component, and then concentrating it.③Using the concentrated solution to full with HPLC, with the mobile phase of methanol-water(7:3,v/v), collecting active component, and then concentrating it.④The concentrated solution puts in 45℃constant temperature to dry oven, and finally we obtained the cream color solid powder, and the purity is 99.845%。...