Isolation,Identification Of Endophytic Fungi From Ginkgo BilobaL. And Study On Antifungal Activity Of The Metabolite

Plant endophytic fungi not only enchance transformation and biosynthesis of sec ondary metabolites in the host plants, and also could produce secondary metabolites with special chemical structures and abundant bioactivities, which could enlarge the boundary of secondary metabolites of host plants. Plant endophytic fungi, as substi tutes of scarce plants resources, are poteinal microbial resources to explore new bioactive compounds.This paper is about the research work based on endophytic fungi from Ginkgo biloba, including isolation of endophytic fungi, identification of endophytic fungion a basis of ITS rDNA sequence, assessment of fungistatic activity. The primary results are as follows:(1) The 55 endophytic fungus were obtained and carried out to evaluate the bi oactivities against six test plant pathogenic fungi Pezicula malicorticis, Valsa mali,PhXTophthora capasici, Verticillium tricorpsis, Fusarium graminearum and Venturia nashicola.Bioassay results showed that 33 strains antagonized at least one test plant pathogenic fungi. Expecially, strain GBT07 displayed antagonistic action extremely a gainst five test pathogens.(2) After excluding the same strains according to morphological characteristics,33 endophytic fungi were belonged to 9 genuses based on ITS rDNA sequence analysis, namely 9 for Colletotrichum spp., 5 for Glomerella spp., 3 for Phomopsis spp., 3 for Guignardia spp. 3 for, 2 for Phyllosticta sppBotryosphaeria spp., 2 for Fusarium spp.,1 for Hypoxylon spp., 1 for Bjerkandera spp. GBT07 named Fusarium solani GBT07.(3) Index for the amount of mycelial biomass and antifungal activity of fermen tion broth, Analyse the fermentation conditions on different carbon and nitrogen sources, as well as temperature and initial pH, established the feat growth conditions for its expanded culture initially.As a large number of fermentation conditions, choosed soluble starch, sodium nitrate as carbon and nitrogen sources,temperature20℃, initial pH=7. Using mechanical agitation fermentation tank to enlarge cultivation str ains, sampling at several time points, respectively.Then test the antifungal activity a nd biomass from each time, and compared with shaking flask fermentation accordingly. Tank fermentation bacteria biomass reached maximum(1.65±0.052)g at 3d, antimicrobial activity was the highest(33.56±1.34)% at 4d,; While the shaking flask fermentation were bacteria biomass maximum(0.82±0.035)g at 5d, antimicrobial activity was the highest(53.20±0.76) % at 7d.(4) Ferment the strain GBT07, the mycelia extractum and broth extractum had obvious antifungal activity. Fllowed by activity tracking,choosed Pezicula malicorticis for indicator strain, using Silicagel column chromatography to separate the antifungal activity componts. Obtained the extremely inhibition fraction Fr2-9 separated from mycelia and Fr2-8 separated from fermention broth. β-Adenosine was purified by p-HPLC.