A Preliminary Study On Isolation, Identification Of Endophytic Fungi Generating Flavoniods In Ginkgo Biloba

Endophytes refer to fungi colonizing healthy plant tissues without causing symptom or apparent injury to the host.Reasearch results in near years show that endophytic fungi can produce some similar physiological active products to the host plant.So studies on the endophytic fungi and their metabolites have been a new way to find medical resources.In this paper,Ginkgo biloba L.,a chinese endemic medicinal plant,was selected as material. A way named tissue print culture was used to isolate endophytic fungi from the tissues distribution fungi in G.biloba.The result indicated that,the superficial disinfection for endophytic fungi isolation was better by 75%ethanol combined with 0.1%HgCl₂ method.The best time for disinfection in HgCl₂ of leaves,leafstalk,basement of leafstalk,caulicle,casca,fibrous root,root were respectively 1 min,2 min,2 min,3 min,4 min,2 min,3 min.78 endophytic fungi were isolated.Seven fungal isolates were found to produce flavoniods which were aquired from roots, stems and leaves of Ginkgo biloba L.collected in the areas of Sichuan,Guizhou and Shandong provinces in China by means of HPLC and AlCl₃ chromatometry.It is displayed that the seven fungal isolates were produced quercetin which is a kind of flavonoid glycoside,the quercetin production of the seven fungal isolates were calculated.The further molecular identification indicated that these fungal isolates belonged to Colletotrichum and Fusarium respectively.The isolate QC102 was indentified as Colletotrichum acutatum Simmonds.which can produce flavoniods up to 8.2μg/mL,and its quercetin producion could be up to 16.8μg/g and 6.3μg/mL in hyphal body and fermentation broth respectively.The research investigate endophytic fungi diversity in G.biloba and 78 strains of endophytic fungi isolated.The strains of them were morphologically and molecularly identified to belong to 10 genera,8 families,7 orders,5 class and 3 phylum.It had shown that the biodiversity of endophytic fungi in G.biloba,and dominant groups were Colletotrichum,Alternaria,Fusarium, Phomopsis.The experiment results indicated that the quantity and microbial population of endophytic fungi of G.biloba exist differences in different tissue or position.The dominant group(s) in leaves were Alternaria and Colletotrichum,in stems and roots was Fusarium.The special groups in leaves were Acremonium,phyllosticta and Schizophyllum,in stems were Trichoderma and Diaporthe,in roots was Leptosphaeria.The research also investigate endophytic fungi from different areas of G.biloba,the result indicated that dominant group from different areas was different.The dominant group of Guizhou University and Chendu was Alternaria;The dominant group of Qinchen and Ya'an was Colletotrichum;The dominant group of Mianyang,Yantai and Pingwu was Fusarium;The dominant group of Zunyi is Phomopsis;The dominant group of Emei was Acremonium.