Diversity,Isolation,Identification And Chemical Constituents Of Endophytic Fungi Form Dioscorea Opposita

Dioscorea opposita Thunb. is one of the genuine medicinal materials in H-enan Province and one of the Chinese traditional medicinal and food homologo-us plants,it enjoy high reputation at home and abroad,At present,scholars at home and abroad mostly focus on the plant itself or the cultivation environment of Dioscorea opposita Thunb.,but little on the microorganisms in the internal microenvironment of Dioscorea opposita Thunb.,In order to discover End ophytic Fungi Resources in Dioscorea opposita Thunb.,The study took Dioscorea opposita Thunb.as the research object?Firstly,GSS sequencing of Dioscorea opposita was carried out to find that endophytic fungi in Dioscorea opposit a were abundant?Secondly,the endophytic fungi in Dioscorea opposita Thunb.were isolated and identified?Then,the strains were sc-reened for IAA?The most obvious strains of IAA positive reaction were cultu-red in four liquid media,and the IAA content in different media was determined?Secondary metabol ites of a selected fungus were studied?A total of 39 endophytic fungi of Dioscorea opposita Thunb.were obtained by tissue cutting and grinding?Gene identification of 5.8S rDNA-ITS region showed that 10 genera of endophytic fungi were isolated,including Alternaria sp.,Fusarium sp.,Talaromyces sp.,Aspergillus sp.,Irpex sp.,Mycosphaer-ella sp.,Ascochyta sp.,and Plectosphaerium sp.Lasp.,Dothiorella sp.and Schizophyllum commune?Screening of IAA secretion by endophytic fungi using Salkowski colorimetric assay,The endophytic fungi LY-6,LY-8 and LY-22 had the ability to secrete IAA? The color reaction of LY-22 was the most obvious?The identificati on results showed that LY-6 and LY-8 were Alternaria sp,and LY-22 were Fusarium acuminatum? Fusarium acuminatum was cultured in PDB?SDB?MB and SNB media,and the content of IAA in its fermentation broth were determined?The results showed that Fusarium acuminatum(LY-22)secreted the most IAA in PDB medium,and the maximum IAA secretion was about 1.8 mg/L?By using the method of HPLC,it was found that the components of ethyl acetate extract and methanol extract from mycelium of endophytic fungus LY-16 were abundant,so the secondary metabolites of the strain were studied,The strain was identified as Talaromyces purpureogenus by gene identification?Using silica gel column,sephadex LH-20 gel column,C8 reverse silica gel column and C18 reverse silica gel column chromatographic separation and purification of extract from Talaromyces purpureogenus,10 compounds were obtained?The compounds were identified by NMR spectroscopy,4 structures were identified at present:1,3-succinic acid(1)and ergosterol(2),peroxyergosterol(3)and sucrose(10),Four compounds were obtained from Talaromyces purpureogenus for the first time?Six compounds have not been identified yet,Their NMR data have been listed in this paper?...