Diversity Analysis Of Endophytic Fungi In Huperzia Serrata And Its Correlation Analysis With Huperzine A Content

Huperzia serrata(Thunb.ex Murray)Trev.is a perennial medicinal fern.Hup-A from H.serrata is very effective in the treatment of Alzheimer's disease.Therefore,there is a huge demand for the wild resources of H.serrata in the market,and the life history of H.serrata is very long and complicated,and this leads to the depletion of its wild resources and the extinction of H.serrata.Existing studies have shown that H.serrata is rich in endophytic fungi,but their diversity,composition and structure of the flora have not been studied clearly.Therefore,carrying out a research on the diversity of endophytic fungi from H.serrata has important theoretical significance for increasing the diversity and taxonomic diversity of the species pool,probing the relationship between fungus and plants,revealing the interaction of microorganisms,regulating plant growth,regulating plant metabolite synthesis and so on.In this study,the traditional endophytic fungi isolation method and ITS amplicon sequencing analysis were used to establish an endophytic fungi resource library of H.serrata,and conduct a more visual and scientific analysis of the diversity and distribution of endophytic fungi.The main research purpose,contents and conclusions are as follows.(1)In this study,the endophytic fungi of H.serrata in different tissues were isolated and identified by different months.A total of 95 endophytic fungi were isolated,23 were isolated from roots,49 were isolated from stems,and 36 were isolated from leaves,indicating that the most endophytic fungi were isolated from stems.Among them,64 plants were identified at the species level,21 fungi were identified at the genus level,and the rest were identified at the family level.28 strains were isolated,which were belonged to the dominant Fusarium genus.(2)In this study,36 samples were subjected to high-throughput amplicon sequencing,and3566 strains of endophytic fungi were identified at the subordinate level.At the phylum level,Basidiomycota accounts for 54% of the total taxa,and Ascomycota accounts for 25%.At the genus level,Cladophialophora(relative abundance accounts for 8%),Sebacina(relative abundance accounts for 3%),and Cladosporium(relative abundance accounts for 2%)are the top three genera with relatively high relative abundance.The results of the analysis showed that:(1)The diversity of endophytic fungi in stems and leaves was significantly higher than that in roots;Cladophialophora genus had the highest relative abundance,and it was distributed in the material of different months.Cladophialophora had high relative abundance in different tissues.Sebacina was a relatively abundant fungus in the root and stem sample groups.Cladosporium is a very abundant fungus unique to root samples.(2)The diversity of endophytic fungi in the sample group in May was significantly higher than that in August and the distribution of endophytic fungi diversity was M5>M11>M2>M8.At the genus level,Russula is a unique endophytic fungus in May samples,and Cladophialophora is a relatively abundant genus among all samples;LEf Se analysis results show that the relative abundance of Dioszegia,Purpureocillium,Candida Hyderabadensis,Halosphaeriaceae had significant differences among sample groups of different months.(3)This study used HPLC to detect the content of Hup-A in H.serrata.The results showed that the distribution order of Hup-A content in H.serrata was leaf>stem>root;the Hup-A content in the sample group of H.serrata was the highest in November.RDA analysis showed that H.serrata leaf tissue has the highest correlation with the content of Hup-A,which is positively related to the higher diversity of endophytic fungi in the leaves.The correlation network analysis showed that 13 genera(Strelitziana?Devriesia?Articulospora?Derxomyces ? Cyphellophora ? Trechispora ? Kurtzmanomyces ? Capnobotryella ?Erythrobasidium?Camptophora?Stagonospora?Lachnum?Golubevia)of H.serrata endophytic fungi showed a very significant positive correlation with Hup-A content(p<0.01).It is speculated that the endophytic fungal colonies of these 13 genera may produce Hup-A or promote the production of Hup-A from H.serrata.