| The healthy tissues of medicinal plants are rich in endophytic fungi resources.Studies have shown that the metabolites of endophytic fungi in medicinal plants have various biological activities such as antioxidant,antibacterial and anti-tumor,which have great potential in drug research and biological control of plant diseases.Magnolia denudate Desr.’Hailuo’ is a traditional Chinese medicinal,the dried flower bud is one of the three sources of Chinese medicinal “Xinyi”.In this study,the research object of this study was the M.denudate Desr.‘Hailuo’ from the Hailuo Mountain,Shijing Township,Huaining County,Anhui Province;isolation,identification and diversity analysis of endophytic fungi in stems,flowers and leaves from different age trees of M.denudate Desr.‘Hailuo’ were carried out,and the antioxidant and antimicrobial activities of the fermentation products of endophytic fungi were studied.The main results are as follows:1、A total of 90 endophytic fungi were isolated and purified from healthy plant tissues such as the stems,leaves and flowers of M.denudate Desr.‘Hailuo’ by tissue separation method.Morphology combined with r DNA-ITS sequence was used for identification.The results showed that,90 strains of endophytic fungi belong to 22 genera,of which 25 strains of Alternaria,21 strains of Diaporthe and 20 strains of Botryosphaeria,account for27.78%,23.33%,and 11.11% of the total number of fungi isolated respectively,these 3genera are the dominant genera in M.denudate Desr.‘Hailuo’;the isolation frequency of other genera endophytic fungi in the remaining was less than 5%.The diversity analysis of endophytic fungi showed that there were difference in the number and population composition of endophytic fungi from different tissues such as flowers,stems and leaves of different age trees,and some endophytic fungi had certain tissue specificity.2、Using DPPH and ABTS+·Free radical scavenging ability as indicators,the antioxidant activity of extracts from fermented mycelia and broth of the endophytic fungi was measured.The results showed that the endophytic fungi from M.denudate Desr.‘Hailuo’all had certain antioxidant activity.In general,the DPPH radical scavenging rate of endophytic fungal fermentation was higher than ABTS+·radical.There were 38 strains with DPPH free radical scavenging rate above 85%,accounting for 42.22% of the total isolated;There were 10 strains with a scavenging rate of ABTS+·free radicals above 85%,accounting for 11.11% of the total number of isolates.3、Using Escherichia coli,Candida albicans,2 kinds of human pathogens and Botrytis cinerea Pers.,Colletotrichum dematium,Pythium aphanidermatum,C.gloeosporioides 4kinds of plant pathogens as indicator bacteria,the plate confrontation method and filter paper method were used to determine the antimicrobial activity of the endophytic fungi.The results showed that 90 strains of endophytic fungi did not show antibacterial activity to2 kinds of human pathogens,but had certain inhibition to the growth of 4 kinds of plant pathogens.Among them,the growth inhibition rates of 26 endophytic fungi against 4 plant pathogens were all above 60%,accounting for 28.89% of the total number of the endophytic fungi isolated.4、The fermentation broth of the 1OS-6 strain with better antifungal activity was extracted with ethyl acetate,n-butanol,petroleum ether and chloroform for antifungal activity re-screening.The results showed that,compared with other solvent extracts,the ethyl acetate extract of the fermentation broth of strain 1OS-6 had a stronger inhibitory effect on C.gloeosporioides.The composition of the ethyl acetate extract was analysed by GC-MS.The the results showed that the main compounds were Oxalic acid,3,5-difluorophenyl undecyl ester,Diethyl Phthalate,Palmitic acid,9-Octadecenoic acid,3-methyl-Octadecane,and 3,7,11-trimethyl-2,6,10-Dodecatrien-1-ol,the relative peak area percentages are 21.53%,2.89%,11.66%,11.57%,2.06%,1.46%,respectively. |
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