| Complex information exchanges and interactions between plant endophytic fungi and their host can help the host deal with environmental stress and promote the host's absorption of nutrients.The secondary metabolites of endophytes mostly served as bioactive agents played important roles in agricultural,industrial and medical applications.,As a traditional medicine of the Li nationality,Blumea balsamifera(L.)DC.has long been used in Hainan province,Whereas reports on its endophytic fungi is very few so far.In this paper,we foucus our attention on three aspects of this plant as follows,1)Comparison of the diversities of endophytic fungi of B.balsamifera(L.)DC.from different habitats 2)Isolation,identification,and activety-guided screen of biocontrol endophytic strains,and 3)investigation of bioactive compounds with unusual structures from selected fungus.This study provides the basis for the development and utilization of endophytic fungi from an endemic medicinal plant B.balsamifera(L.)DC..1?Using high-throughput sequencing technology to analyze the composition and diversity of endophytic fungi grown in natural and rubber tree forest environments.Results showed that there were significant differences in composition of endophytic fungi.The endophytic genus of Blumea balsamifera(L.)DC.leaves under the forest was relatively simple.The results of community composition analysis showed that the dominant genus in the leaves of Blumea balsamifera(L.)DC.under the forest was the unclassified genus of Teratosphaeriaceae,with a relative abundance of 50.29%,while inspection of the leaves of B.balsamifera(L.)DC.grown under natural conditions revealed its dominant genuses of Pseudocercospora and the unclassified genus of Teratosphaeriaceae,and the relative abundance is 24.18% and 19.19%,respectively.2?A total of 58 strains of endophytic fungi were obtained from B.balsamifera of two different biotopes,which belong to 24 genera by molecular biology authenticated technique.Antifungal results showed that the endophyts isolated under rubber tree forest exhibited stronger inhibitory effect on the four strains of anthracnose than that of natural environment.especially endophytic fungi belonging to the genus Talaromyces and Penicillium.Antibacterial assays showed that Fusarium and Diapothe genus from natural environment showed potent inhibitory effects against several tested bacteria.3?The secondary metabolites of the three selected endophytic fungi(Clonostachys rosea from rubber tree forest environments,Xylariaceae sp.and Chaetothyriales sp.from natural conditions)were studied,and a sum of 19 compounds were obtained and identified.Six known compounds were isolated from Clonostachys rosea: Verticillin A(1),(S)-(+)-fusarinolic acid(2),8-hydroxyfusaric acid(3),cerebroside C(4),3-Maleimide-5-oxime(5),and bionectriol A(6).Biological evaluation showed that compounds 1?4 and 6 are displayed strong antibacterial activities against Staphylococcus aureus ATCC 6538?Bacillus subtilis ATCC 9372 and Pseudomonas aeruginosa ATCC 27853.the MIC value of compound 6 on 3 test bacteria reached 2 ?g/m L,which was significantly stronger than that of the positive control streptomycin.Compound 6 showed weaker inhibitory activity against Escherichia coli ATCC 25922 with the MIC value of 16 ?g/m L.The MIC of Compound 1 against P.aeruginosa also reached 2 ?g/m L.Five new compounds including Xylariacin A(7),Xylariacin B(8),Xylariacin C(9),Xylariacin D(10),and Xylariacin E(11),were isolated from Xylariaceae sp.,and antibacterial activity experiments showed that none of them can inhibite P.aeruginosa,B.subtilis,E.coli,and S.aureus at a concentration of 32 ?g/m L.Eight compounds were isolated and identified from fungus Chaetothyriales sp.,including five new compounds(including three new skeletons)Chaetothytone A(12)?Chaetothytone B(13)?Chaetothytone C(14)?Chaetothytone D(15)?Chaetothytone E(16)and three known ones 4,6-dimethylcurvulinic acid(17)?5-hydroxy-2-hydroxymethyl-4H-pyran-4-one(18)?7-epiaustdiol(19)?... |
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