Isolation,Identification And Anti-microbial Activities Of Endophytes From Dendrobium Sinens In Hainan

Playing an important role in the microsystem of plants,endophytes have become a research hotspot due to its high richness in species and biological function..Dendrobium sinense is an orchid species endemic to Hainan,which lives in the tropical rainforest above the altitude of 1500m.D.sinense is also a precious medicinal plant for the Li ethnic group native to Hainan.In this study,the endophytes were separated and systematically analyzed in D.sinense,and the antimicrobial activities were tested to set up a foundation for the in-depth exploration.The result is as below.(1)The separation of endophytes in D.sinense179 endophytic fungi were isolated with five kinds of isolation medium.The number of isolates in different tissues were root 26,stem 45 and leaf 108.The number of endophytic fungi isolated from different medium:1/5PDA<FIM<(Ag)<(PE)<PDA.165 endophytic bacteria were isolated with three kinds of isolation medium.The number of isolates in different tissues were root 13,leaf 50 and stem 102.The number of endophytic bacteria isolated from different medium:Ag<G<NA.(2)Molecular identification of endophytes in Dendrobium sinenseThe endophytic fungi of D.sinense belonged to 45 species in 22 known genera,and the dominant species was Phyllosticta capitalensis.In root,12 species in 8 genera were identified and the dominant species was Hypoxylon investiens.In stem,20 species in 10 genera were identified and the dominant species was Phyllosticta capitalensis.In leaves,23 species in 11 genera were identified and the dominant species was Phyllosticta capitalensis.The endophytic bacteria of D.sinense belonged to 32 species in 7 known genera,and the dominant genera was Staphylococcus.In root,25 species in 5 genera were identified and the dominant species was Staphylococcus epidermidis.In stem,16 species in 6 genera were identified and the dominant species were Bacillus amyloliquefaciens?Staphylococcus aureus and Staphylococcus warneri?(3)The antimicrobial potential of endophytes in D.sinenseIn this study,the antibacterial activity of endophytes in D.sinense was screened by the inhibition zone method and the growth inhibition rate method.55 strains of endophytes with obvious inhibitory circle were obtained.Among them,the 2 endophytic fungi were Pestalotiopsis uvicola and Talaromyces verruculosus.53 endophytic bacteria were 20 species in 4 genera.Among them,25 strains of endophytic bacteria had bacteriostatic effects on six pathogens with 5 species in 2 genera,they were Bacillus amyloliquefaciens,Bacillus subtilis,Bacillus velezensis,Staphylococcus petrasii and Staphylococcus warneri,which are likely to be important microbial resources.(4)The antimicrobial activities of fermentation broth of endophytesThe results showed that the antimicrobial activity of the crude extract of the fermentation broth was higher than that of the crude extract of mycelia inTalaromyces verruculosus and Pestalotiopsis uvicola.The crude extract of Pestalotiopsis uvicola for pathogens have a certain bacteriostatic effect on 11 species of pathogens.The ethyl acetate extracts of Bacillus amyloliquefaciens,Bacillus subtilis,Bacillus velezensis,Staphylococcus warner and Staphylococcus petrasii were used to test the antibacterial activity.The results showed that the extract of Staphylococcus petrasii and Staphylococcus warneri had inhibitory effects on pathogens tested.