Isolation And Identification Of Endophytes In Arundina Graminifolia And Their Biological Activities

Arundina graminifolia?D.Don?Hochr.is a Chinese medicinal herb belonging to Orchidaceae family and Arundina general,which has been widely used for detoxicate,belonged to the secondary protected plants.Endophytes is a class of special microbial resources,widely distributed in the plants,with long-term cooperative coevolution,they can produce the same or similar bioactive compounds with their host,they can also produce novel metabolites.In view of this characteristic,in this thesis,the resources of endophytes from Arundina graminifolia?contain abundant stilbene compounds?and their bioactives were investigated.The results were as follows:1.5 strains endophytic fungi were isolated from Arundina graminifolia?Xishuan Banna,Yunnan,NO.20160331?,33 strains?14 fungal strains,11 bacterial strains,8 actinomycete strains?were isolated from Arundina graminifolia?Nanning,Guangxi,NO.20170311?,which formed the resource base of endophytes in Arundina graminifolia.The morphological observation and molecular biological identification of some endophytes showed that 19strains of endophytic fungi belonged to 11 genera,of which the genus Colletotrichum sp.and Fusarium sp.were the dominant strains of endophytic fungi,Streptomyces is a dominant strain of endophytic actinomycetes in Arundina graminifolia.2.The antioxidant activity of fermentation products in endophytic fungi TJ-1?TJ-2?TJ-3were evaluated,it was found that fermented liquid of TJ-1 and TJ-2 had stronger reduction ability to Fe³⁺,TJ-3 fermented liquid had good scavenging effect on·OH,TJ-3 fermented liquid and TJ-3 mycelium had significantly scavenging activity to DPPH free radicals.3.The antimicrobial activity of fermentation products in endophytic fungi TJ-1?TJ-2?TJ-3 were evaluated,it was found that TJ-3 exhibited broad-spectrum antibacterial activity.The MICs of TJ-3 fermented liquid to Staphylococcus aureus and Salmonella enterica were625?1250?g/m L,which TJ-3 mycelium were 312.5?1250?g/m L;The fermentation products of TJ-3 had different inhibitory effects on 10 kinds of plant pathogenic fungi.Respectively,among them,the inhibitory rate of TJ-3 fermented liquid and mycelium against Colletolrichum higginsianum were 58%and 63%,and the inhibition rate to Phomopsis sp.were 52%and 66%.4.The antiacetylcholinesterase activity of fermentation products in endophytic fungi TJ-1?TJ-2?TJ-3 were evaluated,it was found that the fermentation products of TJ-3exhibited better antiacetylcholinesterase activity.At the concentration of 10 mg/m L,the inhibitory rate of TJ-3 fermented liquid and mycelium on acetylcholineste-rase activity was65.5%and 57.8%,respectively,when the concentration was reduced to 2.5 mg/m L,the inhibition rate of TJ-3 fermented liquid was still 47.9%.In summary,it is concluded that the metabolites of TJ-3 has better bioactivity,and it is a promising source with great potential for development to find antioxidants,antimicrobial or acetylcholinesterase inhibitors.