Research On The Antagonistic Phytopathogen Constituent Of Endophytic Fungi From The Seeds Of Sophora Tonkinensis

The root and rhizome of Sophora tonkinensis Gagnep. have high value of medicinal function such as heat-clearing, detoxicating, detumescence and relieving sore throat, owing to the main chemical composition of alkaloids, flavonoids and polysaccharide contained in it. In previous studies, it has been shown that matrine and oxymatrine are the biological activity constituent in S. tonkinensis, such as antibacterial activity in vitro, antiviral, antitumor, antioxidant and enhance immune activity.The quantity and kind of endophytic fungi from medicinal plants are big and variety. Many new structure of compounds that most have the unique biological activity were extracted from endophytic fungi by academics. In recent years, endophyte, as a new kind of microbial resources, has attracted a great deal of attention. To find and discover new active compounds from endophytes is a hotspot in the research on endophytes. At present, the information on S. tonkinensis endophytic fungi study has not yet to be seen at domestic and overseas, and the study is almost in a blank state. Based on this, the isolates of endophytic fungi from the seeds of S. tonkinensis were preliminary studied, and the main results were as follows:(1) A total of 28 endophytic fungi were isolated from tissue segments of S. tonkinensis seeds with the method of peeling off the skin and disk fragment methodology. The isolates belong to 14 species of two classes Deuteromycetes and Ascomycota. Colletotrichum off. boninense LA79, Colletotrichum graminicola,Colletotrichum hymenocallidis and Diaporthe pseudomangiferae are the dominant species and the isolation percentages are respectively 17.86%, 14.29%,10.71% and 10.71%.(2)The inhibition ratio, which was about the isolates against with Colletotrichum gloeosporioides, Fusarium solani, Alternaria panax Whetz., was tested by the method of microorganism confrontation in plate. The number of isolates with the inhibition ratio of more than 40% was seperately 3,5,2 strains. Penicillium citrinum has the remarkable inhibition to the three phytopathogens with the inhibition rate of more than 50%. And it is Penicillium citrinum with the method of molecular biology identification.(3)Penicillium citrinum was selected as fermentation strain. The fermentation products of Penicillium citrinum were extracted.With the crude concentration of 2.5mg/mL on the PDA plate, the growth of Colletotrichum gloeosporioides and Alternaria panax Whetz.was restricted.(4)The fermented product with the bacteriostatic activity was 137g. And 6 compounds were isolated from the extracts and elucidated by nuclear magnetic resonance. They were emodin, coniochaetones B, penicitrinol A, (22E, 24R)-ergosta-5,7,22-trien-3β-ol, myristic acid and palmitic acid.