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Isolation And Identification Of Quercetin Producing Endophytic Fungus From Herber Houttuyniae

Posted on:2014-10-21Degree:MasterType:Thesis
Country:ChinaCandidate:Y P FangFull Text:PDF
GTID:2250330401973818Subject:Clinical Veterinary Medicine
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Endophytes are microorganisms that live within plants for at least a part of their life cyclewithout causing any visible manifestation of disease in the host. Research results in recent yearsshow that due to the long-term survival of the host plant, the endophytic fungi can produce somesimilar physiological active products. For this reason, the research about endophyte was focusedon the exploring of the symbiotic envolutionary relationship between fungi and the host plant,and their metabolites have been a new way to find medical resources.In this study, materials of Houttuynia cordata Thunb, a medicinal and edible plant wasselected to isolate and identify the endophytic fungi. A way named tissue print culture was usedto isolate endophytic fungi from the tissue of plant. To identify the endophytic fungi based on themorphological features, the way of TLC was used to preliminary test the metabolic metabolitesproduced by endophytic fungi, and the endophytic fungi which can produce biologically activesubstances was determined. Their species were identificated by the method combining themorphological and molecular biology methods. The main results are as follows:1,9endophytic fungal were isolated from roots, stems and leaves of Houttuynia cordataThunb by the way of tissue print culture. The isolated endophytic fungus were numberedaccording to the separation site as YXC-G1,YXC-G2,YXC-G3,YXC-J1,YXC-J2,YXC-J3,YXC-Y1,YXC-Y2and YXC-Y3.2, The secondary metabolites isolated from the endophytic fungi were detected by TLC andHPLC. It is displayed that the five isolated fungal YXC-G1,YXC-G3,YXC-J1,YXC-J2,YXC-J3can produce quercetin which is a kind of flavonoid glycoside, and the quercetinproduction of the five fungal isolated were calculated. The isolate YXC-G3was indentified asAlternaria, which can produce quercetin up to11.2mg/g, and the content of the fermentationbroth of YXC-G3can up to834.2μg/L.3, Methods of molecular biology combined with the morphological features of the fungalisolates were used to identify the species of them. The results of nucleotide sequence of internaltranscribed spacer (ITS) between rDNAs show that the fungal YXC-J1, YXC-J2belong toAlternaria alternate, YXC-J3belongs to Colletotrichum destructivum and YXC-G1was Acrostalagmus luteoalbus and YXC-G3belongs to Alternaria. The study found that the fungibelong to Alternaria alternate was dominant species, and the Alternaria has high production.The endophytic fungi isolated from Houttuynia which can produce quercetin can be used asa candidate strain for industrial fermentation. In addition, we will pay more attention to theisolated endophytic fungi in order to find out similar Houttuynia pharmacologically activemetabolites, and to optimize the culture conditions of the endophytic fungi to improve itsmetabolites production.
Keywords/Search Tags:Houttuynia cordata Thunb, endophytic fungi, secondary metabolites, quercetin, molecular cloning
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