Community Structure of Cultivable Endophytes in Different Organs of Gentiana straminea Maxim and Its Correlation with the Content of Gentiopicrin

Abstract:

In order to study the resource of the endophyte from Gentiana straminea Maxim in Sichuan，the cultivable endophyte in different organs of Gentiana straminea Maxim（roots，stems，leaves and flowers） were isolated and identified by the dilution separation methods and the sequence analysis of 16 S rDNA and ITS-rDNA. Then the content of gentiopicrin in each organ was determined by high performance liquid chromatography（HPLC） and its correlation with the abundance of cultivable endophytes was analyzed. The results showed that 13 strains of cultivable endophytes were separated from Gentiana straminea Maxim as a whole，which belong to 3 phyla，6 classes，8 orders，9 families and 10 genera，and among them，ten strains were bacteria and three were fungi. Meanwhile，there were differences of the quantity and microbial population of the cultivable endophytic bacteria and fungi in different organ or position of Gentiana straminea Maxim. The maximum quantity of endophytic bacteria and fungi were（8.77±0.71）×105 cfu/g and（2.00±1.05）×104 cfu/g respectively and both in the roots of Gentiana straminea Maxim.. Statistical analysis showed that correlations between the content of gentiopicrin and the quantity of cultivable endophytic bacteria and fungi，respectively，were extremely significantly positive（P<0.01）. More over，the quantity of each predominant strain，bacteria QJ2（Duganella sp.），bacteria QJ6（Rahnella sp.），bacteria QJ10（Pseudomonas sp.） fungi QJ11（Aspergillus sp.） and fungi QJ13（Aspergillus sp.），was extremely，significantly and positively related with the content of gentiopicrin，respectively（P<0.01）. The cultivable endophytes in Gentiana straminea Maxim were characterized by abundant genetic diversity and there were differences of the endophytes community structure in different organ of Gentiana straminea Maxim. All the results will serve as the foundation of development and utilization of endophytes in Gentiana straminea Maxim.