光枝勾儿茶内生真菌多样性及抑菌活性研究

o explore the fungal taxa, distribution and antibacterial activity of Berchemia polyphylla var. leioclada, endophytic fungi of B. polyphylla var. leioclada from Guiyang and Qianxi of Guizhou Province were isolated by tissue fragment separation. Based on the methods of molecular biology and statistics, the endophytic fungi were identificated and their diversity were analyzed. The strains with antibacterial activity were screened by microdilution of broth. The results were as follows: (1) There were 191 fungal strains were isolated, which classified into 3 phyla, 5 classes, 10 orders, 15 families and 19 genera. Among all strains, PhyllostictaDiaporthe Botryosphaeria and Colletotrichum were the dominant genus. (2) The fungal endophytes’ Shannon-Weiner diversity index of Berchemia polyphylla var. leioclada in Qianxi (H'Q=2.112) was higher than Guiyang (H'G=1.801), the Sorenson’s similarity coefficients CsG-Q was 0.923. The Shannon-Weiner diversity index of different tissues was stem (H'S =2.004)> root(H'R=1.764)> leaf(H'L=1.654)>fruit(H'F=1.473). The Simpson was stem(DS=0.826)>fruit(DF=0.813)> root(DS=0.765)>leaf(DL=0.721), the similarity index between stem and leaf was the highest which was CsS-L =0.667. (3) 21 endophytic fungi’ secondary metabolites have inhibitory effect on Escherichia coli, Staphylococcus aureus and Salmonella enterica. The isolate Diaporthe sp. QX4G6 fermentation broth extract have relatively high inhibitory effect, which the minimum inhibitory concentration against Escherichia coli, Staphylococcus aureus and Salmonella enterica were 12.5, 6.25 and 12.5 mg·mL-1, and the minimum bactericidal concentration were 12.5, 6.25 and 12.5 mg·mL-1, respectively. The study revealed rich endophytic fungi resources of Berchemia polyphylla var. leioclada and most of fungi have good antibacterial activity, which lay the foundation for the research and development of natural antibacterial drugs or drug sources for endophytic fungi from B. polyphylla var. leioclada.