黄芪发酵过程中内生真菌多样性变化及其发酵液的抑菌作用

Changes of endophytic fungi diversity during Astragali radix fermentation and antibacterial activity of it’s fermentation liquid

以不同发酵时间的黄芪内生真菌发酵液为研究对象,采用Illumina Miseq高通量测序技术揭示黄芪内生真菌发酵过程中真菌多样性的变化。同时,测定发酵液对大肠杆菌(Escherichia coli)和金黄色葡萄球菌(Staphylococcus aureus)的抑菌作用,并初步揭示其可能的抗菌机理。结果表明,黄芪发酵过程中内生真菌的多样性(Shannon指数)和丰富度(Chao指数)随着发酵时间的延长显著减少(P<0.05),真菌的种群组成也发生了变化,未发酵黄芪内生真菌的优势菌属为驼孢锈菌属(Hemileia)和赤霉菌属(Gibberella),而发酵8 d后发酵液的优势菌属为细极链格孢菌(Alternaria tenuissima)和棘豆弯曲牙管蠕孢菌(Undifilum oxytropis)。此外,随着发酵时间在0~8 d范围内的延长,黄芪内生真菌发酵液的抑菌活性也随之增加,且抑菌作用与发酵液对受试菌株细胞形态的破坏有关。

Using the fermentation liquid of endophytic fungi in Astragali radix with different fermentation time as the research objects, the changes of fungal diversity in the fermentation process of endophytic fungi in A. radix were revealed by the Illumina Miseq high-throughput sequencing technology. Meanwhile, the antibacterial effects of fermentation liquid on Escherichia coli and Staphylococcus aureus were determined, and the possible antibacterial mechanism was revealed. The results showed that the diversity (Shannon index) and abundance (Chao index) of endophytic fungi of A. radix during fermentation decreased significantly with the increase of fermentation time (P<0.05), and the fungal population composition also changed. The dominant genera of endophytic fungi in A. radix without fermentation were Hemileia and Gibberella, while the dominant genera of fermentation liquid after fermentation 8 d were Alternaria tenuissima and Undifilum oxytropis. In addition, with the increase of fermentation time (0-8 d), the antibacterial activity of fermentation liquid of endophytic fungi in A. radix increased, and it was related to the damage of cell morphology of the tested strains by fermentation liquid.