School of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.
State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, China.
BMC Microbiol. 2023 Jan 28;23(1):30. doi: 10.1186/s12866-022-02741-5.
Endophytic fungi of medicinal plants, as special microorganisms, are important sources of antibacterial compounds. However, the diversity and antibacterial activity of endophytic fungi from Pinellia Tenore have not been systematically studied.
A total of 77 fungi were isolated from roots, stems, leaves, and tubers of Pinellia ternata and P. pedatisecta. All fungi were belonged to five classes and twenty-five different genera. Biological activities tests indicated that 21 extracts of endophytic fungi exhibited antibacterial activities against at least one of the tested bacteria, and 22 fermentation broth of endophytic fungi showed strong phytotoxic activity against Echinochloa crusgalli with the inhibition rate of 100%. Furthermore, four compounds, including alternariol monomethyl ether (1), alternariol (2), dehydroaltenusin (3) and altertoxin II (4), and three compounds, including terreic acid (5), terremutin (6), citrinin (7), were isolated from Alternaria angustiovoidea PT09 of P. ternata and Aspergillus floccosus PP39 of P. pedatisecta, respectively. Compound 5 exhibited strong antibacterial activities against Escherichia coli, Micrococcus tetragenus, Staphylococcus aureus, and Pseudomonas syringae pv. actinidiae with the inhibition zone diameter (IZD) of 36.0, 31.0, 33.7, 40.2 mm and minimum inhibitory concentration (MIC) values of 1.56, 3.13, 1.56, 1.56 μg/mL respectively, which were better than or equal to those of positive gentamicin sulfate. The metabolite 7 also exhibited strong antibacterial activity against P. syringae pv. actinidiae with the IZD of 26.0 mm and MIC value of 6.25 μg/mL. In addition, the compound 7 had potent phytotoxic activity against E. crusgalli with the inhibition rate of 73.4% at the concentration of 100 μg/mL.
Hence, this study showed that endophytic fungi of P. ternata and P. pedatisecta held promise for the development of new antibiotic and herbicide resources.
药用植物内生真菌作为特殊的微生物，是抗菌化合物的重要来源。然而，尚未系统研究半夏和掌叶半夏内生真菌的多样性和抗菌活性。
从半夏和掌叶半夏的根、茎、叶和块茎中共分离到 77 株真菌，均属于五个纲和二十五个不同属。生物活性测试表明，21 种内生真菌的提取物对至少一种测试细菌具有抗菌活性，22 种内生真菌的发酵液对稗草表现出强烈的植物毒性，抑制率为 100%。此外，从半夏的窄叶弯孢霉 PT09 和掌叶半夏的灰绿曲霉 PP39 中分别分离得到 4 种化合物，包括交替单甲醚（1）、交替醇（2）、去氢阿尔廷辛（3）和交替毒素 II（4），以及 3 种化合物，包括土曲霉酸（5）、土霉素（6）和桔青霉素（7）。化合物 5 对大肠杆菌、微球菌四态、金黄色葡萄球菌和猕猴桃溃疡病菌表现出较强的抗菌活性，抑菌圈直径（IZD）分别为 36.0、31.0、33.7 和 40.2mm，最小抑菌浓度（MIC）值分别为 1.56、3.13、1.56 和 1.56μg/mL，优于或等于阳性对照硫酸庆大霉素。代谢物 7 对猕猴桃溃疡病菌也表现出较强的抗菌活性，抑菌圈直径为 26.0mm，最小抑菌浓度为 6.25μg/mL。此外，化合物 7 对稗草具有较强的植物毒性，在 100μg/mL 浓度下抑制率为 73.4%。
因此，本研究表明，半夏和掌叶半夏的内生真菌具有开发新型抗生素和除草剂资源的潜力。
