Antifungal, Phytotoxic, and Cytotoxic Activities of Metabolites from Epichloe bromicola, a Fungus Obtained from Elymus tangutorum Grass

摘要

The development of high-quality herbage is an important aspect of animal husbandry. Inoculating beneficial fungi onto inferior grass is a feasible strategy for producing new varieties of high-quality herbage. Epichloe bromicola is a candidate fungus that is isolated from Elymus tangutorum. A total of 17 metabolites, 1-17, were obtained from E. bromicola, and their biological activities were assayed. Metabolite 1 exhibited antifungal activities against Alternaria alternata, Fusarium avenaceum, Bipolaris sorokiniana, and Curvularia lunata. EC50 values ranged from 0.7 to 5.3 mu M, which were better than the positive control, chlorothalonil. Metabolite 8 displayed obvious phytotoxic effects toward Lolium perenne and Poa crymophila seedlings, and it was as active as glyphosate. None of these isolated metabolites displayed cytotoxicity against Madin-Darby bovine kidney cells. The IC50 values were greater than 100 mu M, and the metabolites increased the growth of the cells at a concentration of 12.5 mu M. The bioassay indicated that E. bromicola may be a beneficial fungus for producing new varieties of herbage with various resistances. Additionally, metabolite 7, 3-(2'(4 ''-hydroxyphenyl)acetoxy)-2S-methylpropanoic acid, is a new natural product, and its stereochemistry was determined by means of optical rotation computation and chemical reactions.