Secondary Metabolites Of Dark Septate Endophytes Isolated From Yuanjiang Dry-hot Valley,Yunnan Province, Southwest China

Fungi causing asymptomatic infections in plant tissues have been called fungal endophytes. They are quite ubiquitous and have been found in all plant species examined to date. They have been documented to be able to enhance host plants’ resistance to various biotic and abiotic stress.Four secondary metabolites were isolated from the dark septate endophyte K28of Bothriochloa pertusa growing in Yuanjiang dry-hot valley through TLC, Silica gel column chromatography, Gel column chromatography and HPLC. Based upon13CNMR,1HNMR and MS analysis technique, they were identified as phydroxy phenylethanol (LX-1),2-methyl-3-ethanol-4-methoxy cyclopentyl ester (LX-2) and Behenic acid methyl glycol ester (LX-4), while compound LX-3was not identified. The three compounds were reported from DSE the first time.The antifungal and antibacterial tests indicated that LX-1, LX-2and LX-3showed no activity against Escherichia coli, Staphyloccocus aureus and Cochlioholus sativus. However, p-hydroxy phenylethanol exhibited antifungal activity against Fusarium solani, Verticillium dahlia and Phytophthora nicotianae;2-methyl-3-ethanol-4-methoxy cyclopentyl ester showed antifungal activity against Verticillium dahlia and Phytophthora nicotianae and LX-3against Verticillium dahlia. Antifungal activity expressing for Linear regression curve showed that antifungal activity decreased with the concentration of drugs decreasing.The antifungal and antibacterial activities of the metabolites of the endophyte K28showed that endophytic fungi may play an important role in host plant resistance to biotic stress. LX-4(Behenic acid methyl glycol ester) has been found to be able to keep moisture and has been widely used in the cosmetic industry. It may contribute to the dought tolerance of the host plant, however, its ecological role need to be further studied.