Screening of endophytic fungi with anti-phytopathogen activities from Heptacodium miconioides.

Objective: To find anti-phytopathogen compounds from endophytic fungi associated with the endangered species Heptacodium miconioides.

Methods: Fungi from H. miconioides with antifungal activities were isolated according to the plate growth inhibition method. The fungus with preferable antifungal activities was identified by morphological identification and 5. 8S rRNA sequence analysis. The bioactive metabolites were isolated and purified by chromatographic methods; the structures were determined by spectroscopic analysis.

Results: Alternaria solani QZH 10 showed better antifungal activity against Rhizoctorzia solani and Valsa mali with the inhibition rates of 89.1% and 67.9%, respectively. The ethyl acetate crude extract of QZH 10 had strong antifungal activity against Magnaporthe oryzae with the rate of 100. 0% under the concentration of 100 μg/mL. Two antifungal metabolites altersolanol A and 6-O-methylalaternin were isolated and determined from QZH 10. Altersolanol A possessed strong activity against M. oryzae with the inhibition rate of more than 85%, 6-O-methylalaternin had the mightily activity against V. mali with the inhibition rate of 100.0% under the concentration of 100 μg/mL.

Conclusion: Altersolanol A and 6-O-methylalaternin are potential fungicides originated from microorganisms.