Abstract:The endophytic Chaetomium spirale ND35 is a potential biocontrol agent with a wide range of antifungal activities. In this study, production, extraction and purification of the antibiotics by C.spirale ND35, as well as the antifungal activity in vitro and in vivo were systemically investigated in order to explore the mechanism of antibiotics produced by ND35 involved in biocontrol activity. The culture filtrate of the strain ND35 was extracted by ethyl acetate, concentrated, and the brown crude extracts were obtained. Bioassay of antifungal activity showed that the crude extracts significantly suppressed mycelial growth of several phytopathogenic fungi in vitro. The suppression percentage of mycelial growth of the phytopathogens ranged from 14.4% to 72.6% at a concentration of 400μg/mL of the crude extracts, and the inhibition percentage of conidia germination of Curvularia lunata was 54.2% and 75.9% at concentrations of 500μg/mL and 1000μg/mL, respectively. Yield of the crude extracts produced by C.spirale ND35 in PDB reached to the maximum after incubation for 15d. Two active fractions were purified by TLC and HPLC analyses. In greenhouse experiments, the control efficacy of Curvularia leaf spot of maize reached 85.5% and 63.3% with antibiotics extract in 50 fold dilution and 250 fold dilution. The antibiotics produced by strain ND35 as an important determinant involved in antifungal activity as well as the potential to control Curvularia leaf spot of maize.