Discovery of Novel Antioomycete Metabolites from the Marine-Derived Fungus .

In our screening program for natural products that are effective in controlling plant diseases, we found that the culture filtrate of SFC20160907-M11 effectively suppressed the development of tomato late blight disease caused by . Using a bioassay-guided fractionation of antioomycete activity, 12 active compounds (-) were obtained from an ethyl acetate extract of the culture filtrate. Chemical structures of five new compounds - were determined by the extensive analyses of nuclear magnetic resonance (NMR), high resolution mass spectrometry (HRMS), and circular dichroism (CD) data. Interestingly, mycosporulonol () and botrallin () completely inhibited the growth of at concentrations of 8 and 16 μg/mL, respectively. Furthermore, the spray treatment of and (500 μg/mL) successfully protected tomato seedlings against with disease control values of 92%. Taken together, these results suggest that the culture filtrates of SFC20160907-M11 and their bioactive metabolites can be used as new antioomycete agents for Phytophthora late blight control.