Sakuranetin (1) is a flavanone phytoalexin that has been reported to play an important role in disease resistance in rice plants. The rice blast fungus Pyricularia oryzae (syn. Magnaporthe oryzae) has been reported to metabolize 1 to lower its antifungal activity. Here, two flavanones, sternbin (2) and naringenin (3), were identified as metabolites of 1 in P. oryzae suspension culture by liquid chromatography tandem mass spectrometry (LC/MS/MS). The inhibition of 1, 2, and 3 on P. oryzae mycelial growth were 45%, 19%, and 19%, respectively, at a concentration of 100 μm. Thus, 2 and 3 are detoxified metabolites of 1 by P. oryzae.
Keywords: Pyricularia oryzae; Flavonoid; Phytoalexin; Rice.
© 2017 Wiley-VHCA AG, Zurich, Switzerland.