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Updated: Jun 18, 2026
Methods to Inhibit Bacterial Pyomelanin Production and Determine the Corresponding Increase in Sensitivity to Oxidative Stress
Published on: August 31, 2015
Identification of Scytalone Dehydratase Inhibitors Effective against Melanin Biosynthesis Dehydratase
Takayuki Motoyama1, Yasumitsu Kondoh1, Takeshi Shimizu1
1Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Abstract:
Melanin is a secondary metabolite required for the infection of the rice blast fungus Pyricularia oryzae. Melanin biosynthesis enzymes are targets for controlling rice blast disease, and three types of commercial melanin biosynthesis inhibitors (MBIs) including MBI-R, MBI-D, and MBI-P have been developed. However, the occurrence of MBI-D-resistant strains containing scytalone dehydratase (SDH1/RSY1) with V75M mutations has been recently reported. In this study, we aimed to identify inhibitors of SDH1-V75M. We screened the RIKEN Natural Products Depository chemical library using chemical array technology and evaluated the inhibition of SDH1-V75M by candidate compounds. NPD13731 strongly inhibited the activity of wild-type and mutant SDH1. The structure-activity relationship data were used to create a more potent inhibitor 16, which controlled rice blast disease in rice plants infected with MBI-D-resistant P. oryzae. Compound 16, which we named melabiostin, may be used to develop fungicides for controlling rice blast infections.
