Probing the role of tryptophan-derived secondary metabolism in defense responses against Bipolaris oryzae infection in rice leaves by a suicide substrate of tryptophan decarboxylase

► S-α-(Fluoromethyl)tryptophan (S-αFMT) inhibited tryptophan decarboxylase from rice. ► S-αFMT treatment of the rice seedlings reduced deposition of brown material. ► Treated leaves showed enhanced susceptibility to Bipolaris oryzae infection. ► Tryptamine metabolism is part of the effective defense mechanism of rice. ► S-αFMT is a workable tool for analysis of tryptamine metabolism.