N,N-dimethylsphingosine, an inhibitor of sphingosine kinase, induces phytoalexin production and hypersensitive cell death of Solanaceae plants without generation of reactive oxygen species
Uruma. S Shibata. Y Takemoto. D Kawakita. K
Journal of General Plant Pathology ; 2009 [Vol.75] Pages:257-266
Abstract
Plant recognition of elicitors derived from pathogens induces various resistant reactions, including production of reactive oxygen species, hypersensitive cell
death and accumulation of phytoalexins. Previously, we isolated a ceramide elicitor from Phytophthora infestans, which activates O2- production of potato suspension-cultured cells. In this study, we employed nine ceramide-related chemicals to test their elicitor activity. Although, none of the tested chemicals induced O2- production, N,N-dimethylsphingosine (DMS) induced accumulation of phytoalexin in potato tubers. In potato, tobacco and Nicotiana benthamiana, DMS also induced rapid cell death. DMS-treated potato cells stained with 40,6-diamidino-2-phenylindole (DAPI) showed chromatin condensation, and isolated DNA from DMS-treated cells had ladder pattern, confirming that DMS-induced plant cell death is a hypersensitive reaction-like programmed cell death. Involvement of ceramide signaling in induction of plant defense reactions is discussed.
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