title: Pseudomonas syringae infection triggers de novo synthesis of phytosphingosine from sphinganine in Arabidopsis thaliana.
abstract: Sphingolipids are important membrane components and also regulate cell proliferation and apoptosis. We detected a fast increase of the free sphingobase t18:0 (phytosphinganine) in Arabidopsis leaves after inoculation with an avirulent strain of the bacterial pathogen Pseudomonas syringae pathovar tomato, characterized by host cell death reactions. The induction of phytosphinganine was more transient in virulent interactions lacking cell death reactions, suggesting a positive role of t18:0 in the plants' response to pathogens, e.g. the hypersensitive response. In the mutant sphingobase hydroxylase 1 (sbh1-1), Pseudomonas induced elevated free d18:0 levels. As total t18:0 contents (after hydrolysis of ceramides) were not reduced in sbh1-1, the pathogen-triggered t18:0 increase most likely results from de novo synthesis from d18:0 which would require SBH1.
authors: Julius-von-Sachs Institute of Biosciences, Pharmaceutical Biology, Julius-Maximilians-Universität Würzburg, Würzburg, Germany.
authors: Markus
authors: M
authors: Peer
authors: Martin
authors: M
authors: Stegmann
authors: Martin J
authors: MJ
authors: Mueller
authors: Frank
authors: F
authors: Waller
mesh_terms: D017209:Apoptosis; D017360:Arabidopsis / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology; D044224:Pseudomonas syringae; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism
chemical_list: D006899:Mixed Function Oxygenases; C012491:phytosphingosine; D013110:Sphingosine; C005682:safingol