Disruption of the ceramide synthase LOH1 causes spontaneous cell death in Arabidopsis thaliana

Authors

  • Philipp Ternes,

    1. Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
    2. Present address: metanomics GmbH, Tegeler Weg 33, D–10589 Berlin, Germany
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  • Kirstin Feussner,

    1. Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
    2. Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University, D-37077 Göttingen, Germany
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  • Stephanie Werner,

    1. Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
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  • Jennifer Lerche,

    1. Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
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  • Tim Iven,

    1. Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
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  • Ingo Heilmann,

    1. Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
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  • Howard Riezman,

    1. Department of Biochemistry, Sciences II, University of Geneva, CH-1211 Geneva 4, Switzerland
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  • Ivo Feussner

    1. Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
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Author for correspondence:
Philipp Ternes
Tel: +49 30 34807 177
Email: philipp.ternes@metanomics.de

Summary

  • The bioactive lipid ceramide is produced by the enzyme ceramide synthase, which exists in several isoforms in most eukaryotic organisms. Here, we investigated functional differences between the three ceramide synthase isoforms in Arabidopsis thaliana.
  • The biochemical properties of the three ceramide synthases were investigated by comparing lipid profiles of yeast strains expressing LOH1, LOH2 or LOH3 with those of wild-type and loh1, loh2 and loh3 knockout plants. Expression profiles of the ceramide synthases and of the pathogenesis-related gene PR-1 were investigated by real-time PCR.
  • Each ceramide synthase isoform showed a characteristic preference regarding acyl-CoA chain length as well as sphingoid base hydroxylation, which matches the pattern of ceramide and glucosylceramide species found in leaves. After extended culture under short-day conditions, loh1 plants showed spontaneous cell death accompanied by enhanced expression of PR-1. The levels of free trihydroxy sphingoid bases as well as ceramide and glucosylceramide species with C16 fatty acid were significantly elevated while species with C20–C28 fatty acids were reduced.
  • These data suggest that spontaneous cell death in the loh1 line is triggered either by the accumulation of free trihydroxy sphingoid bases or ceramide species with C16 fatty acid.

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