title: Phosphoinositide and inositolpolyphosphate signalling in defense responses of Arabidopsis thaliana challenged by mechanical wounding.
abstract: Various biochemical signals are implicated in Arabidopsis wound signalling, including jasmonic acid (JA), salicylic acid, auxin, and Ca2+. Here, we report on cross-talk of phytohormones with phosphoinositide signals not previously implicated in plant wound responses. Within 30 min of mechanical wounding of Arabidopsis rosette-leaves, the levels of the lipid-derived soluble inositolpolyphosphate, inositol 1,4,5-trisphosphate (InsP(3)), increased four to five-fold. Concomitantly, the precursor lipids, phosphatidylinositol 4,5-bisphosphate, phosphatidylinositol 4-phosphate and phosphatidylinositol transiently depleted, followed by re-synthesis after 30-60 min of stimulation. Increased InsP(3) levels with wounding coincided with JA increases over the first hours of stimulation. In dde2-2-mutant plants deficient in JA biosynthesis, no InsP(3) increase was observed upon wounding, indicating that JA was required for InsP(3) formation, and InsP(3) levels increased in wild-type plants challenged with sorbitol, increasing endogenous JA levels. In InsP 5-ptase plants with attenuated phosphoinositide signalling, the induction of wounding-inducible genes was diminished compared with wild-type plants, suggesting a role for phosphoinositide signalling in mediating plant wound responses. The gene-expression patterns suggest that phosphoinositides contribute to both JA-dependent and JA-independent aspects of wound signalling. Weight gain of Plutella xylostella caterpillars feeding on InsP 5-ptase plants was increased compared with that of caterpillars feeding on wild-type plants. The ecophysiological relevance of phosphoinositide signals in plant defense responses to herbivory is discussed in light of recent findings of inositolpolyphosphate involvement in phytohormone-receptor function.
authors.affiliation: Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
authors.forename: Alina
authors.initials: A
authors.lastname: Mosblech
authors.forename: Sabine
authors.initials: S
authors.lastname: König
authors.forename: Irene
authors.initials: I
authors.lastname: Stenzel
authors.forename: Peter
authors.initials: P
authors.lastname: Grzeganek
authors.forename: Ivo
authors.initials: I
authors.lastname: Feussner
authors.forename: Ingo
authors.initials: I
authors.lastname: Heilmann
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000469:parasitology / Q000502:physiology*; D002118:Calcium / Q000502:physiology; D003517:Cyclopentanes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018527:Hydroponics; D007210:Indoleacetic Acids / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000502:physiology; D007295:Inositol Phosphates / Q000378:metabolism / Q000502:physiology*; D007313:Insecta / Q000472:pathogenicity; D054883:Oxylipins / Q000378:metabolism; D010716:Phosphatidylinositols / Q000502:physiology*; D010935:Plant Diseases; D018515:Plant Leaves / Q000469:parasitology / Q000502:physiology; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction; D013012:Sorbitol / Q000494:pharmacology; D014945:Wound Healing / Q000502:physiology*
chemical_list: D003517:Cyclopentanes; D007210:Indoleacetic Acids; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007295:Inositol Phosphates; D054883:Oxylipins; D010716:Phosphatidylinositols; D013012:Sorbitol; C011006:jasmonic acid; C030737:indoleacetic acid; D015544:Inositol 1,4,5-Trisphosphate; D020156:Salicylic Acid; D002118:Calcium