title: Reassessing the role of phospholipase D in the Arabidopsis wounding response.
abstract: Plants respond to wounding by means of a multitude of reactions, with the purpose of stifling herbivore assault. Phospholipase D (PLD) has previously been implicated in the wounding response. Arabidopsis (Arabidopsis thaliana) AtPLDalpha1 has been proposed to be activated in intact cells, and the phosphatidic acid (PA) it produces to serve as a precursor for jasmonic acid (JA) synthesis and to be required for wounding-induced gene expression. Independently, PLD activity has been reported to have a bearing on wounding-induced MAPK activation. However, which PLD isoforms are activated, where this activity takes place (in the wounded or non-wounded cells) and what exactly the consequences are is a question that has not been comprehensively addressed. Here, we show that PLD activity during the wounding response is restricted to the ruptured cells using (32)P(i)-labelled phospholipid analyses of Arabidopsis pld knock-out mutants and PLD-silenced tomato cell-suspension cultures. pldalpha1 knock-out lines have reduced wounding-induced PA production, and the remainder is completely eliminated in a pldalpha1/delta double knock-out line. Surprisingly, wounding-induced protein kinase activation, AtLOX2 gene expression and JA biosynthesis were not affected in these knock-out lines. Moreover, larvae of the Cabbage White butterfly (Pieris rapae) grew equally well on wild-type and the pld knock-out mutants.
authors.affiliation: Department of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, NL, Amsterdam, the Netherlands.
authors.forename: Bastiaan O R
authors.initials: BO
authors.lastname: Bargmann
authors.forename: Ana M
authors.initials: AM
authors.lastname: Laxalt
authors.forename: Bas
authors.initials: B
authors.lastname: ter Riet
authors.forename: Christa
authors.initials: C
authors.lastname: Testerink
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Merquiol
authors.forename: Alina
authors.initials: A
authors.lastname: Mosblech
authors.forename: Antonio
authors.initials: A
authors.lastname: Leon-Reyes
authors.forename: Corné M J
authors.initials: CM
authors.lastname: Pieterse
authors.forename: Michel A
authors.initials: MA
authors.lastname: Haring
authors.forename: Ingo
authors.initials: I
authors.lastname: Heilmann
authors.forename: Dorothea
authors.initials: D
authors.lastname: Bartels
authors.forename: Teun
authors.initials: T
authors.lastname: Munnik
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002080:Butterflies / Q000502:physiology; D002478:Cells, Cultured; D003517:Cyclopentanes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D007814:Larva / Q000502:physiology; D018551:Solanum lycopersicum / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D054883:Oxylipins / Q000378:metabolism; D010712:Phosphatidic Acids / Q000378:metabolism; D010739:Phospholipase D / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D010712:Phosphatidic Acids; C011006:jasmonic acid; D011494:Protein Kinases; D010739:Phospholipase D