title: Phospholipase D is a negative regulator of proline biosynthesis in Arabidopsis thaliana.
abstract: Accumulation of proline has been observed in a large number of plant species in response to drought and salt stresses, suggesting a key role of this amino acid in plant stress adaptation. Upstream components of the proline biosynthesis signal transduction pathways are still poorly defined. We provide experimental evidence that phospholipase D (PLD) is involved in the regulation of proline metabolism in Arabidopsis thaliana. The application of primary butyl alcohols, which divert part of PLD-derived phosphatidic acid by transphosphatidylation, stimulated proline biosynthesis even without hyperosmotic constraints. Moreover, application of primary butyl alcohols enhanced the proline responsiveness of seedlings to mild hyperosmotic stress. These data indicate that some PLDs are negative regulators of proline biosynthesis and that plants present a higher proline responsiveness to hyperosmotic stress when this regulator is abolished. We clearly demonstrate that PLD signaling for proline biosynthesis is similar to RD29A gene expression and different from the abscisic acid-dependent RAB18 gene expression. Our data reveal that PLDs play positive and negative roles in hyperosmotic stress signal transduction in plants, contributing to a precise regulation of ion homeostasis and plant salt tolerance.
authors.affiliation: Unité de "Physiologie Cellulaire et Moléculaire des Plantes," UMR 7632 CNRS, Université Pierre & Marie Curie, Case 156, 4 place Jussieu, 75252 Paris cedex 05, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Thiery
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Leprince
authors.forename: Delphine
authors.initials: D
authors.lastname: Lefebvre
authors.forename: Mohamed Ali
authors.initials: MA
authors.lastname: Ghars
authors.forename: Elise
authors.initials: E
authors.lastname: Debarbieux
authors.forename: Arnould
authors.initials: A
authors.lastname: Savouré
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D015152:Blotting, Northern; D000440:Butanols / Q000737:chemistry; D002118:Calcium / Q000378:metabolism; D004190:Disasters; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D007477:Ions / Q000378:metabolism; D009995:Osmosis; D010712:Phosphatidic Acids / Q000737:chemistry; D010739:Phospholipase D / Q000378:metabolism / Q000502:physiology*; D011392:Proline / Q000096:biosynthesis* / Q000737:chemistry; D020033:Protein Isoforms; D015398:Signal Transduction; D013997:Time Factors; D020691:rab GTP-Binding Proteins / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D000440:Butanols; D007477:Ions; D010712:Phosphatidic Acids; D020033:Protein Isoforms; C078703:rab18 protein, Arabidopsis; D000040:Abscisic Acid; D011392:Proline; D010739:Phospholipase D; D020691:rab GTP-Binding Proteins; D002118:Calcium