title: Acclimation to salt modifies the activation of several osmotic stress-activated lipid signalling pathways in Chlamydomonas.
abstract: Osmotic stress rapidly activates several phospholipid signalling pathways in the unicellular alga Chlamydomonas. In this report, we have studied the effects of salt-acclimation on growth and phospholipid signalling. Growing cells on media containing 100 mM NaCl increased their salt-tolerance but did not affect the overall phospholipid content, except that levels of phosphatidylinositol phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] were reduced by one-third. When these NaCl-acclimated cells were treated with increasing concentrations of salt, the same lipid signalling pathways as in non-acclimated cells were activated. This was witnessed as increases in phosphatidic acid (PA), lyso-phosphatidic acid (L-PA), diacylglycerol pyrophosphate (DGPP), PI(4,5)P2and its isomer PI(3,5)P2. However, all dose-dependent responses were shifted to higher osmotic-stress levels, and the responses were lower than in non-acclimated cells. When NaCl-acclimated cells were treated with other osmotica, such as KCl and sucrose, the same effects were found, illustrating that they were due to hyperosmotic rather than hyperionic acclimation. The results indicate that acclimation to moderate salt stress modifies stress perception and the activation of several downstream pathways.
authors.affiliation: Section Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands.
authors.forename: Harold J G
authors.initials: HJ
authors.lastname: Meijer
authors.affiliation: Section Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands.
authors.forename: John A J
authors.initials: JA
authors.lastname: van Himbergen
authors.affiliation: Section Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands.
authors.forename: Alan
authors.initials: A
authors.lastname: Musgrave
authors.affiliation: Section Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098XH, Amsterdam, The Netherlands. Electronic address: t.munnik@uva.nl.
authors.forename: Teun
authors.initials: T
authors.lastname: Munnik
mesh_terms: D000064:Acclimatization; D002696:Chlamydomonas / Q000378:metabolism*; D011756:Diphosphates / Q000032:analysis; D005990:Glycerol / Q000031:analogs & derivatives / Q000032:analysis; D007536:Isomerism; D009997:Osmotic Pressure; D010712:Phosphatidic Acids; D010739:Phospholipase D / Q000378:metabolism; D010944:Plants / Q000378:metabolism; D055049:Salt Tolerance; D015398:Signal Transduction / Q000187:drug effects*; D012965:Sodium Chloride / Q000494:pharmacology*; D013395:Sucrose / Q000378:metabolism
chemical_list: D011756:Diphosphates; D010712:Phosphatidic Acids; C408642:diacylglycerol pyrophosphate; D012965:Sodium Chloride; D013395:Sucrose; D010739:Phospholipase D; D005990:Glycerol
keywords: Acclimation; Chlamydomonadaceae; Chlamydomonas moewusii; Green alga; Osmotic stress; Phospholipids; Signal transduction