title: Cold calcium signaling in Arabidopsis involves two cellular pools and a change in calcium signature after acclimation.
abstract: Cold shock elicits an immediate rise in cytosolic free calcium concentration ([Ca2+]cyt) in both chilling-resistant Arabidopsis and chilling-sensitive tobacco (Nicotiana plumbaginifolia). In Arabidopsis, lanthanum or EGTA caused a partial inhibition of both cold shock [Ca2+]cyt elevation and cold-dependent kin1 gene expression. This suggested that calcium influx plays a major role in the cold shock [Ca2+]cyt response and that an intracellular calcium source also might be involved. To investigate whether the vacuole (the major intracellular calcium store in plants) is involved, we targeted the calcium-dependent photoprotein aequorin to the cytosolic face of the vacuolar membrane. Cold shock calcium kinetics in this microdomain were consistent with a cold-induced vacuolar release of calcium. Treatment with neomycin or lithium, which interferes with phosphoinositide cycling, resulted in cold shock [Ca2+]cyt kinetics consistent with the involvement of inositol trisphosphate and inositide phosphate signaling in this response. We also investigated the effects of repeated and prolonged low temperature on cold shock [Ca2+]cyt. Differences were observed between the responses of Arabidopsis and N. plum-baginifolia to repeated cold stimulation. Acclimation of Arabidopsis by pretreatment with cold or hydrogen peroxide caused a modified calcium signature to subsequent cold shock. This suggests that acclimation involves modification of plant calcium signaling to provide a "cold memory."
authors.affiliation: Department of Plant Sciences, University of Oxford, United Kingdom.
authors.forename: H
authors.initials: H
authors.lastname: Knight
authors.forename: A J
authors.initials: AJ
authors.lastname: Trewavas
authors.forename: M R
authors.initials: MR
authors.lastname: Knight
mesh_terms: D000064:Acclimatization; D000331:Aequorin / Q000096:biosynthesis / Q000235:genetics; D001059:Apoproteins / Q000096:biosynthesis / Q000235:genetics; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D003080:Cold Temperature; D017931:DNA Primers; D004533:Egtazic Acid / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D007811:Lanthanum / Q000494:pharmacology; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000235:genetics; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D014026:Nicotiana / Q000502:physiology*; D014617:Vacuoles / Q000378:metabolism
chemical_list: D001059:Apoproteins; D029681:Arabidopsis Proteins; D017931:DNA Primers; C490208:KIN1 protein, Arabidopsis; D010750:Phosphoproteins; D010940:Plant Proteins; D011994:Recombinant Proteins; C060014:apoaequorin; D000331:Aequorin; D004533:Egtazic Acid; D007811:Lanthanum; D017346:Protein Serine-Threonine Kinases; D002118:Calcium