Induction of Abscisic Acid-Regulated Gene Expression by Diacylglycerol Pyrophosphate Involves Ca2+ and Anion Currents in Arabidopsis Suspension Cells

摘要

Diacylglycerol pyrophosphate (DGPP) was recently shown to be a possible intermediate in abscisic acid (ABA) signaling. In this study, reverse transcription-PCR of ABA up-regulated genes was used to evaluate the ability of DGPP to trigger gene expression in Arabidopsis (Arabidopsis thaliana) suspension cells. At5g06760, LTI30, RD29A, and RAB18 were stimulated by ABA and also specifically expressed in DGPP-treated cells. Use of the Ca²⁺ channel blockers fluspirilene and pimozide and the Ca²⁺ chelator EGTA showed that Ca²⁺ was required for ABA induction of DGPP formation. In addition, Ca²⁺ participated in DGPP induction of gene expression via stimulation of anion currents. Hence, a sequence of Ca²⁺, DGPP, and anion currents, constituting a core of early ABA-signaling events necessary for gene expression, is proposed.