Induction of abscisic acid-regulated gene expression by diacylglycerol pyrophosphate involves Ca2+ and anion currents in arabidopsis suspension cells

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 Ca 2+ channel blockers fluspirilene and pimozide and the Ca 2+ chelator EGTA showed that Ca 2+ was required for ABA induction of DGPP formation. In addition, Ca 2+ participated in DGPP induction of gene expression via stimulation of anion currents. Hence, a sequence of Ca 2+ , DGPP, and anion currents, constituting a core of early ABA-signaling events necessary for gene expression, is proposed.