Connections between Sphingosine Kinase and Phospholipase D in the Abscisic Acid Signaling Pathway in \u3ci\u3eArabidopsis\u3c/i\u3e

Abstract

Background: Sphingosine kinase (SPHK) and phospholipaseD(PLD) produce different lipid mediators involved in abscisic acid (ABA) response. Results: Ablation of SPHKs and PLDα1 attenuates ABA-induced production of LCBPs and PA. Phyto-S1P closes stomata in sphk1, sphk2, but not in pldα1, whereas PA closes stomata in all mutants. Conclusion: SPHK acts upstream of PLDα1, whereas PLDα1 promotes SPHK. Significance: The roles of lipid messengers in the ABA signaling pathway are clarified