Abstract
Sphingosine 1-phosphate (S1P) is a sphingolipid metabolite that plays lipid-mediated signaling involved in abscisic acid (ABA) regulation of guard cell turgor. To evaluate mechanisms of S1P signaling involved in the signal-transduction pathway linking ABA to regulate stomatal switching, functional characterization of enzymes that control the intracellular levels of S1P is very important. Here we communicate the functional characterization of an Arabidopsis enzyme involved in the catabolism of S1P, sphingosine-1-phosphate phosphatase (SPP). In order to evaluate whether a SPP-like gene in Arabidopsis (AtSPP1) encodes a functional SPP, we performed an complementation test using an yeast del1 mutant strain and measured the SPP activity using an HPLC-fluorescence detector system. We will report several results on the expression of the AtSPP1 gene using T-DNA knockout mutants.
