Abstract
Phosphatidate phosphohydrolase 1/2 (PAH1/2) is a soluble phosphatidate phosphatase which produces diacylglycerol (DAG) by dephosphorylating phosphatidic acid (PA). PAH plays an important role in lipid metabolism. In pah1pah2, phospholipids as phosphatidylcholine, phosphatidylethanolamine, PA increase more than wild type (Nakamura et al. 2009 PNAS). PA is a metabolic intermediate playing a central role as a signal transducer of abscisic acid (ABA) stress response in higher plants.
We analyzed various ABA stress responses using pah1pah2 mutant. As the result, germination of pah1pah2 was more severely inhibited than that of wild type particularly with ABA treatment, showing that pah1pah2 seed is hypersensitive to ABA. However, the inhibition of stomatal opening in response to ABA treatment was similar between wild type and pah1pah2. Therefore, we suggest that, in ABA signaling, PAH is differently involved in seed germination and leaf drought stress.
