Poster: Intracellular Signaling

Abs # 831: Functional analysis of a phosphatidic acid in ABA signaling during germination

Presenter:	Katagiri, Takeshi , katagiri@rtc.riken.go.jp
Authors	Katagiri, Takeshi  (A)   Shinozaki, Kazuo  (A)
Affiliations:	(A): Laboratory of Plant Molecular Biology, RIKEN Tsukuba Institute

The hormone abscisic acid (ABA) regulates developmental processes and stress responses in plants. In this study we analyzed a role of a phosphatidic acid (PA) in ABA signal transduction during seed germination. A physiological analysis showed PA triggers early signal transduction events that lead to the ABA responses during seed germination. To test the possible role of PA during germination, we measured PA production, and showed that PA increased transiently. Phosphatidic acid phosphatase (PAP) is an enzyme that catalyzes PA to diacylglycerol. We analyzed a role of PAP in PA metabolism during germination. There are four genes for Arabidopsis genome. To identify functional PAP genes during germination process, we analyzed expression of the four PAP genes and phenotypes of their knockout mutants. The PAP-knockout plant revealed a hypersensitive phenotype to ABA and accumulated PA during germination. These results suggest that PAP is involved in seed germination.