An important role of phosphatidic acid in ABA signaling during germination in Arabidopsis thaliana
An important role of phosphatidic acid in ABA signaling during germination in Arabidopsis thaliana
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DOI：
10.1111/j.1365-313x.2005.02431.x
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发表时间：
2005-07-01
期刊：
影响因子：
7.2
通讯作者：
Shinozaki, K
中科院分区：
文献类型：
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作者：
Katagiri, T;Ishiyama, K;Shinozaki, K
磷脂酸 (PA) 在植物中充当脂质信号分子。生理分析表明，PA 会触发早期信号转导事件，从而导致种子萌发过程中对脱落酸 (ABA) 的反应。我们测量了种子萌发过程中 PA 的产量，发现萌发早期 PA 水平有所增加。为了研究 PA 在种子萌发过程中的作用，我们重点研究了 PA 分解代谢酶脂质磷酸磷酸酶 (LPP)。 LPP 催化 PA 转化为二酰基甘油 (DAG)。拟南芥基因组中有4个LPP基因。其中AtLPP2和AtLPP3在种子萌发过程中表达。两个 AtLPP2 T-DNA 插入突变体（lpp2-1 和 lpp2-2）在发芽过程中表现出对 ABA 的超敏性和显着的 PA 积累。此外，双突变体分析表明 ABA 不敏感 4 (ABI4) 与 AtLPP2 上位，但 ABA 不敏感 3 (ABI3) 则不然。这些结果表明 PA 参与 ABA 信号传导，并且 AtLPP2 在发芽过程中的 ABA 信号传导中充当 ABI4 上游的负调节因子，ABI4 编码 AP2 型转录因子。
Phosphatidic acid (PA) functions as a lipid signaling molecule in plants. Physiological analysis showed that PA triggers early signal transduction events that lead to responses to abscisic acid (ABA) during seed germination. We measured PA production during seed germination and found increased PA levels during early germination. To investigate the role of PA during seed germination, we focused on the PA catabolic enzyme lipid phosphate phosphatase (LPP). LPP catalyzes the conversion of PA to diacylglycerol (DAG). There are 4 LPP genes in the Arabidopsis genome. Among them, AtLPP2 and AtLPP3 are expressed during seed germination. Two AtLPP2 T-DNA insertional mutants (lpp2-1 and lpp2-2) showed hypersensitivity to ABA and significant PA accumulation during germination. Furthermore, double-mutant analysis showed that ABA-insensitive 4 (ABI4) is epistatic to AtLPP2 but ABA-insensitive 3 (ABI3) is not. These results suggest that PA is involved in ABA signaling and that AtLPP2 functions as a negative regulator upstream of ABI4, which encodes an AP2-type transcription factor, in ABA signaling during germination.