van der Luit A H, Piatti T, van Doorn A, Musgrave A, Felix G, Boller T, Munnik T
Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, Kruislaan 318, NL-1098 SM Amsterdam, Netherlands.
Plant Physiol. 2000 Aug;123(4):1507-16. doi: 10.1104/pp.123.4.1507.
Phosphatidic acid (PA) and its phosphorylated derivative diacylglycerol pyrophosphate (DGPP) are lipid molecules that have been implicated in plant cell signaling. In this study we report the rapid but transient accumulation of PA and DGPP in suspension-cultured tomato (Lycopersicon esculentum) cells treated with the general elicitors, N,N',N",N"'-tetraacetylchitotetraose, xylanase, and the flagellin-derived peptide flg22. To determine whether PA originated from the activation of phospholipase D or from the phosphorylation of diacylglycerol (DAG) by DAG kinase, a strategy involving differential radiolabeling with [(32)P]orthophosphate was used. DAG kinase was found to be the dominant producer of PA that was subsequently metabolized to DGPP. A minor but significant role for phospholipase D could only be detected when xylanase was used as elicitor. Since PA formation was correlated with the high turnover of polyphosphoinositides, we hypothesize that elicitor treatment activates phospholipase C to produce DAG, which in turn acts as substrate for DAG kinase. The potential roles of PA and DGPP in plant defense signaling are discussed.
磷脂酸（PA）及其磷酸化衍生物二酰基甘油焦磷酸（DGPP）是与植物细胞信号传导有关的脂质分子。在本研究中，我们报道了用通用激发子N，N'，N''，N''' - 四乙酰壳四糖、木聚糖酶和鞭毛蛋白衍生肽flg22处理的悬浮培养番茄（Lycopersicon esculentum）细胞中PA和DGPP的快速但短暂的积累。为了确定PA是源自磷脂酶D的激活还是二酰基甘油（DAG）被DAG激酶磷酸化，采用了一种用[（32）P]正磷酸盐进行差异放射性标记的策略。发现DAG激酶是PA的主要生产者，随后PA被代谢为DGPP。只有当使用木聚糖酶作为激发子时，才能检测到磷脂酶D的次要但重要的作用。由于PA的形成与多磷酸肌醇的高周转率相关，我们推测激发子处理激活磷脂酶C以产生DAG，而DAG又作为DAG激酶的底物。本文讨论了PA和DGPP在植物防御信号传导中的潜在作用。
