Mueller Stefan, Hilbert Beate, Dueckershoff Katharina, Roitsch Thomas, Krischke Markus, Mueller Martin J, Berger Susanne
Julius-von-Sachs-Institut fuer Biowissenschaften, Pharmazeutische Biologie, Biozentrum, Universitaet Wuerzburg, 97082 Wuerzburg, Germany.
Plant Cell. 2008 Mar;20(3):768-85. doi: 10.1105/tpc.107.054809. Epub 2008 Mar 11.
12-oxo-phytodienoic acid and several phytoprostanes are cyclopentenone oxylipins that are formed via the enzymatic jasmonate pathway and a nonenzymatic, free radical-catalyzed pathway, respectively. Both types of cyclopentenone oxylipins induce the expression of genes related to detoxification, stress responses, and secondary metabolism, a profile clearly distinct from that of the cyclopentanone jasmonic acid. Microarray analyses revealed that 60% of the induction by phytoprostanes and 30% of the induction by 12-oxo-phytodienoic acid was dependent on the TGA transcription factors TGA2, TGA5, and TGA6. Moreover, treatment with phytoprostanes and 12-oxo-phytodienoic acid inhibited cell division and root growth, a property also shared by jasmonic acid. Besides being potent signals, cyclopentenones and other lipid peroxidation products are reactive electrophiles that can covalently bind to and damage proteins. To this end, we show that at least two of the induced detoxification enzymes efficiently metabolize cyclopentenones in vitro. Accumulation of two of these metabolites was detectable during Pseudomonas infection. The cyclopentenone oxylipin gene induction profile resembles the defense response induced by a variety of lipophilic xenobiotics. Hence, oxidized lipids may activate chemosensory mechanisms of a general broad-spectrum detoxification network involving TGA transcription factors.
12-氧代-植物二烯酸和几种植物前列腺素是环戊烯酮类氧化脂质，它们分别通过茉莉酸酶促途径和非酶促自由基催化途径形成。这两种类型的环戊烯酮类氧化脂质均能诱导与解毒、应激反应和次生代谢相关的基因表达，这一特征与环戊酮茉莉酸明显不同。微阵列分析显示，植物前列腺素诱导的60%以及12-氧代-植物二烯酸诱导的30%均依赖于TGA转录因子TGA2、TGA5和TGA6。此外，用植物前列腺素和12-氧代-植物二烯酸处理会抑制细胞分裂和根生长，这也是茉莉酸所具有的特性。除了是强效信号外，环戊烯酮和其他脂质过氧化产物还是活性亲电试剂，可与蛋白质共价结合并使其受损。为此，我们表明至少两种诱导的解毒酶在体外能有效代谢环戊烯酮。在假单胞菌感染期间可检测到其中两种代谢产物的积累。环戊烯酮类氧化脂质基因诱导谱类似于多种亲脂性外源性物质诱导的防御反应。因此，氧化脂质可能激活涉及TGA转录因子的一般广谱解毒网络的化学感应机制。
