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Metabolism and signal transduction of the plant immune signal pipecolic acid

植物免疫信号哌可酸的代谢与信号转导

基本信息

批准号：
241352156
负责人：
Professor Dr. Jürgen Zeier, Ph.D.
金额：
--
依托单位：
Institut für Molekulare Ökophysiologie der Pflanzen
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/241352156?language=en
关键词：
Metabolism signal transduction plant immune

项目摘要

Our previous work revealed a critical function for the Lysine-derived plant metabolite pipecolic acid (Pip) in systemic acquired resistance (SAR) and the SAR-associated defense priming phenomenon. In the first period of this project, we have defined the interplay between the immune signals Pip and salicylic acid in the activation of plant defense responses and resistance. Moreover, we showed that the biosynthesis of Pip from L-Lys in plants proceeds via a two-step biochemical process. The alpha-L-Lys-aminotransferase ALD1 catalyzes the conversion of L-Lys to 2,3-dehydropipecolic acid, which is subsequently reduced to Pip. The reductive step involves the action of the plant reductase ORNCD1/SARD4. In addition, we elucidated the biochemical function of the SAR regulator FMO1 as a Pip N-hydroxylase which catalyzes the formation of N hydroxypipecolic acid (Pip-OH) from L-Pip in vitro and in planta. Exogenous Pip-OH complements the immune defects of fmo1 mutant plants and acts as an efficient resistance-enhancing compound in plants towards infection by bacterial and oomycete pathogens. In the next project phase, we aim to further advance the understanding of the Pip metabolic pathway in Arabidopsis. We will biochemically and functionally investigate the reductive step in Pip biosynthesis and the glycosylation of Pip-OH. By using a combination of LC-MS-, NMR-, and GC-MS-based analytical methods, we aim at identifying and characterizing hitherto unknown metabolites involved in Pip metabolic pathway. Both a genetic screen and targeted studies on the role of the immune regulator NPR1 will shed light on the immune signaling processes downstream of Pip-OH accumulation. Analyses of the significance of Pip in SAR long-distance signaling, which had been started in the first project phase, will be continued by using a genetic approach and extended with respect to the function hydroxylated Pip derivatives in this process. Finally, the plant resistance-enhancing action of Pip-OH towards oomycete infection will be investigated at the cytological and molecular levels.

我们之前的工作揭示了赖氨酸衍生的植物代谢物哌可酸 (Pip) 在系统获得性抗性 (SAR) 和 SAR 相关防御启动现象中的关键功能。在该项目的第一阶段，我们定义了免疫信号 Pip 和水杨酸在激活植物防御反应和抗性中的相互作用。此外，我们还发现植物中 L-Lys 生物合成 Pip 是通过两步生化过程进行的。 α-L-Lys-转氨酶 ALD1 催化 L-Lys 转化为 2,3-脱氢哌啶酸，随后还原为 Pip。还原步骤涉及植物还原酶 ORNCD1/SARD4 的作用。此外，我们还阐明了 SAR 调节剂 FMO1 作为 Pip N-羟化酶的生化功能，该酶在体外和植物体内催化 L-Pip 形成 N 羟基哌啶酸 (Pip-OH)。外源 Pip-OH 可以补充 fmo1 突变植物的免疫缺陷，并作为植物中有效的增强抵抗细菌和卵菌病原体感染的化合物。在下一个项目阶段，我们的目标是进一步加深对拟南芥中 Pip 代谢途径的理解。我们将从生化和功能角度研究 Pip 生物合成中的还原步骤和 Pip-OH 的糖基化。通过结合使用基于 LC-MS、NMR 和 GC-MS 的分析方法，我们的目标是鉴定和表征 Pip 代谢途径中迄今为止未知的代谢物。对免疫调节剂 NPR1 作用的遗传筛选和针对性研究都将揭示 Pip-OH 积累下游的免疫信号传导过程。对 Pip 在 SAR 长距离信号传导中的重要性的分析已在项目第一阶段开始，将通过使用遗传方法继续进行，并在此过程中针对羟基化 Pip 衍生物的功能进行扩展。最后，将在细胞学和分子水平上研究 Pip-OH 对卵菌感染的植物抗性增强作用。