Regulation of synthesis and function of 12-oxophytodienoic acid in plant cell signaling

12-氧代植物二烯酸（OPDA）是在叶绿体中由α亚麻酸合成的C18-氧脂素。OPDA在细胞代谢调节和胁迫适应的信号转导中起作用，并作为茉莉酸合成的前体。作为两个在植物逆境适应和生物有机合成方面具有专业知识的小组的共同努力，我们计划解决OPDA作为配体和活性羰基物种的信号传导和调节功能。我们将探讨13-脂氧合酶催化的主要承诺步骤的途径和可能的相互作用的三个途径酶在一个超分子复合物的底物通道的不稳定的中间体的调节。开发一种有效的生物合成途径，用于以克量合成OPDA，以及构建OPDA衍生物作为游离酸或更亲脂的乙酯的文库的可能性，将使得能够在植物和体外实现新的策略。该项目应详细审查OPDA与衍生的还原环戊酮衍生物3-氧代-2（2 '-戊烯基）环戊烷-1-辛酸（OPC-8：0）的功能，该衍生物不含反应性α/β-不饱和羰基部分和不能加工成茉莉酸的乙酯。使用这些工具，我们将确定和表征OPDA和OPC-8：0结合伙伴，并筛选OPDA化作为翻译后修饰，可能参与调节代谢与防御。该项目的四个假设是基于既定的知识和自己的出版和初步工作，并有望解开OPDA功能在植物细胞驯化的新机制。

12-Oxophytodienoic acid (OPDA) is a C18-oxylipin synthesized in the chloroplast from alpha linolenic acid. OPDA functions in cell signaling for metabolic regulation and stress acclimation and as precursor of jasmonic acid synthesis. As joint effort of two groups with expertise in plant stress acclimation and bioorganic synthesis, we plan addressing the signaling and regulatory function of OPDA as ligand and reactive carbonyl species. We will explore the regulation of 13-lipoxygenases catalyzing the primary committed step of the pathway and the likely interaction of the three pathway enzymes in a supramolecular complex for substrate channeling of labile intermediates. The development of an efficient biosynthetic route for OPDA synthesis in gram amounts, and the possibility to construct a library of OPDA derivatives as free acids or more lipophilic ethylesters will enable realizing novel strategies in planta and in vitro. The project shall scrutinize the function of OPDA in comparison to the derived reduced cyclopentanone derivative 3-oxo-2(2’-pentenyl) cyclopentane-1-octanoic acid (OPC-8:0) devoid of the reactive alpha/beta-unsaturated carbonyl moiety and the ethylester which cannot be processed to jasmonic acid. Using these tools we will identify and characterize OPDA and OPC-8:0 binding partners, and screen for OPDAylation as posttranslational modification possibly involved in regulating metabolism versus defense. The four hypotheses of the project are based on established knowledge and own published and preliminary work and are expected to unravel novel mechanisms of OPDA function in plant cell acclimation.