The JAZ(Z) of jasmonates: exploring the JA-signaling pathway employing rationally designed jasmonate analogues

食品和（生物）能源的供应已成为现代社会面临的巨大挑战。解决这一问题的办法之一可能是植物研究的创新，旨在提高作物产量，提高植物对生物和非生物胁迫的抵抗力。了解植物对其生理过程的控制可能有助于设计和开发更加环保和可持续的农业新策略。植物产生激素、蛋白质和防御化合物来响应环境信号。许多植物对生物和非生物胁迫的反应都是由植物激素协调的，其中茉莉酸盐起着核心作用。茉莉酸盐是以茉莉酸（JA）为基本成分的脂质衍生化合物。JA- ile是JA的异亮氨酸缀合物，是高等植物中控制大多数JA相关反应的最具生物活性的茉莉酸盐。JA-Ile-内酯是两种新型合成的JA-Ile类似物，它们在体内的作用方式似乎与JA-Ile“相似”。ja - il -内酯能选择性诱导野生烟草烟碱积累，但不能诱导其他ja诱导的次生代谢产物。此外，用ja - il -内酯处理的植物不会像用JA-Ile处理时那样表现出典型的生长减少（在高等植物中，当植物免疫系统因响应环境挑战或应用茉莉酸盐（如JA-Ile）而被激活时，可以观察到生长减少）。此外，ja - il -内酯在烟草早期发育阶段促进植物生长，同时保护烟草免受昆虫食草动物的侵害。据推测，ja - il -内酯促进特定植物蛋白（JAZ）降解的能力控制着植物对内酯感知（通过SCFCOI1受体复合物）下游植物反应的单个方面。本项目拟采用药物化学、分子和计算工具探索拟南芥中合成的ja - il -内酯引发植物反应的分子基础。以ja - il -内酯为分子探针，详细研究了这些化合物在感知和信号传导机制方面的奇异性。以拟南芥为模式植物将有助于验证在野生烟草中观察到的现象在多大程度上可以推广到高等植物。此外，还将探索ja - il -内酯或类似的茉莉酸盐在自然界中存在的可能性。了解这些新的ja - il -衍生物的作用模式将有助于更好地理解ja -信号通路，并可能有助于揭示植物如何在保护自己免受病原体和食草动物攻击的同时保持其生长能力。此外，ja - il -内酯可能是一类新的小分子，具有作为半生物作物保护剂和/或研究植物信号的分子探针的潜力。

The supply of food and (bio-) energy has become a huge challenge for modern society. One of the solutions to this problem can be innovation in plant research aiming to produce higher crop yields and plants more resistant to biotic and abiotic stresses. Understanding the control of plants over their physiological processes may help to design and develop new strategies for a more environmentally friendly and sustainable agriculture.Plants produce hormones, proteins and defense-compounds in response to environmental cues. Many plant responses to biotic and abiotic stressors are coordinated by phytohormones, of which jasmonates play a central role. Jasmonates are lipid-derived compounds with jasmonic acid (JA) as a basic constituent. JA-Ile is the isoleucine conjugate of JA and it is the most bioactive jasmonate controlling the majority of the JA-associated responses in higher plants. JA-Ile-lactones are two novel synthetic JA-Ile analogues which seem to act in a ‘similar’ manner to JA-Ile in vivo. JA-Ile-lactones can selectively induce nicotine accumulation in wild tobacco plants, but fail inducing some other JA-inducible secondary metabolites. Additionally, plants treated with JA-Ile-lactones do not show classical growth reduction as when they are treated with JA-Ile (growth reduction is observed in higher plants when the plant immune system is activated either in response to environmental challenges or by application of jasmonates, e.g. JA-Ile). Furthermore, JA-Ile-lactones potentiated plant growth at early developmental stages and simultaneously provided protection to the tobacco plants against insect herbivores. It is hypothesized that the capability of JA-Ile-lactones to promote degradation of particular plant proteins (JAZ) controls singular aspects of plant responses downstream to lactone perception (via SCFCOI1 receptor complex) by the plant. In this project it is proposed to employ pharmacochemical, molecular and computational tools to explore, in A. thaliana, the molecular basis of plant responses elicited by the synthetic JA-Ile-lactones. Employing JA-Ile-lactones as molecular probes, the singularities in the perception and signaling mechanism of these compounds will be studied in detail. Working with A. thaliana as the model plant will help to verify to which extent the phenomena observed in wild tobacco can be generalized to higher plants. Furthermore, the possibility that JA-Ile-lactones or an analogous jasmonate exist in nature will be explored as well. Understanding the mode of action of these new JA-Ile-derivatives will contribute to the better understanding of the JA-signaling pathway and may help to reveal how plants maintain their ability to grow while protecting themselves against pathogens and herbivore attacks. Moreover, JA-Ile-lactones might constitute a new class of small molecules with potential utilization as semi-bio crop protecting agents and/or molecular probes to study plant signaling.