Gene Expression Laboratory, Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, Biophore, CH-1015 Lausanne, Switzerland.
Sci Signal. 2010 Feb 16;3(109):cm3. doi: 10.1126/scisignal.3109cm3.
Plants possess a family of potent fatty acid-derived wound-response and developmental regulators: the jasmonates. These compounds are derived from the tri-unsaturated fatty acids alpha-linolenic acid (18:3) and, in plants such as Arabidopsis thaliana and tomato, 7(Z)-, 10(Z)-, and 13(Z)-hexadecatrienoic acid (16:3). The lipoxygenase-catalyzed addition of molecular oxygen to alpha-linolenic acid initiates jasmonate synthesis by providing a 13-hydroperoxide substrate for formation of an unstable allene oxide by allene oxide synthase (AOS). This allene oxide then undergoes enzyme-guided cyclization to produce 12-oxophytodienoic acid (OPDA). These first steps take place in plastids, but further OPDA metabolism occurs in peroxisomes. OPDA has several fates, including esterification into plastid lipids and transformation into the 12-carbon prohormone jasmonic acid (JA). JA is itself a substrate for further diverse modifications, including the production of jasmonoyl-isoleucine (JA-Ile), which is a major biologically active jasmonate among a growing number of jasmonate derivatives. Each new jasmonate family member that is discovered provides another key to understanding the fine control of gene expression in immune responses; in the initiation and maintenance of long-distance signal transfer in response to wounding; in the regulation of fertility; and in the turnover, inactivation, and sequestration of jasmonates, among other processes.
茉莉酸。这些化合物来源于三不饱和脂肪酸α-亚麻酸（18:3），在拟南芥和番茄等植物中，还来源于 7(Z)-、10(Z)-和 13(Z)-十六碳三烯酸（16:3）。脂氧合酶催化向α-亚麻酸中添加分子氧，为全反式-12-羟基十八碳烯酸合酶（AOS）提供 13-氢过氧化物底物，从而启动茉莉酸合成，生成不稳定的丙二烯氧化物。然后，丙二烯氧化物经酶引导环化生成 12-氧代植二烯酸（OPDA）。这些初始步骤发生在质体中，但进一步的 OPDA 代谢发生在线粒体中。OPDA 有几种命运，包括酯化形成质体脂质和转化为 12-碳前激素茉莉酸（JA）。JA 本身也是进一步多样化修饰的底物，包括茉莉酰异亮氨酸（JA-Ile）的产生，JA-Ile 是越来越多茉莉酸衍生物中主要的生物活性茉莉酸。每个新发现的茉莉酸家族成员都为理解免疫反应中基因表达的精细调控、创伤响应中长距离信号传递的启动和维持、生育能力的调控以及茉莉酸的周转、失活和隔离等过程提供了另一个关键。
