Staswick Paul E, Tiryaki Iskender, Rowe Martha L
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA.
Plant Cell. 2002 Jun;14(6):1405-15. doi: 10.1105/tpc.000885.
Jasmonic acid (JA) and related cyclopentanones are critical plant signaling molecules, but their mode of action at the molecular level is unclear. A map-based approach was used to identify the defective gene in the Arabidopsis JA response mutant jar1-1. JAR1 is 1 of 19 closely related Arabidopsis genes that are similar to the auxin-induced soybean GH3 gene. Analysis of fold predictions for this protein family suggested that JAR1 might belong to the acyl adenylate-forming firefly luciferase superfamily. These enzymes activate the carboxyl groups of a variety of substrates for their subsequent biochemical modification. An ATP-PPi isotope exchange assay was used to demonstrate adenylation activity in a glutathione S-transferase-JAR1 fusion protein. Activity was specific for JA, suggesting that covalent modification of JA is important for its function. Six other Arabidopsis genes were specifically active on indole-3-acetic acid (IAA), and one was active on both IAA and salicylic acid. These findings suggest that the JAR1 gene family is involved in multiple important plant signaling pathways.
茉莉酸（JA）及相关环戊酮是关键的植物信号分子，但其在分子水平上的作用模式尚不清楚。采用基于图谱的方法来鉴定拟南芥茉莉酸反应突变体jar1-1中的缺陷基因。JAR1是与生长素诱导的大豆GH3基因相似的19个拟南芥紧密相关基因之一。对该蛋白家族折叠预测的分析表明，JAR1可能属于形成酰基腺苷酸的萤火虫荧光素酶超家族。这些酶激活各种底物的羧基以便随后进行生化修饰。采用ATP-PPi同位素交换试验来证明谷胱甘肽S-转移酶-JAR1融合蛋白中的腺苷酸化活性。该活性对茉莉酸具有特异性，表明茉莉酸的共价修饰对其功能很重要。其他六个拟南芥基因对吲哚-3-乙酸（IAA）具有特异性活性，还有一个对IAA和水杨酸均有活性。这些发现表明JAR1基因家族参与多个重要的植物信号通路。
