Department of Horticulture, University of Wisconsin, Madison, Wisconsin, United States of America.
PLoS One. 2013;8(4):e60505. doi: 10.1371/journal.pone.0060505. Epub 2013 Apr 1.
In a screen for delayed floral organ abscission in Arabidopsis, we have identified a novel mutant of CORONATINE INSENSITIVE 1 (COI1), the F-box protein that has been shown to be the jasmonic acid (JA) co-receptor. While JA has been shown to have an important role in senescence, root development, pollen dehiscence and defense responses, there has been little focus on its critical role in floral organ abscission. Abscission, or the detachment of organs from the main body of a plant, is an essential process during plant development and a unique type of cell separation regulated by endogenous and exogenous signals. Previous studies have indicated that auxin and ethylene are major plant hormones regulating abscission; and here we show that regulation of floral organ abscission is also controlled by jasmonic acid in Arabidopsis thaliana. Our characterization of coi1-1 and a novel allele (coi1-37) has also revealed an essential role in apical dominance and floral meristem arrest. In this study we provide genetic evidence indicating that delayed abscission 4 (dab4-1) is allelic to coi1-1 and that meristem arrest and apical dominance appear to be evolutionarily divergent functions for COI1 that are governed in an ecotype-dependent manner. Further characterizations of ethylene and JA responses of dab4-1/coi1-37 also provide new information suggesting separate pathways for ethylene and JA that control both floral organ abscission and hypocotyl growth in young seedlings. Our study opens the door revealing new roles for JA and its interaction with other hormones during plant development.
在对拟南芥花器官延迟脱落的筛选中，我们鉴定到 CORONATINE INSENSITIVE 1（COI1）的一个新突变体，该蛋白已被证明是茉莉酸（JA）的共受体。虽然 JA 已被证明在衰老、根发育、花粉开裂和防御反应中具有重要作用，但人们对其在花器官脱落中的关键作用关注甚少。脱落，或器官从植物主体上的分离，是植物发育过程中的一个基本过程，是一种受内源性和外源性信号调控的独特的细胞分离类型。先前的研究表明，生长素和乙烯是调节脱落的主要植物激素；在这里，我们表明茉莉酸也调节拟南芥花器官的脱落。我们对 coi1-1 和一个新等位基因（coi1-37）的特征描述也揭示了其在顶端优势和花分生组织停滞中的重要作用。在这项研究中，我们提供了遗传证据，表明延迟脱落 4（dab4-1）与 coi1-1 等位，分生组织停滞和顶端优势似乎是 COI1 的进化分歧功能，受生态型依赖性方式调控。对 dab4-1/coi1-37 的乙烯和 JA 反应的进一步特征也提供了新的信息，表明乙烯和 JA 有独立的途径，控制花器官脱落和幼苗中下胚轴的生长。我们的研究为 JA 及其与植物发育过程中其他激素的相互作用开辟了新的研究领域。
