Um Tae Young, Lee Han Yong, Lee Sangyool, Chang Sun Hyun, Chung Pil Joong, Oh Ki-Bong, Kim Ju-Kon, Jang Geupil, Choi Yang Do
Department of Agricultural Biotechnology, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.
Graduate School of International Agricultural Technology and Crop Biotechnology Institute, GreenBio Science and Technology, Seoul National University, Pyeongchang, South Korea.
Front Plant Sci. 2018 Dec 18;9:1866. doi: 10.3389/fpls.2018.01866. eCollection 2018.
The jasmonic acid (JA) and gibberellic acid (GA) signaling pathways interact to coordinate stress responses and developmental processes. This coordination affects plant growth and yield, and is mediated by interactions between the repressors of each pathway, the JASMONATE ZIM-DOMAIN PROTEIN (JAZ) and DELLA proteins. In this study we attempted to identify rice () JAZs that interact with rice DELLAs such as SLENDER RICE 1 (SLR1). Analysis of protein-protein interactions showed that OsJAZ8 and OsJAZ9 interact with SLR1; OsJAZ9 also interacted with the SLR1-LIKE (SLRL) protein SLRL2. Based on this broader interaction, we explored the function of OsJAZ9 in JA and GA responses by analyzing transcript levels of the JA-responsive gene and the GA-responsive gene in -overexpressing () and mutant plants. and encode key transcription factors controlling JA and GA responses, respectively, and JA and GA antagonistically regulate their expression. In , the expression of was downregulated and the expression of was upregulated. By contrast, in mutants, the expression of was upregulated and the expression of was downregulated. These observations indicated that regulates both JA and GA responses in rice, and this finding was supported by the opposite expression patterns of , downstream targets of OsbHLH148 and OsPIL14, in the and plants. Together, these findings indicate that OsJAZ9 suppresses JA responses and promotes GA responses in rice, and the protein-protein interaction between OsJAZ9 and SLR1 is involved in the antagonistic interplay between JA and GA.
茉莉酸（JA）和赤霉素（GA）信号通路相互作用，以协调胁迫反应和发育过程。这种协调影响植物的生长和产量，并且由每条通路的阻遏物——茉莉酸ZIM结构域蛋白（JAZ）和DELLA蛋白之间的相互作用介导。在本研究中，我们试图鉴定与水稻DELLA蛋白如细长水稻1（SLR1）相互作用的水稻JAZ蛋白。蛋白质-蛋白质相互作用分析表明，OsJAZ8和OsJAZ9与SLR1相互作用；OsJAZ9还与类SLR1（SLRL）蛋白SLRL2相互作用。基于这种更广泛的相互作用，我们通过分析JA反应基因和GA反应基因在OsJAZ9过表达（OX）和OsJAZ9突变体植株中的转录水平，探究了OsJAZ9在JA和GA反应中的功能。这两个基因分别编码控制JA和GA反应的关键转录因子，并且JA和GA拮抗调节它们的表达。在OsJAZ9过表达植株中，该基因的表达下调，而该基因的表达上调。相比之下，在OsJAZ9突变体中，该基因的表达上调，而该基因的表达下调。这些观察结果表明，OsJAZ9调节水稻中的JA和GA反应，并且这一发现得到了OsbHLH148和OsPIL14的下游靶标在OsJAZ9过表达和OsJAZ9突变体植株中相反表达模式的支持。总之，这些发现表明，OsJAZ9在水稻中抑制JA反应并促进GA反应，并且OsJAZ9与SLR1之间的蛋白质-蛋白质相互作用参与了JA和GA之间的拮抗作用。
