抗病是作物分子育种的重要目标，发掘新的与抗病相关的遗传资源并探究其功能是生物学研究的热点。我们在研究白叶枯病菌响应的水稻lncRNA时筛选到一个侵染诱导表达的lncRNA ALEX1，提高其表达可以激活水稻茉莉酸（JA）信号并增强白叶枯病抗性。我们还发现ALEX1与生长素响应因子OsARF3互作并阻止其相分离的形成，提示二者可能共同调控JA通路。本项目拟围绕ALEX1如何调控OsARF3相分离影响JA信号和抗病性这一关键科学问题，进一步开展如下研究：（1）利用ALEX1和OsARF3功能获得/缺失植株分析其对抗病性的影响；（2）探明ALEX1和OsARF3的定位及互作关键位点或结构域；（3）通过IP-MS、FRAP、体外重构以及ChIP-seq等技术研究OsARF3相分离的组成、特征及调控JA信号的分子机制。本项目的立项和实施可为植物抗病研究和作物分子育种提供新的思路和遗传资源。

Disease resistance is one of the most important goals in crop molecular breeding. Discovering new genetic resources related to disease resistance and exploring their functions is a hot research topic in current biology. Previously, we studied rice lncRNAs in response to Xanthomonas oryzae pv. Oryzae (Xoo), and screened an Xoo infection-induced lncRNA ALEX1. Elevating ALEX1 expression in rice could activate jasmonate (JA) signaling and enhance rice resistance to Xoo. We also found that ALEX1 interacts with the auxin response factor OsARF3 and prevents the formation of OsARF3 phase separation in the nuclear. These results suggested that ALEX1 may regulate the jasmonate pathway and rice resistance to bacterial blight by inhibiting OsARF3 phase separation. This proposal aims to further study the key scientific issues of how ALEX1 regulates OsARF3 phase separation affecting jasmonate pathway and bacterial blight resistance, and further perform the following research: (1) Using the gain- or loss-of-function transformants of ALEX1 and OsARF3 to analyze their function in the resistance to bacterial blight; (2) Exploring the localization and the key sites or domains of ALEX1 and its interacted protein OsARF3; (3) Using IP-MS, FRAP, in vitro phase-separation assays with purified proteins and ChIP-seq to study the composition and droplet-like properties of OsARF3 phase separation and to demonstrate the downstream molecules of OsARF3 phase separation in JA signaling. Approval and implementation of the project can not only reveal the new features and function of plant lncRNAs, but also can provide new ideas and genetic resources for plant disease resistance research and crop molecular breeding.