胡杨离子平衡调控的PeHSF-WRKY1-HA1分子网络研究

Maintaining ionic homeostasis is critical for plant cells to cope with saline environments. Salt-resistant Populus euphratica possess a strong ability to maintain a high expression of the plasma membrane (PM) H+-ATPase (PeHA1), which contributes to K+/Na+ homeostasis and withstanding ionic toxicity. The present study aims to assess the salt-induced transcription factors in Populus euphratica, and their roles in the mediation of PeHA1 transcription. PeHA1 promoter regions harbor W-box, which can be recognized and activated by WRKY. Moreover, PeWRKY1 contains cis-acting heat shock elements (HSEs) in the promoter. The heat shock transcription factors (HSFs) may upregulate PeWRKY1 expression by directly binding the cis-acting HSEs. We plan to investigate i) how PeWRKY1 bind to the W-box in the PeHA1 promoter regions, and ii) how PeHSF bind to the HSEs in the PeWRKY1 promoter regions, thus exerting regulation of target genes transcription and promoting salt tolerance. The object of this study is to establish and evaluate the role of a salt signaling network, i.e., PeHSF-WRKY1-HA1, in the mediation of ionic homeostasis. Our results are beneficial to explore the regulation mechanism of PM H+-ATPase and signaling pathway in salt response of salt-resistant tree species.

植物保持胞内离子平衡对适应盐生境至关重要。在盐胁迫下，胡杨维持质膜H+-ATPase基因（PeHA1）的高表达有助于重建离子平衡。本项目拟从PeHA1启动子区域的顺式元件入手，解析胡杨PeHA1基因的表达调控机制。研究发现，胡杨质膜PeHA1的启动子区域具有与转录调节因子WRKY专一性结合的W-box；并且，PeWRKY1启动子区域含有与热激转录因子HSF专一结合的热激元件HSEs。本项目拟探究转录调节因子PeWRKY1如何调控胡杨质子泵基因的表达；在此基础上，探讨胡杨热激转录因子PeHSF如何与PeWRKY1启动子互作并调控PeWRKY1的表达，最终建立胡杨盐胁迫信号转导的PeHSF-WRKY1-HA1分子网络。预期成果对揭示胡杨质膜H+-ATPase调控机制、以及树木的盐胁迫信号转导具有重要意义。

植物保持胞内离子平衡对适应盐生境至关重要。在盐胁迫下，胡杨维持质膜H+-ATPase基因（PeHA1）的高表达有助于重建离子平衡。本项目克隆了PeHA1启动子，通过解析该区域的顺式元件，发现胡杨质膜PeHA1的启动子区域具有与转录调节因子WRKY专一性结合的W-box。另外，通过克隆、分析胡杨PeWRKY1启动子，发现该区域含有与热激转录因子HSF专一结合的热激元件HSEs。本项目利用酵母单杂、DNA亲和纯化测序（DAP-seq）、荧光素酶报告基因、凝胶阻滞、病毒诱导基因沉默（VIGS）等技术研究了（1）转录调节因子PeWRKY1如何调控胡杨质子泵基因的表达和（2）胡杨热激转录因子PeHSF如何与PeWRKY1启动子互作并调控PeWRKY1的表达，最终建立了胡杨盐胁迫信号转导的PeHSF-WRKY1-HA1分子网络。研究成果对揭示胡杨质膜H+-ATPase调控机制、以及树木的盐胁迫信号转导具有重要意义。